PART A&B: TECHNICAL SPECIFICATION FOR OUTDOOR 11 KV … · SF6 insulated VCB of suitable rating -...
Transcript of PART A&B: TECHNICAL SPECIFICATION FOR OUTDOOR 11 KV … · SF6 insulated VCB of suitable rating -...
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PART A&B: TECHNICAL SPECIFICATION FOR OUTDOOR 11 KV RING MAIN UNIT
SWITCHGEAR
1.1 GENERAL:
1.1.1 All equipment and material shall be designed manufactured and tested in
accordance with the latest applicable IEC standard.
1.1.2 Equipment and material conforming to any other standard, which ensures equal or
better quality, may be accepted. In such case copies of English version of the
standard adopted shall be submitted.
1.1.3 The electrical installation shall meet the requirement of Indian Electricity Rules-1956
as amended up to date; relevant IS code of practice and Indian Electricity Act-1910.
In addition other rules and regulations applicable to the work shall be followed. In case any discrepancy ,the
most stringent and restrictive one shall be binding.
1.1.4 The high-tension switchgear offered shall in general comply with the latest issues
including amendments of the following standards but not restricted to them.
1.2 SCOPE:
Design, Engineering, Manufacture, assembly, Stage testing, inspection and testing before supply and delivery at site,
Erection, Installation, testing & Commissioning of Ring Main units outdoor type SF6 filled , with various combinations
of load break isolators & breakers. The scope includes Supply, Erection, testing and commissioning of outdoor type
RMU with necessary take off terminal units for future automations contains load break isolators, breaker and
associated accessories, equipments. (including civil works and earthing- Erection of earthing by using GI strip
(minimum 35 mm strip) with earthing plate including cost of coal/salt to RMU). The Installation of 11KV Outdoor SF6
Insulated RMU covering erection,testing and commissioning with associated equipment including civil work of RMU,
drawing and Bom(Bill of Material) of civil work submit by bidder along with technical details.
The RMUs should be provided with necessary take off terminal units for future automations and all these units should
be shielded in a outdoor metal-body for making them suitable for outdoor use. The insulation/dielectric media inside
the stainless steel welded tank should be SF6 gas. The RMUS should be Modular ,extensible type on both sides with
provision of attaching/connecting with SNAP FIT arrangement W/o External Busbars additional load break switches
and circuit breakers in future whenever required. Alternatively Extension shall be possible by adding trunking
chambers and required accessories or by plug-in bushing type arrangement.
The Package scope of work shall include survey, design, manufacture, FAT and delivery,
installation and commissioning of new SCADA enabling equipments of new “SCADA-Ready”
The RMU should have compatibility with OPEN PROTOCOL SCADA system.
Ring Main Units capable of being monitored and controlled by the SCADA/DMS. The RMU should have the castle lock
for avoiding dual supply and safety purpose.
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Where relevant, the RMU scope of work shall be coordinated with the work to be carried out under the project’s other
construction packages & associated materials to the designated destinations as per this tender specification and Bill of
quantities. Includes supply of relevant 11KV cable termination kits per this tender Specification.
Each RMU shall include its own power supply unit (including auxiliary power transformer, batteries, and battery
charger), which shall provide a stable power source for the RMU. The RMUs will be connected to the FRTU which will
be procured, supplied and installed as a part of Part A of R-APDRP. The RMU will also supply 230VAC 500VA for FRTU.
Refer Annexure-1.
FRTU, MODEM, Power and I/O cable interface between FRTU and Control panel of RMU/sectionaliser are excluded in
the scope of supply and these items will be provided by DISCOM/SIA.
Each new RMU shall be equipped with main-line load break switches and a fault passage indicator (FPI). Furthermore,
to protect each of its lateral / transformer feeders, it shall be equipped with a corresponding set of circuit breakers
and self-powered numerical relays. The RMU shall include potential-free contacts and control contacts so as to
connect to SCADA/DMS via FRTUs, so as to:
� Monitor and control the open/closed status of the RMU circuit breakers and load break switches.
� Monitor the local/remote position of RMU motorised (in case if failure of motor) manually-operated
switches that can be used to enable and disable remote monitoring.
� Monitor the health of the power supply, which will include battery failure and low voltage indications.
� Monitor the open/closed status of RMU earthing switches.
� Monitor the open/closed status of RMU enclosure doors in case of Hinge doors.
� Monitor for low SF6 gas pressure indication.
� Monitor for circuit breaker relay operations.
� Monitor for indication of main-circuit fault detected by the RMU’s FPI.
1.2.1 Configurations Required:-
11KV RMU
a) 2-Way , 11KV Gas (SF6) Insulated RMU with One 630A load break switches
and One SF6 Insulated VCB of suitable rating -
b) 3-way , 11KV ,Gas (SF6) Insulated RMU with 2Nos 630A load break switch
and 1No. SF6 insulated VCB of suitable rating -
c) 4-way ,11KV Gas (SF6) Insulated RMU with 2Nos 630A Load break switches
and 2Nos , SF6 Insulated VCB of suitable rating –
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d) 5-way , 11KV ,Gas (SF6) Insulated RMU with 2Nos 630A load break switch
and 3No. SF6 insulated VCB of suitable rating -
e) 6-way ,11KV Gas (SF6) Insulated RMU with 3Nos 630A Load break switches
and 3Nos , SF6 Insulated VCB of suitable rating –
PLS NOTE: THE NOMINAL CURRENT RATING OF VCB SHALL BE ACCORDING TO LOAD OF THE FEEDER AND
ACCORDINGLY SUITABLE RELAY SHALL BE PROVIDED AND ANY CHANGE IN COMBINATION/CONFIGURATION SHALL
BE EXECUTED WITH THE APPROVAL OF CHIEF ENGINEER OF RESPECTIVE DISCOM.
1.1 This Specification provides for design, manufacture, inspection and testing before dispatch, packing and
delivery F.O.R.(Destination) of SF6 insulated RMUs with necessary take off terminal units for future automations,
compatible with SCADA system other accessories and auxiliaries equipment and mandatory spares, described herein
and required for their satisfactory operation.
1.2. The objective of the RMUs is for extremely small construction width, compact, maintenance free, independent
of climate, easy installation, operational reliability, Safe and easy to operate, minimum construction cost, minimum
site work and minimum space requirement.
1.3. The RMUs shall conform in all respects to high standards Of Engineering design, workmanship and latest
revisions of relevant standards at the time of offer.
RMU to be installed on Plinth Erection of plinth with cost of cement etc as per below requirement Plinth size
minimum 5’x4’x2’ or as per required Cement ratio 1: 2 : 4 ;Weight of RMU 510 kg to 1000 kg.
1.4. The type of the 11 KV circuit breaker shall be VCB and insulating medium for load break isolators, Earth switch,
11 KV Buses and other associated equipments should be SF6 gas.
� Necessary current sensors / transformers for protection and metering (wherever required).
� All necessary dry (potential-free) contacts for indications relevant to RMU monitoring status and control.
� A PT Panel including auxiliary power transformer for measurement of system voltage and for charging the
batteries.
� Battery and battery charger, to provide stable as per motor rating, 24 VDC, power for the RMU’s motors.
� Capacitor voltage dividers serving live-line cable indicators.
1.3 GENERAL:
The Ring Main Unit shall be installed at 11 KV junction points to have continuous supply by isolating faulty sections.
The RMU shall be extensible on both sides and consists of the following combinations of load break switches and
Circuit breakers for a nominal voltage of 12 KV using SF6 gas as insulating and Vacuum as arc quenching medium.
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The RMU and combination shall be tropicalised and outdoor metal enclosed type. The RMU metal parts shall be of
high thickness, high tensile steel which must be grit/short blasted, thermally sprayed with Zinc alloy, phosphate or
should follow the 7 tank pre-treatment process and be subsequently painted with polyurethane based powder paint.
The overall paint layer thickness shall be not less than 80 microns.
Relevant IE rules for clearances, safety and operation inside the enclosure shall be applicable. The enclosure shall be IP
54 and type tested for weather proof at EREDA/CPRI.
All live parts except for the cable connections in the cable compartments shall be insulated with SF6 gas. The SF6 gas
tank shall be made of robotic or TIG or MIG welded stainless steel, to have the best weld quality. The gas cubicle shall
be metal enclosed with stainless Steel of thickness as per IEC tested/ designed so as to provide safety and to avoid
leakage of gas and should be provided with a pressure relief arrangement away from operator.
Both the load break switches and the tee off circuit breaker must be motorized.
The cable box of isolators and circuit breakers both should be of front access type as per site requirement.
Any accidental over pressure inside the sealed chamber shall be limited by the opening of a pressure-limiting device in
the top or rear-bottom part of the tank or enclosure. Gas will be release to the rear of the switchboard away from the
operator and should be directed towards the bottom, into the trench to ensure safety of the operating personnel and
the pedestrians / civilians. All the manual operations should be carried out on the front of the switchboard.
GENERAL TECHNICAL REQUIREMENTS
1 Fixed type SF-6 gas insulated / Vacuum circuit breakers. It should be maintenance free, having stainless steel
robotically/ TIG / MIG welded enclosure for IN DOOR / OUTDOOR RMU. However, offer with high quality of the
welding which has necessary extensive leakage test with leak rate of 0.1% per annum can be accepted. The RMUs to
be used are only outdoor type.
2 Low gas pressure devices- 1.2 Bar pressure. RMU should have full rating with 0.0 Bar gas pressure.
3 Live cable indicators- High operator safety.
4 Fully Rated integral ear thing switch on each device.
5 Self powered Microprocessor Based relay- Does not require any external source of power.
6 Units fully SCADA Compatible. Retrofitting at site possible at a later date. Line switches (Load break switches) as well
as T- OFF circuit Breaker can be operated by remote. ( Manual operations should be possible in case of motor failure.)
7 For indoor Cable boxes should be front access and interlocked with earth switch. No rear /side access required. For
outdoor RMUs cable boxes shall be on front.
8 Cable testing possible without disconnection of cables.
9 Compact in dimension.
10 Circuit Breaker with self powered O/C & E/F RELAY.
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11 Low pressure, sealed for life equipment, can operate at “0” bar pressure.
12 Cable ear thing switch on all switching device-standard, for operator safety.
13 Enclosure with IP 54 standard protection for OUTDOOR RMUs and IP2X for INDOOR RMUs
14 All live parts should be inside a stainless steel enclosure for out door type RMU & minimum 2 mm thickness of
stainless steel robotically/TIG/MIG welded enclosure for Outdoor / indoor RMU.
TECHNICAL AND GUARANTEED PARTICULARS:
The bidders shall furnish all guaranteed technical particulars as called for in Schedule “A” of this specification.
Particulars which are subject to guarantee shall be clearly marked. Bids lacking information in G.T.P are liable to be
rejected
The Entire units or minimum three functions of RMU shall be enclosed in a single compact metal clad, outdoor
enclosure suitable for all weather conditions. The switchgear/steel gas tank shall be filled with SF6 as per IEC/IS
Standards relative pressure to ensure the insulation and breaking functions. The steel gas tank must be sealed for life
and shall meet the “sealed pressure system” criteria in accordance with the IEC 298 standard. The RMU must be a
system for which no handling of gas is required throughout the 20 years of service life.
The RMU shall have a design such that in the event of an internal arc fault, the operator shall be safe. This should be in
accordance with IEC 298 and relevant Test certificates shall be submitted with the Tender.
The offered switchgear and control gear should be suitable for continuous operation under the basic service
conditions indicated below. Installation should be in normal indoor conditions in accordance with IEC 60694.
Ambient temperature – 10 degree C to + 45 degree C
Relative humidity - up to 95%
Altitude of installation - up to 1000m, IEC 60120
1.3.1 The RMU shall be tested for an internal arc rating of 20 kA for 1 Sec. for 11 KV RMU. Suitable temperature rise
test on the RMU shall be carried out & test reports shall be submitted with tender for technical bid evaluation.
Each switchboard shall be identified by an appropriately sized label, which clearly indicates the functional units and
their electrical characteristics.
The switchgear and switchboard shall be designed so that the position of the different devices is visible to the
operator on the front of the switchboard and operations are visible as well.
The entire system shall be totally encapsulated. There shall be no access to exposed conductors. In accordance with
the standards in effect, the switchboards shall be designed so as to prevent access to all live parts during operation
without the use of tools.
The entire 11 KV RMU are insulated by inert gas (SF6) suitable for operating voltage up to 13.8KV respectively. The 11
KV circuit breakers must be VCB breaker. It is necessary to fit an absorption material in the tank to absorb the
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moisture from the SF6 gas. The SF6 insulating medium shall be constantly monitored via a temperature compensating
gas pressure indicator offering a indication at different temperature ranges, having distinctive RED and GREEN zones
for safe operation.
All the RMUs must be routine tested for the following at factory in India:-
� Micro-ohm test for the assembly inside the tank.
� Circuit breaker analyzer test so as to ensure the simultaneous closing of all poles for VCB.
� SF6 gas leak test.
� Partial Discharge test on the complete gas tank so as to be assure of the proper insulation level and high
product life.
� High voltages withstand.
� Secondary test to ensure the proper functioning of the live line indicators, fault passage indicators and relays.
1.3.2Sulphur Hex fluoride Gas(SF6 GAS)
The SF6 gas shall comply with IEC 376,376A, and 376B and shall be suitable in all respects for use in 11 KV RMUs under
the operating conditions. The SF6 shall be tested for purity, dew point air hydrolysable fluorides and water content as
per IEC 376,376A and 376B and test certificate shall be furnished to the owner indicating all the tests as per IEC 376
for each Lot of SF6 Gas.
DIELECTRIC MEDIUM
SF6 / VCB GAS shall be used for the dielectric medium for 11KV RMUS in accordance with IEC376. It is preferable to fit
an absorption material in the tank to absorb the moisture from the SF6 / VCB gas and to regenerate the SF6 / VCB gas
following arc interruption. The SF6 / VCB insulating medium shall be constantly monitored via a temperature
compensating gas pressure indicator offering a simple go, no-go indication.
General structural and mechanical construction:
The offered RMU should be of the fully arc proof metal enclosed, free standing, floor mounting, flush fronted type,
consisting of modules assembled into one or more units. Each unit is made of a cubicle sealed-for life with SF6 / VCB
and contains all high voltage components sealed off from the environment.
The overall design of the indoor switchgear should be such that front access only is required. It should be possible to
erect the switchboard against a substation wall, with HV and LV cables being terminated and accessible from the front.
The units should be constructed from Minimum 2 mm thick stainless steel sheets. However, Offer with type test
report of pressure withstand test for gas filled compartment with pressure relief device test as per cl. no. 6-103-1 of
IEC 62271-200-2003 can be accepted for 2mm stainless steel tank thickness. The design of the units should be such
that no permanent or harmful distortion occurs either when being lifted by eyebolts or when moved into position by
rollers.
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For outdoor RMUs a weather proofing process shall be carried out. SHEET METAL MUST BE GRIT BLASED /
THERMALLY SPRAYED AND POLYURETHANE PAINTED WITH ABOUT 70 MICRON THICKNESSES, TO ACHIVE
OUTDOOR WORTHINESS AND CORROSION PROOF NESS.
- RMU ENCLOSURE MUST BE SHIELDED AGAINST SOLAR IRRADIATION AND TESTED FOR A
AMBIENT OF 45 DEGREE C WITHOUT DERATING OF THE EQUIPMENT.
The cubicle should be have a pressure relief device. In the rare case of an internal arc, the high pressure caused by the
arc will release it, and the hot gases is allowed to be exhausted out at the bottom / top / rear of the cubicle. A
controlled direction of flow of the hot gas should be achieved.
The switchgear should have the minimum degree of protection (in accordance with IEC 60529)
- IP 67 for the tank with high voltage components
- IP 2X for the front covers of the mechanism
- IP 3X for the cable connection covers
- IP 54 for the outdoor enclosure.
1.4 STANDARDS:
Unless otherwise specified elsewhere in this Specification, the RMU, Switchboard (Switchgear), Load break isolators,
Instrument Transformers and other associated accessories shall conform to the latest revisions and amendments
thereof to the following standards.
1. IEC 60 298/IEC 62 271-200/IS 12729:1988 - General requirement for Metal Enclosed Switchgear
2. IEC60129/IEC62271-102/IS 9921 - Alternating current disconnector’s (Load break isolators) and earthing switch
3. IEC 62 271-100 & 200/IEC 60 056/IS 13118:1991 - Specification for alternating current circuit breaker
4. IEC 62 271-1/IEC 60694 - Panel design, SF6/Vacuum Circuit Breakers
5. IEC 60044-1/IEC 60185/IS 2705:1992 - Current Transformer
6. IEC 60265/IS 9920:1981- High voltage switches.
7. IEC 376 - Filling of SF6 gas in RMU.
8. IEC 60273/IS: 2099 - Dimension of Indoor & Outdoor post insulators i. with voltage > 1000 Volts.
9. IEC 60529/IS 13947(Part-1) - Degree of protection provided by
i. enclosures for low voltage switchgear and
ii. Control gear.
10. Indian Electricity Rules/IS Code
Equipment meeting with the requirements of any other authoritative standards, which ensures equal or better quality
than the standard mentioned above shall also be acceptable. If the equipments, offered by the Bidder conform to
other standards, salient points of difference between the standards adopted and the specific standards shall be clearly
brought out in relevant schedule. In case of any difference between provisions of these standards and provisions of
this specification, the provisions contained in this specification shall prevail. One copy of such standards with authentic
English Translations shall be furnished along with the offer.(Hard copy)
Applicable Standards
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� The RMUs shall be manufactured to the highest quality consistent with best practice and workmanship
and in full accord with the Supplier’s quality assurance plan. The RMUs shall conform to the Indian or IEC
international standards that are applicable. These include the standards listed in Table 1Error! No text of
specified style in document.-1 below.
Table 1Error! No text of specified style in document.-1: Applicable Standards
Standard Description
IS 3427 AC metal enclosed switchgear and control gear for rated voltages above 1 kV and up
to and including 52 kV
IS 12063 Classification of degrees of protection provided by enclosures of electrical
equipment
IS 9920
(Parts 1 to 4) High Voltage Switches
IS 9921
(Parts 1 to 5) Specification for AC disconnectors and earthing switches for voltages above 1000 V
IS 13118 HV AC Circuit Breakers
IS 10601 Dimensions of terminals of HV Switchgear and Control gear
IS 12729 General requirements of switchgear and control gear for voltages exceeding 1000 V
IEC 1330 High voltage/Low voltage prefabricated substations
IEC 60694 Common clauses for MV switchgear standards
IEC 6081 Monitoring and control
IS 2705 Current Transformers
IS 3156 Voltage transformers
IS 8686 Specification for Static Protective Relays
IEC 62271-
200 Standards for high voltage metal clad switchgear up to 52 KV.
INDIAN
ELECTRCIATY
REGULATION
2011
This is to be as per Central Electricity Authority (Safety Requirement for
Construction, Operation & Maintenance of Electrical Plants and Electric Lines)
Regulations, 2011
1.5 THE STANDARDS MENTIONED ABOVE ARE AVAILABLE FROM:
IEC - (INTERNATIONAL ELECTRO-TECHNICAL COMMISSION, BUREAU CENTRAL DE LA COMMISSION, ELECTRO
TECHNIQUE INTERNATIONAL, 1, RUE DE VEREMBE, GENEVA, SWITZERLAND.)
ISO - INTERNATIONAL STANDARD ORGANISATION
1.6 SPECIFIC REQUIREMENTS IN RMU:-
1.6.1 CLIMATE CONDITIONS
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The climatic conditions under which the equipment should operate satisfactory are as under:
� Maximum ambient air temperature :40-45 deg. C
� Minimum ambient air temperature :10 deg.C
� Maximum daily average ambient air temperature :40 C
� Maximum humidity :100%
� Altitude above M.S.L. (maximum) :1000 metres
� Average annual rainfall(mm) :925
� Max. wind pressure(Kg/sq.m) :200
� Seismic level(Horizontal accn.) :0.3 g
� Iso-ceraunic level(Days per Year) :50
� Average thunder storm days per annum :50
1.6.2 Distribution Network Electrical Parameters
The main parameters of the distribution network are as follows:
� Nominal system voltage: 11 kV (rms)
� Highest system voltage: 12 kV (rms)
� Number of phases: 3
� Frequency: 50 Hz
� Variation in frequency: 49.5 Hz to 50.5 Hz
� Type of earthing: Solid
� Power frequency withstand voltage: 28 kV
� Basic impulse withstand voltage : 75 kV
1.7 RMU OUTDOOR METAL CLAD ENCLOSURE.
The RMU enclosure must be a metallic, it shall follows an industrialized process of manufacturing. The RMU and
combination shall be tropicalised and outdoor metal enclosed type. The RMU metal parts shall be of high thickness,
high tensile steel which must be grit/short blasted, thermally sprayed with Zinc alloy, phosphate or should follow the 7
tank pre-treatment process and be subsequently painted with polyurethane based powder paint. The overall paint
layer thickness shall be not less than 80 microns.
The rating of enclosure shall be suitable for operation on three phase, three wire, 11 KV, 50 cycles, A.C. System with
short-time current rating of 20KA for 3 seconds for 11 KV with RMU Panels.
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The enclosure should have two access doors one for the operation and relay monitoring and other for the cable
access. Both the doors should have the locking facility to prevent the access to operating mechanism to avoid
unauthorized operating of RMU and relay.
RMU Design Features
All design features of the proposed RMU, as described in the supplier’s bid and in the bid’s reference materials, shall
be fully supported by the equipment actually delivered. The key design features include those that relate to:
� Maintainability, expandability, and life span
� Ability to operate in severe outdoor environmental conditions.
� Immunity to electrical stress and disturbance.
� Acceptable insulation properties.
� Convenient FRTU interconnection features.
INDOOR RMU
1. MODULAR DESIGN, PANEL TYPE WITH FRONT CABLE ACCESS.
2. RMU MUST BE MADE OF ROBOTICALLY / TIG / MIG WELDED STAINLESS STEEL.
3. Offered RMU must be extensible.
OUT DOOR RMU
1. Stainless steel enclosure for OUT DOOR RMU application. The manufacturers shall conform the normal
current ratings mentioned in GTP at 45 deg. Ambient without derating or as per IEC Standard
2. Enclosure with I.P.54 standard protection.
3. Offered RMU must be extensible.
4. Cable boxes shall be on Front/ side sides.
5. RMU ENCLOSURE MUST BE SHIELDED AGAINST SOLAR IRRADIATION AND TESTED FOR AMBIENT OF 45
DEGREE C. The manufacturers shall conform the normal current ratings mentioned in GTP at 45 deg. Ambient
without derating, however, design for higher ambient temperature than 45 degree may be admissible.
1.8 TAKE OFF TERMINAL UNITS FOR AUTOMATION:
The RMU should be provided with necessary take off terminal units for automations, located in the front recesses / LV
cubical of the RMU. The connectivity to the FRTU for SCADA purpose shall be provided. Refer Annexure-1 for general
arrangement of the termainals.
1.9 ISOLATORS (LOAD BREAK TYPE)
The load break isolators for Incoming and Outgoing supply must be provided. These should be fully insulated by SF6
gas. The load break isolators shall consist of 630 Amp fault making/load breaking spring assisted ring switches, each
with integral fault making earth switches. The switch shall be naturally interlocked to prevent the main and earth
switch being switched “ON‟ at the same time. The selection of the main and earth switch is made by a lever on the
facia, which is allowed to move only if the main or earth switch is in the off position. The load break isolators should
have the facility for remote operation. Each load break switch shall be of the triple pole, simultaneously operated,
automatic type with quick break contacts and with integral earthing arrangement.
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The isolating distance between the OFF and the ON position in the isolator should be sufficient to withstand dielectric
test as per IS/IEC, so as to have enough isolating distance for ensuring safety during DC injection for Cable testing.
Load break switch should have the following
� Motor operated 12 KV, 630A Load Break switch and manually operated Earthing Switch with making capacity.
� “Live Cable” LED Indicators thru Capacitor Voltage Dividers mounted on the bushings.
� Mechanical ON/OFF/EARTH Indication
� Anti-reflex operating handle
� Cable Testing facility without disconnecting the cable terminations, cable joints and terminal protectors on the
bushings.
Cable terminations
� Cable boxes suitable for 1 X 3C x 300 sq mm XLPE Cable with right angle Cable Termination Protectors.
1.10 EARTHING OF ISOLATORS AND BREAKERS (EARTH SWITCH)
Necessary arrangements are provided at Load break isolators Breaker for selecting Earth position. Mechanical
interlocking systems shall prevent the RMU function from being operated from the “ON” to “Earth On” position
without going through the “OFF” position.
1.11 DISTRIBUTION TRANSFORMER/FEEDER BREAKER (VACUUM)
The VCB breaker for the controlling of DT/Feeder Breaker must be provided inside welded stainless steel SF6
gas tank with the outdoor metal clad enclosure. The VCB circuit breaker must be a spring assisted three positions with
integral fault making earth switch. The selection of the main/earth switch lever on the facia, which is allowed to move
only if the main or earth switches is in the off position.
The manual operation of the circuit breaker shall not have an effect on the trip spring. This should only be discharged
under a fault (electrical) trip; the following manual reset operation should recharge the trip spring and reset the circuit
breaker mechanism in the main off position.
The circuit breaker shall be fitted with a mechanical flag, which shall operate in the event of a fault (electrical) trip
occurring. The “tripped” flag should be an unambiguous colour differing from any other flag or mimic.
Both the circuit breaker and ring switches are operated by the same unidirectional handle.
The protection on the circuit breaker shall comprise of the following components:-
- 3 class X protection CT‟s,
- a low burden trip coil and
- a self powered (No external DC or AC source required) IDMT
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protection relays (Numeric/Micro processor based) 3 x over current and earth fault element shall be Definite Time
type relay . The protection system should be suitable for protecting transformers of rated power from 250 KVA on
wards. The relay should be housed within a pilot cable box accessible.
Circuit Breaker should have the following:
- Motor operated 200 A / 630A SF6 insulated Vacuum circuit breaker and Ear thing Switch with making capacity
- Mechanical tripped on fault indicator
- Auxiliary contacts 4NO and 4NC
- Anti-reflex operating handle
- “Live Cable” LED Indicators thru Capacitor Voltage Dividers mounted on the bushings.
- O/C + E/F self powered relay
- Shunt Trip circuit for external trip signal
- Mechanical ON/OFF/EARTH Indication
- Cable boxes suitable for 1 X 3C x 300 sq mm XLPE Cable with right angle Cable Termination / protectors / boots
TECHNICAL DATA
1 Ring Main Unit, Electrical data
Electrical data and service conditions
Rated voltage KV 12/15.5 KV
1 Power frequency withstand voltage KV 28 / 35
2 Impulse withstand voltage KV 75 / 95
3 Rated frequency Hz 50
4 Rated current busbars A 630
5 Rated current (cable switch) A 630
6 Rated current (T-off) A 200 / 630
Breaking capacities:
7 active load A 630
8 closed loop (cable switch) A 630
9 off load cable charging (cable switch) A 135
10 earth fault (cable switch) A 200
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11 earth fault cable charging (cable switch) 115
12 short circuit breaking current (T-off circuit
breaker)
kA 20 / 21
13 Rated making capacity kA 52
14 Rated short time current 3 sec. kA 20 / 21
Ambient temperature:
15 Maximum value °C + 45
16 Maximum value of 24 hour mean °C + 40
17 Minimum value °C 0
18 Altitude for erection above sea level4 m ...1000
19 Relative humidity Max 95%
2 Ring Main Unit Technical data (11KV/22KV)
No. General data, enclosure and dimensions
1 Standard to which Switchgear complies IEC
2 Type of Ring Main Unit Metal Enclosed, Panel type, Compact
Module.
3 Number of phases 3
4 Whether RMU is type tested Yes
5 Whether facility is provided with pressure relief Yes
6 Insulating gas SF6
7 Nominal operating gas pressure
1.4 bar @ 20° C. However offer with
Nominal operating gas pressure shall be as
per manufacturer standard and suitable to
satisfy the rated dielectric strength can be
accepted
8 Gas leakage rate / annum 0.075%
9 Expected operating lifetime 30 years
10 Whether facilities are provided for gas monitoring Yes, temperature compensated manometer
can be delivered
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11 Material used in tank construction Stainless steel sheet, minimum 2 mm
No. Operations, degree of protection and colours
1 Means of switch operation separate handle
2 Means circuit breaker operation separate handle and push buttons
3 Rated operating sequence of Circuit Breaker O - 3min-CO-3min-CO
4 Total opening time of Circuit Breaker approx. 45ms
5 Closing time of Circuit Breaker approx. 40ms
6 Mechanical operations of switch (co) 1000
7 Mechanical operations of CO earthing switch 1000
8 Mechanical operations of circuit breaker (co) 2000
9 Principle switch / earth switch 3 position combined switch / earth switch
Degree of protection:
10 High Voltage live parts, SF6 / VCB tank IP 67
11 Front cover mechanism IP 2X
12 Cable covers IP 3X
13 Outdoor Enclosure IP 54
Colours:
14 Front cover
15 Side and cable cover
1.12 BUSHINGS
The units are fitted with the standardized bushings that comply with IEC standards. All the bushings are the same
height from the ground and are protected by a cable cover.
1.13 CABLE BOXES
All the cable boxes shall be air insulated suitable for dry type cable terminations and should have front/side access.
The cable boxes at each of the two ring switches should be suitable for accepting HV cables of sizes 3c x 300 sq.mm
and circuit breaker cable suitable up to 3c x 300 sq.mm. The cable boxes
for an isolator in its standard design should have sufficient space for connecting two cables per phase .Necessary Right
angle Boot should be supplied to the cable terminations .The type of the Right angle Boot should be cold applied
insulating Boot.
1.14 CABLE TESTING FACILITY
It shall be possible to test the cable after opening the cable boxes. The cable boxes should open only after operation of
the earth switch. Thus ensuring the earthing of the cables prior to performing the cable testing with DC injection.
1.15 VOLTAGE INDICATOR LAMPS AND PHASE COMPARATORS
The RMU shall be equipped with a voltage indication to indicate whether or not there is voltage on the cable. There
should be a facility to check the synchronization of phases with the use of external device. It shall be possible for the
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each of the function of the RMU to be equipped with a permanent voltage indication as per IEC 601958 to indicate
whether or not there is voltage on the cables.
1.16 EXTENSIBLE
Each combination of RMU shall have the provision for extension by load break isolators / breakers in future, with
suitable accessories and necessary Bus Bar. The equipment shall be well designed to provide any kind of extension /
trunking chamber for connecting and housing extensible Busbars. Extensible isolators and circuit breakers shall be
individually housed in separate SF6 gas enclosures. Multiple devices inside single gas tank / enclosure will not be
acceptable. In case of extensible circuit breakers, the Breaker should be capable of necessary short circuit operations
as per IEC at 20 KA, and the Breaker should have a rated current carrying
capacity of 200 A to 630 A.
1.17 WIRING & TERMINALS:
The wiring should be of high standard and should be able to withstand the tropical weather conditions. All the wiring
and terminals (including take off terminals for future automation, DC, Control wiring), Spare terminals shall be
provided by the contractor. The wiring cable must be standard single-core non-sheathed, Core marking (ferrules),
stripped with non-notching tools and fitted with end sleeves, marked in accordance with the circuit diagram with
printed adhesive marking strips.
The wiring should be of high standard and should be able to withstand the tropical weather conditions. All wiring shall
be provided with single core multi-strand copper conductor wires with P.V.C insulation.
The wiring shall be carried out using multi-strand copper conductor super flexible PVC insulated wires of 650/1100V
Grade for AC Power, DC Control and CT circuits. Suitable colored wires shall be used for phase identification and
interlocking type ferrules shall be provided at both ends of the wires for wire identification. Terminal should be
suitably protected to eliminate sulphating. Connections and terminal should be able to withstand vibrations. The
terminal blocks should be stud type for controls and disconnecting link type terminals for CT leads with suitable spring
washer and lock nuts.
Flexible wires shall be used for wiring of devices on moving parts such as swinging Panels (Switch Gear) or panel doors.
Panel wiring shall be securely supported, neatly arranged readily accessible and connected to equipment terminals,
terminal blocks and wiring gutters. The cables shall be uniformly bunched and tied by means of PVC belts and carried
in a PVC carrying trough.
The position of PVC carrying trough and wires should not give any hindrance for fixing or removing relay casing,
switches etc., Wire termination shall be made with solder less crimping type of tinned copper lugs. Core identification
plastic ferrules marked to correspond with panel wiring diagram shall be fitted with both ends of each wire. Ferrules
shall fit tightly on the wire when disconnected. The wire number shown on the wiring shall be in accordance with the
IS.375.
All wires directly connected to trip circuits of breaker or devices shall be distinguished by addition of a red color
unlettered ferrule.
Inter-connections to adjacent Panels (Switch Gear) shall be brought out to a separate set of Terminal blocks located
near the slots or holes to be provided at the top portion of the panel. Arrangements shall be made for easy
connections to adjacent Panels (Switch Gear) at site and wires for this purpose shall be provided and bunched inside
the panel. The bus wire shall run at the top of the panel.
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Terminal block with isolating links should be provided for bus wire. Ateast 10% of total terminals shall be provided as
spare for further connections. Wiring shall be done for all the contacts available in the relay and other equipment and
brought out to the terminal blocks for spare contacts. Color code for wiring is preferable in the following colours.
� Voltage supply : Red, Yellow, Blue for phase and Black for Neutral
� CT circuits : similar to the above
� DC circuits : Grey for both positive and negative
� 250V AC circuits : Black for both phase and neutral
� Earthing : Green
The wiring shall be in accordance to the wiring diagram for proper functioning of the connected equipment. Terminal
blocks shall not be less than 650V grade and shall be piece-molded type with insulation barriers.
The terminal shall hold the wires in the tight position by bolts and nuts with lock washers. The terminal blocks shall be
arranged in vertical formation at an inclined angle with sufficient space between terminal blocks for easy wiring.
The terminals are to be marked with the terminal number in accordance with the circuit diagram and terminal
diagram. The terminals should not have any function designation and are of the tension spring and plug-in type.
Clear empty Space shall be mandatorily provided in RMU Panel for mounting FRTU Panel. Dimensions details of
required space for FRTU are about 1500 mm H x 600 mm W x 300 mm D. 230V AC Supply for charging of FRTU battery
should be available. The Aux supply will be taken through the PT provided for metering in RMU. We require 230V AC
and not 110V AC. FRTU will require power up to 500 VA depending upon RMU configuration. The PT must have
sufficient burden for meeting the aforesaid requirement also for battery charging.
1.18 EARTHING
The RMU outdoor metal clad, Switch Gear, Load break isolators, Vacuum circuit breakers shall be equipped with an
earth bus securely fixed along the base of the RMU.
The size of the earth bus shall be made of IEC/IS standards with tinned copper flat for RMU and M.S.Flat for
Distribution Transformer, earth spike and neutral earthing. Necessary terminal clamps and connectors shall be
included in the scope of supply.
All metal parts of the switchgear which do not belong to main circuit and which can collect electric charges causing
dangerous effect shall be connected to the earthing conductor made of copper having CS area of minimum 75 mm.
Each end of conductor shall be terminated by M 12/equivalent quality and type of terminal for connection to earth
system installation. Earth conductor location shall not obstruct access to cable terminations.
The following items are to be connected to the main earth conductor by rigid or copper conductors having a minimum
cross section of 75 mm (a) earthing switches (b) Cable sheath or screen (c) capacitors used in voltage control devices,
if any.
The metallic cases of the relays, instruments and other panel mounted Equipment‟s shall be connected to the earth
bus by independent copper wires of size shall be made of IEC/IS standards. The colour code of earthing wire shall be
green. Earthing wires shall be connected on the terminals with suitable clamp connectors and soldering shall not be
permitted.
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1.19 ACCESSORIES & SPARES:
The following spares and accessories shall be supplied along with the main equipments at free of costs. This shall not
be included in the price schedule.
1. Charging lever for operating load break isolators & circuit breaker of each RMU.
2. The pressure gauges indications - 1 numbers
Provision shall be made for padlocking the load break switches/ Circuit breaker, and the earthing switches in either
open or closed position with lock & master key.
1.20 TESTING OF EQUIPMENT & ACCESSORIES:
Provision for testing CTs,PTs, Relays, Breakers and Cables shall be made available. Procedure and schedule for
Periodical & Annual testings of equipments, relays, etc. shall be provided by the supplier.
1.20.1 TYPE TEST
The Tenderers should, along with the tender documents, submit copies of all Type test certificate of their make in full
shape as confirming to relevant ISS/IEC of latest issue obtained from a International/National Govt. Lab/Recognized
laboratory.
The above type test certificates should accompany the drawings for the materials duly signed by the institution who
has type test certificate. The details of type test certificate as per Schedule F.
1.20.2 ACCEPTANCE AND ROUTINE TESTS
All acceptance and routine tests as stipulated in the latest IEC- shall be carried out by the supplier in the presence of
DISCOM’s representative. The supplier shall give at least 7 days advance intimation to the DISCOM to enable them to
depute their representative for witnessing the tests. The partial discharge shall be carried out as routine test on each
and every completely assembled RMU gas tank and not on a sample basis. As this test checks and guarantees for the
high insulation level and thus the complete life of switchgear.
1.20.3 ADDITIONAL TESTS
The DISCOM reserves the right for carrying out any other tests of a reasonable nature at the works of the
supplier/laboratory or at any other recognized laboratory/research institute in addition to the above mentioned type,
acceptance and routine tests at the cost of the Board to satisfy that the material complies with the intent of this
specification.
1.20.4 PRE-COMMISSIONING TESTS
All the pre-commissioning tests will be carried out in the presence of the DISCOM’s testing engineer and necessary
drawing manual and periodical test tools shall be arranged to be supplied.
During the above tests the contractor representative should be present till the RMUs are put in to service.
1.21 INSPECTION:
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The inspection may be carried out by the DISCOM at any stage of manufacture. The supplier shall grant free access to
DISCOM’s representative at a reasonable time when the work is in progress. Inspection and acceptance of any
equipment under this specification by the DISCOM shall not relieve the supplier of his obligation of furnishing
equipment in accordance with the specification and shall not prevent subsequent rejection if the equipment is found
to be defective.
The supplier shall keep the DISCOM informed in advance, about the manufacturing programme so that arrangement
can be made for inspection. The DISCOM reserves the right to insist for witnessing the acceptance/routine testing of
the bought out items. The DISCOM has rights to inspect the supplier’s premises for each and every consignment for
type & routine test.
No material shall be dispatched from its point of manufacture unless the material has been satisfactorily inspected
and tested / unless the same is waived by the DISCOM in writing.
1.21.1 : QUALITY ASSURANCE PLAN:
The bidder shall invariably furnish following information along with his offer / in case of event of order.
I. Statement giving list of important raw materials including but not limited to
a) Contact material
b) Insulation
c) Sealing material
d) Contactor, limit switches, etc. in control cabinet.
Name of sub-suppliers for the raw materials, list of standards according to which the raw materials are tested, list of
test normally carried out on raw materials in presence of Bidder’s representative, copies of test certificates.
II. Information and copies of test certificates as in (I) above in respect of bought out accessories & raw materials.
III. List of areas in manufacturing process, where stage inspections are to be carried out.
IV. Normally carried out for quality control and details of such tests and inspections.
V. Special features provided in the equipment to make it maintenance free.
VI. List of testing equipment available with the Bidder for final testing of RMUs and associated combinations vis-à-vis
the type, special, acceptance and routine tests specified in the relevant standards. These limitations shall be very
clearly brought out in the relevant schedule i.e. schedule of deviations from specified test requirements. The supplier
shall, within 15days from the date of receipt of Purchase Order submit following information to the DISCOM.
a) List of raw materials as well bought out accessories and the names of sub-suppliers selected from those furnished
along with offer.
b) Necessary test certificates of the raw material and bought out accessories.
c) Quality Assurance Plan (QAP) with hold points for DISCOM’s inspection. The quality assurance plan and hold points
shall be discussed between the DISCOM and supplier before the QAP is finalized.
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The supplier shall submit the routine test certificates of bought out items and raw material, at the time of routine
testing of the fully assembled breaker.
1.22 TRAINING:
The supplier shall give rigorous training to the engineers & staff for 2 days in attending trouble shooting and
maintenance.
1.23 SCADA CONNECTIVITY:
Provision shall be made in all the RMUs with necessary take off terminal units for automations and connectivity with
FRTU. The all RMUs shall be motorized type and compatible for SCADA operation. All the I/O signals need to be
brought to the Terminal Strip on a Din Rail, also the Din Rail should have space to mount the MFT’s provided by SIA.
All the DI’s, AI’s and DO’s should be provided as potential free and control contacts. The CT/PT should provide
metering grade core for connecting MFT provided with FRTU. The RMU will also supply 230VAC 500VA for FRTU. Refer
Annexure-1.
The RMU should be provided with provision of following minimum signals available at separate SCADA terminal box.
Minimum signals for SCADA/DMS - to be wired
to Separate TBs
CB close / open potential free contacts
LBS close / open potential free contacts
LBS & CB Earth Switch close /open potential free contacts
CB Test/Service Position potential free contacts
Spring charge Status indication potential free contacts
SF6 gas pressure low potential free contacts
O/C Operated potential free contacts
E/F Operated potential free contacts
Local/Remote potential free contacts
Common Power Supply Healthy potential free contacts
Motor MCB Healthy Status potential free contacts
Battery charger Fail potential free contacts
RMU Door Open potential free contacts
CB Trip Coil Healthy potential free contacts
CT & PT For SCADA Metering
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FPI Control FPI remote resetting for SCADA
CB control Control from SCADA
LBS Control Control from SCADA
1.24 DOCUMENTATION and DRAWINGS
All drawings shall conform to relevant International Standards Organization (ISO) Specification. All drawings shall be in
ink and suitable for microfilming.
The tenderer shall submit along with his tender dimensional general arrangement drawings of the equipments,
illustrative and descriptive literature in triplicate for various items in the RMUs which are all essentially required for
future automation.
I. Schematic diagram of the RMU panel
II. Instruction manuals
III. Catalogues of spares recommended with drawing to indicate each items of spares
IV. List of spares and special tools recommended by the supplier.
V. Copies of Type Test Certificates as per latest IS/IEC.
VI. Drawings of equipments, relays, control wiring circuit, etc.
VII. Foundation drawings of RMU and D.T.Structure.
VIII. Dimensional drawings of each material used for item VII.
IX. Actual single line diagram of RMU/RMUs with or without Extra combinations shall be made displayed on the
front portion of the RMU so as to carry out the operations easily.
The following should be supplied to each consignee circle/town along with the initial supply of the equipments
ordered.
a. Copies of printed and bound volumes of operation, maintenance and erection manuals in English along with
the copies of approved drawings and type test reports etc.
b. Sets of the manuals as above shall be supplied to the Chief Engineer/Distribution. A soft copy of the all
Technical and Drawing furnished in a CD
1.25 NAME PLATE:
Each RMU and its associated equipments shall be provided with a nameplate legible and indelibly marked with at least
the following information.
a. Name of manufacturer
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b. Type, design and serial number
c. Rated voltage and current
d. Rated frequency
e. Rated symmetrical breaking capacity
f. Rated making capacity
g. Rated short time current and its duration
h. Purchase Order number and date
i. Month and Year of supply
j. Rated lighting impulse withstand voltage
k. Feeder name (Incoming and Outgoing), DTs Structure name, 11000 Volts Dangers etc.
NOTE:
I) THE WORD RATED NEED NOT APPEAR ON THE NAME PLATE. RECOGNIZED ABBREVIATIONS MAY BE USED TO
EXPRESS THE ABOVE PARTICULARS.
II) WHETHER THE CIRCUIT BREAKER IS FITTED WITH CLOSING/TRIPPING DEVICES NECESSITATING AN AUXILIARY
SUPPLY SHALL BE STATED EITHER ON THE CIRCUIT BREAKER NAME PLATE OR ANY OTHER ACCEPTABLE
POSITION.
1.26 FAULT PASSAGE INDICATORS (FPI):
These shall facilitate quick detection of faulty section of line. The fault
indication may be on the basis of monitoring fault current flow through the device.
The unit should be self-contained requiring no auxiliary power supply. The FPI shall
be integral part of RMU. The FPI shall have LCD/LED display, automatic reset
facility. FPI Reset from SCADA will be through momentary closure of a potential free contact from FRTU.
The sensors to be bushing mounted. The number of FPI should be put in all the three phases of the outgoing branch of
the RMUs
FPI should have suitable connectivity with the FRTUs for the SCADA purpose.
The FPI inside the RMU may be non communicable and hard wired to the TB for the signals
Fault Passage indicator OK
Fault Passage indicator operated
1.27 TROPICALISATION
Due regard should be given to the climatic conditions under which the equipment is to work. Ambient temperatures
normally vary between 20 deg C and 40 deg C, although direct sun temperature may reach 45 deg C. The climate is
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humid and rapid variations occur, relative humidity between 60% and 95% being frequently recorded, but these values
generally correspond to the lower ambient temperatures. The equipment should also be designed to prevent ingress
of vermin, accidental contact with live parts and to minimize the ingress of dust and dirt. The use of materials which
may be liable to attack by termites and other insects should be avoided.
1.28 Motorization :
All the functions within the RMU i.e Isolators/Breakers should be fitted with motor mechanism and closing coil making
it suitable to make it on from remote.( However, manual mechanism should be possible in case of failure/ non working
of motor)
Other Accessories (required with RMU) :-
a) Shunt Trip Coil ( Coil voltage shall be indicated later on)
b) Battery & Battery Charger.
c) 4NO+4NC auxiliary contacts.
1.29 Metering:
Multifunction Energy meter shall be provided by DISCOMS with, of accuracy class of 0.5 at incoming isolator of all
RMUs. The Metering CTs and PTs of suitable rating shall be
provided and wired in SCADA terminal TBs.
1.30 TECHNICAL SPECIFICATION FOR RMU
1.30.1 11KV Bus Bar
I. Current Carrying Capacity : 630 Amps.
II. Short time rating current for 3 secs. : 20 KA for 11kv
III. Insulation of bus bar : SF6
IV. Bus bar connections : Anti-oxide grease
1.31 PARAMETERS FOR SWITCH GEAR OF DT AND LOAD BREAK ISOLATORS
I. Type : Metal enclosed
II. No of Phases : 3
III. No. of poles : 3
IV. Rated voltage :12 KV
V. Operating voltage :11 KV(+10% to -20%)
VI. Rated lightning impulse withstand voltage :75 KV
VII. Rated power frequency withstand voltage :28 KV
VIII. Insulating gas :SF6
IX. Rated filling level for insulation :As Per IEC.
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Max.permissible site altitude at the above gas pressures : 1000m
(The operating pressure has to be adjusted for greater altitudes)
Isolating distance between ON and OFF position in isolator :80 mm (min).
Rated short time current :20 KA.for 11kv
Rated short time :3s
Rated peak withstand current :50 KA.
No of operations in Short circuit :15Nos (minimum)
Operating mechanism: Circuit breaker with spring assisted anti reflex mechanism.
Rated current (Bus): :630 A
Rated current (breaker) :200 A
Circuit Breaker interrupter :SF6 insulated VCB
Rated frequency : 50 Hz
Rated operating sequence :O-3min- CO
Number of mechanical/Remote operations for earthing : As per IEC
& Ring switches & Number of mechanical/ Remote operations for circuit breakers 60298
1.32 PRINCIPAL FEATURES
Sr.
No
DESCRIPTION Breaker
1 Circuit label Yes
2 Mimic diagram Yes
3 Supply voltage indication Yes
4 Current Transformer Yes
5 Self Powered based Microprocessor based IDMT
Relay (3OL)/EL
Yes
6 Anti - Reflexing Relay Yes
7 Interlock to defeat the operation of the line side
earthing when the line side isolator is ON.
Yes
8 Interlock to defeat the operation of the earthing
when the breaker is in service position and is ON.
Yes
9 Breaker ON/OFF indication Yes
10 Spring Charge indication / Spring assisted
mechanism.
Yes
11 Fault Tripping indication Yes
12 Bus bar end caps Yes
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13 Whether the SF6 gas pressure gauge indicator and
filling arrangement.
Yes
14 Whether the spring assisted mechanism with
operating handle for ON/OFF.
Yes
15 Whether the earth positions with arrangement for
padlocking in each position and independent
manual operation with mechanically operated
indicator are provided
Yes
16 RMUs are provided with necessary take off
terminals for future automation.
Yes
1.33 Earthing switch for 11 KV Line side Isolation and DT
Rated short time current : 20 KA.for 11kv.
Rated short time :3s
Rated peak withstand current :50 KA
Interlocking facility:
1) Between 11 KV Line side isolator “ON”&Earthing.
2) Between 11 KV DT side breaker on close condition &earthing
1.34 Current Transformers for breaker
CT Type : Tape wound
CT Description : The CTs of breaker shall be Suitable for sensing the minimum
primary variable current in the order of 10-100 A and the secondary current for the CT is 1 A. The CT
shall be housed in outside SF6 chamber for testing and Maintenance
Accuracy Class :class X/5P10 protection
Rated burden : Suitable for self powered relay and metering.
PART A&B: TECHNICAL SPECIFICATION FOR OUTDOOR 22 KV RING MAIN UNIT
SWITCHGEAR
1.1 GENERAL:
1.1.1 All equipment and material shall be designed manufactured and tested in
accordance with the latest applicable IEC standard.
1.1.2 Equipment and material conforming to any other standard, which ensures equal or
better quality, may be accepted. In such case copies of English version of the
standard adopted shall be submitted.
1.1.3 The electrical installation shall meet the requirement of Indian Electricity Rules-1956
as amended up to date; relevant IS code of practice and Indian Electricity Act-1910.
In addition other rules and regulations applicable to the work shall be followed. In case any discrepancy ,the
most stringent and restrictive one shall be binding.
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1.1.4 The high-tension switchgear offered shall in general comply with the latest issues
including amendments of the following standards but not restricted to them.
1.2 SCOPE:
Design, Engineering, Manufacture, assembly, Stage testing, inspection and testing before supply and delivery at site,
Erection, Installation, testing & Commissioning of Ring Main units outdoor type SF6 filled , with various combinations
of load break isolators & breakers. The scope includes Supply, Erection, testing and commissioning of outdoor type
RMU with necessary take off terminal units for future automations contains load break isolators, breaker and
associated accessories, equipments. (including civil works and earthing- Erection of earthing by using GI strip
(minimum 35 mm strip) with earthing plate including cost of coal/salt to RMU). The Installation of 11KV Outdoor SF6
Insulated RMU covering erection,testing and commissioning with associated equipment including civil work of RMU,
drawing and Bom(Bill of Material) of civil work submit by bidder along with technical details.
The RMUs should be provided with necessary take off terminal units for future automations and all these units should
be shielded in a outdoor metal-body for making them suitable for outdoor use. The insulation/dielectric media inside
the stainless steel welded tank should be SF6 gas. The RMUS should be Modular ,extensible type on both sides with
provision of attaching/connecting with SNAP FIT arrangement W/o External Busbars additional load break switches
and circuit breakers in future whenever required. Alternatively Extension shall be possible by adding trunking
chambers and required accessories or by plug-in bushing type arrangement.
The Package scope of work shall include survey, design, manufacture, FAT and delivery,
installation and commissioning of new SCADA enabling equipments of new “SCADA-Ready”
The RMU should have compatibility with OPEN PROTOCOL SCADA system.
Ring Main Units capable of being monitored and controlled by the SCADA/DMS. The RMU should have the castle lock
for avoiding dual supply and safety purpose.
Where relevant, the RMU scope of work shall be coordinated with the work to be carried out under the project’s other
construction packages & associated materials to the designated destinations as per this tender specification and Bill of
quantities. Includes supply of relevant 22KV cable termination kits per this tender Specification.
Each RMU shall include its own power supply unit (including auxiliary power transformer, batteries, and battery
charger), which shall provide a stable power source for the RMU. The RMUs will be connected to the FRTU which will
be procured, supplied and installed as a part of Part A of R-APDRP. The RMU will also supply 230VAC 500VA for FRTU.
Refer Annexure-1.
FRTU, MODEM, Power and I/O cable interface between FRTU and Control panel of RMU/sectionaliser are excluded in
the scope of supply and these items will be provided by DISCOM/SIA.
Each new RMU shall be equipped with main-line load break switches and a fault passage indicator
(FPI). Furthermore, to protect each of its lateral / transformer feeders, it shall be equipped with a corresponding set of
circuit breakers and self-powered numerical relays. The RMU shall include potential-free contacts and control contacts
so as to connect to SCADA/DMS via FRTUs, so as to:
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� Monitor and control the open/closed status of the RMU circuit breakers and load break switches.
� Monitor the local/remote position of RMU motorised (in case if failure of motor) manually-operated
switches that can be used to enable and disable remote monitoring.
� Monitor the health of the power supply, which will include battery failure and low voltage indications.
� Monitor the open/closed status of RMU earthing switches.
� Monitor the open/closed status of RMU enclosure doors in case of Hinge doors.
� Monitor for low SF6 gas pressure indication.
� Monitor for circuit breaker relay operations.
� Monitor for indication of main-circuit fault detected by the RMU’s FPI.
1.2.1 Configurations Required:-
22 KV RMU
a) 2-Way , 22 KV Gas (SF6) Insulated RMU with One 630A load break switches
and One SF6 Insulated VCB of suitable rating -
b) 3-way , 22 KV ,Gas (SF6) Insulated RMU with 2Nos 630A load break switch
and 1No. SF6 insulated VCB of suitable rating -
c) 4-way ,22 KV Gas (SF6) Insulated RMU with 2Nos 630A Load break switches
and 2Nos , SF6 Insulated VCB of suitable rating –
d) 5-way , 22 KV ,Gas (SF6) Insulated RMU with 2Nos 630A load break switch
and 3No. SF6 insulated VCB of suitable rating -
e) 6-way ,22 KV Gas (SF6) Insulated RMU with 3Nos 630A Load break switches
and 3Nos , SF6 Insulated VCB of suitable rating –
PLS NOTE: THE NOMINAL CURRENT RATING OF VCB SHALL BE ACCORDING TO LOAD OF THE FEEDER AND
ACCORDINGLY SUITABLE RELAY SHALL BE PROVIDED AND ANY CHANGE IN COMBINATION/CONFIGURATION SHALL
BE EXECUTED WITH THE APPROVAL OF CHIEF ENGINEER OF RESPECTIVE DISCOM.
1.1 This Specification provides for design, manufacture, inspection and testing before dispatch, packing and
delivery F.O.R.(Destination) of SF6 insulated RMUs with necessary take off terminal units for future automations,
compatible with SCADA system other accessories and auxiliaries equipment and mandatory spares, described herein
and required for their satisfactory operation.
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1.2. The objective of the RMUs is for extremely small construction width, compact, maintenance free, independent
of climate, easy installation, operational reliability, Safe and easy to operate, minimum construction cost, minimum
site work and minimum space requirement.
1.3. The RMUs shall conform in all respects to high standards of Engineering design, workmanship and latest
revisions of relevant standards at the time of offer.
RMU to be installed on Plinth Erection of plinth with cost of cement etc as per below requirement Plinth size
minimum 5’x4’x2’ or as per required Cement ratio 1: 2 : 4 ;Weight of RMU 510 kg to 1000 kg.
1.4. The type of the 22 KV circuit breaker shall be VCB and insulating medium for load break isolators, Earth switch,
22 KV Buses and other associated equipments should be SF6 gas.
� Necessary current sensors / transformers for protection and metering (wherever required).
� All necessary dry (potential-free) contacts for indications relevant to RMU monitoring status and control.
� A PT Panel including auxiliary power transformer for measurement of system voltage and for charging the
batteries.
� Battery and battery charger, to provide stable as per motor rating, 24 VDC, power for the RMU’s motors.
� Capacitor voltage dividers serving live-line cable indicators.
1.3 GENERAL:
The Ring Main Unit shall be installed at 22 KV junction points to have continuous supply by isolating faulty sections.
The RMU shall be extensible on both sides and consists of the following combinations of load break switches and
Circuit breakers for a nominal voltage of 24 KV using SF6 gas as insulating and Vacuum as arc quenching medium.
The RMU and combination shall be tropicalised and outdoor metal enclosed type. The RMU metal parts shall be of
high thickness, high tensile steel which must be grit/short blasted, thermally sprayed with Zinc alloy, phosphate or
should follow the 7 tank pre-treatment process and be subsequently painted with polyurethane based powder paint.
The overall paint layer thickness shall be not less than 80 microns.
Relevant IE rules for clearances, safety and operation inside the enclosure shall be applicable. The enclosure shall be IP
54 and type tested for weather proof at EREDA/CPRI.
All live parts except for the cable connections in the cable compartments shall be insulated with SF6 gas. The SF6 gas
tank shall be made of robotic or TIG or MIG or Laser or manually welded stainless steel, to have the best weld quality.
The gas cubicle shall be metal enclosed with stainless Steel of thickness as per IEC tested/ designed so as to provide
safety and to avoid leakage of gas and should be provided with a pressure relief arrangement away from operator.
Both the load break switches and the tee off circuit breaker must be motorized.
The cable box of isolators and circuit breakers both should be of front access type as per site requirement.
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Any accidental over pressure inside the sealed chamber shall be limited by the opening of a pressure-limiting device in
the top or rear-bottom part of the tank or enclosure. Gas will be release to the rear of the switchboard away from the
operator and should be directed towards the bottom, into the trench to ensure safety of the operating personnel and
the pedestrians / civilians. All the manual operations should be carried out on the front of the switchboard.
2.2 GENERAL TECHNICAL REQUIREMENTS
2.2.1 Fixed type SF-6 gas insulated / Vacuum circuit breakers. It should be maintenance free, having stainless steel
robotically/ TIG / MIG /Laser/ Manually welded enclosure for IN DOOR / OUTDOOR RMU. However, offer with high
quality of the welding which has necessary extensive leakage test with leak rate of 0.1% per annum can be accepted.
The RMUs to be used are only outdoor type.
2.2.2 Low gas pressure devices- 1.2 Bar pressure. RMU should have full rating with 0.0 Bar gas pressure.
2.2.3 Live cable indicators- High operator safety.
2.2.4 Fully Rated integral ear thing switch on each device.
2.2.5 Self powered Microprocessor Based relay- Does not require any external source of power.
2.2.6 Units fully SCADA Compatible. Retrofitting at site possible at a later date. Line switches (Load break switches) as
well as T- OFF circuit Breaker can be operated by remote. ( Manual operations should be possible in case of motor
failure.)
2.2.7 For indoor Cable boxes should be front access and interlocked with earth switch. No rear /side access required.
For outdoor RMUs cable boxes shall be on front.
2.2.8 Cable testing possible without disconnection of cables.
2.2.9 Compact in dimension.
2.2.10 Circuit Breaker with self powered O/C & E/F RELAY.
2.2.11 Low pressure, sealed for life equipment, can operate at “0” bar pressure.
2.2.12 Cable ear thing switch on all switching device-standard, for operator safety.
2.2.13 Enclosure with IP 54 standard protection for OUTDOOR RMUs and IP2X for INDOOR RMUs
2.2.14 All live parts should be inside a stainless steel enclosure for out door type RMU & minimum 2 mm thickness of
stainless steel robotically/TIG/MIG/Manually welded enclosure for Outdoor / indoor RMU. However, more / less
thickness than 2 mm of stainless steel tank as per IEC tested design may be admissible.
TECHNICAL AND GUARANTEED PARTICULARS:
The bidders shall furnish all guaranteed technical particulars as called for in Schedule “A” of this specification.
Particulars which are subject to guarantee shall be clearly marked. Bids lacking information in G.T.P are liable to be
rejected
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The Entire units or minimum three functions of RMU shall be enclosed in a single compact metal clad, outdoor
enclosure suitable for all weather conditions. The switchgear/steel gas tank shall be filled with SF6 as per IEC/IS
Standards relative pressure to ensure the insulation and breaking functions. The steel gas tank must be sealed for life
and shall meet the “sealed pressure system” criteria in accordance with the IEC 298 standard. The RMU must be a
system for which no handling of gas is required throughout the 20 years of service life.
The RMU shall have a design such that in the event of an internal arc fault, the operator shall be safe. This should be in
accordance with IEC 298 and relevant Test certificates shall be submitted with the Tender.
The offered switchgear and control gear should be suitable for continuous operation under the basic service
conditions indicated below. Installation should be in normal indoor conditions in accordance with IEC 60694.
Ambient temperature - 10 degree C to +45 degree C
Relative humidity - up to 95%
Altitude of installation - up to 1000m, IEC 60120
1.3.1 The RMU shall be tested for an internal arc rating of 16 kA for 1 Sec. for 22 KV RMU. Suitable temperature rise
test on the RMU shall be carried out & test reports shall be submitted with tender for technical bid evaluation.
Each switchboard shall be identified by an appropriately sized label, which clearly indicates the functional units and
their electrical characteristics.
The switchgear and switchboard shall be designed so that the position of the different devices is visible to the
operator on the front of the switchboard and operations are visible as well.
The entire system shall be totally encapsulated. There shall be no access to exposed conductors. In accordance with
the standards in effect, the switchboards shall be designed so as to prevent access to all live parts during operation
without the use of tools.
The entire 22 KV RMU are insulated by inert gas (SF6) suitable for operating voltage up to 24 KV respectively. The 22
KV circuit breakers must be VCB breaker. It is necessary to fit an absorption material in the tank to absorb the
moisture from the SF6 gas. The SF6 insulating medium shall be constantly monitored via a temperature compensating
gas pressure indicator offering a indication at different temperature ranges, having distinctive RED and GREEN zones
for safe operation.
All the RMUs must be routine tested for the following at factory in India:-
� Micro-ohm test for the assembly inside the tank.
� Circuit breaker analyzer test so as to ensure the simultaneous closing of all poles for VCB.
� SF6 gas leak test.
� Partial Discharge test on the complete gas tank so as to be assure of the proper insulation level and high
product life.
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� High voltages withstand.
� Secondary test to ensure the proper functioning of the live line indicators, fault passage indicators and relays.
1.3.2Sulphur Hex fluoride Gas(SF6 GAS)
The SF6 gas shall comply with IEC 376,376A, and 376B and shall be suitable in all respects for use in 22 KV RMUs under
the operating conditions. The SF6 shall be tested for purity, dew point air hydrolysable fluorides and water content as
per IEC 376,376A and 376B and test certificate shall be furnished to the owner indicating all the tests as per IEC 376
for each Lot of SF6 Gas.
DIELECTRIC MEDIUM
SF6 / VCB GAS shall be used for the dielectric medium for 22 KV RMUS in accordance with IEC376. It is preferable to fit
an absorption material in the tank to absorb the moisture from the SF6 / VCB gas and to regenerate the SF6 / VCB gas
following arc interruption. The SF6 / VCB insulating medium shall be constantly monitored via a temperature
compensating gas pressure indicator offering a simple go, no-go indication.
General structural and mechanical construction:
The offered RMU should be of the fully arc proof metal enclosed, free standing, floor mounting, flush fronted type,
consisting of modules assembled into one or more units. Each unit is made of a cubicle sealed-for life with SF6 / VCB
and contains all high voltage components sealed off from the environment.
The overall design of the indoor switchgear should be such that front access only is required. It should be possible to
erect the switchboard against a substation wall, with HV and LV cables being terminated and accessible from the front.
The units should be constructed from Minimum 2 mm thick stainless steel sheets. However, Offer with type test
report of pressure withstand test for gas filled compartment with pressure relief device test as per cl. no. 6-103-1 of
IEC 62271-200-2003 can be accepted for 2mm stainless steel tank thickness. The thickness of stainless steel tank more
/ less than 2 mm may be admissible with relevant IEC tests. The design of the units should be such that no permanent
or harmful distortion occurs either when being lifted by eyebolts or when moved into position by rollers.
For outdoor RMUs a weather proofing process shall be carried out. SHEET METAL MUST BE GRIT BLASED /
THERMALLY SPRAYED AND POLYURETHANE PAINTED WITH ABOUT 70 MICRON THICKNESSES, TO ACHIVE
OUTDOOR WORTHINESS AND CORROSION PROOF NESS.
- RMU ENCLOSURE MUST BE SHIELDED AGAINST SOLAR IRRADIATION AND TESTED FOR A
AMBIENT OF 45 DEGREE C WITHOUT DERATING OF THE EQUIPMENT.
The cubicle should be have a pressure relief device. In the rare case of an internal arc, the high pressure caused by the
arc will release it, and the hot gases is allowed to be exhausted out at the bottom / top / rear of the cubicle. A
controlled direction of flow of the hot gas should be achieved.
The switchgear should have the minimum degree of protection (in accordance with IEC 60529)
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- IP 67 for the tank with high voltage components
- IP 2X for the front covers of the mechanism
- IP 3X for the cable connection covers
- IP 54 for the outdoor enclosure.
1.4 STANDARDS:
Unless otherwise specified elsewhere in this Specification, the RMU, Switchboard (Switchgear), Load break isolators,
Instrument Transformers and other associated accessories shall conform to the latest revisions and amendments
thereof to the following standards.
1. IEC 60 298/IEC 62 271-200/IS 12729:1988 - General requirement for Metal Enclosed Switchgear
2. IEC60129/IEC62271-102/IS 9921 - Alternating current disconnector’s (Load break isolators) and earthing switch
3. IEC 62 271-100 & 200/IEC 60 056/IS 13118:1991 - Specification for alternating current circuit breaker
4. IEC 62 271-1/IEC 60694 - Panel design, SF6/Vacuum Circuit Breakers
5. IEC 60044-1/IEC 60185/IS 2705:1992 - Current Transformer
6. IEC 60265/IS 9920:1981- High voltage switches.
7. IEC 376 - Filling of SF6 gas in RMU.
8. IEC 60273/IS: 2099 - Dimension of Indoor & Outdoor post insulators i. with voltage > 1000 Volts.
9. IEC 60529/IS 13947(Part-1) - Degree of protection provided by
i. enclosures for low voltage switchgear and
ii. Control gear.
10. Indian Electricity Rules/IS Code
Equipment meeting with the requirements of any other authoritative standards, which ensures equal or better quality
than the standard mentioned above shall also be acceptable. If the equipments, offered by the Bidder conform to
other standards, salient points of difference between the standards adopted and the specific standards shall be clearly
brought out in relevant schedule. In case of any difference between provisions of these standards and provisions of
this specification, the provisions contained in this specification shall prevail. One copy of such standards with authentic
English Translations shall be furnished along with the offer.(Hard copy)
Applicable Standards
� The RMUs shall be manufactured to the highest quality consistent with best practice and workmanship
and in full accord with the Supplier’s quality assurance plan. The RMUs shall conform to the Indian or IEC
international standards that are applicable. These include the standards listed in Table 1Error! No text of
specified style in document.-1 below.
Table 1Error! No text of specified style in document.-2: Applicable Standards
Standard Description
IS 3427 AC metal enclosed switchgear and control gear for rated voltages above 1 kV and up
to and including 52 kV
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IS 12063 Classification of degrees of protection provided by enclosures of electrical
equipment
IS 9920
(Parts 1 to 4) High Voltage Switches
IS 9921
(Parts 1 to 5) Specification for AC disconnectors and earthing switches for voltages above 1000 V
IS 13118 HV AC Circuit Breakers
IS 10601 Dimensions of terminals of HV Switchgear and Control gear
IS 12729 General requirements of switchgear and control gear for voltages exceeding 1000 V
IEC 1330 High voltage/Low voltage prefabricated substations
IEC 60694 Common clauses for MV switchgear standards
IEC 6081 Monitoring and control
IS 2705 Current Transformers
IS 3156 Voltage transformers
IS 8686 Specification for Static Protective Relays
IEC 62271-
200 Standards for high voltage metal clad switchgear up to 52 KV.
INDIAN
ELECTRCIATY
REGULATION
2011
This is to be as per Central Electricity Authority (Safety Requirement for
Construction, Operation & Maintenance of Electrical Plants and Electric Lines)
Regulations, 2011
1.5 THE STANDARDS MENTIONED ABOVE ARE AVAILABLE FROM:
IEC - (INTERNATIONAL ELECTRO-TECHNICAL COMMISSION, BUREAU CENTRAL DE LA COMMISSION, ELECTRO
TECHNIQUE INTERNATIONAL, 1, RUE DE VEREMBE, GENEVA, SWITZERLAND.)
ISO - INTERNATIONAL STANDARD ORGANISATION
1.6 SPECIFIC REQUIREMENTS IN RMU:-
1.6.1 CLIMATE CONDITIONS
The climatic conditions under which the equipment should operate satisfactory are as under:
� Maximum ambient air temperature :40-45 deg. C
� Minimum ambient air temperature :10 deg.C
� Maximum daily average ambient air temperature :40 C
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� Maximum humidity :100%
� Altitude above M.S.L. (maximum) :1000 metres
� Average annual rainfall(mm) :925
� Max. wind pressure(Kg/sq.m) :200
� Seismic level(Horizontal accn.) :0.3 g
� Iso-ceraunic level(Days per Year) :50
� Average thunder storm days per annum :50
Distribution Network Electrical Parameters
The main parameters of the distribution network are as follows:
� Nominal system voltage: 22 kV (rms)
� Highest system voltage: 24 kV (rms)
� Number of phases: 3
� Frequency: 50 Hz
� Variation in frequency: 49.5 Hz to 50.5 Hz
� Type of earthing: Solid
� Power frequency withstand voltage: 50 kV
� Basic impulse withstand voltage : 125 kV
1.7 RMU OUTDOOR METAL CLAD ENCLOSURE.
The RMU enclosure must be a metallic, it shall follows an industrialized process of manufacturing. The RMU and
combination shall be tropicalised and outdoor metal enclosed type. The RMU metal parts shall be of high thickness,
high tensile steel which must be grit/short blasted, thermally sprayed with Zinc alloy, phosphate or should follow the 7
tank pre-treatment process and be subsequently painted with polyurethane based powder paint. The overall paint
layer thickness shall be not less than 80 microns.
The rating of enclosure shall be suitable for operation on three phase, three wire, 11 KV, 50 cycles, A.C. System with
short-time current rating of 16 KA for 3 seconds for 22 KV with RMU Panels.
The enclosure should have two access doors one for the operation and relay monitoring and other for the cable
access. Both the doors should have the locking facility to prevent the access to operating mechanism to avoid
unauthorized operating of RMU and relay.
1 RMU Design Features
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All design features of the proposed RMU, as described in the supplier’s bid and in the bid’s reference materials, shall
be fully supported by the equipment actually delivered. The key design features include those that relate to:
� Maintainability, expandability, and life span
� Ability to operate in severe outdoor environmental conditions.
� Immunity to electrical stress and disturbance.
� Acceptable insulation properties.
� Convenient FRTU interconnection features.
INDOOR RMU
1. MODULAR DESIGN, PANEL TYPE WITH FRONT CABLE ACCESS.
2. RMU MUST BE MADE OF ROBOTICALLY / TIG / MIG /LASER/ MANUALLY WELDED STAINLESS STEEL.
3. Offered RMU must be extensible.
OUT DOOR RMU
6. Stainless steel enclosure for OUT DOOR RMU application. The manufacturers shall conform the normal
current ratings mentioned in GTP at 45 deg. Ambient without derating or as per IEC Standard
7. Enclosure with I.P.54 standard protection.
8. Offered RMU must be extensible.
9. Cable boxes shall be on Front side.
10. RMU ENCLOSURE MUST BE SHIELDED AGAINST SOLAR IRRADIATION AND TESTED FOR AMBIENT OF 45
DEGREE C. The manufacturers shall conform the normal current ratings mentioned in GTP at 45 deg. Ambient
without derating, however, design for higher ambient temperature than 45 degree may be admissible.
1.8 TAKE OFF TERMINAL UNITS FOR AUTOMATION:
The RMU should be provided with necessary take off terminal units for automations, located in the front recesses / LV
cubical of the RMU. The connectivity to the FRTU for SCADA purpose shall be provided.
1.9 ISOLATORS (LOAD BREAK TYPE)
The load break isolators for Incoming and Outgoing supply must be provided. These should be fully insulated by SF6
gas. The load break isolators shall consist of 630 Amp fault making/load breaking spring assisted ring switches, each
with integral fault making earth switches. The switch shall be naturally interlocked to prevent the main and earth
switch being switched “ON‟ at the same time. The selection of the main and earth switch is made by a lever on the
facia, which is allowed to move only if the main or earth switch is in the off position. The load break isolators should
have the facility for remote operation. Each load break switch shall be of the triple pole, simultaneously operated,
automatic type with quick break contacts and with integral earthing arrangement.
The isolating distance between the OFF and the ON position in the isolator should be sufficient to withstand dielectric
test as per IS/IEC, so as to have enough isolating distance for ensuring safety during DC injection for Cable testing.
Load break switch should have the following
� Motor operated 24 KV, 630A Load Break switch and manually operated Earthing Switch with making capacity.
� “Live Cable” LED Indicators thru Capacitor Voltage Dividers mounted on the bushings.
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� Mechanical ON/OFF/EARTH Indication
� Anti-reflex operating handle
� Cable Testing facility without disconnecting the cable terminations, cable joints and terminal protectors on the
bushings.
Cable terminations
� Cable boxes suitable for 1 X 3C x 300 sq mm XLPE Cable with right angle Cable Termination Protectors.
1.10 EARTHING OF ISOLATORS AND BREAKERS (EARTH SWITCH)
Necessary arrangements are provided at Load break isolators Breaker for selecting Earth position. Mechanical
interlocking systems shall prevent the RMU function from being operated from the “ON” to “Earth On” position
without going through the “OFF” position.
1.11 DISTRIBUTION TRANSFORMER/FEEDER BREAKER (VACUUM)
The VCB breaker for the controlling of DT/Feeder Breaker must be provided inside welded stainless steel SF6
gas tank with the outdoor metal clad enclosure. The VCB circuit breaker must be a spring assisted three positions with
integral fault making earth switch. The selection of the main/earth switch lever on the facia, which is allowed to move
only if the main or earth switches is in the off position.
The manual operation of the circuit breaker shall not have an effect on the trip spring. This should only be discharged
under a fault (electrical) trip; the following manual reset operation should recharge the trip spring and reset the circuit
breaker mechanism in the main off position.
The circuit breaker shall be fitted with a mechanical flag, which shall operate in the event of a fault (electrical) trip
occurring. The “tripped” flag should be an unambiguous colour differing from any other flag or mimic.
Both the circuit breaker and ring switches are operated by the same unidirectional handle.
The protection on the circuit breaker shall comprise of the following components:-
- 3 class X protection CT‟s,
- a low burden trip coil and
- a self powered (No external DC or AC source required) IDMT
protection relays (Numeric/Micro processor based) 3 x over current and earth fault element shall be Definite Time
type relay . The protection system should be suitable for protecting transformers of rated power from 250 KVA on
wards. The relay should be housed within a pilot cable box accessible.
Circuit Breaker should have the following:
- Motor operated 200 A - 400 A – 600 A / 630A SF6 insulated Vacuum circuit breaker and Ear thing Switch with
making capacity.
- Mechanical tripped on fault indicator
- Auxiliary contacts 4NO and 4NC
- Anti-reflex operating handle
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- “Live Cable” LED Indicators thru Capacitor Voltage Dividers mounted on the bushings.
- O/C + E/F self powered relay
- Shunt Trip circuit for external trip signal
- Mechanical ON/OFF/EARTH Indication
- Cable boxes suitable for 1 X 3C x 300 sq mm XLPE Cable with right angle Cable Termination / protectors / boots.
4.0 TECHNICAL DATA
4.1 Ring Main Unit, Electrical data
Electrical data and service conditions
Rated voltage KV 24/26 KV
1 Power frequency withstand voltage KV 50
2 Impulse withstand voltage KV 125
3 Rated frequency Hz 50
4 Rated current busbars A 630
5 Rated current (cable switch) A 630
6 Rated current (T-off) A 200-400-600/ 630
Breaking capacities:
7 active load A 630
8 closed loop (cable switch) A 630
9 off load cable charging (cable switch) A 135
10 earth fault (cable switch) A 200
11 earth fault cable charging (cable switch) 115
12 short circuit breaking current (T-off circuit
breaker)
kA 20 / 21
13 Rated making capacity kA 50/52.5
14 Rated short time current 3 sec. kA 16
Ambient temperature:
15 Maximum value °C + 45
16 Maximum value of 24 hour mean °C + 40
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17 Minimum value °C 10
18 Altitude for erection above sea level4 m ...1000
19 Relative humidity Max 95%
4.2 Ring Main Unit Technical data (22KV)
No. General data, enclosure and dimensions
1 Standard to which Switchgear complies IEC
2 Type of Ring Main Unit Metal Enclosed, Panel type, Compact
Module.
3 Number of phases 3
4 Whether RMU is type tested Yes
5 Whether facility is provided with pressure relief Yes
6 Insulating gas SF6
7 Nominal operating gas pressure
1.4 bar @ 20° C. However offer with
Nominal operating gas pressure shall be as
per manufacturer standard and suitable to
satisfy the rated dielectric strength can be
accepted
8 Gas leakage rate / annum 0.075%
9 Expected operating lifetime 30 years
10 Whether facilities are provided for gas monitoring Yes, temperature compensated manometer
can be delivered
11 Material used in tank construction
Stainless steel sheet, minimum 2 mm ( Less
/ More than 2 mm thickness may be
admissible subject to IEC testing)
No. Operations, degree of protection and colours
1 Means of switch operation separate handle
2 Means circuit breaker operation separate handle and push buttons
3 Rated operating sequence of Circuit Breaker O - 3min-CO-3min-CO
4 Total opening time of Circuit Breaker approx. 45ms
5 Closing time of Circuit Breaker approx. 40ms
6 Mechanical operations of switch (co) 1000
7 Mechanical operations of CO earthing switch 1000
8 Mechanical operations of circuit breaker (co) 2000
9 Principle switch / earth switch 3 position combined switch / earth switch
Degree of protection:
10 High Voltage live parts, SF6 / VCB tank IP 67
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11 Front cover mechanism IP 2X
12 Cable covers IP 3X
13 Outdoor Enclosure IP 54
Colours:
14 Front cover
15 Side and cable cover
1.12 BUSHINGS
The units are fitted with the standardized bushings that comply with IEC standards. All the bushings are the same
height from the ground and are protected by a cable cover.
1.13 CABLE BOXES
All the cable boxes shall be air insulated suitable for dry type cable terminations and should have front access. The
cable boxes at each of the two ring switches should be suitable for accepting HV cables of sizes 3c x 300 sq.mm and
circuit breaker cable suitable up to 3c x 300 sq.mm. The cable boxes
for an isolator in its standard design should have sufficient space for connecting two cables per phase of 3c x 150
sq.mm. Necessary Right angle Boot should be supplied to the cable terminations .The type of the Right angle Boot
should be cold applied insulating Boot.
1.14 CABLE TESTING FACILITY
It shall be possible to test the cable after opening the cable boxes. The cable boxes should open only after operation of
the earth switch. Thus ensuring the earthing of the cables prior to performing the cable testing with DC injection.
1.15 VOLTAGE INDICATOR LAMPS AND PHASE COMPARATORS
The RMU shall be equipped with a voltage indication to indicate whether or not there is voltage on the cable. There
should be a facility to check the synchronization of phases with the use of external device. It shall be possible for the
each of the function of the RMU to be equipped with a permanent voltage indication as per IEC 601958 to indicate
whether or not there is voltage on the cables.
1.16 EXTENSIBLE
Each combination of RMU shall have the provision for extension by load break isolators / breakers in future, with
suitable accessories and necessary Bus Bar. The equipment shall be well designed to provide any kind of extension /
trunking chamber for connecting and housing extensible Busbars. Extensible isolators and circuit breakers shall be
individually housed in separate SF6 gas enclosures. Multiple devices inside single gas tank / enclosure will not be
acceptable. In case of extensible circuit breakers, the Breaker should be capable of necessary short circuit operations
as per IEC at 16 KA, and the Breaker should have a rated current carrying
capacity of 200 A-400A-600/630 A.
1.17 WIRING & TERMINALS:
The wiring should be of high standard and should be able to withstand the tropical weather conditions. All the wiring
and terminals (including take off terminals for future automation, DC, Control wiring), Spare terminals shall be
provided by the contractor. The wiring cable must be standard single-core non-sheathed, Core marking (ferrules),
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stripped with non-notching tools and fitted with end sleeves, marked in accordance with the circuit diagram with
printed adhesive marking strips.
The wiring should be of high standard and should be able to withstand the tropical weather conditions. All wiring shall
be provided with single core multi-strand copper conductor wires with P.V.C insulation.
The wiring shall be carried out using multi-strand copper conductor super flexible PVC insulated wires of 650/1100V
Grade for AC Power, DC Control and CT circuits. Suitable colored wires shall be used for phase identification and
interlocking type ferrules shall be provided at both ends of the wires for wire identification. Terminal should be
suitably protected to eliminate sulphating. Connections and terminal should be able to withstand vibrations. The
terminal blocks should be stud type for controls and disconnecting link type terminals for CT leads with suitable spring
washer and lock nuts.
Flexible wires shall be used for wiring of devices on moving parts such as swinging Panels (Switch Gear) or panel doors.
Panel wiring shall be securely supported, neatly arranged readily accessible and connected to equipment terminals,
terminal blocks and wiring gutters. The cables shall be uniformly bunched and tied by means of PVC belts and carried
in a PVC carrying trough.
The position of PVC carrying trough and wires should not give any hindrance for fixing or removing relay casing,
switches etc., Wire termination shall be made with solder less crimping type of tinned copper lugs. Core identification
plastic ferrules marked to correspond with panel wiring diagram shall be fitted with both ends of each wire. Ferrules
shall fit tightly on the wire when disconnected. The wire number shown on the wiring shall be in accordance with the
IS.375.
All wires directly connected to trip circuits of breaker or devices shall be distinguished by addition of a red color
unlettered ferrule.
Inter-connections to adjacent Panels (Switch Gear) shall be brought out to a separate set of Terminal blocks located
near the slots or holes to be provided at the top portion of the panel. Arrangements shall be made for easy
connections to adjacent Panels (Switch Gear) at site and wires for this purpose shall be provided and bunched inside
the panel. The bus wire shall run at the top of the panel.
Terminal block with isolating links should be provided for bus wire. Ateast 10% of total terminals shall be provided as
spare for further connections. Wiring shall be done for all the contacts available in the relay and other equipment and
brought out to the terminal blocks for spare contacts. Color code for wiring is preferable in the following colours.
� Voltage supply : Red, Yellow, Blue for phase and Black for Neutral
� CT circuits : similar to the above
� DC circuits : Grey for both positive and negative
� 250V AC circuits : Black for both phase and neutral
� Earthing : Green
The wiring shall be in accordance to the wiring diagram for proper functioning of the connected equipment. Terminal
blocks shall not be less than 650V grade and shall be piece-molded type with insulation barriers.
The terminal shall hold the wires in the tight position by bolts and nuts with lock washers. The terminal blocks shall be
arranged in vertical formation at an inclined angle with sufficient space between terminal blocks for easy wiring.
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The terminals are to be marked with the terminal number in accordance with the circuit diagram and terminal
diagram. The terminals should not have any function designation and are of the tension spring and plug-in type.
Clear empty Space shall be mandatorily provided in RMU Panel for mounting FRTU Panel. Dimensions details of
required space for FRTU are about 1000 mm H x 600 mm W x 300 mm D. 230V AC Supply for charging of FRTU battery
should be available. The Aux supply will be taken through the PT provided for metering in RMU. We require 230V AC
and not 110V AC. FRTU will require power up to 110 VA depending upon RMU configuration. The PT must have
sufficient burden for meeting the aforesaid requirement also for battery charging.
1.18 EARTHING
The RMU outdoor metal clad, Switch Gear, Load break isolators, Vacuum circuit breakers shall be equipped with an
earth bus securely fixed along the base of the RMU.
The size of the earth bus shall be made of IEC/IS standards with tinned copper flat for RMU and M.S.Flat for
Distribution Transformer, earth spike and neutral earthing. Necessary terminal clamps and connectors shall be
included in the scope of supply.
All metal parts of the switchgear which do not belong to main circuit and which can collect electric charges causing
dangerous effect shall be connected to the earthing conductor made of copper having CS area of minimum 75 mm.
Each end of conductor shall be terminated by M 12/equivalent quality and type of terminal for connection to earth
system installation. Earth conductor location shall not obstruct access to cable terminations.
The following items are to be connected to the main earth conductor by rigid or copper conductors having a minimum
cross section of 75 mm (a) earthing switches (b) Cable sheath or screen (c) capacitors used in voltage control devices,
if any.
The metallic cases of the relays, instruments and other panel mounted Equipment‟s shall be connected to the earth
bus by independent copper wires of size shall be made of IEC/IS standards. The colour code of earthing wire shall be
green. Earthing wires shall be connected on the terminals with suitable clamp connectors and soldering shall not be
permitted.
1.19 ACCESSORIES & SPARES:
The following spares and accessories shall be supplied along with the main equipments at free of costs. This shall not
be included in the price schedule.
1. Charging lever for operating load break isolators & circuit breaker of each RMU.
2. The pressure gauges indications - 1 numbers
Provision shall be made for padlocking the load break switches/ Circuit breaker, and the earthing switches in either
open or closed position with lock & master key.
1.20 TESTING OF EQUIPMENT & ACCESSORIES:
Provision for testing CTs,PTs, Relays, Breakers and Cables shall be made available. Procedure and schedule for
Periodical & Annual testings of equipments, relays, etc. shall be provided by the supplier.
1.20.1 TYPE TEST
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The Tenderers should, along with the tender documents, submit copies of all Type test certificate of their make in full
shape as confirming to relevant ISS/IEC of latest issue obtained from a International/National Govt. Lab/Recognized
laboratory.
The above type test certificates should accompany the drawings for the materials duly signed by the institution who
has type test certificate. The details of type test certificate as per Schedule F.
1.20.2 ACCEPTANCE AND ROUTINE TESTS
All acceptance and routine tests as stipulated in the latest IEC- shall be carried out by the supplier in the presence of
DISCOM’s representative. The supplier shall give at least 7 days advance intimation to the Board to enable them to
depute their representative for witnessing the tests. The partial discharge shall be carried out as routine test on each
and every completely assembled RMU gas tank and not on a sample basis. As this test checks and guarantees for the
high insulation level and thus the complete life of switchgear.
1.20.3 ADDITIONAL TESTS
The Board reserves the right for carrying out any other tests of a reasonable nature at the works of the
supplier/laboratory or at any other recognized laboratory/research institute in addition to the above mentioned type,
acceptance and routine tests at the cost of the Board to satisfy that the material complies with the intent of this
specification.
1.20.4 PRE-COMMISSIONING TESTS
All the pre-commissioning tests will be carried out in the presence of the Board testing engineer and necessary
drawing manual and periodical test tools shall be arranged to be supplied.
During the above tests the contractor representative should be present till the RMUs are put in to service.
1.21 INSPECTION:
The inspection may be carried out by the DISCOM at any stage of manufacture. The supplier shall grant free access to
DISCOM’s representative at a reasonable time when the work is in progress. Inspection and acceptance of any
equipment under this specification by the DISCOM shall not relieve the supplier of his obligation of furnishing
equipment in accordance with the specification and shall not prevent subsequent rejection if the equipment is found
to be defective.
The supplier shall keep the DISCOM informed in advance, about the manufacturing programme so that arrangement
can be made for inspection. The DISCOM reserves the right to insist for witnessing the acceptance/routine testing of
the bought out items. The DISCOM has rights to inspect the supplier’s premises for each and every consignment for
type & routine test.
No material shall be dispatched from its point of manufacture unless the material has been satisfactorily inspected
and tested / unless the same is waived by the DISCOM in writing.
1.21.1 QUALITY ASSURANCE PLAN:
The bidder shall invariably furnish following information along with his offer / in case of event of order.
I. Statement giving list of important raw materials including but not limited to
a) Contact material
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b) Insulation
c) Sealing material
d) Contactor, limit switches, etc. in control cabinet.
Name of sub-suppliers for the raw materials, list of standards according to which the raw materials are tested, list of
test normally carried out on raw materials in presence of Bidder’s representative, copies of test certificates.
II. Information and copies of test certificates as in (I) above in respect of bought out accessories & raw materials.
III. List of areas in manufacturing process, where stage inspections are to be carried out.
IV. Normally carried out for quality control and details of such tests and inspections.
V. Special features provided in the equipment to make it maintenance free.
VI. List of testing equipment available with the Bidder for final testing of RMUs and associated combinations vis-à-vis
the type, special, acceptance and routine tests specified in the relevant standards. These limitations shall be very
clearly brought out in the relevant schedule i.e. schedule of deviations from specified test requirements. The supplier
shall, within 15days from the date of receipt of Purchase Order submit following information to the DISCOM.
a) List of raw materials as well bought out accessories and the names of sub-suppliers selected from those furnished
along with offer.
b) Necessary test certificates of the raw material and bought out accessories.
c) Quality Assurance Plan (QAP) with hold points for DISCOM’s inspection. The quality assurance plan and hold points
shall be discussed between the DISCOM and supplier before the QAP is finalized.
The supplier shall submit the routine test certificates of bought out items and raw material, at the time of routine
testing of the fully assembled breaker.
1.22 TRAINING:
The supplier shall give rigorous training to the engineers & staff for 2 days in attending trouble shooting and
maintenance.
1.23 SCADA CONNECTIVITY:
Provision shall be made in all the RMUs with necessary take off terminal units for automations and connectivity with
FRTU. The all RMUs shall be motorized type and compatible for SCADA operation. All the I/O signals need to be
brought to the Terminal Strip on a Din Rail, also the Din Rail should have space to mount the MFT’s provided by SIA.
All the DI’s should be provided as potential free contacts. The CT/PT should provide metering grade core for
connecting MFT provided with FRTU. Refer Annexure-1.
The RMU should be provided with provision of following minimum signals available at separate SCADA terminal box.
Minimum signals for SCADA/DMS - to be wired
to Separate TBs
CB close / open potential free contacts
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LBS close / open potential free contacts
LBS & CB Earth Switch close /open potential free contacts
CB Test/Service Position potential free contacts
Spring charge Status indication potential free contacts
SF6 gas pressure low potential free contacts
O/C Operated potential free contacts
E/F Operated potential free contacts
Local/Remote potential free contacts
Common Power Supply Healthy potential free contacts
Motor MCB Healthy Status potential free contacts
Battery charger Fail potential free contacts
RMU Door Open potential free contacts
CB Trip Coil Healthy potential free contacts
CT & PT For SCADA Metering
FPI Control FPI remote resetting for SCADA
CB control Control from SCADA
LBS Control Control from SCADA
1.24 DOCUMENTATION and DRAWINGS
All drawings shall conform to relevant International Standards Organization (ISO) Specification. All drawings shall be in
ink and suitable for microfilming.
The tenderer shall submit along with his tender dimensional general arrangement drawings of the equipments,
illustrative and descriptive literature in triplicate for various items in the RMUs which are all essentially required for
future automation.
I. Schematic diagram of the RMU panel
II. Instruction manuals
III. Catalogues of spares recommended with drawing to indicate each items of spares
IV. List of spares and special tools recommended by the supplier.
V. Copies of Type Test Certificates as per latest IS/IEC.
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VI. Drawings of equipments, relays, control wiring circuit, etc.
VII. Foundation drawings of RMU and D.T.Structure.
VIII. Dimensional drawings of each material used for item VII.
IX. Actual single line diagram of RMU/RMUs with or without Extra combinations shall be made displayed on the
front portion of the RMU so as to carry out the operations easily.
The following should be supplied to each consignee circle/town along with the initial supply of the equipments
ordered.
a. Copies of printed and bound volumes of operation, maintenance and erection manuals in English along with
the copies of approved drawings and type test reports etc.
b. Sets of the manuals as above shall be supplied to the Chief Engineer/Distribution. A soft copy of the all
Technical and Drawing furnished in a CD
1.25 NAME PLATE:
Each RMU and its associated equipments shall be provided with a nameplate legible and indelibly marked with at least
the following information.
a. Name of manufacturer
b. Type, design and serial number
c. Rated voltage and current
d. Rated frequency
e. Rated symmetrical breaking capacity
f. Rated making capacity
g. Rated short time current and its duration
h. Purchase Order number and date
i. Month and Year of supply
j. Rated lighting impulse withstand voltage
k. Feeder name (Incoming and Outgoing), DTs Structure name, 11000 Volts Dangers etc.
NOTE:
III) THE WORD RATED NEED NOT APPEAR ON THE NAME PLATE. RECOGNIZED ABBREVIATIONS MAY BE USED TO
EXPRESS THE ABOVE PARTICULARS.
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IV) WHETHER THE CIRCUIT BREAKER IS FITTED WITH CLOSING/TRIPPING DEVICES NECESSITATING AN AUXILIARY
SUPPLY SHALL BE STATED EITHER ON THE CIRCUIT BREAKER NAME PLATE OR ANY OTHER ACCEPTABLE
POSITION.
1.26 FAULT PASSAGE INDICATORS (FPI):
These shall facilitate quick detection of faulty section of line. The fault
indication may be on the basis of monitoring fault current flow through the device.
The unit should be self-contained requiring no auxiliary power supply. The FPI shall
be integral part of RMU. The FPI shall have LCD/LED display, automatic reset
facility. FPI Reset from SCADA will be through momentary closure of a potential free contact from FRTU.
The sensors to be bushing mounted. The number of FPI should be put in all the three phases of the outgoing branch of
the RMUs
FPI should have suitable connectivity with the FRTUs for the SCADA purpose.
The FPI inside the RMU may be non communicable and hard wired to the TB for the signals. Refer Annexure-1
Fault Passage indicator OK
Fault Passage indicator operated
1.27 TROPICALISATION
Due regard should be given to the climatic conditions under which the equipment is to work. Ambient temperatures
normally vary between 20 deg C and 40 deg C, although direct sun temperature may reach 45 deg C. The climate is
humid and rapid variations occur, relative humidity between 60% and 95% being frequently recorded, but these values
generally correspond to the lower ambient temperatures. The equipment should also be designed to prevent ingress
of vermin, accidental contact with live parts and to minimize the ingress of dust and dirt. The use of materials which
may be liable to attack by termites and other insects should be avoided.
1.28 Motorization :
All the functions within the RMU i.e Isolators/Breakers should be fitted with motor mechanism and closing coil making
it suitable to make it on from remote.( However, manual mechanism should be possible in case of failure/ non working
of motor)
Other Accessories (required with RMU) :-
a) Shunt Trip Coil ( Coil voltage shall be indicated later on)
b) Battery & Battery Charger.
c) 4NO+4NC auxiliary contacts.
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1.29 Metering:
Multifunction Energy meter shall be provided by DISCOMS with, of accuracy class of 0.5 at incoming isolator of all
RMUs. The Metering CTs and PTs of suitable rating shall be
provided and wired in SCADA terminal TBs.. Refer Annexure-1.
1.30 TECHNICAL SPECIFICATION FOR RMU
1.30.1 11KV Bus Bar
I. Current Carrying Capacity : 630 Amps.
II. Short time rating current for 3 secs. : 16 KA for 22 kv
III. Insulation of bus bar : SF6
IV. Bus bar connections : Anti-oxide grease
1.31 PARAMETERS FOR SWITCH GEAR OF DT AND LOAD BREAK ISOLATORS
I. Type : Metal enclosed
II. No of Phases : 3
III. No. of poles : 3
IV. Rated voltage :24KV
V. Operating voltage :22 KV(+10% to -20%)
VI. Rated lightning impulse withstand voltage :125 KV
VII. Rated power frequency withstand voltage :50 KV
VIII. Insulating gas :SF6
IX. Rated filling level for insulation :As Per IEC.
Max.permissible site altitude at the above gas pressures : 1000m
(The operating pressure has to be adjusted for greater altitudes)
Isolating distance between ON and OFF position in isolator :80 mm (min).
Rated short time current :16 KA.for 22 kv
Rated short time :3s
Rated peak withstand current :50/52.5 KA.
No of operations in Short circuit :15 Nos (minimum)
Operating mechanism: Circuit breaker with spring assisted anti reflex mechanism.
Rated current (Bus): :630 A
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Rated current (breaker) :200-400-600/630 A
Circuit Breaker interrupter :SF6 insulated VCB
Rated frequency : 50 Hz
Rated operating sequence :O-3min- CO
Number of mechanical/Remote operations for earthing : As per IEC
& Ring switches & Number of mechanical/ Remote operations for circuit breakers 60298
1.32 PRINCIPAL FEATURES
Sr.
No
DESCRIPTION Breaker
1 Circuit label Yes
2 Mimic diagram Yes
3 Supply voltage indication Yes
4 Current Transformer Yes
5 Self Powered based Microprocessor based IDMT
Relay (3OL)/EL
Yes
6 Anti - Reflexing Relay Yes
7 Interlock to defeat the operation of the line side
earthing when the line side isolator is ON.
Yes
8 Interlock to defeat the operation of the earthing
when the breaker is in service position and is ON.
Yes
9 Breaker ON/OFF indication Yes
10 Spring Charge indication / Spring assisted
mechanism.
Yes
11 Fault Tripping indication Yes
12 Bus bar end caps Yes
13 Whether the SF6 gas pressure gauge indicator and
filling arrangement.
Yes
14 Whether the spring assisted mechanism with
operating handle for ON/OFF.
Yes
15 Whether the earth positions with arrangement for
padlocking in each position and independent
manual operation with mechanically operated
indicator are provided
Yes
16 RMUs are provided with necessary take off
terminals for future automation.
Yes
1.33 Earthing switch for 22 KV Line side Isolation and DT
Rated short time current : 16 KA.for 22 kv.
Rated short time :3s
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Rated peak withstand current :50/52.5 KA
Interlocking facility:
1) Between 22 KV Line side isolator “ON”&Earthing.
2) Between 22 KV DT side breaker on close condition & earthing
1.34 Current Transformers for breaker
CT Type : Tape wound
CT Description : The CTs of breaker shall be Suitable for sensing the minimum
primary variable current in the order of 10-200 A and the secondary current for the CT is 1 A. The CT
shall be housed in outside SF6 chamber for testing and Maintenance
Accuracy Class :class X/5P10 protection
Rated burden : Suitable for self powered relay and metering.
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PART A&B: TECHNICAL SPECIFICATION FOR FIXING OF END TERMINATION AND
STRAIGHT THROUGH JOINTS FOR OUTDOOR 11/22 KV RING MAIN UNIT
SWITCHGEAR
Fixing of end termination & straight through joints.
1.
(i) Contractor should clarify the make of cable end termination. The heat & shrink type end termination shall be utilized for the job.
(ii) After completing work of cable laying end termination, following test shall be carried out jointly by engineer in charge of DISCOM and contractor.
(iii) Insulation resistance test before & after with 5 KV insulation tester. (A) Hypo test (iv) Contractor has to furnish Guaranteed Technical Parameters (GTP) type test
certificate of various tests conducted at any Govt./ NABL approved laboratory for the End Termination Kit they intend to supply for this job. The test certificate should not be prior to 5 years from the date of tender. The contractor shall have to submit the same with technical bid and failure in which technical bid will be disqualified & the price bid of that party will not be opened.
(v) One competent skilled supervisor shall have to co-ordinate the site authority and he has to do all communication with engineer in charge of DISCOM.
(vi) It is essential to have suppliers certificate of training for cable jointing of cable jointer. (vii) Jointer has to ensure safety while making joints so that other nearby cables will not
damaged. (viii) The material of End termination kit will be inspected at manufacturer’s works by the
inspector of DISCOM. The bidder has to give inspection call 15 days in advance to S.E. (O&M) for the works to be carried out in their jurisdiction.
2 The Bidder shall have to supply cable end Terminal kit as per IS 13573-1992 with latest amendment No. 2, 1998 IEEE 48-1990 and shall be Class -1, ESI-09-13 performance specification for high voltage cable accessories.
3 The work of laying of cable along the road / road crossing to be carried out by Horizontal Drilling Machine / Auger boring machine enclosed in HDPE Pipe only.
CLASS OF TERMINATION:
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The XLPE 11/22 KV Link Line shall be class 1 termination as per appropriate ISI code nos.
i.e. IEEE-48-1990.
APPLICABLE STANDARDS:
IS 13573-1992 with latest amendment – Latest amendment No. 2, 1998. IEEE 48-1990. The
termination shall be Class 1. ESI-09-13 performance specification for high voltage cable
accessories. The cable accessories being supplied in the form of kit which has different
components to be assembled at site.
MATERIALS:
The term 11 KV / 22 kV XLPE Cable refers to extruded or Molded Polymeric. Polymeric
material which are cross linked by gamma radiation to develop elastic memory and supplied
in an expanded or otherwise deformed size and shape. Bidders should submit the proof
that the tubes are cross linked by gamma radiations. However chemically cross linked,
crotch seal and lug seals are permitted.
For end termination kit, the insulation over the ferrules should be reinsulated by dual wall
tubing. This should have an inner insulating layer vulcanized to an outer semi-conducting
layer. This is required to ensure reconnection of cable insulation screen of the core from one
end of the joint to the other. The dual wall tubing ensures that there is no entrapment of air
pockets between the insulating and semi-conducting layers.
FOR JOINTS:
11 kV / 22 kV XLPE underground flexible polymeric tubing, preferably black colored pre coated with adhesive
shall be provided for sealing the exposed metallic sheaths and sheath/earth connections.
PROVISION OF ADDITIONAL CREEPAGE INDOOR / OUTDOOR TERMINATIONS:
Single piece, 11/22 KV XLPE underground cable, weather sheds having non-tracking, erosion and
weather resistant properties shall be supplied with the kits for application over non-tracking tubing.
The quantity of sheds to be supplied shall depend on voltage grade and indoor/outdoor application
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and shall be indicated along with offer. Each shed shall give an additional creepage length of at least
100mm.
INSULATION AND SCREEN REINSTATEMENT FOR END TERMINAL KITS: The reinstatement of insulation shall be by means of heat shrinkable, flexible, polymeric tubing
made from a discharge resistant polymer, preferably colored red. The tubing after complete
recovery shall have a minimum wall thickness to ensure provisions of adequate insulation in step.
EARTH & SCREEN CONTINUITY FOR TERMINATION: Screen continuity by using tinned copper mesh and earth continuity by using tinned copper
braids of appropriate size shall be provided for transfer of screen/earth.
In termination, tinned copper braids of appropriate size or equivalent current carrying
capacity of cable conductor along with copper lugs of appropriate size shall be provided for
continuity of screen to armour to the earth.
LUGS & FERRULES: The requisite number and type of aluminum/ copper lugs/ferrules shall be provided for termination/joints. The Lugs
and ferrules for XLPE cables shall be crimping type suitable for compacted circular conductor having two nos. of holes.
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Guaranteed Technical Particulars Annexure a
for Heat Shrink Outdoor end termination on 11 KV (E) XLPE Cable
Sr.No Particulars Unit Guaranteed Values
1.0 APPLICABLESTANDARDS As per IS:13573
2.0 GUARANTEED PARTICULARS For the nominal (phase to phase) System Voltages Maximum system voltage
KV 11KV - 12KV
2.1 A.C. withstand voltage (ph / ground) Time duration
KV Mins 35KV1Min.
2.2 Partial Discharge at 2 Uo pC <5 pC
2.3 Impulse Withstand, 1.2 / 50 / Us kV 75KV
2.4
Load Cycle Test a) Each Cycle Heating Duration Temperature Cooling duration b)Number of Cycles c) Continuous phase to ground Voltage Withstand
Hrs ºC Hrs KV
5 100 3 63 2.5Uo
2.5 ThermalWithstandShortcircuitcurrent1Sec. Ka As per IS:13573
2.6 Dynamic short circuit withstand Ka Peak 2.55 xls as per IS:13573
2.7 DC Voltage KV 48 KV for 30 Mins.
3.0 KITPARTICULARS
3.1 Material of the tubing/ moulded party Polyolefin
3.2 Method of stress control High permittivity Material.
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3.3 Method of environmental seal H. S. Black Insulating Tubes
3.4
List of items included in the Kit a) For Terminations b) Allowable Kit storage Temperature. c) Kit self life
ºC Years Yes. Normal Ambient Temperature. More than 5 years.
4.0 Cable Termination Instruction Manuals Yes/ No Yes
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Guaranteed Technical Particulars Annexure b Heat Shrink Straight through joint on 11 KV (E) XLPEC able
Sr.No. Particulars Unit Guaranteed Values
1.0 APPLICABLESTANDARDS
AsperIS:13573
GUARANTEEDPARTICULARS
For the nominal (phase to phase)
2.0 System Voltage KV 11KV
Maximum system voltage KV 12KV
A.C. withstand voltage Dry (ph/ground) KV 35KV 2.1
Time duration Mins 1 Min.
2.2 Partial Discharge at 2 Uo pC <5pC
2.3 Impulse Withstand, 1.2/50/Us kV 75KV
Load Cycle Test
a) Each Cycle Heating Duration Hrs 5
Temperature ºC 100
2.4 Cooling Hrs. 3
b) Number of Cycles
63
c) Continuous phase to ground voltage Withstand kV 2.5 Uo
Water tightness test KV
60 Nos. at 2.5Uo as per above cycles.
2.5 ThermalWithstandShortcircuitcurrent1Sec.
ka As per IS;13573
2.6 Dynamic short circuit withstand ka Peak
2.55 xls As per IS:135373
2.7 DC Voltage kV 48 kV for 30 Mins.
3.0 KITPARTICULARS
3.1 Material of the tubing/ moulded party Polyolefin
3.2 Method of stress control
High permittivity Material.
3.3 Method of environmental seal
H.S. Black Insulating Tubes.
List of items included in the Kit Yes/No
a) For joints Yes
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3.4 b) Allowable Kit storage Temperature ºC Normal Ambient Temperature
c) Kit shelf life Years More than 5 years
4.0 Cable Termination Instruction Manuals
Yes/No Yes
Guaranteed Technical Particulars Annexure c
Heat Shrink Indoor termination on 22 kV (E) XLPE Cable
Sr.No. Particulars Unit Guaranteed Values
1.0 APPLICABLESTANDARDS As per IS:13573
GUARANTEEDPARTICULARS
For the nominal (phase to phase) 2.0
System Voltage KV 22 KV
Maximum system voltage KV 24 KV
2.1 A.C. withstand voltage Dry (ph/ground)
KV 35 KV
Time duration Mins 1 Min.
2.2 Partial Discharge at 2 Uo pC <5pC
2.3 Impulse Withstand, 1.2 / 50 / Us kV 125KV
Load Cycle Test
a)Each Cycle Heating Duration Hrs 5
Temperature ºC
100
2.4 Cooling duration Hrs. 3
b) Number of Cycles 126
c) Continuous phase to ground voltage Withstand kV 2.5 Uo
2.5 Thermal Withstand Short circuit current 1 Sec. ka AsperIS:13573
2.6 Dynamic short circuit withstand ka Peak
2.55xlsAsperIS:135373
2.7 DC Voltage kV 96kVfor30Mins.
3.0 KITPARTICULARS
3.1 Material of the tubing/ moulded party
Polyolefin
3.2 Method of stress control High permittivity Material.
3.3 Method of environmental seal H.S. Anti tracking Tubes.
List of items included in the Kit
a) For Terminations Yes
3.4 b) Allowable Kit storage Temperature ºC Normal Ambient Temperature
c) Kit shelf life Years Morethan5years
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4.0 Cable Termination Instruction Manuals
Yes/No Yes
Guaranteed Technical Particulars Annexure-d Heat Shrink straight through joint on 22 kV (E) XLPE Cable
Sr. No. Particulars Unit Guaranteed Values
1.0 APPLICABLESTANDARDS As per IS:13573
GUARANTEEDPARTICULARS
For the nominal (phase to phase) 2.0
System Voltage KV 22KV
Maximum system voltage KV 24KV
2.1 A.C. withstand voltage Dry (ph/ground)
KV 55KV
Time duration Mins 1 Min.
2.2 PartialDischargeat2Uo pC <5pC
2.3 ImpulseWithstand,1.2/50/Us kV 125KV
Load Cycle Test
a) Each Cycle Heating Duration Hrs 5
Temperature
ºC 100
Cooling duration Hrs. 3 2.4
b) Number of Cycles 63
c) Continuous phase to ground voltage Withstand
kV 2.5 Uo
Water tightness test KV
60 Nos. at 2.5 Uo as per above cycles.
2.5 Thermal Withstand Short circuit current 1 Sec. ka AsperIS:13573
2.6 Dynamic short circuit withstand ka Peak
2.55xlsAsperIS:135373
2.7 DC Voltage kV 96kVfor30Mins.
3.0 KITPARTICULARS
3.1 Material of the tubing/ moulded party
Polyolefin
3.2 Method of stress control High permittivity Material.
3.3 Method of environmental seal H.S. Anti tracking Tubes.
List of items included in the Kit
a) For Joints Yes
3.4 b) Allowable Kit storage Temperature ºC Normal Ambient Temperature
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c) Kit shelf life Years Morethan5years
4.0 Cable Termination Instruction Manuals
Yes/No Yes
Guaranteed Technical Particulars Annexure -e
Heat Shrink outdoor termination on 22 kV (E) XLPE Cable
Sr.No. Particulars Unit Guaranteed Values
1.0 APPLICABLESTANDARDS As per IS:13573
GUARANTEEDPARTICULARS
For the nominal (phase to phase) 2.0
System Voltage KV 22KV
Maximum system voltage KV 24KV
2.1
A.C. withstand voltage Dry (ph/ground) KV 55KV
Time duration Mins 1 Min.
2.2 Partial Discharge at 2 Uo pC <5pC
2.3 ImpulseWithstand,1.2/50/Us kV 125KV
Load Cycle Test
a) Each Cycle Heating Duration Hrs 5
Temperature
ºC 100
2.4 Cooling duration Hrs. 3
b) Number of Cycles 117
c) Continuous phase to ground voltage Withstand
kV 2.5 Uo
Leak Tightness 9 Cycles
2.5 Thermal Withstand Short circuit current 1 Sec. ka AsperIS:13573
2.6 Dynamic short circuit withstand ka Peak
2.55xlsAsperIS:135373
2.7 DC Voltage kV 96kVfor30Mins.
3.0 KITPARTICULARS
3.1 Material of the tubing/ moulded party Polyolefin
3.2 Method of stress control High permittivity Material.
3.3 Method of environmental seal H.S. Anti tracking Tubes.
List of items included in the Kit
a) For Terminations Yes
3.4 b) Allowable Kit storage Temperature ºC Normal Ambient Temperature
c) Kit shelf life Years Morethan5years
4.0 Cable Termination Instruction Manuals
Yes/No Yes
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PART A&B :Technical specifications of cable work
1.1 SCOPE
This chapter covers the requirements for the selection, installation and jointing of
power cables for low, medium and high voltage applications upto and including 22 KV.
For details not covered in these Specifications, IS:1255-1983 shall be referred to. All
references to BIS-Specifications and codes are for codes with amendments issued upto
date i.e. till the date of call of tender.
1.2 TYPES OF CABLES
1.2.1 The cables for applications for low and medium voltage (upto and including
1.1KV) supply shall be one of the following: -
(i) PVC insulated and PVC sheathed, conforming to IS:1554 (Part-1)- 1988
(ii) Cross linked polyethylene insulated, PVC sheathed (XLPE), conforming
to IS: 7098 (Part-1)- 1988.
1.2.2 The cables for applications for high voltage (above 1.1KV but upto and including
22 KV supply) supply shall be one of the following: -
(i) PVC insulated and PVC sheathed, conforming to IS:1554 (Part-2)- 1988.
(ii) Paper insulated, lead sheathed (PILCA) conforming to IS:692-1973
(iii) Cross linked polyethylene (XLPE) insulated, PVC sheathed conforming to
IS:7098 (Part-2)- 1985.
1.2.3 The cables for applications above 11KV but upto and including 22KV supply
shall be one of the following: -
(i) Paper insulated lead sheathed (PILCA) conforming to IS: 692-1973.
(ii) Cross linked, polyethylene insulated (XLPE) conforming to IS:7098
(Part-2)-1985.
1.2.4 The cables shall be with solid or stranded aluminium conductors, as specified.
Copper conductors may be used, only in special applications, where use of aluminium
conductors is not technically acceptable.
1.2.5 Where paper insulated cables are used in predominantly vertical situation, these
shall be of non-draining type.
1.3 ARMOURING AND SERVING
1.3.1 All multicore cables liable for mechanical damage and all HV cabkes
(irrespective of the situation of installation) shall be armoured. Where armouring is
unavoidable in dingle core cables, either the armour should be made of nonmagnetic
material, or it should be ensured that the armouring is not shorted at terminations, thus
preventing the flow of circulating currents therein.
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1.3.2 Short runs of cables laid in pipes, closed masonary trenches and similar protected
or secured enclosures need not be armoured.
1.3.3 PVC and XLPE cables, when armoured, shall have galvanized steel wires (flat or
round) for armouring.
1.3.4 Paper insulated cables shall have for armouring, a double layer of steel tape for
normal applications. Steel wire armouring is preferred where the cables are liable to
tensile stresses in applications such as vertical runs, suspended on brackets or laid in soil
that is likely to subside.
1.3.5 Serving over armouring in paper insulated cables shall consist of a complete layer
or layers of suitable compounded Hessian materials.
1.4 SELECTION OF CABLE SIZES
1.4.1 The cable sizes shall be selected by considering the voltage drop in the case of
MV (distribution) cables and Current carrying capacity in the case of HV (feeder) cables.
Due consideration should be given for the Prospective short circuit current and the period
of its flow, especially in the case of HV cables.
1.4.2 While deciding upon the cable sizes, derating factors for the type of cable and
depth of laying, grouping, ambient temperature, ground temperature, and soil resistivity
shall be taken into account.
1.4.3 Guidance for the selection of cables shall be served from relevant Indian
Standards such as IS:3961 (Part-1)-1967 for paper insulated lead sheathed cables, IS:
3961 (Part-2)-1967 for PVC insulated and PVC sheathed heavy duty cables, IS: 5819-
1970 for recommended short circuit ratings of high voltage PVC cables, IS: 1255-1983
on code of practice for installation and maintenance of power cables upto and including
22 KV rating etc.
1.5 STORAGE AND HANDLING
1.5.1 Storage
(i) The cable drums shall be stored on a well drained, hard surface, so that the
drums do not sink in the ground causing rot and damage to the cable drums. Paved
surface is preferred, particularly for long term storage.
(ii) The drums shall always be stored on their flanges, and not on their flat
sides.
(iii) Both ends of the cables especially of PILCA cables should be properly
sealed to prevent ingress/ absorption of moisture by the insulation during storage.
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(iv) Protection from rain and sun is preferable for long term storage for all
types of cables. There should also ventilation between cable drums.
(v) During storage, periodical rolling of drums once in, say, 3 months through
90 degrees shall be done, in the case of paper insulated cables. Rolling shall be done in
the direction of the arrow marked on the drum.
(vi) Damaged battens of drums etc. should be replaced as may be necessary.
1.5.2 Handling
(i) When the cable drums have to be moved over short distances, they should
be rolled in the direction of the arrow marked on the drum.
(ii) For manual transportation over long distances, the drum should be
mounted on cable drum wheels, strong enough to carry the weight of the drum and pulled
by means of ropes. Alternatively, they may be mounted on a trailer or on a suitable
mechanical transport.
(iii) For loading into and unloading from vehicles, a crane or a suitable lifting
tackle should be used. Small sized cable drums can also be rolled down carefully on a
suitable ramp or rails, for unloading, provided no damage is likely to be caused to the
cable or to the drum.
1.6 INSTALLATION
1.6.1 General
(i) Cables with kinks, straightened kinks or any other apparent defects like
defective armouring etc. shall not be installed.
(ii) Cables shall not be bent sharp to a small radius either while handing or in
installation. The minimum safe bending radius for PVC/XLPE (MV) cables shall be 12
times the overall diameter of the cable. The minimum safe bending radius for
PILCA/XLPE (HV) cables shall be as given in Table-II. At joints and terminations, the
bending radius of individual cores of a multi core cable of any type shall not be less than
15 times its overall diameter.
(iii) The ends of lead sheathed cables shall be sealed with solder immediately
after cutting the cables. In case of PVC cables, suitable sealing compound/tape shall be
used for this purpose, if likely exposed to rain in transit storage. Suitable heat shrinkable
caps may also be used for the purpose.
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1.6.2 Route
Before the cable laying work is undertaken, the route of the cable shall be decided
by the Engineer-in-Charge considering the following.
(i) While the shortest practicable route should be preferred, the cable route
shall generally follow fixed developments such as roads, foot paths etc. with proper
offsets so that future maintenance, identification etc. are rendered easy. Cross country run
merely to shorten the route length shall not te adopted.
(ii) Cable route shall be planned away from drains and near the property,
especially in the case of LV/MV cables, subject to any special local requirements that
may have to be necessarily complied with.
(iii) As far as possible, the alignment of the cable route shall be decided after
taking into consideration the present and likely future requirements of other services
including cables enroute, possibility of widening of roads/lanes etc.
(iv) Corrosive soils, ground surrounding sewage effluent etc. shall be avoided
for the routes.
(v) Route of cables of different voltages.
(a) Whenever cables are laid along well demarcated or established roads, the
LV/MV cables shall be laid farther from the kerb line than HV cables.
(b) Cables of different voltages, and also power and control cables shall be
kept in different trenches with adequate separation. Where available space is restricted
such that this requirement cannot be met, LV/MV cables shall be laid above HV cables.
(c) Where cables cross one another, the cable of higher voltage shall be laid at
a lower level than the cable of lower voltage.
1.6.3 Proximity to communication cables
Power and communication cables shall as far as possible cross each other at right
angles. The horizontal and vertical clearances between them shall not be less than 60cm.
1.6.4 Railway crossing Cables under railway tracks shall be laid in spun reinforced concrete, or cast iron
or steel pipes at such depths as may be specified by the railway authorities, but not less
than 1m, measured from the bottom of the sleepers to the top of the pipe. Inside railway
station limits, pipes shall be laid upto the point of the railway station limits, pipes shall be
laid upto a minimum distance of 3m from the center of the nearest track on either side.
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1.6.5 Way Leave
Way leave for the cable route shall be obtained as necessary, from the appropriate
authorities, such as, Municipal authorities, Department of telecommunication, Gas
Works, Railways, Civil Aviation authorities, Owners of properties etc. In case of private
property, Section 12/51 of the Indian Electricity Act shall be complied with.
1.6.6 Methods of laying
The cables shall be laid direct in ground, pipe, closed or open ducts, cable trays or
on surface of wall etc. The method(s) of laying required shall be specified in the tender
schedule of work.
1.6.7 Laying direct in ground
1.6.7.1 General
This method shall be adopted where the cable route is through open ground, along
roads/lanes, etc. and where no frequent excavations are likely to be encountered and
where re-excavation is easily possible without affecting other services.
1.6.7.2 Trenching
(i) Width of trench
The width of the trench shall first be determined on the following basis
(Refer figure 1)
(a) The minimum width of the trench for laying a single cable shall be 35cm
(b) Where more than one cable is to be laid in the same trench in horizontal
formation, the width of the trench shall be increased such that the inter-axial spacing
between the cables, except where otherwise specified, shall be at least 20cm.
© There shall be a clearance of at least 15cm between axis of the end cables
and the sides of the trench.
(ii) Depth of trench
The depth of the trench shall be determined on the following basis (Refer figure 1): -
(a) Where the cables are laid in a single tier formation, the total depth of
trench shall not be less than 75cm for cables upto 1.1KV and 1.2m for cables above
1.1KV.
(b) When more than one tier of cables is unavoidable and vertical formation
of laying is adopted, the depth of the trench in (ii) a above shall be increased by 30cm for
each additional tier to be formed.
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© Where no sand cushioning and protective covering are provided for the
cables as per 2.6.7.3(i)(b), 2.6.7.3(vii)(c) and 2.6.7.3(ix)(d) below, the depth of the trench
as per (ii)(a) and (b) above shall be increased by 25cm.
(iii) Excavation of trenches
(a) The trenches shall be excavated in reasonably straight lines. Wherever
there is a change in the direction, a suitable curvature shall be adopted complying with
the requirements of clause 2.6.1(ii).
(b) Where gradients and changes in depth are unavoidable, these shall be
gradual.
© The bottom of the trench shall be level and free from stones, brick bats etc.
(d) The excavation should be done by suitable means-manual or mechanical.
The excavated soil shall be stacked firmly by the side of the trench such that it may not
fall back into the trench.
(e) Adequate precautions should be taken not to damage any existing cable(s),
pipes or any other such installations in the route during excavation. Wherever trickd, tiles
or protective covers or bare cables are encountered, further excavation shall not be
carried out without the approval of the Engineer-in-Charge.
(f) Existing property, if any, exposed during trenching shall be temporarily
supported adequately as directed by the Engineer-in-Charge. The trenching in such cases
shall be done in short lengths, necessary pipes laid for passing cables therein and the
trench refilled in accordance with clause 2.6.7.4.
(g) It there is any danger of a trench collapsing or endangering adjacent
structures, the sides may be left in place when back filing the trench.
(h)Excavation through lawns shall be done in consultation with the Department
concerned.
1.6.7.3
Laying of cable in trench
(i) Sand cushioning
(a) The trench shall then be provided with a layer of clean, dry sand cushion
of not less than 8cm in depth, before laying the cables therein.
(b) However, sand cushioning as per (a) above need not be provided for MV
cables, where there is no possibility of any mechanical damage to the cables due to heavy
or shock loading on the soil above. Such stretches shall be clearly specified in the tender
documents.
© Sand cushioning as per (a) above shall however be invariably provided in
the case of HV cables.
(ii) Testing before laying All the time of issue of cables for laying, the cables shall be tested for continuity
and insulation resistance (See also clause 2.8.1)
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(iii) The cable drum shall be properly mounted on jacks, or on a cable wheel at a
suitable location, making sure that the spindle, jack etc. are strong enough to carry the
weight of the drum without failure, and that the spindle is horizontal in the bearings so as
to prevent the drum creeping to one side while rotating.
(iv) The cable shall be pulled over on rollers in the trench steadily and uniformly
without jerks and strain. The entire cable length shall as far as possible be laid off in one
stretch. PVC/XLPE cables less than 120sq.mm. size may be removed by “Flaking” i.e. by
making one long loop in the reverse direction.
Note: - For short runs and sizes upto 50sq.mm. of MV cables, any other suitable method
of direct handing and laying can be adopted without strain or excess bending of the
cables.
(v) After the cable has been so uncoiled, it shall be lifted slightly over the rollers
beginning from one and by helpers standing about 10m apart and drawn straight. The
cable shall then be lifted off the rollers and laid in a reasonably straight line.
(vi) Testing before covering
The cables shall be tested for continuity of cores and insulation resistance (Refer clause
2.8.1) and the cable length shall be measured, before closing the trench. The cable end
shall be sealed /covered as per clause 2.6.1 (iii)
(vii) Sand covering
Cables laid in trenches in a single tier formation shall have a covering of dry sand of not
less than 17cm above the base cushion of sand before the protective cover is laid.
In the case of vertical multi-tier formation, after the first cable has been laid, a sand
cushion of 30cm shall be provided over the base cushion before the second tier is laid. If
additional tiers are formed, each of the subsequent tiers also shall have a sand cushion of
30cm as stated above. Cables in the top most tiers shall have final sand covering not less
than 17cm before the protective cover is laid.
Sand covering as per (a) and (b) above need not be provided for MV cables where a
decision is taken by the Engineer-in-Charge as per sub clause (i)(b) above, but the inter
tier spacing should be maintained as in (b) above with soft soil instead of sand between
tiers and for covering.
Sand cushioning as per (a) and (b) above shall however be invariably provided in the case
of HV cables.
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(viii) Extra loop cable
(a) At the time of original installation, approximately 3m of surplus cable shall be left
on each terminal end of the cable and on each side of the underground joints. The surplus
cable shall be left in the form of a loop. Where there are long runs of cables such loose
cable may be left at suitable intervals as specified by the Engineer-in-Charge.
(b) Where it may not be practically possible to provide separation between cables
when forming loops of a number of cables as in the case of cables emanating from a
substation, measurement shall be made only to the extent of actual volume of excavation,
sand filling etc. and paid for accordingly.
(ix) Mechanical protection over the covering
(a) Mechanical protection to cables shall be laid over the covering in accordance with
(b) and (c) below to provide warning to future excavators of the presence of the cable
and also to protect the cable against accidental mechanical damage by pick-axe blows etc.
(b) Unless otherwise specified, the cables shall be protected by second class brick of
nominal size 22cmX11.4cmX7 cm or locally available size, placed on top of the sand (or,
soil as the case may be). The bricks shall be placed breadth-wise for the full length of the
cable. Where more than one cable is to be laid in the same trench, this protective covering
shall cover all the cables and project at least 5cm over the sides of the end cables.
© Where bricks are not easily available, or are comparatively costly, there is no
objection to use locally available material such as tiles or slates or stone/cement concrete
slabs. Where such an alternative is acceptable, the same shall be clearly specified in the
tender specifications.
(d) Protective covering as per (b) and (c) above need not be provided only for MV
cables, in exceptional cases where there is normally no possibility of subsequent
excavation. Such cases shall be particularly specified in the Tender specifications.
(e) The protective covering as per (b) and (c) above shall, however invariably be
provided in the case of HV cables.
1.6.7.4 Back filling
(i) The trenches shall be then back-filled with excavated earth, free from
stones or other sharp ended debris and shall be rammed and watered, if necessary in
successive layers not exceeding 30cm depth.
(ii) Unless otherwise specified, a crown of earth not less than 50mm and not
exceeding 100mm in the center and tapering towards the sides of the trench shall be left
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to allow for subsidence. The crown of the earth however, should not exceed 10 Cms so as
not to be a hazard to vehicular traffic.
(iii) The temporary re-statements of roadways should be inspected at regular
intervals, particularly during wet weather and settlements should be made good by further
filling as may be required.
(iv) After the subsidence has ceased, trenches cut through roadways or other
paved areas shall be restored to the same density and materials as the surrounding area
and –re-paved in accordance with the relevant building specifications to the satisfaction
of the Engineer-in-Charge.
(v) Where road beams or lawns have been cut out of necessity, or kerb stones
displaced, the same shall be repaired and made good, except for turfing /asphalting, to the
satisfaction of the Engineer-in-Charge and all the surplus earth or rock shall be removed
to places as specified.
1.6.7.5 Laying of single core cables
(i) Three single core cables forming one three phase circuit shall normally be
laid in close trefoil formation and shall be bound together at intervals of approximately
1m.
(ii) The relative position of the three cables shall be changed at each joint at
the time of original installation, complete transposition being effected in every three
consecutive cable lengths.
1.6.7.6 Route markers
(i) Location
Route markers shall be provided along the runs of cables at locations approved by the
Engineer-in-Charge and generally at intervals not exceeding 100m. Markers shall also be
provided to identity change in the direction of the cable route and at locations of
underground joints.
(ii) (a) Plate type marker
Route markers shall be made out of 100mm X 5mm GI/ aluminium plate welded / bolted
on 35mm X 35mm X 6mm angle iron, 60cm long. Such plate markers shall be mounted
parallel to and at about 0.5m away from the edge of the trench.
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(b) CC marker
Alternatively, cement concrete 1:2:4 (1 cement:2 coarse sand: 4 graded stone aggregate
of 20mm in size) as shown in figure 2 shall be laid flat and centered over the cable. The
concrete markers, unless otherwise instructed by the Engineer-in-Charge, shall project
over the surrounding surface so as to make the cable route easily identifiable.
(c) Inscription
The words ‘CPWD-MV/HV CABLE’ as the case may be, shall be inscribed on the
marker.
1.6.8 Laying in pipes / closed ducts
1.6.8.1 In locations such as road crossing, entry in to buildings, paved areas etc. cables
shall be laid in pipes or closed ducts. Metallic pipe shall be used as protection pipe for
cables fixed on poles of overhead lines.
1.6.8.2
(i) Stone ware pipes, GI, CI or spun reinforced concrete pipes shall be used for
cables in general; however only GI pipe shall be used as protection pipe on poles.
(ii) The size of the pipe shall not be less than 10cm in diameter for a single cable and
not less than 15cm for more than one cable.
(iii) Where steel pipes are employed for protection of single core cable feeding AC
load, the pipe should be large enough to contain both cables in the case of single phase
system and all cables in the case of poly phase system.
(iv) Pipes for MV and HV cables shall be independent ones.
1.6.8.3
(i) In the case of new construction, pipes as required (including for anticipated future
requirements) shall be laid alongwith the civil works and jointed according to the CPWD
Building Specifications.
(ii) Pipes shall be continuous and clear of debris or concrete before cables are drawn.
Sharp edges if any, at ends shall be smoothened to prevent damage to cable sheathing.
(iii) These pipes shall be laid directly in ground without any special bed except for SW
pipe which shall be laid over 10cm thick cement concrete 1:5:10 (1 cemtnt:5coarse
sand:10 graded stone aggregate of 40mm nominal size) bed. No sand cushioning or tiles
need be used in such situations.
1.6.8.4 Road crossings
(i) The top surface of pipes shall be at a minimum depth of 1m from the pavement
level when laid under roads, pavements etc.
(ii) The pipes shall be laid preferably askew to reduce the angle of bend as the cable
enters and leaves the crossing. This is particularly important for HV cables.
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(iii) When pipes are laid cutting an existing road, care shall be taken so that the soil
filled up after laying the pipes is rammed well in layers with watering as required to
ensure proper compaction. A crown of earth not exceeding 10cm should be left at the top.
(iv) The temporary re-instatements of roadways should be inspected at regular
intervals, particularly after a rain, and any settlement should be made good by further
filling as may be required.
(v) After the subsidence has ceases, the top of the filled up trenches in roadways or
other paved areas shall be restored to the same density and material as the surrounding
area in accordance with the relevant CPWD Building Specifications to the satisfaction of
the Engineer-in-Charge.
1.6.8.5 Manholes shall be provided to facilitate feeding/drawing in of cables with
sufficient working space for the purpose. They shall be covered by suitable manhole
covers. Sizes and other details shall be indicated in the Schedule of work.
1.6.8.6 Cable entry into the building
Pipes for cable entries to the building shall slope downwards from the building. The pipes
at the building end shall be suitably sealed to avoid entry of water, after the cables are
laid.
1.6.8.7 Cable-grip / draw-wires, winches etc. may be employed for drawing cables
through pipes / closed ducts.
1.6.8.8 Measurement for drawing/ laying cables in pipes/ closed duct shall be on the basis
of the actual length of the pipe / duct for each run of the cable, irrespective of the length
of cable drawn through.
1.6.9 Laying in open ducts
1.6.9.1 Open ducts with suitable removable covers (RCC slabs or chequered plates) are
generally provided in sub-stations, switch rooms, plant rooms, workshops etc. for taking
the cables. The cable ducts should be of suitable dimensions for the number of cables
involved.
1.6.9.2
(i) Laying of cables with different voltage ratings in the same duct shall be avoided.
Where it is inescapable to take HV & MV cables same trench, they shall be laid with a
barrier between them or alternatively, one of the two (HV &MV) cables may be taken
through pipe(s).
(ii) Splices or joints of any type shall not be permitted inside the ducts.
1.6.9.3
(i) The cables shall be laid directly in the duct such that unnecessary crossing of
cables is avoided.
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(ii) Where specified, cables may be fixed with clamps on the walls of the duct or
taken in hooks/brackets/troughs in ducts.
1.6.9.4
Where specified, ducts may be filled with dry sand after the cables are laid and covered
as above, or finished with cement plaster, specially in high voltage applications.
1.6.10
Laying on surface
1.6.10.1
This method may be adopted in places like switch rooms, workshops, tunnels, rising
(distribution) mains in buildings etc. This may also be necessitated in the works of
additions and/or alterations to the existing installation, where other methods of laying
may not be feasible.
1.6.10.2
Cables may be laid in surface by any of the following methods as specified:
(a) Directly clamped by saddles or clamps,
(b) Supported on cradles,
(c) Laid on troughs/trays, duly clamped.
1.6.10.3
(i) The saddles and clamps used for fixing the cables on surface shall comply with
the requirements given in Table-III.
(ii) Saddles shall be secured with screws to suitable approved plugs. Clamps shall be
secured with nuts on to the bolts, grouted in the supporting structure in an approved
manner.
(iii) In the case of single core cables, the clamps shall be of non-magnetic material. A
suitable non-corrosive packing shall be used for clamping unarmoured cables to prevent
damage to the cable sheath.
(iv) Cables shall be fixed neatly without undue sag or kinks.
1.6.10.4
The arrangement of laying the cables in cradles is permitted only in the case of cables of
1.1KV grade of size exceeding 120sq.mm. In such cases, the cables may be suspended on
MS flat cradles of size 50mmX5mm which in turn shall be fixed on the wall by bolts
grouted into the wall in an approved manner at a spacing of not less than 60cm.
1.6.10.5
All MS components used in fixing the cables shall be either galvanized or given a coat of
red oxide primer and finished with 2 coats of approved paint.
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1.6.11 Laying on cable tray
1.6.11.1
This method may be adopted in places like indoor substations, air-conditioning plant
rooms, generator rooms etc. or where long horizontal runs of cables are required within
the building and where it is not convenient to carry the cable in open ducts. This method
is preferred where heavy sized cables or a number of cables are required to be laid. The
cable trays may be either of perforated sheet type or of ladder type.
1.6.11.2 Perforated type cable tray
(i) The cable tray shall be fabricated out of slotted/perforated MS sheets as
channel sections, single or double bended. The channel sections shall be supplied in
convenient lengths and assembled at site to the desired lengths. These may be
galvanished or painted as specified. Alternatively, where specified, the cable tray may be
fabricated by two angle irons of 50mmX50mmX6mm as two longitudinal members, with
cross bracings between them by 50mmX5mm flats welded/bolted to the angles at 1 m
spacing. 2mm thick MS perforated sheet shall be suitably welded/bolted to the base as
well as on the two sides.
(ii) Typically, the dimensions, fabrication details etc. are shown in figure
3A,B and C.
(iii) The jointing between the sections shall be made with coupler plates of the
same material and thickness as the channel section. Two coupler plates, each of minimum
200mm length, shall be bolted on each of the two sides of the channel section with 8mm
dia round headed bolts, nuts and washers. In order to maintain proper earth continuity
bond, the paint on the contact surfaces between the coupler plates and cable tray shall be
scraped and removed before the installation.
(iv) The maximum permissible uniformly distributed load for various sizes of
cables trays and for different supported span are given in Table IV. The sizes shall be
specified considering the same.
(v) The width of the cable tray shall be chosen so as to accommodate all the
cables in one tier, plus 30 to 50% additional width for future expansion. This additional
width shall be minimum 100mm. The overall width of one cable tray shall be limited to
800mm.
(vi) Factory fabricated bends, reducers, tee/cross junctions, etc. shall be
provided as per good engineering practice. (Details are typically shown in figure 3). The
radius of bends, junctions etc. shall not be less than the minimum permissible radius of
bending of the largest size of cable to be carried by the cable tray.
(vii) The cable tray shall be suspended from the ceiling slab with the help of
10mm dia MS rounds or 25mmX5mm flats at specified spacing (based on Table III). Flat
type suspenders may be used for channels upto 450mm width bolted to cable trays.
Round suspenders shall be threaded and bolted to the cable trays or to independent
support angles 50mmX50mmX5mm at the bottom end as specified. These shall be
grouted to the ceiling slab at the other end through an effective means, as approved by the
Engineer-in-Charge, to take the weight of the cable tray with the cables.
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(viii) The entire tray (except in the case of galvanized type) and the suspenders
shall be painted with two coats of red oxide primer paint after removing the dirt and rust,
and finished with two coats of spray paint of approved make synthetic enamel paint.
(ix) The cable tray shall be bonded to the earth Terminal of the switch bonds at
both ends.
(x) The cable trays shall be measured on unit length basis, along the center
line of the cable tray, including bends, reducers, tees, cross joints, etc. and paid for
accordingly.
1.6.11.3 Ladder type cable tray
(i) The ladder type of cable tray shall be fabricated of double bended channel
section longitudinal members with single bended channel section rungs of cross members
welded to the base of the longitudinal members at a center to center spacing of 250cm.
(ii) Alternatively, where specified, ladder type cable trays may be fabricated
out of 50mmX50mmX6mm (minimum) angle iron for longitudinal members, and
30mmX6mm flat for rungs.
(iii) Typical details of fabrication and dimensions of both the types of trays are
shown in figure 4A,B,C and D.
(iv) The maximum permissible loading, jointing of channel sections, width of
the cable tray, provision of elbows, bends, reducers, horizontal tee/ cross junctions etc.
suspension of cable tray from the ceiling slab; painting and measurement of the cable tray
shall be as per sub-clauses (ii) to (x) below clause 2.6.11.2, except that the overall width
of one cable tray may be limited to 800mm.
1.6.11.4 Cables laid on cable trays shall be clamped on to the tray at suitable
intervals as per Table-III.
1.6.12 Cable identification tags
Whenever more than one cable is laid / run side by side, marker tags as approved,
inscribed with cable identification details shall be permanently attached to al the cables in
the manholes / pull pits / joint pits / entry points in buildings / open ducts etc. These shall
also be attached to cables laid direct in ground at specified intervals, before the trenches
are backfilled.
1.7 JOINTING
1.7.1 Location
(i) Before laying a cable, proper locations for the proposed cable joints, if
any, shall be decided, so that when the cable is actually laid, the joints are made in the
most suitable places. As far as possible, water logged locations, carriage ways,
pavements, proximity to telephone cables, gas or water mains, inaccessible places, ducts,
pipes, racks etc. shall be avoided for locating the cable joints.
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(ii) Joints shall be staggered by 2m to 3m when joints are to be done for two
or more cables laid together in the same trench.
1.7.2 Joints pits
(i) Joint pits shall be of sufficient dimensions as to allow easy and
comfortable working. The sides of the pit shall be well protected from loose earth falling
into it. It shall also be covered by a tarpaulin to prevent dust and other foreign matter
being blown on the exposed joints and jointing materials.
(ii) Sufficient ventilation shall be provided during jointing operation in order
to disperse fumes given out by fluxing.
1.7.3 Safety precaution
(i) A caution board indicating “CAUTION – CABLE JOINTING WORK IN
PROGRESS” shall be displayed to warn the public and traffic where necessary.
(ii) Before jointing is commenced, all safety precautions like isolation,
discharging, earthing, display of caution board on the controlling switchgear etc. shall be
taken to ensure that the cable would not be inadvertently charged from live supply.
Metallic armour and external metallic bonding shall be connected to earth. Where
“Permit to work” system is in vogue, safety procedures prescribed shall be complied
with.
1.7.4 Jointing materials
(i) Jointing materials and accessories like conductor ferrules, solder, flux,
insulating and protective tapes, filling compound, jointing boxes, heat shrinking joint kit
etc. of right quality and correct sizes, conforming to relevant Indian Standards, wherever
they exist, shall be used.
(ii) The design of the joint box and the composition of the filing compound
shall be such as to provide an effective sealing against entry of moisture in addition to
affording proper electrical characteristic to joints.
(iii) Where special type of splicing connector kits or epoxy resin spliced joints
or heat shrinkable jointing kits are specified, materials approved for such application
shall be used. Storing as well as jointing instructions of the manufacturer of such
materials shall be strictly followed.
1.7.5 Jointer Jointing work shall be carried out by a licensed/ experienced (where there is no
licensing system for jointers) cable jointer.
1.7.6 Cable work with joints
(i) About 3m long surplus cable shall be left on each side of joints as laid
down in clause 1.6.7.3 (viii).
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(ii) Insulation resistance of cables to be jointed shall be tested as per clause
1.8.1. Unless the insulation resistance values are satisfactory, jointing shall not be done.
(iii) Cores of the cables must be properly identified before jointing.
(iv) Where cable is to be jointed with the existing cable, the sequence should
be so arranged as to avoid crossing of cores wile jointing.
(v) Whenever the aluminium conductor is exposed to outside atmosphere, a
highly tenacious oxide film is formed which makes the soldering of aluminium conductor
difficult. This oxide film should be removed by using appropriate type of flux.
(vi) The clamps for the armour shall be clean and tight.
1.7.7 Jointing procedure
While it would be necessary to follow strictly the instructions for jointing
furnished by the manufacturers of cables and joint kits, a brief on the jointing procedures
is given for general guidance in Appendix F.
1.8 TESTING
1.8.1 Testing before laying
All cables, before laying, shall be tested with a 500V megger for cables of 1.1KV
grade, or with a 2500/5000V megger for cables of higher voltage. The cable cores shall
be tested for continuity, absence of cross phasing, insulation resistance from conductors
to earth / armour and between conductors.
1.8.2 Testing before backfilling
All cables shall be subjected to the above mentioned tests, before covering the
cables by protective covers and back filling and also before taking up any jointing
operation.
1.8.3 Testing after laying
(i) After laying and jointing, the cable shall be subjected to a 15 minutes
pressure test. The test pressure shall be as given in Table VI. DC pressure testing may
normally be preferred to AC pressure testing.
(ii) In the absence of facilities for pressure testing as above, it is sufficient to
test for one minute with 1000V megger for cables of 1.1KV grade and with 2500/5000V
megger for cables of higher voltages.
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PART A&B :TECHNICAL SPECIFICATION FOR 11 / 22 kV XLPE POWER CABLE (CROSS LINKED POLYTHELENE DRY GAS CURED) IS IN SEPARATE PDF DOCUMENT
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PART-C TECHNICAL SPECIFICATIONS FOR 11kV FAULT PASSAGE
INDICATOR (FPI) with RTU
3.1 SCOPE:
Supply of overhead Fault Passage Indicators (FPI) for overhead lines to be installed on 11 KV lines.
The objective of this remote communicable FPI is to quickly identification of the faulty circuit and
automatic update to the SCADA control center over remote communication.
3.2 PURPOSE:
To locate the exact passage of faults on overhead lines. The FPI shall indicate both transient as well
as permanent faults on the O/H lines
3.3 OPERATION:
The Fault Passage Indicator shall operate on either passing over of the absolute threshold current
(user settable) or the current variation (di/dt).
Upon the installation of the indicator, the FPI shall adjust itself to the network frequency and voltage
of perform required function.
3.4 FAULT TYPES:
The FPI shall detect and indicate both earth faults as well as phase to phase faults. In addition to this,
the FPI shall also detect and indicate transient and permanent faults.
3.4.1 INRUSH RESTRAINT:
The FPI shall be equipped to filter out the inrush current due to transformer magnetizing currents
thus avoiding the possible false indication of faults.
3.4.2 RESET:
Once the fault is cleared, the FPI shall reset itself upon the power return, it shall also have a facility
of resetting with settable time duration and the manual reset.
3.5 TRANSIENT FAULT EVOLUTION:
If FPI is busy in flashing on transient fault and if the permanent fault occurs, the FPI shall
automatically change the priority and shall start flashing differently to show the permanent fault;
thus helping maintenance crew to review the priorities.
Salient Technical Features of FPI
Offered 11 kV Clip-on / Pole mounting, Remotely monitored ,Outdoor unit Fault Passage Indicator
(FPI) should have compatibility with OPEN PROTOCOL SCADA system.
1. It should operate on either passing over of the absolute threshold current (user settable) or
the current variation(di /dt)
2. It should adjust itself to the network frequency and voltage to perform required function.
3. It should detect and indicate both earth faults as well as phase to phase faults
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4. It should also detect and indicate transient and permanent fault
5. It should be equipped to filter out the inrush current due to transformer magnetizing
currents thus avoiding the possible false indication of faults
6. Once the fault is cleared, the FPI shall reset itself upon the power return. It shall also have a
facility of resetting with settable time duration and the manual reset
7. If FPI is busy in flashing on transient fault and if the permanent fault occurs, the FPI shall
automatically change the priority and shall start flashing differently to show the permanent
fault; thus helping maintenance crew to review the priorities
8. The lithium battery provided inside the FPI should be trouble free of 10 years life and
replaceable type, in the case of battery failures and
9. 9.The FPI should have some self-test possibility usable when the FI is on the line (powered or
not)
10. Installation of FPI should be possible on live lines using an isolated hot stick with shot gun
type termination
11. It should support communication system SNMP, Master station(s) using 60870-5-
104protocol, protocol over GPRS/CDMA, , and forming IPSec VPN based security.
3.6 RTU for FPI:
The RTU should enable the communication, one side with the FPI units, via a spread spectrum
license-free radio frequency with low power consumption and the other side with the distant
acquisition system through a long range communication medium over mobile telephone network
(3G/GPRS/CDMA) others via the local RS232 port. The RTU should be capable of forming IPsec VPN
connectivity.
3.6.1 Basic Functions
The RTU should be able to store the date and time stamping of all events from communicable FPI
and send all requested events to the SCADA application. This RTU should have the facility to change
the FPI setting over remote operation. This RTU should have the memory capacity to store last 100
stamped events.
3.6.2 Description
The RTU should be available in a Pole-mounted enclosure, able to house a battery and a battery
charger, with external AC supply.
The main board includes:
• A short range low power spread spectrum radio for communication with the FPI
� For long range communication:
• One communication medium with its embedded modem (GPRS/CDMA) or o one RS232 port
for external communication.
• One RS232 local parameter setting port
• 6 digital inputs, for alarm information to SCADA application
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• 3 digital dry contact outputs set to repeat phase faults (phase A, B, or C) from FPI or short
range communication faults or battery faults for transmission by an external RTU.
3.6.3 Detail Characteristics
Sr.
No.
Details Specific Requirement
1 Type Spread spectrum low power licence-free
2 Frequency Free Band allowed in India
3 RF output FCC part 15.249 and AS/NZS 4268:2003 approved radio.
4 Communication media Embedded GPRS modem
5 Communication protocol DNP3, IEC 870-5-103/104
6 Type I(min), I(max), I(mean) and I(inst)
7 Number of HV lines monitored
per RTU
9 phases
8 mechanical Large enclosure
Small box Cabinet
100 m
9 Earth fault indication (phase A, B, or C), (beginning time, ending time)
10 Phase fault or Imax b Phase fault indication (phase A, B, or C), (beginning time,
ending time)
11 Transient fault detection if
enabled
Transient fault indication and time stamping
12 Voltage loss indication Voltage loss indication (phase A, B, or C) and time stamping
and Voltage recovery time indication
13 Equipment monitoring Equipment monitoring
14 Local radio communication
faulty
Communication with FPI Nos. XX faulty (after a number of
attempts) and time stamping
15 FPI battery alarm Battery low in FPI no.x and time stamping
16 RTU battery alarm Battery low in RTU and time stamping
17 AC supply alarm AC supply alarm External AC supply off
18 Inputs 6 digital inputs
19 Outputs 3 relay outputs 220 Vac/1 A
20 Local archive of Date and time
stamped events and measures
100 events
21 Downloading of local archive Remote via SCADA application
22 Power supply In built Battery of suitable rating
23 Operating temperature -25°C to +70°C
24 Storage temperature -40°C to +85°C
25 Mechanical Large enclosure
Small box Cabinet
Mechanical Large enclosure Small box Cabinet
26 Dimensions in cm 430x330x200
27 Net weight in kg 8 kg
28 Protection level IP 54
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29 Standards Standards
30 Vibrations and shocks test IEC 68-2-6 and 68-2-29
31 EMI/EFI immunity IEC 801-3 and FCC Part 15
32 Salt spray and humidity tests IEC 68-2-11 and 68-2-30
TECHNICAL DATA for FPI
No. Nominal operation Voltage 4 to 66 kV
1 Power Frequency 50 Hz
2 Conductor diameter 5 to 30 mm
3 MV neutral arrangement Independent / Solidly earthed
Fault Detection Parameters
4 Di trigger setting 6-12-25-60-90-120-160A-Off
5 Current setting trigger value 100-200-500-800A
6 Transient fault detection On / Off facility required
7 Flash duration (user settable) 2-4-8-16 hours
8 Inrush transient duration 3 Sec
9 Loss of voltage condition U < 45% Un
10 Fault confirmation Voltage drop within 70s after fault detection
Reset (Permanent Faults)
11 Automatic power return reset U > 70% Un during 70S
12 Timer reset 4-16 hours
13 Manual reset By magnet
Fault Indication
14 Indication Red flash light
15 Light power 40 Lumens
16 Visible angle 360 deg.
17 Standard total flash duration 400-800 hours
18 Battery Lithium with life > 10 years
Environment
19 Operating temperature 0 to +85 deg. C
20 Storage temperature 0 to +85 deg. C
21 Protection level IP 54 IK7
Test
22 Short circuit withstand 25 KA / 170 ms
23 Dielectric test 125 KV
Site Condition
25 Ambient Temperature 0-50 deg C
26 Relative humidity 10-100%
27 Average annual rainfall 750 mm
28 Altitude 300 m Max
29 Wind pressure 195Kg/m2 upto 30m
Technical description
30 Rated operating voltage 11 kV
31 Rated frequency 50 Hz
32 Trip current 30-500A
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33 Fault current minimum duration 50 ms
CODES AND STANDARDS:-
The equipment proposed to be designed, manufactured and tested in compliance with the latest
version of IEC Standards.
Electro-magnetic compatibility IEC-61000-6-2 and FCC part 15
IP65 Protection level IEC-60529
Damp Heat cycle Test (Humidity & Heat cycle ) IEC-68-2-30
Salty fog IEC-68-2-11
Sinus wave vibration & Shocks IEC-68-2-6 , IEC-68-2-29
Dielectric Test IEC 60060-1
Temperature aging IEC-68-2-14
Short circuit ANSI 495 (part 4.4.8)
EMI / EFI immunity IEC -801
Device Enclosure IP 65
SCADA compatibility of FPIs: -
The FPI should be provided with provision of necessary terminal blocks which shall be used for
connecting the RTUs for automations as mentioned in below table:
O/C operated Potential free contact
E/F operated Potential free contact
Fault passage indicator OK Potential free contact
Command for reset FPI Potential free contact
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PART-D. Pole Mounted Load Break Switches / Sectionalizers with
Integrated remote communication capabilities
2.12 SCOPE
This specification covers requirements for outdoor Pole-mounted load break switches /
sectionalizers that have programmable fault detection and sectionalizer features,onload operable ,
and that are intended for source and down-line duty on rural distribution networks at nominal A.C.
voltages of 15 kV.
The 11kV sec. Should be provided with potential free contacts and control contacts (suitable
connector) for SCADA remote (FRTU) integration. Refer Annexure-1.
230V AC Supply for charging of FRTU battery should be available. FRTU will require power up to 60
VA.
2.13 NORMATIVE REFERENCES
The following standards contain provisions that, through reference in the text, constitute
requirements of this specification at the time of publication the revisions indicated were valid. All
standards are subject to review and parties to purchasing agreements based on this specification are
encouraged to investigate the possibility of applying the most recent revisions of the standards listed
below.
IEC 60265-1 High Voltage Switches
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code).
UNIPEDE NORM (SPEC) 13 (1995): Automation and Control Apparatus for Generating Stations and
Substations: Electromagnetic Compatibility Immunity Requirements.
2.14 DEFINITIONS AND ABBREVIATIONS
2.14.1 Automatic Detection Group Selection (ADGS):
An automated feature to determine and activate a pre-programmed group of detection settings
based on the direction of power flow.
2.14.2 Auto-recloser (AR):
A mechanical switching device that, after opening, closes automatically after a predetermined time.
2.14.3 Cold load pick-up (CLP) feature:
A feature that allows modification of the over-current fault detection characteristics in order to
prevent false fault detection under conditions of system energisation.
2.14.4 Dead time:
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Also referred to as "Reclosing Interval". This is the time between the instant that the current is
interrupted by the AR and the instant the contact of the AR closes as a result of an automatic reclose
operation.
2.14.5 Definite time:
A fault detect event occurs if the current exceeds the fault threshold setting for a time equal to the
definite time setting.
2.14.6 Effectively earthed system:
An earthed system in which the healthy phase power frequency phase-to-earth over voltages
associated with earth faults are limited to 80% of the highest phase-to-phase voltage of the system.
2.14.7 Pickup:
The fault detection elements are monitored and an element “picks up” when the measured current
exceeds the preset level of the specific element. Typical detection elements are Phase, Earth and
Sensitive Earth Fault (SEF).
2.14.8 Pole-mounted remote terminal unit (PMRTU):
A remote terminal unit that is designed for pole mounting and that operates specific polemounted
equipment remotely.
2.14.9 Sequence reset time:
The time duration after a supply interruption occurred before the sectionalising sequence resets if
the Sectionalizer does not detect another fault.
2.14.10 Sectionalizing:
The ability of the load break switch to count the operations of an upstream AR and to open during
the dead time of the AR after a configurable number of supplies interrupts.
2.14.11 Secure control:
A single mechanically non-latching switch that effects one state of a control function only. An
example of which is either a non-latching switch or two separate push buttons that affect one state
of a control function only in each position. If a control is activated repeatedly it only effects that
state and does not change the state of the control.
2.14.12 Sensitive earth fault (SEF):
A relay that is sensitive to very low earth fault currents and in which the operating settings are for
current magnitude and definite time delay.
2.14.13 Supervisory:
Remote control and indications of an LBS or a FRTU by means of a telecommunications link.
2.14.14 Supply Interruption:
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A fault pickup followed by a “no current” and “no voltage” condition is called a Supply
Interruption. This condition typically occurs when an upstream recloser trips due to a downstream
fault.
2.14.15 Toggled control:
A single mechanically non-latching switch/push-button that enables a single control function on the
first operation of the switch/push-button and disables the function on the second operation of the
same switch/push button.
2.15 REQUIREMENTS
2.15.1 General
The load break switch / Sectionalizer shall be suitable for use on non-effectively earthed and
effectively earthed networks and under the system conditions and service conditions as
follows:
a) Nominal system voltage (U) (r.m.s.) - 11 kV;
b) Load current - 630 A;
c) Fault make capacity (r.m.s.) 16 kA;
d) Lightning Impulse Withstand Voltage (BIL) - 125 kV
e) System frequency - 50 Hz;
f) Number of phases - 3;
g) Interrupting medium - Puffer
h) Insulation medium - SF6
i) Minimum no load mechanical operations - 3000
j) Minimal number of rated load operations - 600
k) Operating Mechanism - LV motor
l) Altitude - up to 3000 m;
(For altitudes above 1000m derate in accordance with ANSI C37.60)
m) Ambient temperature minimum - -30°C;
maximum - 40-45 °C;
n) Maximum daily variation - 35 °C;
o) Pollution level - medium/heavy
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(special applications);
p) Lightning activity - high.
2.15.2 Mounting
2.15.2.1 The LBS shall be suitable for single pole/DP mounting. The recloser
shall be mounted on channel on D.P. Structure.
2.15.2.2 Adequately rated lifting eyes shall be provided and they shall be
designed to allow the completely assembled LBS (surge arresters
fitted) to be lifted without recourse to a sling spreader. The diameter of
the eyes shall be a minimum of 30mm.
2.15.2.3 Suitable mounting brackets for surge arresters shall be provided on
the line side and on the load side of the LBS, adjacent to the bushings.
2.15.2.4 The LBS shall be fitted with an external M12 earthing stud, complete
with a nut, lock nut and spring washer. The earth stud shall be welded
to the tank for optimal earthing connection.
2.15.2.5 Each bushing of the LBS shall be marked x, xx and xxx for the normal
line side and I, II and III for normal load side.
2.15.2.6 A detailed drawing of the single pole LBS mounting arrangement with
surge arresters fitted shall be provided. The minimum phase-to-earth
clearances shall be indicated on the drawing.
2.15.2.7 The mass of the mounting hardware, the LBS and the control cabinet
and cable shall be stated in the tender documentation.
2.15.3 Bushings
2.15.3.1 Terminals
The preferred arrangement for termination is an insulated bushing arrangement achieved by using
epoxy resin bushings and silicone rubber bushing boots together with 3 meters XLPE insulated water
blocked cable tails.
2.15.3.2 Material
The following bushing materials are acceptable:
� Aromatic epoxy resin with Silicone rubber boots Porcelain bushings and EPDM rubber are
not acceptable.
Details of the type and creepage shall be provided in the tender documentation. Minimum
acceptable creepage is 770 mm.
2.15.4 Finish
2.15.5 All interior and exterior ferrous surfaces of the LBS and control cabinets shall be
manufactured from 316 marine grade stainless steel. All support structures and
associated bolts and nuts with these parts, shall be hot-dip galvanized.
2.15.6 Suitable precautions shall be implemented to prevent corrosion due to the use of
dissimilar materials.
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2.16 CONTROL EQUIPMENT
2.16.1 Control cabinet
2.16.1.1 Cabinets that house equipment for protection and control shall be mounted independently
of the LBS.
2.16.1.2 Suitable ultraviolet-resistant cable,7 m long, shall be provided to connect the LBS to the
control cabinet. If shorter or longer cables are required, the length will be specified in the
tender documentation.
2.16.1.3 It shall be possible to disconnect the cable at the LBS while the LBS is connected to the
power system, without causing damage or malfunction: care shall be taken that CTs are not
open circuited. A robust, multipin weatherproof connector shall be supplied. The female
part of the connector shall be mounted on the LBS and the male part shall be mounted on
the cable. Preference will be given to products supplying connectors at both the LBS and
the control cabinet.
2.16.1.4 Cabinets shall be adequately sealed and dust protected and shall be internally treated to
prevent moisture condensation. The degree of protection shall be suitable for purpose.
2.16.1.5 The supplier shall ensure that the equipment housed in the control cabinet can withstand
the heating effect of direct solar radiation without causing failure and/or malfunction.
Details shall be provided in the tender documentation.
2.16.1.6 The cabinet shall make provision for bottom entry of three cables. This shall be done with
pre-punched holes, two 21 mm and one 32 mm in diameter. The holes shall be suitably
blanked off.
2.16.1.7 The cabinet shall be fitted with an external M10 earthing stud with a nut, lock nut and a
serrated washer.
2.16.1.8 The door of the cabinet shall be fitted with a robust fastening arrangement that is capable
of being secured by a padlock that has a shackle of 8 mm diameter.
2.16.1.9 The cabinet shall be easily removable for workshop repair purposes.
2.16.1.10Electronic control equipment
2.16.1.11The controls shall not suffer any damage if one or more polesof the load break switch fail
to respond to either a trip or a close command.
2.16.1.12 Electronic modules shall perform continuous diagnostic monitoring and shall contain
hardware and software watchdog checking.
Space required for mounting FRTU Panel. Dimensions details for FRTU are about 1000Hx600Wx300D
2.17 DETECTION CHARACTERISTICS
2.17.1 General
2.17.1.1 The following detection elements shall be available: over-current
(O/C), earth fault (E/F) and sensitive earth fault (SEF).
2.17.1.2 Each of the detection elements is monitored with independent definite
time settings as per relay coordination calculation w.r.t. concern S/s and fault thresholds.
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2.17.1.3 The ratio of drop-off current to pick-up current shall be at least 90% for
all detection functions.
2.17.1.4 The SEF function shall be equipped with harmonic filtering to prevent
operation when harmonics are present in the primary residual earth
currents. A low pass filter with 3rd harmonic rejection > 28dB shall be
supplied. Both the SEF function and its filter shall be described in the
tender documentation.
2.17.1.5 The LBS and Control element shall support multiple detection groups
and this shall meet the requirements specified below:
� The LBS shall have a minimum of 4 independent detection groups. The Detection Groups
shall have clear indication and shall be marked as "I, II, III, IV" or "A, B, C, D"
� Each detection group shall have the facility to configure O/C, E/F and SEF fault detection
current and definite time. The detection parameters used in one of the detection groups
shall be available for use in any or all of the other detection groups.
� Changes to any of the detection parameter of the non active detection group shall not affect
the detection functionality of the active detection group.
� Information about activation of any of the detection groups shall be recorded in history and
shall be easily assessable. Information about fault detection shall clearly indicate the
detection group active at the time of a fault.
� LBS and Control element shall have the facility for Automatic detection group selection.
Automatic Detection Group Selection shall have the facility to be turned ON or OFF with
password protection or other form of access control.
2.17.2 Over-current (O/C) element
2.17.2.1 The over-current pick-up setting range shall be selectable from 10 A to
1260 A in the steps not greater than 10 A.
2.17.2.2 The Definite Time for fault to persist setting range shall be selectable
from 0.05 to 100.0 sec in the steps not greater than 0.1 sec.
2.17.2.3 A cold load pick-up (CLP) feature shall be provided that allows user
selectable modification of detection element characteristics under
conditions of system power restoration.
The pick-up current setting of the O/C element may be modified with a settable factor to increase
the pick-up current for the CLP duration.
The CLP function shall have the following characteristics:
• the CLP function shall not in any way interfere with any of the other
functions‟ / elements' pick-up current settings except as mentioned above;
• the CLP functionality shall be such that the active duration of the CLP is
selectable from 0 min to 200 min in 1 min steps; and
• the modification factor should be settable from 1 to 5 in steps of 0,1.
2.17.3 Earth fault (E/F) element
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2.17.3.1 The earth fault setting range shall detect primary earth fault currents
down to 20 A. The E/F pick-up setting range shall be selectable from
20 A to 1260 A in the steps not greater than 10 A.
2.17.3.2 The Definite Time for fault to persist setting range shall be selectable
from 0.05 to 100.0 sec in the steps not greater than 0.1 sec.
2.17.4 Sensitive earth fault (SEF) element
2.17.4.1 A primary earth fault current of 4A to 20A in steps not exceeding 1A
shall be detectable.
2.17.4.2 The Definite Time for fault to persist setting range shall be selectable
from 0.05 to 100.0 sec in the steps not greater than 0.1 sec.
2.17.5 Sectionalising Functions
2.17.5.1 The number of detected faults to trip shall be selectable to be 1, 2, 3 or 4.
2.17.5.2 The sequence reset time shall be selectable from 5s to 120s in 1s steps.
2.18 STATISTICAL MEASUREMENT FUNCTIONS
2.18.1 The characteristics of the statistical measurement functions shall be as follows
2.18.1.1 Measurement shall be done with one of the following methods:
� three-phase-3-wire method; and
� or the three-phase-4-wire method
2.18.1.2 Quantities to be measured/calculated with specified accuracy are:
� r.m.s. phase-to-phase and phase-to-ground ±2.5%;
voltage of all three phases (% of rated voltage):
� r.m.s current per phase ± 2.5%;
(within rated current range):
� three phase active power in kW: ± 5%;
� three phase reactive power in kVARs: ± 5%;
� total three-phase active energy in kWh: ± 5%;
� Power factor: ± 5%;
� Maximum demand ± 5%.
2.18.1.3 The real power energy and maximum demand measurement shall be
integrated with respect to time. Energy values shall be calculated with
selectable time integration periods of 5 min, 15 min, 30 min or 60 min.
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The data buffer shall work on the FIFO principle and a minimum size
for the data buffer shall store values for 4 months on the 30 minutes
integration period.
2.18.1.4 The voltage factor of the voltage transformers shall be a minimum of 1.9
2.18.1.5 LBS and Control element shall have the facilities to record the
cumulative number and duration of outages. The information shall be
assessable locally or remotely using a SCADA system. The following
parameters shall be recorded:
� Cumulative total number of outages;
� Cumulative total outage duration; and
� Time and duration of each outage in the form of an event log.
2.19 LOCAL CONTROL AND INDICATION
2.19.1 The local control and indication shall be as given in Table 1.
Table 1: Minimum specification of local controls and indications
1 Item 2 Features 3 Remarks
Local control (See Note 1) Local/Remote 2 position key switchable
Load break switch open Secure control (Note 3)
Load break switch close Secure control (Note 3)
Sectionalizer ON/OFF Secure or Toggled control.
Local indication (See Note 1) Local/Remote See Note 3
Load break switch open
Load break switch closed
Sectionalizer trip
Sectionalizer ON/OFF
Controller not healthy See Note 2
SF6 Alarm
O/C operated
E/F operated See 2.19.9
AC fail
DC abnormal See 2.24.5.3
DC fail
Charger fail
2.19.1.1 Notes (preferable)
Note 1: The local control and the local indication features on the control panel shall be labeled as
presented in column 2, where applicable. The type of switch used for local control shall not
allow for a conflict to exist between the switch position and the function status.
Note 2: The 'Controller not healthy' indication shall indicate the control equipment not healthy
(watchdog) function operated. It shall not operate during the normal polemounted switch
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operating cycle. This indication should remain active until the unhealthy state that initiated it
returns to normal.
Note 3:The two-position switch (labeled as below) shall allow the LBS controller to be set in the
following modes:
Remote: In this mode a local operator can trip the LBS and change the mode. A remote operator can
trip or close the LBS.
Local: In this mode a local operator can trip and close the LBS. A remote operator can only trip the
LBS.
2.19.2 All local controls and indications shall be accessible in adverse weather condition.
2.19.3 The LBS shall be provided with external levers to permit manual operation, using an
insulated operating stick, to open, close, lock-out and reset the LBS from ground
level. Where these operations can be performed at the control cabinet, it shall only
be necessary to provide a mechanical means to open and lockout the load break
switch using an insulated operating stick.
2.19.4 The LBS status shall be clearly visible from ground level. "Opened" shall be indicated
with a green "OFF". A red "ON" shall indicate "Closed". Alternative indications shall
be subject to approval by the purchaser.
2.19.5 Pressure relief facilities shall be provided to enable the LBS to withstand safely the
effects of excessive pressure rise due to an internal fault.
2.19.6 Malfunction of the LBS shall not pose a safety hazard to the operator due to the
recoil or backlash of items such as external operating rods, cranks and levers.
2.19.7 Easily available (i.e. maximum of one keystroke) local indication of detection
operation shall be provided for at least the last operation of the LBS. The function,
phase involved and the current magnitude shall be indicated.
2.19.8 Switches used for local control shall offer the type of control described in table 1 i.e.
secure or toggled control. Electronic keypad controls shall offer 'quick key' (maximum
of one keystroke) access to the controls in Table 1 if not implemented with switches.
2.19.9 LBSs using SF6 as an arc extinguishing medium shall:
2.19.9.1 Provide a low gas pressure indication at a gas pressure that enables
safe operation of the LBS;
2.19.9.2 Be provided with a method of inhibiting any operation of the LBS in the
event of the gas pressure dropping below a safe pressure.
2.20 REMOTE CONTROL AND INDICATION
2.20.1 The remote controls and indications shall be as given in Table 2. and Annexure-1
Table 2: Minimum specification of remote controls and indications
1 Item 2 Features 3 Remarks
Remote control Load break switch open Secure
control
Load break switch close Secure
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control
Sectionalizer ON/OFF Secure
control
Remote
indication
Local/Remote (See Note 5)
Load break switch open Load break switch closed Sectionalizer trip
Sectionalizer ON / OFF
Sectionalizer trip (See Note 6)
SF6 Alarm
O/C operated
E/F operated See 2.19.9
A.C. fail
D.C. abnormal
D.C. fail See 2.24.5.3
Charger fail
Analogue indication:-
• r.m.s. phase-to-phase and phase to ground voltage of all three phases
• r.m.s current per phase three-phase active power in kW
• three-phase reactive power in kvars total three-phase active energy in kWh
• Power factor
• Maximum demand
2.20.1.1 Notes (Preferable)
Note 4: The two-position switch (labeled as below) shall allow the LBS controller to be set in the
following modes:
Remote: In this mode a local operator can trip the LBS and change the mode.
A red in the mote operator can trip or close the LBS.
Local: In this mode a local operator can trip and close the LBS. A remote operator can only trip the
LBS.
Note 5:The LBS indication shall give an alarm with any Sectionalizer attempt.
Note 6 : The MFT is not required in the scope however CT and PT is required as per the detail
Specification.
Current Transformers for breaker
CT Type :Tape wound
CT Description :The CTs of breaker shall be suitable for sensing the minimum primary variable
current in the order of 10-100 A and the secondary current for the CT is 1 A. The CT
shall be housed in outside SF6 chamber for testing and Maintenance.
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Accuracy Class :class X/5P10 protection
Rated burden : Suitable for self powered relay and metering
PT : PT should be provide as per our requirement mention in power supply 2.24
2.21 OPERATION INTERLOCKING
Prevent the removal of respective cable covers if Isolator is ‘ON’- Electrical/Mechanicaland
Prevent the closure of isolator or circuit breaker if respective cable cover is open-
Electrical/Mechanical.
2.21.3.1 All operating, detection and communications parameters.
2.21.3.2 An event record containing at least 3000 events (a detection event is
defined as all operations in a sequence until successful sequence
reset or sectionalizer trip). The actual number available shall be stated
in the tender documentation.
2.21.3.3 Refer to 2.18.1.3.
2.21.3.4 Maximum demand information. Maximum demand shall have the
facilities to be configured for weekly and/or monthly demand.
2.21.4 A pointer shall be provided to indicate up to where the data was last read. This will
enable regular uploading of the data without re-loading of previously read data.
2.21.5 All events shall be time and date stamped with a resolution of at least 10ms relative
to the onboard clock.
2.24 POWER SUPPLIES
2.24.1
2.24.2 Primary supply: Preference will be given to the ability to obtain primary power directly
from the HV power system requiring no additional primary supply connection.
2.24.3 Test supply: The LBS shall accept an external AC 230 V 50 Hz supply.
2.24.4 Optional supply: The LBS shall accept an external DC 110 V supply.
2.24.5 Auxiliary supply: An auxiliary supply with the following minimum characteristics shall
be provided:
2.24.5.1 One battery and constant voltage charger with current limiting shall be
part of the LBS. Battery standby time shall not be less than 24 h,
allowing for ten LBS operations and a Transmit : Receive : Standby
duty cycle of 5:5:90 from a 5 W output radio. The battery shall
recharge to 80% of its capacity in a maximum of 15 h. The total
number of LBS operations under the above communications scenario
shall be at least 10. Details will be stated in the tender documentation.
2.24.5.2 Batteries shall be disconnected at the manufacturer's specified
minimum voltage.
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2.24.5.3 'Battery Low' indication shall be available locally and remotely and
shall include a battery test. The indication of "Battery Low" status shall
allow for a further ten LBS operations.
2.24.5.4 The minimum battery life expectancy shall be 5 years. Details of the
guaranteed life expectancy of the battery shall be stated in the tender
documentation.
� 230V AC Supply for charging of FRTU battery should be available. FRTU will require power up
to 60 VA.
2.25 MAINTENANCE AND COMMISSIONING
2.25.1 All the communications equipment shall be easily accessible in the control cabinet. Wiring of
communications links in the control cabinet shall permit the connection of a temporary
protocol-monitor. It shall be possible to perform secondary injection testing while the LBS is
communicating with the Centre.
2.25.2 It shall be Possible to disconnect the LBS and connect a simulated switch to the control
cabinet for testing purposes.
2.25.3 The LBS shall not malfunction while the radio is transmitting via an antenna in close proximity
and the control cabinet door is open.
2.25.4 Provision shall be made in the control cabinet for isolating the power supply to/from the
following:
� battery;
� battery charger;
� Primary supply to the control cabinet electronics.
2.26 RATING PLATE
Each LBS shall bear a rating plate of an intrinsically corrosion-resistant material, indelibly marked
with the sea-level rating for which the equipment has been type tested. The rating plate shall be
indelibly marked with:
� the manufacturer's name;
� the equipment type designation and serial number of the LBS;
� the mass, in kilograms;
� the date of manufacture; and
� Auxiliary supply voltage (if applicable).
2.27 ADDITIONAL INFORMATION
The following shall be submitted with the tender.
2.27.1 Load break switch details
� manufacturer;
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� type designation;
� place of manufacture;
� fault make capacity; 3s 1s nd
� Critical current (maximum instantaneous peak).
2.27.2 A schematic-wiring diagram of the LBS offered.
2.27.3 A general-arrangement drawing of the LBS offered.
2.27.4 Details of the maintenance and operating equipment, procedures needed and a
detailed parts list of the various components.
2.27.5 A description of the LBS operation, with instruction and maintenance manuals,
including maintenance schedules, fault detection characteristics, communications
facilities, the method of applying settings and controls, together with any software required
and the cost thereof. The software requirements shall be stated in the tender
documentation.
2.27.6 Details and the cost of any available portable calibration and diagnostic test set that may be
used to perform the functionality described in 2.24.1, 2.24.2 and 2.24.3. Details of the test
set shall be given in the tender document.
2.27.7 A list of recommended spares and tools.
2.27.8 The method of changing detection settings shall be stated in the tender documentation.
2.27.9 Details of technical back-up facilities available. These details shall be stated in the
tender documentation.
2.27.10 Details of the class, ratio(s) and burden of the detection current transformer
and voltage transformer, if supplied, shall be stated in the tender documentation.
2.27.11 The supplier shall include the following details of measurement current
transformers (not internal to the LBS) that can be supplied with the LBS. The
following details shall be provided:
� available ratio(s) and accuracy class; method of fitting; and
� effect on creepage distance and BIL
2.27.12 Where applicable details of the low gas pressure alarm/lock-out philosophy;
2.27.13 Details of LBS service history:
� how many in service, where and for what period; and
� Contact names and numbers.
2.27.14 Details of LV trip/close motor if available as an option
2.27.15 Power requirements for a close operation
2.27.16 The maximum achievable separation between the control unit and the load break switch.
2.27.17 Full details of the protocol implementation and the complete point database.
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2.28 TESTS
2.28.1 Type tests
The load break switch / sectionalizer shall have been type tested in accordance with, and found to
comply with, the requirements of IEC 60265-1 for the following, and the appropriate values shall be
stated in the tender documentation:
2.28.1.1 Operating duty.
2.28.1.2 Making current.
2.28.1.3 Insulation (dielectric tests).
2.28.1.4 Radio interference voltage.
2.28.1.5 Temperature rise.
2.28.1.6 Mechanical operations.
2.28.1.7 Control equipment surge withstand capability.
2.28.2 The control cabinet and associated electronics shall have been type tested in accordance with
UNIPEDE NORM (SPEC)13 (1995): Automation and Control Apparatus for Generating Stations
and Substations: Electromagnetic Compatibility Immunity Requirements. The environment
shall be considered as falling in the HV substation category, according to NORM (SPEC)13.
2.28.3 Test records (on identical equipment) in the form of validated copies of test certificates issued
by a recognized testing authority shall be submitted with the tender documentation.
2.29 ROUTINE TESTS
2.29.1 Routine tests, as required in the relevant standards, shall be carried out as a
normalrequirement of the contract and, unless otherwise agreed upon, shall be witnessed by
the purchaser or by his appointed representative. No additional charge shall be levied for such
tests or for the production or presentation of documentation related to routine tests.
2.29.2 Duplicate copies of routine test certificates shall be supplied together with the equipment
when the latter is delivered to the final destination stated in the order.
2.30 PACKING/DOCUMENTATION
2.30.1 Packing
All equipment shall be carefully packed to prevent damage or deterioration during normal
transportation, handling and storage.
Each container shall bear the following information on the outside of the container:
� The address of the destination
� The gross mass, in kilograms
� The name of the manufacturer
� The purchaser's order number and port of destination
2.31 DOCUMENTATION
Each LBS shall be supplied complete with the documentation specified in Items 2.27.1,
2.27.2, 2.27.3 and 2.27.4, together with the routine test certificates specified in 2.29
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ANNEXURE 1
FRTU requirements with respect to RMU/Sectionalizer A. Introduction: The purpose of the document is to specify FRTU requirements with respect to RMU/Sectionalize requipment. The requirements can be broadly specified as; 1. Space for mounting FRTU. 2. Mounting holes. 3. ‘SCADA Interface’ module. 4. 230VAC auxiliary power source with earthing point. All these are to be provided in RMU/Sectionalizer Cabinet/Panel.
B. Mounting requirements: For the purpose of safety and compactness it is required that FRTU be mounted in RMU/Sectionalizer cabinet so, suitable mounting space for FRTU to be provided inside cabinet. The size of FRTU and typical arrangement of FRTU is as shown in Appendix-1. Since the FRTU will be mounted inside the panel, mounting holes are to be provided. The mounting holes can be provided on a mounting plate or any other suitable arrangement. The details of mounting holes are shown in Appendix-1.
C. Connectivity requirements: The connectivity of signals between FRTU and RMU/Sectionalizer is required to be hardwired instead of serial communication. The disadvantages of serial communication are; 1. Increase in response time due to additional poll based monitoring and control. 2. Single point of failure.
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3. Dependency on additional component (RMU/Sectionalizer IED). 4. Troubleshooting is complex than hardwired signals. 5. Maintenance issues considering above points in large number of RMU/Sectionalizer locations. Since connectivity of FRTU with the RMU/Sectionalizer will be hardwired signals, all the I/O signals required for SCADA are to be terminated on the ‘SCADA Interface’ module. The ‘SCADA Interface’ and its typical arrangement are as shown in Appendix-1. Typical list of I/O signals required for SCADA is shown in Table-1. The material required to be provided is as shown in Table-2.