TS-2 A

TECHNICAL SPECIFICATION OF 145 KV SF6 CIRCUIT BREAKERS

1.1 STANDARDS

S.No. Standard

1. IEC 62271-100 and IS-13118

2. IEC - 376

3. IEC - 137

4. IEC - 71

5. IEC - 694

6. IS - 2147

7. IS - 2516

8. IS - 5578 & 11353

9. IS - 2629

10. IS - 2099

11. IS - 4379

12. IS - 7285

Title

Specification for alternating current circuit Breakers.

Specification for acceptance of new supply of SF6.

Bushing for A.C. Voltage.

Electrical Clearances.

Common clauses for high voltage switch gear and control gear standard.

Degrees of Protection Provided for enclosures for low voltage switch gear and control gear.

Specification for circuit Breaker

Making and arrangement for switch gear bus bar, Main Connections and auxiliary wiring.

Recommended Practice for hot dip galvanizing of iron and steel.

High voltage Porcelain bushings.

Identification of the contents of Industrial Gas Cylinders.

Seamless high carbon steel cylinders for permanent and high pressure liquefiable gas.

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1.2 PRINCIPAL PARAMETERS

FOR 145 kV SF6 Circuit Breakers

1. Rated nominal system voltage

2. Rated voltage

3. Rating of C.B.

4. Rated frequency

5. System neutral earthing

6. Type of C.B.

7. No. of poles

8. Installation

9. Rated normal current

10. Rated short circuit breaking

11. Rated duration of short circuit

12. Transient frequency voltage

13. Terminal faults

14. Short line fault

15. Rated short circuit making capacity(peak)

16. Operation duly cycle

17. Total breaking time

18. 1.2/50 microsecond lightning impulsewithstand voltage to earth

19. One minute power frequency drywithstand voltage to earth

20. Temperature rise

132KV

145KV

7900 MVA

50 Hz

Effectively earthed

SF 6

3 - (gang operated)

Outdoor

1250 Amp.

1. RMS value of A.C. component current of the rated short circuit breaking current 31.5KV for 1Sec.

2. D.C.component as per IEC-62271 - 100

1 Sec.

The rated transient recovery voltage of the breaker shall be used on 4parameters method as defined in IEC 62271-100

1st pole of clear factor 1.5 value of 4 parameter as per IEC62210

As per IEC

80 KA

0-t-co-t1 -co

t = 0.3 Sec.

t1 = 3 min.

3 cycles

650 KV (min.)

275 KV (RMS)

Final Steady State Temperature rise of current carrying part shall not exceed the limits specified in IEC 62271-100 with a site reference

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ambient temperature of 500C

21. Operating mechanism Mechanical spring/Electro pneumatic.

22. Type of tripping Trip free

23. Number of auxiliary contacts 12 Nos NO. and 12 Nos NC

24. No. of trip coils 2 Nos.

25. No. of closing coils 1 No.

26. Breaking line charging current 50 Amps. at 145KV

27. Interrupting capacity in KA for 31.5 KA (RMS)kilometric faults

28. Arcing time (at 100% interruption 25 milliseconds.capacity)

29. Minimum dead time 300 milliseconds.

30. No. of break per phase One

31. Tripping and closing control circuit 110 V.DCvoltage

1.3 CIRCUIT BREAKER REQUIREMENTS

i) The Circuit Breaker shall comprise of three identical pole units linked togetherelectrically and pneumatically, complete with first filling of SF6 gas, 2 nos. unit air compressors with common local air receiver, air and gas piping, operating mechanism, complete with Terminal Connectors / anti pumping device and wiring etc.

ii) The local air receiver, pipes and fittings shall have adequate mechanical strength and shall remain air tight. Each breaker shall also be provided with space heater (thermostatically controlled), operation counter, pressure gauges, and gas density detectors (Temperature compensated gas pressure switch).

iii) The circuit breaker units shall be suitable for mounting at ground level with concrete plinth including standard supporting frame. Suitable steel structures, supporting column for mounting the circuit breaker shall also be supplied along with the breaker.

2.0 ADDITIONAL DUTY REQUIREMENTS

The SF6 circuit breaker shall be capable of meeting with the following additional duty requirements.

2.1 RECOVERY VOLTAGE & POWER FACTOR

The circuit breaker shall be capable of interrupting the rated power with recovery voltage equal to the rated maximum service voltage at rated frequency and at power factor not exceeding 0.15.

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2.2 RESTRIKING VOLTAGES

The breaker shall be re-strike free. The breaker shall conform to the requirements of latest edition of IEC-62271-100 for re-striking voltage, rate of rise of re-striking voltage, natural frequency etc. The design of the breaker shall be such that even without using any shunt resistance across contacts, it shall break the currents up to guaranteed values without exceeding the over voltage as indicated in IEC-62271-100

2.3 LINE CHARGING CURRENT INTERRUPTING CAPACITY

The circuit breaker shall be designed so as to be capable of interrupting line charging currents without undue rise in voltage on the supply side and without any re-strike voltage and without showing signs of undue strain .

2.4 BREAKING CAPACITY FOR KILOMETRIC FAULTS

Clearing short line faults (kilometric faults), with the source impedance behind the bus, the breaking capacity shall be equivalent to fault current of 31.5 KA rms for 1 second for 145 KV breakers.

2.5 OUT OF PHASE CLOSING

The breaker shall be capable of breaking 25% of the rated symmetrical short circuit breaking capacity at twice the rated voltage under out of phase i.e .phase opposition conditions as per IEC-267

2.6 TRANSFORMER CHARGING CURRENT BREAKING CAPACITY

The breaker shall be capable of small inductive currents i.e., breaking steady and transient magnetizing current those occurring while switching unloaded transformers having rating 40/20 MVA , 132/33 KV power transformers at 145 KV without giving rise to undue over voltage and without re-strike.

2.7 AUTOMATIC RAPID RECLOSING

The operating duty of the circuit breaker shall be “O-Dead Time-CO-Re-closing Time-CO” in accordance with latest edition of IEC-62271-100. The values of dead time and reclaiming time shall be 0.3 second and 3 min. respectively.

2.8 TEMPERATURE RISE

The maximum temperature attained by any part of the equipment when inservice at site under continuous full load conditions and exposed to the directrays of sun, shall be within the limits of concerned IEC.

2.9 CAPABILITY TO WITHSTAND MECHANICAL STRESSES

The complete circuit breaker assembly shall be able to withstand a wind force

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of 150kg/m2 and 0.3 g of seismic accelerating force in any direction due to earthquake shocks for such occurrence.

3.0 OPERATING MECHANISM

3.1 GENERAL REQUIREMENTS

3.1.1.1 The circuit breaker operating mechanism shall be highly reliable and will havesufficient energy to provide full making and latching current ability of 80 KA on all the poles, simultaneously.

3.1.2.1 The circuit breakers shall be power operated by compressed air pneumatic/ mechanical mechanism. Change The three poles of the breaker shall operate simultaneously through a mechanical coupling.

3.1.3.1 Provision shall be made for local electrical control and a local/remote selector switch with enough contacts in the cubicle of breaker. In local position the switch shall isolate the close and trip circuit completely. Provision shall be made for local electrical control and a local/remote selector switch with enough contacts in the cubicle of breaker in local position the switch shall isolate the close and trip circuit completely. if technically compatible with design of breaker a manual emergency local tripping arrangement shall be provided on the breaker for use in an emergency of during maintenance. This emergency trip is intended for use should a failure of any part of D.C. control circuits including breaker trip coil take place preventing remote electrical tripping.

3.1.4.1 Operating mechanism shall be suitable for high speed re-closing and shall be trip free and with anti-pumping device (as per definition of clause-5, IEC62271-100) for closing of breaker electrically and either mechanically or pneumatically. It shall be strong, rigid, positive and fast in operation. There shall be no objectionable rebound and the operating mechanism shall not require any critical adjustment.

3.1.5.1 Breaker shall be provided with ON/OFF mechanical indicator in a position, so that a man standing on ground may easily see it, with the mechanism housing closed. An operation counter shall also be provided which shall be visible from the ground even with mechanism housing closed.

3.1.6.1 Working parts of the mechanism shall be made of corrosion resisting material. Bearings which require grease shall be equipped with pressure type grease fittings. Bearing pins, bolts, nuts and other parts shall be adequately pinned or locked to prevent loosening of charging adjustment with repeated operation of the breaker. Working parts of the mechanism shall be made of corrosion resisting material bearings which require grease shall be equipped with pressure type grease fittings. Bearing pins. Bolts, nuts and other parts shall be adequately pinned or locked to prevent loosening of charging adjustment with repeated operation of the breaker.

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3.1.7 CONTROL

3.1.7.2 Electrical tripping of the breakers shall be performed by shunt trip coils. However, provision shall be made for local electrical controls for this purpose.

3.1.7.3 The mechanism shall normally be suitable for remote electrical operations from control room. Purchaser shall feed both the trip circuits from independent station batteries of 110 Volts DC.

3.1.7.4 The closing coil shall operate correctly at all values of voltage between 85% and 110% of the rated DC voltage. The shunt trip coil shall operate correctly under all operating conditions of the circuit breaker and all values of supply voltage between 70% and 110% of voltage.

3.2.0 PNEUMATICALLY OPERATED MECHANISM

3.2.1 145 KV Breakers pneumatically operated mechanism shall obtain supply ofcompressed air system with one compressor only.

Operating mechanism shall be capable of operations with (2) two trip coils by independent trip circuits, pressure switches, coils each connected to different sets of protective relays.

3.2.2 The breaker shall be provided with a compressor system. Independently adjustable switches with insulated contacts shall be provided on each circuit breaker for purposes of lower pressure alarm and lockout in case of insufficient pressure to complete a closing, opening or re-closing duty.

3.2.3 The pressure switches with adjustable contacts and isolating values to actuate a lockout device shall be provided. This lockout device, with provision for remote alarm indication shall be incorporated in each circuit breaker to prevent operation whenever the pressure of the air operating mechanism is below the required value for satisfactory operation. The scheme should permit operation of all blocking and alarm relays as soon as the pressure transient present during the rapid pressure drop has been damped and a reliable pressure measurement can be made. Such facilities shall be provided for the following conditions :

1. Trip lockout pressure

2. Close lockout pressure

3. Low pressure alarm

4. Auto re-close lockout pressure

3.2.4 After failure of supply the local air receiver and operating mechanism shall becapable of two closing and two opening operations at rated fault currents.

3.3.0 SPRING OPERATED MECHANISM

3.3.1 Spring operated mechanism shall be complete with motor. Opening spring andclosing spring with limit switch for automatic charging and other necessary

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accessories to make the mechanism. A complete operating unit shall also be provided.

3.3.2 As long as power is available to the motor, a continuous sequence of the closing and opening operations shall be possible. The motor shall have adequate thermal rating for this duty.

3.3.3 After failure of power supply to the motor one close open operation shall be possible with the energy contained in the operating mechanism.

3.3.4 Break operation shall be independent of the motor which shall be used solely for compressing the closing spring. Facility for manual charging of the closing spring shall also be provided. The motor rating shall be such that it requires not more than 30 seconds for full charging of the closing spring

3.3.5 Closing action of circuit breaker shall compress the opening spring ready fortripping.

3.3.6 When closing springs are discharged after closing a breaker. Closing springs shall be automatically charged for the nest operation and an indication of this shall be provided in the local and remote control cabinet.

3.3.7 Provisions shall be made to prevent a closing operation of the breaker when the spring is in the partial charged condition. Mechanical interlocks shall be provided in the operating mechanism to prevent discharging of closing springs when the breaker is already in the closed position.

3.3.8 The spring operating mechanism shall have adequate energy stored in theoperating spring to close and latch the circuit breaker against the rated makingcurrent and also to provide the required energy for the tripping mechanism ifcase the tripping energy is derived from the operating mechanism.

3.3 OPERATING MECHANISM HOUSING

3.3.1 Operating mechanism and all accessories shall be enclosed in a weather proof.Vermin proof mechanism cabinet of high strength epoxy base painted/ galvanized steel sheet construction of appropriate thickness hinged doors giving access to the mechanism at the front shall be provided. Suitable gaskets shall be provide to make the mechanism housing water proof. Dust and vermin proof. The housing latch shall accommodate pad lock requiring a 12 mm dia hole pad lock and duplicate keys shall be furnished by the Bidder. A common marshalling box for the three poles of the breaker shall be provided along with supply of tubing

3.3.2 The operating mechanism shall have aluminum casting suitable for outdoor duty. Control coils and auxiliary switches shall be fixed on operating mechanism. All electrical accessories including heater other than control coils and auxiliary switch shall be mounted inside one common control cabinet (marshalling box) which shall be made of 2mm thick sheet steel. All mechanical and electrical components inside the cabinet shall be mounted on angled frame. The cabinet shall be duly painted and IP55 protected suitable for

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out door purpose. The cubicle shall have padlock arrangement on door.

3.3.3 Suitable 230 volts A.C. heaters shall be amounted in the housing to prevent condensation and shall be controlled by thermostat so that the cubicle temperature is always maintained approximately 10 deg C above the outside Air temperature. ON/OFF switch and fuses/MCB shall also be provided.

3.3.4 Terminal block shall be furnished in the mechanism housing. Terminals for D.C. and A.C. shall be provided separately and isolated from each other. Terminal for the control and other circuit shall be suitable for accommodating 3 core 2.5mm2 copper conductor cable leads. Spare terminals for control wiring shall be provided. All wiring in the house shall be of standard insulating material and shall be such that it shall not support combustion. Suitably rated switches for A.C. supply shall be provided in the mechanism to enable the control supply to the breaker to be cut off. A light point with a control switch shall also be provided.

4.0 TERMINAL BLOCK AND WIRING :

4.1 Terminal connectors in the terminal block shall be of ELMEX make and havethe following features and must be provided with shorting and disconnecting links to facilitate isolation of any desired connection or circuit.

4.2 For the safe contact condition and lightness of screws the terminal body, bridge, pressure pad and the screws shall be of high strength brass. The outer surfaces of all metal parts shall be coated suitably for protection against atmospheric effect.

4.3 SCREW LOCKING

All the screws shall be secured by reaction principals against unintentional self loosening.

4.4 THREADING

The threading parts shall be such that if the screws are adequately tightened for checking purposes it shall not break or become free. For studs and screws female threads shall be provided by using flawless taps to get strong threads.

4.5 CLAMPING OF CONDUCTORS

Terminal connector shall be such that the conductor can be fixed with adequate contact pressure and without undue damage to the conductor. While tightening the screws/nuts the terminal connectors shall not move or get displaced. For easy connections of even the thinnest conductor and providing rigid connections without any damage, the bottom of the terminal body shall be flat. The terminal connector shall also be suitable for accommodating at least 3 crores of 2.5 sq. mm., copper conductor cable without any preparation viz. lugs, clamping soldering etc. The contact pressure shall not be transferred through insulating material. Gripping of conductor shall be made effective by a pressure pad between metal surfaces only.

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4.6 TERMINAL BLOCK HOUSING

These shall be made from high grade melamine, thermosetting molding powder having the highest unit tracking property. The impact strength shall be in between 0017-0019 kg-m tested in accordance with clause 0.3.2 table 1 of IS:3669 B-1966, testing method must be adopted as per clause II of IS 2221 of 1962.

4.7 TERMINAL BLOCKS

Terminal blocks shall be of disconnecting type.

4.8 SHORTING LINKS

Circuit Isolation Link

The circuit isolation link shall be provided in each and every connector of terminal blocks.

Shorting Links

The provision of permanent (removable) shorting links in each terminal connector shall be done (whenever required), so that any two adjacent terminals can be shorted effectively (maximum) to consecutive five terminal Connectors.

4.9 MOUNTING DEVICE

The terminals shall be mounted by clipping action at two points on the aluminum/steel channel as per DIN 46277/1 and these shall be easily removable without affecting the mounting of adjacent terminals.

4.10 MARKING/ LABLES/FERRULES/TERMINAL NOS

The marking labels on each side of ends shall be fitted permanently with duly engraved descriptions. The embossing shall be of permanent type scratch proof and suited to tropical climatic condition. The size shall be such that these may easily be inserted on the P.V. C. insulation 2.5mm2, copper conductor cable and shall not come out itself.

4.11 MOUNTING FOR TERMINALS

The terminal connectors shall be mounted in such a fashion that connections are made on lifting up the disconnecting link.

4.12 END CLAMPS

To avoid side ward movement and to hold the terminals closely together, the end clamps shall be provided at both the ends of the terminal.

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4.13 TESTING BUSH AND SCHEMATIC DIAGRAM

The testing bushes shall be provided on the top and bottom of each terminal of terminal block. A schematic diagram shown on a PVC plate with screen printing of permanent nature (non-scratch able, clearly visible) shall be riveted / affixed on the side of control cubicle door. Similarly the terminal block arrangement on separate plate shall be riveted on the control/cubicle door.

4.14 COLOUR OF TERMINAL BLOCKS

The following colours of terminal blocks shall be used:

a) For A.C. circuit terminal block : Red colour

b) For D.C. circuit terminal block : Conventional colour

4.15 VOLTAGE AND CURRENT CARRYING CAPACITY

The rating of terminal connector shall be of 15 Amps. and 250 volts D.C foruninterrupted duty, complete with insulting barriers at both end of terminalblock (if necessary).

4.16 ELECTRICAL TRENCH

Terminal connector housing shall be provided with a through and throughrunning recess i.e. electrical trench on both sides of terminal for removing dustwith blower.

5.0 A.C. CIRCUITS

5.1 HEATERS

The controlling fuse/MCB, link and switch/MCB for the heater shall be provided in its own pole cabinet. The thermostat at a preset of 50 deg C permanently shall be provided in the cubicle to control the individual heater.

5.2 D.C. CIRCUIT

No local fuse and links shall be provided in the circuit breakers cubicle for theD.C. circuits. Suitable rotary switch/MCB shall be provided in such cases.

5.3 AUXILIARY CIRCUIT BREAKERS CONTACTS (USED IN TRIPPINGAND CLOSING CIRCUITS)

Circuit breaker’s auxiliary contacts used in the tripping/closing circuit for breaking of tripping/closing currents shall be rated for not less than 10 Amps. 110 Volts D.C. The material of contacts and their arrangement shall be such that the contact resistance shall be minimum to avoid unnecessary heating and contact pressure shall not reduce before at least 10,000 operations.

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5.4 PRESSURE LOCKOUT CONTACTOR

For the purpose of locking out, an auxiliary contactor in conjunction withair/gas pressure switch in closing/tripping circuits to be used.

5.5 COLOUR OF WIRING

The following colour shall be used in the wiring :

a) A.C. circuit : Black

b) D.C. circuit : Grey

c) Earthing : Green

6.0 BUSHING AND INSULATORS

6.1 Porcelain used for bushing shall be homogenous free from lamination, cavitiesand other flaws or imperfections that might affect the mechanical or dielectric quality and shall be thoroughly vitrified, tough and impervious to moisture.

6.2 Glazing of the porcelain shall be uniform and brown in colour, free from blisters, bums and other defects. Bushing shall be designed to have ample insulation, mechanical strength and rigidity for the conditions under which they will be used all bushings of identical rating shall be interchangeable.

6.3 Puncture strength of bushings shall be greater than flashover value. When operating at normal rated voltage, there shall be no electric discharge between the conductor and bushings which would cause corrosion or injury to conductors, insulators, or supports by the formation of substances produced by chemical action. No radio disturbance shall be caused by the bushings when operating at the normal rated voltage.

6.4 All iron parts shall be given zinc chrome coating hot dip galvanized and all joints shall be airtight. Surfaces of the joints shall be airtight. Surface of the porcelain parts shall be made smooth by grinding and metal parts by machining. Bushing design shall be such as to ensure a uniform compression on the joints.

6.5 The basic insulation level of the bushings, insulating porcelains and the external insulator supports etc. shall be 1050KV (peak) and shall be suitable for insulation in heavily polluted atmosphere with minimum total creepage distance of 6125mm as per relevant IEC. The minimum clearance in air between phases and live parts to earth shall be as per relevant IEC.

6.6 The high pressure air passage in the hollow insulator should be protected by suitable insulating tube which should withstand static. Air pressure equal to twice the normal working pressure.

6.7 Oil filled bushing should be free from oil leakage and should be designed to prevent accumulation of explosive gases and to provide adequate oil circulation to remove internal heat. Adequate means should be provided to accommodate

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conductor expansion and there should not be any undue stressing of any part due to temperature changes. They should be equipped with liquid level indicators and means for sampling and draining oil from the nushings.

7.0 CONTACTS :

7.1 Main contacts shall have ample area and contact pressure for carrying the ratedcurrent and the short time rated current of the breaker without excessive temperature rise which may cause pitting or welding. Contacts shall be easily replaceable and shall have a minimum of movable parts and adjustments to accomplish these results. Main contacts shall be the first to open and the last to close so that there will be little contact burning and wearing.

7.2 Arcing contacts, if provided, shall be the first to close and last to open and shallbe easily accessible for inspection and replacement. Tips of arcing and maincontacts shall be silver plated or have a tungsten alloy tipping.

8.0 INTERLOCKS

8.1 All the three poles shall trip simultaneously on a pneumatic/electricalcommand. Pole discrepancy timer relay shall be supplied with each breaker totrip the breaker as well as to give a remote trip discrepancy alarm.

8.2 The following air / gas pressure alarm / inter lock shall be provided on thecircuit breaker each with 2 contacts :

i. Low pressure pre-locking alarm switch

ii. Low pressure closing / tripping lockout interlock.

iii. Low pressure auto re-closing lockout interlock.

9.0 AUXILIARY SWITCHES

9.1 Each circuit breaker shall be provided with10 normally open & 10 normallyclosed cotacts on each pole and 12 normally open and 12 normally closedcontacts common for all three pole operations. All switches shall be positivelydriven (not by spring) in both directions.

9.2 Normal position of auxiliary switches refers to contact position when circuitbreaker is open.

10.0 PNEUMATIC SYSTEM

All compressed air cabin connections specially between ceramic and metallic components shall be completely tight for pressures up to twice the rated pressure for breaker operation. The gaskets used for these joints shall have a long life under climatic conditions as already specified in this specification. Necessary arrangement for draining the condensed moisture from the lower points in the pneumatic system should be incorporated.

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11.0 UNIT COMPRESSED AIR SYSTEM

11.1 Each SF6 Circuit Breaker should consist of two number unit compressors. Eachcompressor shall be capable to feed air for all operations of the circuit breaker satisfactorily. The other compressor shall be as stand by for emergency purposes although both will run simultaneously. All necessary electrical/pneumatic connections between compressors and each pole of circuit breaker shall be carried out by Bidder.

11.2 The initial filling time of the compressed air system shall not be more than 72.75 minutes (approx) with compressor running under normal operating conditions. The minimum running time of the compressor for replenishing the air system from the present starting pressure to the rated pressure shall not be more than 10 minutes. The flow capacity of all the valves shall be at least 20% greater than the total compressor capacity.

11.3 The complete details of compressor unit air receivers, the automatic control equipment and other accessories included in the plant shall also be supplied along with the breaker and compressor units. The complete system scheme and layout of automatic control equipment and air compressor equipment shall be furnished with circuit breaker/compressor plant.

11.4 A clock / counter shall be provided in the control cubicle of the compressor unitfor registering the total nos. of operations / cumulative operation time of thecompressor unit.

11.5 The Unit compressed air system shall meet the following requirements:-

a) The compressed air system shall be provided with necessary piping,piping accessories, control valves, safety valves, filters, reducing valves, isolating valves, drain ports etc. Also the unit compressed air system shall be provided with suitable anti-vibration pads.

b) The compressors shall be of air cooled type and mounted within the operating mechanism housing OR on civil foundation with canopy(cover).

c) The air receiver shall have stored energy for 2 CO operations of thebreaker at the blocking pressure for auto re closing duty withoutrefilling. The unit compressor shall be capable of building up requiredpressure for another 2 CO operations within 30 minutes.

11.6 Air Compressor

a. The air compressor shall be of air cooled type complete with cylinderfabrication, drive motor etc. The compressor shall be rated for the following duty :

i. Total running time of Compressor to Not exceeding 80 minutesbuild up the Rated pressure from Atmospheric pressure.

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ii. Normal running air changing

iii. Air changing time after one Close-open operation from Rated pressure

Not exceeding 15 minutes

considering 10% leakage per day

Not exceeding 15 minutes

b. Compressor shall be driven by automatically controlled motors conforming tothe requirements.

c. The compressor shall be provided with automatic adjustable unloading deviceduring starting.

11.7 Air Receivers

a. Air receiver shall be designed in accordance with the latest edition of theASME Code for Pressure Vessel - Section VIII of BS 5179 A corrosionallowance of 3.0 mm shall be provided for shell and dished ends.

Receivers shall be hot dip galvanized.

b. Connections for air inlet and outlet, drain and relief valves shall be flanged typeor screwed type only.

c. Accessories such as suitable sized safety valve to relieve full compressor discharge at a set pressure equal to 1.1 times the maximum operating pressure, blow off valve, auto drain tap with isolating and by-pass valve, dial type pressure gauge and drain valve and test connection shall be provided.

d. Air receiver shall have at least 50% spare capacity, calculated on the basis oftotal air requirement for 2 CO operations.

11.8 Quality of Air

Compressed air used shall be dry and free of dust particle and fully compatible with the materials used in the pneumatic operating mechanism. Arrangement for conditioning the compressed air if required shall be provided as an integral part of air compressor system.

11.9 Control and Control Equipment

a. The compressor control shall be of automatic start/stop type initiated bypressure switches.

b. All the necessary compressor control equipment shall be housed in a totally enclosed sheet steel cabinet also conforming to requirements. Pressure gauges and other indicating devices control switches shall be mounted on the control cabinet.

c. A glass window shall be provided for viewing the indicating instrument/gauges.

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11.10 Compressed Air Piping, Valves and Fittings

a. The flow capacity of all valves shall be a least 20% greater than the totalcompressor capacity.

b. The high pressure pipe and air system shall be such that after one O-0.3 sec-COoperation the breaker shall be capable of performing one CO operation within 3minutes.

c. All compressed air piping shall be bright annealed, seamless phosphorousDeoxidized Non-Arsenical Copper alloy as per BS : 2874 or stainless steel pipe(C-106 of BS : 2871-1957)

d. All joints and connections in the piping system shall be brazed or flared asnecessary.

e. All compressed air piping shall be carried out in accordance with BS : 162.

f. Compressed air piping system shall be completed with Saddle clamps tosupport the piping system at suitable intervals. Necessary bolts, nuts, pipefixing clamps etc. shall be included in the Scope of Bidder.

11.11 Tests

In accordance with the requirement, the compressors and its accessories shallconform to type tests and routine tests as per applicable standards.

12.0 TERMINAL CONNECTORS

12.1 6 nos. terminal connectors shall be provided with each circuit breaker. Theseshall be suitable for ACSR ZEBRA conductor. The terminal pad of equipment and terminal connector shall be manufactured from same materials i.e., Aluminum alloy. The temperature of the clamps shall not exceed 80 deg C Corona rings shall be provided at the breaker terminal, if required.

12.2 Two clamp type grounding terminals, each suitable for clamping the grounding conductor, shall be provided on each circuit breaker.

12.3 Terminal connector should be designed for current ratings and shall comply inall respects including temperature rise, resistance, tensile strength and shortcircuit current withstand capacity tests as specified in IS:5561-1970 or latestrevision thereof.

13.0 SULPHUR HEXAFLUORIDE GAS (SF6)

a. The SF6 gas shall comply with IEC-376, 376A and 376B and shall be suitablein all respects for use in the switchgear under the operating conditions.

b. The high pressure cylinders in which the SF6 gas is shipped and stored at site shall comply with requirements of the following standards and regulations:

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IS:4379- Identification of the contents of industrial gas cylinders.

IS:7311- Seamless high carbon steel cylinders for permanent andHigh pressure liquefiable gases.

c. The SF6 gas shall, be tested for purity, dew point air hydrolysable fluorides andwater contents as per IEC-376, 376-A and 376-B and test certificates shall befurnished to Purchaser.

14.0 SPECIFIC REQUIREMENT OF SF6 C.B.

14.1 Circuit breakers shall be of single pressure type with two air compressor forpneumatic operations. Circuit breakers shall be so designed that upon loss ofpressure the gap between open contacts shall be suitable to withstand at leastthe rated voltage at zero gauge pressure of gas.

14.2 Design and construction of the circuit breaker shall be such that there shall beno possibility of gas leakage and moisture content.

14.3 In the interrupter assembly there shall be an absorbing product box to eliminateSF6 decomposition products and moisture.

14.4 When pole unit (interrupter) is removed SF6 gas shall not drain out from thepole. Facility shall be available so that a complete pole unit can readily bereplaced by another pole unit without disturbing the other poles.

14.5 Material used in the construction of circuit breakers shall be such as to fullycompatible with SF6.

14.6 Each pole shall form an enclosure filled with SF6 gas. The pressure of pole shall be monitored and regulated by individual pressure switches. Adequate O-ring seals with test hole for leakage test of the internal seal shall be provided on each static joint.

14.7 Sufficient SF6 gas shall be provided to fill all the breakers installed at a substation. Rate of leakage of SF6 gas shall not be more than 1% per year.

14.8 The circuit breaker shall have facilities as to reduce the gas pressure within the circuit breaker to a value not exceeding 8 mill bars within 4 hours or less. The breaker shall be capable of withstanding this degree vacuum without distortion or failure of any part.

14.9 The Circuit Breakers shall be designed for pressure withstand values, much higher than the rated operating pressures to minimize damages to operators in the event of gas or vapors escaping under pressure.

14.10 SF6 gas shall comply with IEC-376 and be suitable in all respects for use incircuit breakers under the operating conditions.

14.11 The high pressure cylinders, in which the SF6 gas is dispatched and stored at site, shall comply with the requirements of the local regulation and by-laws.

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14.12 Sufficient SF6 gas shall be provided to fill all the circuit breakers installed plusan additional 20% of the quantity to compensate for losses during futureoperations.

15.0 MOUNTING STRUCTURE

15.1 The circuit breaker shall be suitable for mounting directly on plinth. Suitablesteel structures, supporting column for mounting the circuit breakers shall also be supplied along with the breaker. The steel structures shall be pillar/lattice type and galvanized as per relevant IS. The drawing of the offered steel structure should be sent with each breaker along with other technical details etc.

16.0 INTERPOLE WIRING

Necessary electrical wires/air pipes required or inter pole connections shall also be in the scope of supply. All cables to be used by Bidder shall be armored and shall be as per IS-1544 (1100 volts grade) only copper conductor shall be used. Minimum size of conductor shall be 2.5 sq. mm (copper).

17.0 INSULATION REQUIREMENT OF CIRCUIT BREAKERS

The insulation phase to ground, the insulation between open contacts and the insulation between phases of the completely assembled circuit breaker shall be capable of withstanding satisfactorily dielectric test voltage corresponding to the basic insulation level of 1050KV (peak).

The minimum clearance in air between phases and live parts to earth should be as per IEC. The breaker poles should be suitable to be placed 4.5 meters apart center to center.

18.0 FITTING AND ACCESSORIES

Following fittings and accessories shall be provided as an integral part of theequipment.

i. Pneumatic operating mechanism housing completes with provisions ofpadlocks and keys.

ii. Space heaters with automatic thermostat control.

iii. Two unit compressors with common air receiver for 245 KV Breaker &One unit compressor with air receiver for 145 KV Breaker

iv. Operation counter

v. Pressure gauges

vi. Gas density detectors (Temperature compensated pressure switch)

vii. Local/remote change over switch.

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viii. Manually operated tripping push button/lever (mech.), convenientlylocated to trip all 3 phases simultaneously

ix. Control switch to cut off control power supply (A.C. supply only).

x. Fuses as required

xi. Two earthing terminals

xii. Anti pumping relay

xiii. Pole discrepancy relay

xiv. Rating and diagram plate as per IEC.

xv. Main jumper terminal connectors (6 nos.)

xvi. Spare 20% SF6 gas with cylinder.

19.0 NAME PLATE

Each circuit breaker shall be provided with a name plate and followinginformation shall be provided :

i. Manufacturers name and trade mark.

ii. Serial No.

iii. Rated voltage

iv. Rated insulation level

v. Rated frequency

vi. Rated normal current

vii. Rated short circuit breaking current

viii. Weight

ix. Rated duration of short circuit.

x. Rated supply voltage of closing and opening device.

xi. Rated pressure of compressed gas supply for operation.

xii. Specification No.

xiii. Year of supply

xiv. Name of Purchaser

20.0 TYPE TESTS

The Bidder shall furnish the certified copies of type tests already carried out on offered 145 KV SF-6 circuit breaker. They shall include but not limited to the following tests-

a) Making capacity breaking capacity and short time current rating tests.

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b) Operation tests and mechanical endurance tests.

c) Temperature rise tests of the main and auxiliary circuits and measurement of the resistance of the main circuit.

d) Impulse voltage dry and wet withstand tests and one minute power frequency voltage dry and wet withstand test.

e) Line charging breaking current test.

f) Tests to prove the rated transient recovery voltage and RRRV of the circuit breaker.

g) Short line fault tests.

H) Out of phase switching tests

I) Braking small, inductive current test.

j) Switching impulse voltage test.

k) Measurement of RIV level.

l) Partial discharge test.

m) Corona extinction voltage tests.

ROUTINE TESTS

20.1 The Bidder shall completely assemble and test each SF6 circuit breaker in accordance with IEC-62271-100 amendment there of to ensure satisfactory working of all the component parts and assembled breaker as a whole.

20.2 Following routine tests, whether included in the manufacturer’s routine test ornot, shall be carried out on each circuit breaker.

20.2.1 One minute power frequency voltage dry withstand test as per IEC-62271-100

(i) At 110% of rated voltage and maximum pressure

(ii) At 70% of rated voltage and minimum pressure

(iii) At rated voltage and rated pressure

(iv) Tripping at 70% of rated voltage and minimum pressure

20.2.2 Measurement of the resistance of the main circuits as per IEC 62271-100.

20.2.3 Speed curves for each circuit breaker shall be obtained with the help of suitableoperation analyzer to determine breaker contact movement during opening, closing auto-re closing and trip free operation under normal as well as limiting operating conditions (control voltage) pneumatic pressure etc. The test shall show the speed of contact at various stages of operation, travel of contact opening, opening time, closing time, shortest time between separation and meeting of contact at break/make operation etc.

20.2.4 High voltage test on control and auxiliary circuits.

20.2.5 Routine test performed on breaker operating mechanism as per IEC.

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20.2.6 Routine test reports of compressor unit associated with the circuit breaker shallbe furnished.

20.2.7 Routine test report of terminal connectors shall be furnished in accordance toIS-5561-1970.

21.0 SITE TESTS

21.1 The test mentioned under clause nos.20.2.2, 20.2.3 and 20.2.4 shall beconducted on the completely assembled breaker at site

21.2 All vessels / accessories which operate under pressure shall be tested according to relevant standards and six copies of the test certificate incorporating the following minimum information shall be submitted for each breaker.

Description of item, Bidder/manufacturer sl. no., date of manufacture and test, drawing’s number, material composition, working and design pressure, details of test carried out and reference standards, test results identification, mark, name and seal of approval of testing authority shall be furnished by the Bidder.

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TS-2 B

TECHNICAL SPECIFICATIONS OF 36 KV VACUUM CIRCUIT BREAKERS

1.0 STANDARD

The 36KV Vacuum circuit breaker shall comply with the requirements of latest issue of IEC-62210 except where specified otherwise in this specification. Equipment having better quality than the standards mentioned may also be considered provided documentary evidences are furnished.

2.0 PRINCIPLE PARAMETERS

The 36KV Vacuum circuit breaker shall be suitable for outdoor operation insolidly grounded system under climatic conditions specified and should have thefollowing ratings:-

i) Nominal system voltage 33 KV

ii) Highest system voltage 36 KV

iii) Rates voltage 36 KV

iv) Interrupting capacity 1000 KVA

v) Rated normal current 1250 A

vi) Rated frequency 50 c/s

vii) Rated basic insulation level 170 KV

viii) Rated short circuit current 25 KA

ix) Rated short circuit making current 35 KA

x) Rated operating sequence 0-0. 3 Sec.-Co-3 min-Co

xi) Total break time for any current 5-6 c/sup to the rated breaking current

xii) Control circuit voltage 110 VDC

3.0 GENERAL

3.1 The 36KV Vacuum circuit breaker shall be supplied as a complete unit in allrespects.

3.2 The Vacuum circuit breakers shall provide for rapid and smooth interruption of current under all conditions, completely suppressing all undesirable phenomenons, even under the most severe conditions or while interrupting small currents, loading or logging reactive currents. The rate of rise of restriking voltage across the circuit breaker, switching on inductive or capacitive load,

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should not exceed 2,5 times the normal phase to neutral voltage. The total break time for the circuit breaker throughout the range of their operating duly shall be stated in the Bid and guaranteed particulars of the breaker.

3.3 MOUNTING

The circuit breaker shall be suitable for mounting on galvanized steel structures.The prices of necessary structures for mounting the circuit breakers shall beincluded in the cost of circuit breakers.

3.4 CONSTRUCTION

3.4.1 The circuit breaker shall consist of three identical phases used with a commonoperating mechanism

3.4.2 Circuit breaker should include the prices of necessary special tools for the erection & maintenance. List of such tools should be furnished with the Bid.

3.5 OPERATING DUTY

Operating duty of the breaker should be 0-0.4 Sec. CO-3 min-CO.

3.6 TEMPERATURE RISE

The maximum temperature attained by any part of the equipment, when in service at site under continuous full load condition and exposed to the direct rays of sun, shall not exceed the permissible limit specified in the relevant standard. When the standards specify limits of temperature rise, these shall not exceed when corrected for the difference between ambient temperature at site and the ambient temperature specified in the approved specification.

3.7 INSULATION OF CIRCUIT BREAKER

The insulation to ground between open contact and between phases of the completely assembled circuit breakers shall be capable of withstanding satisfactorily dielectric test voltage corresponding to the basic insulation level i.e. 170 KV.

3.8 OPERATING MECHANISM

3.8.1 General

3.8.2 The circuit breaker operating mechanism shall be highly reliable and will havesufficient energy to provide full making and latching current ability of all the poles simultaneously.

3.8.3 The circuit breakers shall be power operated by motorized spring mechanism. The three poles of the breaker shall operate simultaneously through a mechanical coupling.

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3.8.4 The operating mechanism shall be strong, positive quick and removable withoutdisturbing other parts of the breaker. The mechanism of breaker shall be a suchthat the failure of spring will not prevent tripping. The mechanism shall be tripfree electrically and mechanically.

3.8.5 All working parts in the mechanism shall be of corrosion resistant material andall bearings which require grossing shall be equipped with pressure greasefittings.

3.8.6 Suitable anti pumping feature shall be incorporated in the circuit breaker. There shall be no objectionable rebound and the operating mechanism shall not require any critical adjustment.

3.8.7 It shall be strong, rigid, positive and fast in operation, Provision shall be made for local electrical control and local/remote selection with enough contacts in the cubicle of the breaker. Manual emergency local tripping arrangement shall be provided on the breaker for use in emergency during maintenance. This emergency trip is intended for use, shall a failure of any part of D.C. control circuits including trip coil takes place preventing remote electrical tripping.

The control circuits shall be designed to operate on 110V DC

3.8.8 Breaker shall be provided with ON/OFF mechanical indicator in position so that a man standing on ground may easily see it, with the mechanism housing closed. The operation counter shall be provided.

3.8.9 Electrical tripping of the breaker shall be performed by shunt trip coil. A shunt trip coil shall operate correctly under all operating conditions of the circuit breaker and all values of supply voltage between 70% to 110% of the rated voltage. A closing release shall operate correctly at all values of voltage between 80% to 110% of the rated voltage.

3.8.10 Working parts of the mechanism shall be made of corrosion resisting material. Bearings which require grease shall be equipped with pressure type grease fittings. Bearing pins, bolt-nuts and other parts shall be adequately pinned or locked to prevent loosening or changing adjustment with repeated operation of the breaker.

3.8.11 Power supply for auxiliaries will be available at 415 volts 3 phases 50 hertz, 230volts, single phase, 50 Hertz or 110 volts D.C.

4.0 OPERATING MECHANISM HOUSING

4.1 Operating mechanism and all accessories shall be enclosed in a weather proofcabinet of high strength steel sheet construction, the thickness of which shall not be less than 2 mm. Hinged doors giving access to the mechanism at the front shall be provided. Suitable gaskets to make the mechanism housing water proof, dust proof and vermin proof. The housing latch shall accommodate padlock. A common marshalling box for the three poles of the breaker shall be provided suitable 230 volts A.C. heaters shall be mounted in the housing to prevent condensation, so that the cubicle temperature is always maintained

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approximately 100C above the outside air temperature.

Miniature circuit breaker shall also be provided. Terminal board shall be furnished in the mechanism housing. Terminals for D.C. shall be isolated for each other. Terminal for the control and other circuits shall be suitable for accommodating 2.5 sq.mm. stranded copper conductor cable leads. Spare terminals for control wiring in the housing shall be provided. Insulation material shall be such that it shall not support combustion, suitable rated switches for A.C. supply shall be provided in the mechanism to enable control supply of the breaker to be cut off. A 5A, 3 pin plug point with a control switch shall be provided.

5.0 BUSHING AND INSULATORS

5.1 Porcelain used for bushing shall be homogenous, free from lamination, cavitiesand other flaws of imperfections that might affect the mechanical or dielectric quality and shall be thoroughly vitrified, tough and impervious to moisture.

5.2 Glazing of the porcelain shall be uniform and brown in colour, free from blisters, burns and other defects. Bushing shall be designed to have ample insulation, mechanical strength and rigidity for the conditions under which they will be used. All bushing of identical rating shall be interchangeable.

5.3 Puncture strength of bushings shall be greater than flashover value, when operating at normal rated voltage. There shall be no electric discharge between the conductor and bushings which could cause corrosion or injury to conductors, insulators or supports by the formation of substance produced by chemical action, No radio disturbance shall be caused by the bushings when operating at the normal rated voltage.

5.4 All iron parts shall be given hot dip zinc/chrome coating and all joints shall be air tight. Porcelain parts shall be designed by grinding and metal parts by machining. Bushing design shall be such as to ensure a uniform compression on the joints.

5.5 The basic insulation level, of the breaking chamber porcelain, insulator supports etc shall be 170KV peak and shall be suitable for insulation in heavily polluted atmosphere with minimum total creepage distance as per relevant IEC.

5.6 The minimum clearance in air between phase and live parts to earth shall be asper IEC.

5.7 Necessary cable glands for the cables of the operating mechanism shall beprovided along with a large common gland plate. Total requirement and size ofthe cable glands will be as below: -

1. 2 x 2.5 sq.mm. Cu Cable 4 nos.

2. 4 x 2.5 sq.mm. Cu Cable 5 nos.

3. 6 x 2.5 sq.mm. Cu Cable 3 nos.

4. 10 x 2.5 sq.mm. Cu Cable 1 no.

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6.0 CONTACTS

Main contacts shall have ample area and contact pressure for carrying the ratedcurrent and the short time rated current of the breaker without excessivetemperature rise which may cause pitting or welding.

7.0 INTERLOCKS

7.1 Provision shall be made to enable mechanical/electrical interlocking withopening or closing of the isolator with the circuit breaker 3 nos. castel locks with one key for each circuit breaker as well as associated isolators shall be supplied along with the circuit breaker. A switch (KS) which will be actuated by the insertion of key shall be provided

7.2 The following interlocks shall be provided on the vacuum circuit breaker eachwith 2 contacts.

7.2.1 Spare contact for tripping.

7.2.2 All the three poles of the breaker shall trip simultaneously on an electricalcommand.

8.0 AUXILIARY SWITCHES

8.1 Circuit breaker shall be provided with 6 normally open and 6 normally closedcontacts. All switches shall be driven positively i.e. (not by spring) in bothdirections.

8.2 Normal position of auxiliary switches refer to contact positions when circuitbreaker is open.

9.0 TERMINAL CONNECTORS

6 nos. rigid type aluminum terminal connectors each suitable for ACSR Twin Panther/ Twin Moose conductor with 90 mm, centre to centre spacing shall be provided with each circuit breaker.

The temperature at the clamp shall not exceed 800C. Two number grounding terminals suitable for clamping the ground conductor shall be provided on breaker. The terminal connector shall conform in respect of temperature rise, tensile strength and short circuit breaking current withstanding capacity tests etc. as per IS 5561-1970 or its latest revision thereof.

10.0 TERMINAL BLOCK AND WIRING

10.1 Terminal connection in the terminal block shall have the following features andmust be provided with shorting links.

10.2 For the safe contact conditions and tightness of screws, the terminals, body bridge, pressure pad and the screws shall be of high strength brass. The outer

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surface of all metal parts shall be nickel plated for protection against atmospheric effects.

10.3 24 nos. terminals for current transformers as spares shall be provided in the circuit breaker cubicle on a separate terminal block. Elmex make terminals shall be provided. These terminals shall have a facility of inserting testing bushes. Four number testing bushes shall also be supplied fitted in the terminal block.

10.4 SCREW LOCKINGAll the screw shall be secured by reaction principle against unintentional self loosening.

10.5 THREADINGThe threading parts shall be such that if the screws are adequately tightened for checking purposes shall not break or become free. For studs and screws, female threads shall be produced by using flaw less taps to get strong threads.

10.6 CLAMPING OF CONDUCTORS

Terminal connector shall be such that the conductors can be fixed with adequate contact pressure and without undue damage to the conductor, while tightening the screw or nuts, the terminals connectors shall not move or get displaced.

For the easy connections even the cheapest conductor and providing rigid connections without any damage, the bottom of the terminal body shall be flat.

The terminal connector shall also to suitable for accommodating at least 2 cores of 2.5 sq. mm. copper conductor cable without any pre-operation vis lugs, clamping, soldering etc.

10.7 TERMINAL BLOCKS

These shall be made from high grade melamine thermosetting molding power having the highest unit tracking property. The impact strength shall be between 0017-0019 tested in accordance with clause no. 3.2 table-1 of IS 3669 B-1966. Testing method must be adopted as per clause-II of IS 2221 of 1962. Terminal blocks shall be snap on type to facilitate easy removal of terminal from the channel and thus the dust may be removed from the terminal block housing.

10.8 SHORTING LINKS

The provision of permanent (removable) shorting links in each terminal connector shall be provided (where over required so that any two adjacent terminals can be shorted effectively.

10.9 MOUNTING DEVICE

The terminal shall be mounted by clipping action at two points on the aluminum/steel channel as per DIN 46277 and these shall be easily removable without affecting the mounting of adjacent terminal.

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10.10 MARKING LABLES

The marking labels on each side of ends shall be fitted permanently duly engraved descriptions. The embossing shall be of permanent type scratch proof and suited to tropical climatic condition. The size shall be such that these may easily as inserted on the P.V.C. insulation of 2.5 mm, copper conductor cable and shall not come out itself.

10.11 DIMENSION OF CLEARANCES AND CREEPAGE DISTANCES

This will be such that auxiliary circuitry can withstand the routine test requirement of 2KV for 1 minute in line with IEC 62210.

10.12 MOUNTING FOR TERMINALS

The terminal connectors shall be mounted in such a fashion that connections are made on lifting up the disconnecting link.

10.13 END CLAMPS

To avoid side ward movement and to hold the terminals closely together, the endclamps shall be provided at both the ends of the terminals.

10.14 COLOUR OF TERMINAL BLOCKS

The following colours of terminal blocks shall be used.

a) For A.C. circuit terminal block - Red colour.

b) For D.C. circuit terminal block - Conventional colour.

11.0 FITTING AND ACCESSORIES :-

Following fittings and accessories shall be provided as an integral part of theequipment.

Sl.No. Description of fitments Quantity

1. Vacuum interrupters 3

2. Set of porcelain insulator housingVacuum interrupter 3and glass fiber drive rod

3. Galvanized steel support structure with foundation 1bolts

4. Three phase interphase assembly connected to 1common Operating shaft.

5. Motor/manually charged independent spring closing 1mechanism having :-

i. Mechanical ON/OFF indicator

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ii. Spring charged indicator

iii. Manual trip/close device (mechn.) to trip allthe three phases simultaneously

iv. Operation counter

v. Spring charging motor

vi. Tripping and closing coil suitable for 110V DC

6. Local contril panel comprising

i. Local/remote selector switch 1

ii. Control I/R/C with pistol Grip handle(spring return to neutral type)

iii. pole MCB suitable 'or AC supply rated6 Amps for heater circuit.

iv. 75 watt, 230 V & anticondensation heater withthermostat and switch.

v. Antipumping contactor.

vi. Cable gland plate.

vii. Set of 13 Nos. control cable glands.

7. Spring charging handle 1

8. Set of 3 nos. castel lock with 1 key 1

9. Spare terminals for CT 24

10. Earthing terminals 2

12.0 NAME PLATE

12.1 The firm shall affix a name plate on each vacuum circuit breaker havingfollowing informations:

i. Manufacturer's name and trade mark.

ii. Sr. Number

iii. Rated Voltage

iv. Rated insulation level

v. Rated frequency

vi. Rated normal current

vii. Rated short circuit breaking current

viii. Weight

ix. Rated supply voltage of closing and opening devices

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x. Year of supply

12.2 A metallic plate containing schematic diagram/wiring diagram etc, embossedover it shall be affixed in the control cubicle of the breaker.

13.0 A.C. CIRCUITS

13.1 HEATERS

The controlling M.C.B. for the heater circuit of the control cabinet shall be provided.

13.2 D.C. CIRCUITS

No local fuse and links shall be provided to the circuit breaker's cubicles in the D.C. circuits.

13.3 AUXILLIARY CIRCUIT BREAKER CONTACTS (Used in Tripping and Closing Circuits)

Circuit breaker auxiliary contacts used in trip closing circuit shall be rated for not less than Amps at 110 volts D.C.

The materials of contacts and their arrangement shall be such that the contact resistance shall be minimum to avoid unnecessary heating and contact pressure shall not reduce before at least 10,000 operations.

13.4 COLOUR OF WIRING

The following colours shall be used in the wiring

a. A.C. Circuit Black

b. D.C. Circuit Grey

c. Earthing Green

12.0 MOUNTING STRUCTURES

12.1 Suitable mounting frames for installing the circuit breaker shall be suppliedalongwith the breaker. The mounting structures shall be made of steel, suitabletreated and galvanized for outdoor duty as per relevant ISS. The drawing of thesteel structures shall also be furnished for approval.

13.0 TESTS

13.1 TYPE TEST

Each circuit breaker shall comply with the type tests and test reports shall be furnished alongwith the Bid.

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13.2 ROUTINE TEST :

13.2.1 Routine tests as per IEC-66 shall be carried out in each circuit breaker in the

presence of Purchaser’s representative if so desired. All test reports shall be

submitted and get approved from the before the dispatch of the equipment.

13.2.2 Following routine tests whether included in the manufacturer's routine test or not

shall be carried out on each circuit breaker.

13.2.2.1 One minute power frequency voltage dry withstand tests as per IEC 62210

13.2.2.2 Routine tests of breaker operating mechanism as per IEC 62210 or its latest

version.

13.2.2.3 Measurement of the resistance of the main circuits as per IEC 62210

13.2.2.4 To determine breaker contact movement during opening, closing operation

under normal as well as limiting operating condition, control voltage etc. The tests shall show the speed of contacts at various stages of operation travel of contacts, closing time, shortest time between separation and meeting of contacts at break/make operation etc.

13.2.2.5 High voltage test on control and auxiliary circuits.

14.0 SITE TESTS

The tests mentioned under clause 14.2.2.2 to 14.2.2.5 shall be conducted on the completely assembled breaker at site provided that testing equipments are made available at site by the Purchaser.

15.0 COMPLETENESS OF CONTRACT

Any fittings, accessories or apparatus which might not have been mentioned in the specn, but which are usually necessary for the equipment of similar

nature, are to be provided by the Bidder without extra cost. All apparatus must be complete in all detail whether mentioned in the specification. or not.

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