1. Technical Specification -MCC

8/12/2019 1. Technical Specification -MCC

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Umiam Stage-II (R&M Works) Vol.

Motor Control Center

I.6 SCOPE

6.1 This section of the specification covers the design, engineering, manufacture, testing

before dispatch and guarantee for two years of Station Power Supply Facilities for Umiam

Stage-II Hydro Electric Power Station as stated below:

6.1.1 The scope of supply shall include all parts, accessories, spares, etc., which are

necessary for construction, operation and maintenance of complete equipment though these

are not individually and specifically stated or enumerated. Corresponding parts of all the

equipments and the spares shall be of the same material, dimensions, workmanship and finish

and shall be interchangeable. All the materials and workmanship shall be of suitable

commercial quality as have proven successful in their respective uses in similar services and

under similar conditions.

6.1.2 The scope of the supply includes the following:

No. Qty

(1) Motor Control Center One (1) set

6.1.3 In addition to the above, the bidders shall offer following services:

The Contractor shall design the facilities without modification and/or changing the major

important relative locations and spaces for the MCCs. Refer to relevant drawings and

subsection of this specification.

I-6.3 QUANTITY AND RATINGS OF MCCs

6.3.1 Required number

One (1) set of Motor Control Center shall be supplied. The set shall be composed of

following cubicles and main components.

Name of Cubicle Required number Main Components

Motor Control Centers One(1) Molded case circuit breakers,

contactors, thermal overload

realys, control devices, relays,

switches, status & fault

indications. etc.

6.3.3 Ratings


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(1) AC 415 V circuits

(a) Operating Duty Continuous

(b) Rated Voltage AC 415 V

(c) Rated Frequency 50 Hz

(d) Rated Nominal Current for Bus 400 A

(e) Rated Short-time Withstand Current for bus 12 kA, 2 second

6.3.4 Temperature Rises

Limits of temperature and temperature rises for various parts, materials of the metal-

enclosed switchgear shall be complied with the latest edition of IEC 60947.

I-6.4 CONSTRUCTIONS OF STATION POWER SUPPLY FACILITIES

The station power supply facilities shall be designed to comply with the requirements in the

latest edition of the IEC 60947 & IEC 60439 standard.

The station power supply facilities shall be equipped with protection of equipment against

external influences and protection against approach to or contact with live parts and

against contact moving parts to meet with the requirement of IP 31 degree of theprotection.

The frame of the station power supply facilities shall be made of angle steel. The enclosure

and

separation of those, on the other hand, shall be made of hot or cold rolled steel of which

thickness

shall not be less than 2 mm. But, 1.6mm or more thickness could be acceptable for the-top

plate of those.

Ventilating openings and outlets, for the station power supply facilities shall be so

provided that IP 31 degree of the protection also required on the enclosure is obtained. The

wire mesh or the equivalent having suitable mechanical strength may be acceptable to

apply for the ventilating openings and outlets Lifting eyebolts or other means for handling

shall be provided at the top four corners of each board of the station power supply facilities

.An earthing copper-made conductor shall be provided extending the whole length of the

station power supply facilities.

The main bus shall be three-phase air insulated high-conductivity copper barswith ample


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The individual temperature detector leads shall comprise a three-conductor cable

which is oil, moisture, and heat resistant. The cable shall have armor protection

against mechanical damage. The conductors shall be stranded, tinned, copper with

insulation system having a temperature rating of at least 105 C.

The leads from speed signal devices to governor through terminal boxes and fromtemperature detectors to thermometers and/or temperature recorders through terminal

boxes shall be shielded. Outlet leads from transducers shall also be shielded. In

addition, any other outlet cables that would be subject to induced signals should be

shielded.

All instruments, relays and auxiliary devices or equipment and accessories shall be

furnished, mounted and wired.

Wiring thereof shall be connected by crimp-type terminals (e.g. AMP terminal).

(2) The wirings shall be gathered to one place to facilitate the connection with

outgoing cable Connection of which shall be made at terminal blocks.

(3) Both ends of low voltage wires shall be terminated by crimp-type terminals with

insulation colored sleeve (e.g. AMP terminal pre-insulated) and provided with

the terminal number rings, and the number shall be recorded in the wiring

diagram.

(4) The interior wirings of the control cabinets, control boards, motor control

centers, metal-enclosed cubicles and switch boxes shall be concentrated to the

terminal blocks with removable transparent insulation cover and the terminal

numbers installed at the lower part of the equipment in order to be connected

easily to external cables.

(5) DC circuit shall be separated by a terminal block provided on each control

board, cubicle, motor control center, control cabinet and control box for easy

detection at grounding fault.

(6) The terminal blocks shall be of the 1100 V molded block type with insulating

barrier between terminals. The terminal block for current transformer

secondary circuit shall be of short-circuit type. The terminal block shall be

attached with a removable transparent insulation cover and the terminal

numbers.


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(7) Each terminal block shall have marking strips, and shall be equipped with the

crimp-type terminal (e.g. AMP terminal pre-insulated) for No. 12 AWG (3.5

mm2 equal) or larger to make connection with outgoing cable. The terminal

blocks shall be provided with twenty-five (25) per cent of the employed but not

less than ten (10) additional terminals as spares for each control boards,cubicle and cabinet besides the necessary number. Two (2) or more external

wires shall not be connected at one (1) terminal.

(8) The terminals of motors or other equipment shall have pressure compression

type terminal lugs with which outgoing cables are to be connected.

(9) Test terminals shall be provided on all electrical enclosures where current and

voltage transformer secondary circuits are connected the terminal shall be of

the flush type for plug system with dust-proof cover.

2.13 Cables and Electrical Conduit

(1) Cable shall conform to IEC, ICEA, IS or JIS standards specified in the relevant

clause.

(2) The Bidder shall furnish all cables that will be used for controlling, operating

and supplying power for the Equipment of the Renovation and Modernization

Project, in quantity as required.

(3) The cables shall not have cut or scratches in the insulation or protective covering

or in the C conductors. No splices shall be made in the conductors except at the

terminal blocks of the Equipment. All cables shall be marked by the Bidder at

each end with mark bands attached by the cable code numbers at cable

installation. Such cable mark bands shall be provided by the Bidder. Drawings

indicating the cable routes and cable codes shall be submitted by the Bidder

before installation.

(4) The electrical conduits and the accessories shall conform to ANSI C80-l, NEMA

FB-l or JIS standards.

(5) The Bidder shall furnish all conduits, accessories and fitting which will be

required for laying the cables in quantity as required.


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Umiam Stage-II (R&M Works) Vol.-I

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(6) All bends of conduits shall be gradual and smooth to permit the pulling of

insulated electrical wires and cables without undue stress or damage of the

insulation covering or sheath. Ends of conduit shall be fitted with bushing in

order not to injure sheath of cables or insulation coverings.

2.14 Color Coding of Wiring(1) The following color identification shall be applied to the insulation of wires used

for back wiring of control boards, cubicles, motor control centers, control

cabinets, control boxes and auxiliary equipment.

Secondary circuit of voltage transformer Red

Secondary circuit of current transformer Black

DC circuit Blue

AC circuit except power circuit Yellow

Neutral circuit Light grey

Grounding circuit Green

(2) Three (3) phase outgoing cables shall be color coded as follows:

Phase A (or Phase U, or R) Red

Phase B (or Phase V, or S) Yellow

Phase C (or Phase W, or T) Blue

Neutral Light grey

Ground Green

(3) DC supply shall be color coded as follows:

Positive White

Negative Black

Common Light grey

2.15. Name Plates and Marking

All nameplates, card-plates, and designation shall meet the requirement of actual usage.

Name plates, card-plates, instruction plates, warning signs, and any markings whatever

on the Equipment, parts and accessories thereof shall be in the English language.


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The name plates provided on the top of the panel and/or the boards installed in the

power house, such as the cubicles for 11 -kV metal-enclosed switchgears, the panels for

control and protection boards, and the panels for station power supply facilities shall be

made of transparent materials with engraved from back-side and named- with black

letters and white ground.

The name plates provided on the surfaces of the turbines and generators shall be made

of stainless steel or bronze and the name plates of other equipments shall be preferably

made of stainless steel and indicated with the manufacturers standard indication

methods.

Aluminum photo name plates shall be acceptable for card-plates, instruction plates,

warning signs and, any marking on the panel and/or the boards installed in the power

house.

The name plates made of paper and/or corrosion-prone materials shall not be accepted.

The switch handles shall be engraved with the device function number colored in white.

The Bidder shall submit a list of the plates and/or designation for approval.

If the Bidder wants to provide to attach or affix some plates and/or labels on the

Equipment in order to give special cautions, information and/or instructions to all the

persons, visitors, operators, workers, etc. who will access the Equipment, the plates

and/or labels shall be written in English.

The detailed to be shown on the nameplates, etc. shall be indicated on the drawings for

approval.

2.16. General Requirements of the Equipment

(I) All the Equipment and parts shall be new and durable for long-term use, and

shall satisfy all requirements with which complete products should generally

comply even if such requirements are not provided in the Specifications.

(2) All the Equipment shall be of a convenient construction for disassembling,

inspection and erection. All the Equipment shall have markings, such as the

centerline mark, match mark, etc., in order to facilitate the Installation at the

Site.

(3) All surfaces of water passages shall be of even and smooth finish, and provided


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with a smooth-contoured hydraulic surface.

(4) The Bidder shall furnish all foundation materials necessary for Installation of the

Equipment including foundation base and foundation bolts and nuts.

(5) Conductors shall not be joined by soldering except for inevitable positions.

(6) Unless otherwise specified, induction motors shall be of the direct-on line starting,

drip-proof type. When these are operated, it shall not show any trouble at the rise

of both voltage and frequency of power source by 30%, resulting from the full load

rejection of the turbine-generator.

(7) Magnetic contactor used in various switches shall be made of arc resistant metal

and have sufficient capacity against closing of inrush current and tripping of over

load current, and the contact part shall be free from over-wearing and miss-contact

for a long period of service.

(8) Electric contact of dial type thermometers, thermal relays, oil level relays, oil

pressure relays, air pressure relays, limit switches, etc. shall be able to break a

current or possible maximum inductive load (2A) at 110 V DC safely.

(9) The contact surfaces (both male and female) for the circuit sheet (plug-in type

printed card) shall be gold-plated. All circuit sheets shall be suitably treated toprevent damage to connection or components by hydrogen sulphide gas.

(10) The relays (control relays, protection relays and auxiliary relays) and meters shall

be air-sealed to prevent corrosion by hydrogen sulphide gas.

(11) The cubicles, boards, motor control centers and control cabinets shall be provided

with target type group fault indicators, unless otherwise specified in the

Specifications.

When any trouble is detected, the trouble shall be distinguished on these indicators and

contacts shall be provided in the indicators for indication.

(12) Each control board and cubicle shall be provided with at least one compact

fluorescent lamp (AC 240V, 50 Hz) inside for interior lighting, and shall be

provided with a door switch. Each cubicle, board, motor control center and control


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cabinet shall be provided with a moisture preventing heater (AC 240 V, 50 Hz) with

a switch and a thermostat, and with AC 240 V, 15 A, conventional receptacles.

(13) Each cubicle, board and control cabinet shall be provided with hinged door with

key-handle, which can be opened by a master key.

(14) The bushings, insulators and porcelain housing used in the Equipment shall have

sufficient mechanical and dielectric strength and shall meet the requirements of US

C38l4, JIS C3824, JIS C385l , ANSI C-76.l or relevant National/International

standards. The surface color of the porcelain shall be chocolate brown

(15) Parts of the Equipment which require inspection and/or replacement shall be

fastened with bolts and nuts instead of built-in bolts.

(16) The ground terminals of the Equipment shall be of the bolt-fastened type, suitable

for hard drawn copper stranded conductor.

For grounding connections in connected boards, such as control board in the

control room etc., an adequate ground bus of copper bar extending the full width of the

broad shall be provided on the lower part of the board, and the secondary circuits of

instrument transformers and shielded tapes of cables, etc. shall be connected to it.

Furthermore the ground bus of copper bar shall be connected mutually and firmly with

that of adjacent board.

(2)Design and Construction

The Motor Control Centre (MCC) shall be installed to supply low voltage power source from the AC

distribution board to auxiliary equipment for the generating units. Each circuit for auxiliary

equipment in the MCC shall be equipped with an individual breaker with an adequate frame and

over-current trip circuit.

The MCC shall also be equipped with automatic start & stop functions (sequence) for the auxiliary

equipment. The MCC shall be completely wired and equipped with sequential controllers, starters,

instruments, protective relays, switches, and lamps, indications and so on required for automatic

sequential controlling and for manual operating the auxiliary equipment to be installed in the power

station.

The auxiliary equipment to be controlled by the MCC are listed below (Refer to the drawing) :


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(2) Requirements for MCC

An independent auxiliary control cubicle shall be provided for the MCC, and shall be installed in

line with the MCC cubicles. The auxiliary control cubicle shall be equipped with all control devices,

relays and wiring necessary for auxiliary control. The status indications (30S) and fault indications

(30F) and manual/automatic changeover switch for each auxiliary shall be mounted on the front

panel of cubicle. Power Supply for MCC shall be through 225 AF/225A incomer from Common-2

AC Distribution Board.

All units in the MCC shall be completely accessible and removable from the front side.

All equipment in the power circuit shall be rated for 1100 volts. The main buses shall be rated for400A and shall withstand 12,000A for 2 seconds under fault conditions without mechanical or

thermal damage.

A grounding bus shall be arranged on the back near the bottom of cubicle.

All starters shall be of combination type with moulded case circuit breakers. The magnetic starters

shall be equipped with three (3) overload relays (single phase) and also with at least two (2) spare

auxiliary contacts (normally open and normally close ones). All overload relays shall be of manually

reset type and adjustable for each motor current at site.

The control voltage shall be 220V AC. If necessary, control transformers with an adequate rating

and suitable protection shall be provided for the MCC cubicles. Counter-measure shall be taken for

each starter to reduce an inrush current at motor starting, if necessary.

i)

Industrial type ammeters for each unit shall be mounted on the front panel of MCC

and shall have a suppressed scale for starting current and motor full load current

deflections at roughly two-thirds of the scale.

j) All ratings indicated in the MCC and name plates mounted on the MCC shall be written inEnglish. All indications and name plate shall be indicated in the approval drawings.

I 6.6 Description of the Operation

Refer to the control block diagrams & MCC SLD for details of Motors & Control Logic


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Two (2) governor oil pumping units for Unit 1 & Unit 2

The start and stop of the oil pumps shall be controlled automatically by the pressure relays

for the pressure oil tank. Pressure oil pumps shall have provision for starting (sequential

operation) during machine starting/stopping from Plant Control System. Changeover of the

oil pump from regular use to stand-by or vice versa shall be manually made by the selector

switch, and each pump shall start and stop manually by the switch mounted on the motor

control center(MCC). Motor capacity is 7.5kW. Starting method is direct-on line.

One (1) automatic valve at intake line from penstock

MCC shall have facility for control of motor for automatic opening & closing of automatic

valve at intake line of penstock valve during machine starting/stopping.

One (1) sand discharge valve for filtering tankMotor operated sand discharge valve shall be operated by a timer through the Motor Control

Center (MCC).

Motor rating is 0.2 kW.

Two (2) automatic main strainers & two(2) sand discharge valves for automatic main

strainers

Motor driven strainers shall be provided for the cooling water supply system. One (1)

strainer shall be used for normal (duty) operation, while the other shall serve as a stand-by.

The main strainer shall be operated by an adjustable timer and/or a differential pressure

switch through the Motor Control Center (MCC). Changeover of the strainer form normal

use to standby or vice versa shall be manually made by the selector switch, and each strainer

shall also start & stop manually by the switch mounted on the Motor Control Center.

Motor rating for automatic strainers is 0.4 kWand for sand discharge valves is 0.2 kW.

Two (2) L.P. air compressor units for common

One (1) compressor shall be used for normal (duty) operation, while the other shall service

as a stand-by. The standby compressor shall automatically start when main compressor willfail to operate.

The start and stop of the compressor shall be controlled automatically by the pressure relays

for the main air tank. Changeover of the compressor from regular use to stand-by or vice

versa shall be manually operated by the selector switch mounted on the motor control center.

Two (2) drainage & dewatering pumping units for power house drain pit


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One (1) pump shall be used for normal (duty) operation, while the other shall service as a

stand-by. The stand-by pump shall start automatically when the water level in the pit

becomes higher than the predetermined level or the normal operating pump fails, and stop

automatically when the water level becomes lower than the predetermined level. Start and

stop operation for the pumps shall be controlled from the Motor Control Center (MCC).

6.7 Spare Parts

S. No. Description Quantity

1 Electromagnetic Contactor One(1) each type

2 Molded case circuit breaker One(1) each type

3 Lamp (In case of LED applied, LED shall be

supplied instead)

Two(2) sets

4 Thermal relay (Each type) Two(2) nos

6.8 Test

Supplier shall provide all type tests reports as per IEC. Routine tests shall be done as per suppliers

own test procedure. Supplier shall submit list of routine tests to be conducted in factory along with

the offer.

6.9 Painting

(1) All the Equipment shall be painted as herein specified. The painting of metalwork shall

include the preparation of the metal surfaces, paint application, protection and drying of the

paint coating as well as the supplying of materials necessary for the entire painting work.

Paints shall be the products of recognized and reputable manufacturers, and proposed

paints shall be approved by Owner.

No painting is required on bronze or corrosion-resisting steel, on rolling or sliding

surfaces or on metal surfaces to be embedded in concrete.

All finished mating surfaces of ferrous metal, including gear teeth, screw threads, bores of

servomotor cylinders, pistons, stems, etc., shall be protected with a heavy coating of

rust preventative compound which shall be readily removable with mineral spirits or

safety solvents.

(2) All metal surfaces to be painted shall be properly treated or cleaned as described herein

prior to the application of paints.


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One coat of coal-tar-epoxy resin paint or equivalent shall be applied to all welded and damaged areas

to a minimum dry film thickness of 30 microns.

After completion of installation, the Bidder shall apply two or three coats of coal-tar-epoxy resin paint

or equivalent to a minimum dry film thickness of 300 microns.

Paint needed for the repair and finishing coat shall be furnished by the Bidder together with the

Equipment in quantity requited.

(9) Surfaces exposed to oil such as the interiors of bearing oil reservoirs shall be sand blasted

to SSPC Specification SP 10 and coated with four coats of oil resistant paint to a minimum

dry film thickness of 60 microns at the Site.

(10) All exterior surfaces of non-embedded piping shall be solvent cleaned and shall be given a

field-applied prime coat followed by a coat of finish paint to be selected. The Bidder shall

furnish the prime coat paint and finished paint as required.

The piping and valves shall be coated with appropriate color paint in compliance with color schedule.

6.10. Packing

(1) All the Equipment shall be carefully packed so as to withstand transportation by sea and

land in tropical moist climate. The electrical equipment shall be completely protected

against moisture and rust from salt water and rain. The same precaution and care shall be

taken for the Equipment and Components that cannot be packed or crated. Machine

finished surfaces of the Equipment shall be adequately protected by rust preventive means.

(2) The spare parts shall be packed and crated firmly to withstand storage for a long time, and

those in need of rust preventive treatment shall be so treated. The spare parts shall bepacked separately from other articles and absolute care shall be taken to prevent spare parts

being packed or crated in the same box or crated with the Equipment or the installation

materials. Packages of spare parts shall carry with notation, which clearly indicates that the

contents are spare parts and shall be accompanied by a list of contents, which sets forth

instruction for handling and storing

1. Technical Specification -MCC

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