SECTION-4 CHAPTER-4

TECHNICAL SPECIFICATION

FOR 36 kV VACUUM CIRCUIT BREAKER (630A & 2000 A)

1. Scope: 1.1 This specification covers the design, manufacture, inspection and testing before dispatch,

packing & delivery at site of 36 kV Vacuum Circuit Breaker complete with all accessories including terminal connectors & supporting structure required for satisfactory operation in various sub-stations in the state.

1.2 It is not the intent to specify completely herein all the details of design and construction of

36kV Vacuum Circuit Breaker. However, 36kV V.C.B. shall conform in all respect to the high standard of design and workmanship and be capable of performing in continuous commercial operation up to Bidder's guarantee in a manner acceptable to HVPNL, who will interpret the meanings of drawings and specifications and shall have the power to reject any work or material which in his judgment are not in accordance there with. The circuit breaker offered shall be complete with all parts, necessary for their effective and trouble free operation. Such components shall be deemed to be within the scope of supply, irrespective of whether they are specifically brought out in the commercial order or not.

2. Standards:

The 36kV Vacuum Circuit Breaker shall conform to the latest editions and amendments available at the time of supply of the standards listed here under: Sr. No.

Standard Ref. No. ISS

Title IEC

1. ISS 13118 Specification for High Voltage Alternating Current Circuit Breaker.

IEC-56

2. ISS 2071 (Part-I) Method of High voltage testing General definitions and test Equipment.

IEC-601

3. ISS 3716 Application guide to insulation Co-ordination.

IEC-71-2

4. ISS 2099 Bushing for alternating voltage 1000 volts.

IEC-137

5. ISS 4759 Hot dip zinc coating on structural steel and other allied products

6. ISS 2633 Method for testing uniformity of coating on zinc coated articles.

7. ISS 2147 Degree of Protection provided by enclosures for low voltage switch gear and control.

8. -- Indian Electricity Rules, 1956 --

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2.1 Equipment meeting with the requirement of other authoritative standards which ensure equal or better quality then the standards mentioned above shall also be acceptable. Where the equipment offered by the Bidder Conforms to other standards, salient points of difference between the standards adopted and the specified standards shall be clearly brought out in the offer. Four copies of reference standards in English language shall be furnished alongwith the offer.

3. Climatic Conditions: The 36 kV Vacuum Circuit Breakers shall be suitable for continuos satisfactory operation

under climatic conditions listed below: 1. Location In the State of Haryana Pradesh 2. Max. Ambient Air-temperature 500C 3. Min. Ambient Air-temperature -2.50 C 4. Average daily Ambient temp. 320 C 5. Max. Relative humidty 100%C 6. Annual rainfall 900 mm 7. Max. Wind pressure 195 Kg/meter2 8. Isoceraunic level (days/year) 45 9. Altitude above mean Sea-level less than 1000 meter 10. Seismic level (Horizontal Acceleration) 0.3 g

4. Principal Parameters

I) Nominal system voltage 33kV(RMS)

ii) Highest system voltage 36kV(RMS)

iii) No. Of poles 3

iv) Frequency 50±2.5 Hz

v) Interrupting Capacity 1000 MVA 2500 MVA

vi) Basic Insulation level 170 kV (P)

vii) Operating duty 0.3min-co-3min-co

viii) Total break time for any current 3 cycles max.(60 ms)

upto the rated breaking current. ix) Control circuit voltage i) 220 volts DC ±10% to –15%

ii) 240 volts +10% to - 15% for single phase AC supply

iii) 415 volts 10% to - 15% for 3 phase AC supply

x) Continuous current rating 630 Amp. 2000Amp.

at ambient temperature of 50oC xi) Short Circuit breaking 16 KA for 1 second 40 KA for 1 second

current. xii) Creepage distance 900 mm or more

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5. General Technical Requirements 5.1.1 The circuit breaker shall consist of 3 phase vacuum circuit breaker consist of porcelain clad

for each phase mounted on common clad and mechanically connected for gang operation. The unit shall be capable of with-standing pressure resulting from any specified performance of the breaker.

5.1.2 Material used in construction of circuit breakers shall be acceptable of withstanding the degree of vacuum without distortion or failure of any part.

5.1.3 The circuit breaker shall be supplied complete in all respect with necessary lifting tools, foundation bolts and other accessories considered necessary by Bidders for the satisfactory operation.

5.1.4 The vacuum interrupter bottles shall be completely maintenance free.

5.1.5 Tips of main contacts shall be heavily silver plated.

5.1.6 All equipment accessories and wiring shall have tropical protection, involving special treatment of metal and insulation against fungus, insects and corrosion.

5.1.7 The safety clearances of all live parts of the equipment shall be as per relevant standards.

5.1.8 Electrical as well as mechanical indicator shall be provided to show open and close positions of breaker. It shall be located in a position where it will be visible to a man standing on the ground with mechanism housing closed. And operation counter shall also be provided with each breaker.

5.2 Mounting: The circuit breakers shall be suitable for mounting on steel structures. The prices of necessary frames for mounting & including connecting material of the circuit breakers shall be quoted for separately.

5.3 Bushing & Insulator: The basic insulation level of the bushings and support insulator shall be as per clause 4(vi) and the circuit breakers shall be suitable for installation in heavily polluted atmosphere. The porcelain used shall be homogenous and free from cavities or other flaws. These shall be designed to have adequate insulation, mechanical strength and rigidity for satisfactory operation under conditions specified above. All the bushings of identical ratings shall be interchangeable. The puncture voltage shall be entirely free from disturbances, when operating at voltage up to a voltage 10% above rated voltage and shall also be free from external and internal corona. Metal parts and hardware shall be hot dip galvanized as per ISS-2633 latest edition.

5.4 Operating Mechanism: 5.4.1 The circuit breaker shall be designed for remote control from the control room and in

addition there shall be provision for manual operation of circuit breaker during maintenance and for local electrical tripping and closing.

5.4.2 The circuit breaker shall have a mechanical 'open' and 'closed' indicators in addition to facilities for remote electrical indications

5.4.3 The operating mechanism shall be electrical motor operated spring closing mechanism type. The motor shall operate at 240 volts Single phase or 415 volts three phase AC supply with a voltage variation +10% to - 15% in Clause – 4 (ix). The mechanism shall be trip free

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electrically and mechanically. All working parts in the mechanism shall be of corrosion resistant material and all bearings which require greasing shall be equipped with pressure grease fittings. The mechanism shall be strong and quick action and shall be removable without disturbing the other parts of circuit breakers. The mechanism of the breaker shall be such that failure of any spring will not prevent tripping and will not cause tripping or closing

5.4.4 The operating mechanism along with its accessories shall be mounted in the weather proof sheet steel cabinet of 2 mm CRCA or 2.64 mm thick M.S sheet with hinged doors of 3 mm thick M.S sheet & lock device located near the circuit breaker. The local control switch and the breaker position indicator shall be provided in this cabinet. The circuit breaker shall also be provided with means for manual operation for maintenance purpose.

5.4.5 The control circuit shall be designed to operate on 220 volt DC and it shall be possible to adapting it to work on other voltage by simply changing the operating coils. The closing coil shall be designed to operate satisfactorily at control voltage from 85% to 110% of the normal voltage. It shall also be ensured that the trip coil can operate from 70% to 110% of the normal DC voltage as provided in IS: 13118/91. An AC heater shall be provided in the cabinet to prevent moisture condensation. The 2000A VCB should have the provision of Double Trip Coil.

5.4.6 Necessary cable glands for the cables of the operating mechanism shall also be provided. The Bidder will use the terminal block of moulded dielectric having brass studs for termination of HVPNL's control cables to be laid for remote control of the circuit breaker including its automatic tripping under fault condition. The entire small wiring to be carried out by the manufacturer at the time of constructing the circuit breaker shall be terminated at the terminal block with the help of lugs duly crimped on to the cable cores. The Bidder will supply sufficient number of cable glands & lugs for the HVPNL's use at the time of erection of equipment.

5.4.7 Thermostat controlled space heater, internal illumination lamp and 3 pin 5 Amp. socket with individual ON/OFF switches shall be provided in the cabinet.

5.5 TERMINAL CONNECTOR: Each circuit breaker shall be provided with requisite number of clamp type bimetallic terminal connectors suitable for single/twin/triple 0.4/0.5 Sq. inch ACSR Zebra/Moose Conductor. Two nos. terminal earth connectors for earthling connection shall also be supplied.

5.6 Interlocking: Provision shall be made to enable electrical interlocking with the opening or closing of the isolator when breaker is closed etc. Provision should also be made for light indication arrangement on control & relay panel when the electrical motor is in operation for charging spring, so that breaker is not operated from remote during the charging cycle. All electrical & mechanical interlock which are necessary for safe & satisfactory operation shall be furnished.

5.7 AUXILIARY SWITCHES: At least eight pairs of auxiliary contacts each of the normally open and normally closed type shall be provided in circuit breaker for customer's use for the remote indication and control scheme of the circuit breaker and for providing safety interlocking with associated equipment by the HVPNL. Contact shall be provided with trip coil for pre close and post close supervision of trip circuit.

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5.8 Temperature rise limit: The temperature rise on any part of equipment shall not exceed the max. temperature rise limit specified in ISS-13118 over an ambient temperature of 500C.

5.9 Erection Tools: Special tools and standard accessories required for assembly and for maintenance of the breakers should also form a part of the supply. Necessary list should be supplied with the tender.

5.10 Rating Plate: Circuit breaker and its operating device shall be provided with a rating plate marked with but not limited to following data.

1. Manufacturer's name, Type of breaker.

2. Serial Number. 3. Rated voltage. 4. Rated normal continuous current. 5. Rated insulation level. 6. Rated frequency. 7. Rated short time breaking current with rated duration. 8. Total weight of breaker.

6.0 TESTS 6.1 Type Tests: The equipment should be offered type test. Test reports should not more then seven years

old reckoned from date of bid opening in respect of all the tests carried out in accredited laboratories (based on ISO/IEC) by a reputed accreditatic body or witnessed by HVPN or another electric power utility and be submitted by the successful bidder to HVPNL for approval as schedule given in Bar Chart.

i) Impulse withstand voltage test ii) Power frequency voltage withstand dry test on main circuit iii) Short circuit withstand capability test iv) Mechanical endurance test v) Temperature rise test vi) Radio interference voltage (RIV) vii) Measurement of the resistance of main circuit viii) Short time withstand current and peak withstand current test

6.2 Routine Tests: As per quality assurance program (QAP). 6.3 Acceptance Tests: The following acceptance tests as stipulated in the relevant ISS-13118 shall be carried out

by the Supplier in presence of HVPNL representative, unless dispensed with in writing by the HVPNL.

i) Power frequency voltage withstand dry test on main circuit ii) Voltage withstand test on control and auxiliary circuits iii) Measurement of resistance of the main circuit

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iv) Mechanical operating test v) Design and visual test

7.0 Inspection: 7.1 The inspection may be carried out by the HVPNL at any stage of manufacture. The

successful Bidder shall grant free access to the HVPNL's representative at a reasonable time when the work is in progress. Inspection and acceptance of any equipments under this specification by the HVPNL shall not relieve the Bidder 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 Bidder shall keep the HVPNL informed in advance about the manufacturing programme so that arrangement can be made for inspection.

7.2 The HVPNL reserves the right to insist for witnessing the acceptance/routine testing of the bought out items.

7.3 No material shall be despatched from the point of manufacture unless the material has been satisfactorily inspected tested and further despatch authorised by HVPNL.

8.0 DOCUMENTATION: 8.1 The successful bidder shall submit four sets of following drawings for HVPNL approval.

List of Drawings and documents:

The Bidder shall furnish four sets or relevant descriptive and illustrative published literature pamphlets and the following drawings for preliminary study along with the offer.

a) General outline drawings showing dimensions and shipping weights, quantity of insulating media etc.

b) Sectional views showing the general constructional features of the circuit breaker including operating mechanism, arcing chambers, contacts with lifting dimensions for maintenance.

c) Schematic ideograms of breaker offered for control supervision and re-closing.

d) Structural drawing, design calculations and loading data for support structures.

e) Foundation drilling plan and loading data for foundation design. NOTE: All above drawings should be a minimum space (14x10cm) for stamping the

approval of drawings by HVPNL.

8.2 TEST REPORTS: i Four copies of type test reports shall be furnished to the HVPNL within one month of

conducting the tests. One copy will be returned duly certified by the HVPNL to the bidder within three weeks thereafter and on receipt of the same, bidder shall commence with the commercial production of the concerned material.

ii Four copies of acceptance test reports shall be furnished to the HVPNL. One copy will be returned, duly certified by the HVPNL and only there afterwards the material shall be despatched.

iii All records of routine test report shall be maintained by the Bidder at his works for periodic inspection by the HVPNL.

iv All test reports of tests conducted during manufacture shall be maintained by the Bidder. These shall be produced for verification as and when requested for by the HVPNL.

8.3 GUARANTEES: i) The Bidder shall guarantee that the material, workmanship and performance of the plant

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and accessories shall meet the requirement of this specification.

ii) Should the Bidder wish to depart from the provision of the specifications either on account of manufacturing practice or any other reasons he shall draw attention to the proposed points of departure in his bid and submit such full information, drawings and specification so that merit or his such proposal may be full under-stood. This specification shall be held binding unless the departures have been fully recorded as required above.