Section-8-Circuit Breakers
Section-8-Circuit Breakers
Section-8-Circuit Breakers
Section - 8
220 KV, 132 KV SF6 GAS CIRCUIT BREAKERS AND 33 KV VACUUM CIRCUIT
BREAKERS
2.0 STANDARDS:
2.1 The circuit breakers shall conform to the latest revisions with amendments
available of relevant standards, rules and codes, some of which are listed herein
for ready reference.
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Sl.No. Standard Title
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1. * IEC 62271-100 Ed.1.0 (2001) Specification for alternating current
circuit breakers.
9. IS-2629 Recommended practice for hot dip galvanizing of iron and steel.
13. IS-7285 Seamless high carbon steel cylinders for permanent and high
pressure liquifiable gases.
14. IS-802 Code of practice for use of structural steel (Part-I) in overhead
transmission line towers.
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2.2 Equipment meeting with the requirements of any other authoritative standards,
which ensure equal or better quality than the standard mentioned above shall also be
acceptable, if the equipment offered by the Bidder conforms to any other standards,
salient points of difference between the standards adopted and the specific standards
shall be clearly brought out in relevant schedule. Four copies of such standards with
authentic English translations, shall be furnished along with the offer.
Each of the foregoing supplies shall be made available by the Purchaser at the
terminal point for each circuit breaker for operation of accessories and auxiliary
equipment. Bidder's scope include supply of interconnecting cables, terminal
boxes etc., The above supply voltage may vary as indicated below and all
devices shall be suitable for continuous operation over the entire range of
voltages.
a) AC component 40 31.5 25
(kA rms)
b) % DC component corresponding to corresponding to corresponding to
minimum opening minimum opening minimum
time as per time as per opening time as
IEC-56. IEC-56. per IEC-56.
22. Permissible limit of temperature As per clause 5.28 As per clause 5.28 As per clause
Rise of this of this 5.28 of this
Specification Specification Specification
31. No. of closing and tripping coils. Two trip coils Two trip coils Two trip coils
and one close coil and one close coil and one close
with Anti-pump- with Anti-pump- coil with Anti-
ing arrangement. ing arrangement. pump-ing
arrangement.
(Bidders offering lesser clearances for spacing must substantiate the same with adequate
information on impulse test withstand capability of equipment).
5.1 220 kV & 132 kV Circuit breakers offered shall be sulphur hexa-flouride (SF6)
type only and 33 kV Circuit breakers shall be vacuum type only.
5.2 Any part of the breakers, especially the removable ones, shall be freely
interchangeable without the necessity of any modification at site.
5.3.a) 220 kV SF6 Circuit Breaker shall comprise of three identical single pole units
and are meant for single pole re-closure. In this case pole discrepancy special
features including relays, timers etc., provided to minimize pole discrepancy and
to avoid single phasing shall be highlighted in the bid. Complete circuit breaker
with all the items necessary for successful operation shall be supplied, including
but not limited to the following:
5.3.b) 132 kV SF6 Circuit Breaker and 33 kV vacuum Circuit Breakers shall comprise
of three identical single pole units and are not meant for single pole re-closure.
The units for these breakers shall be linked together mechanically. Complete
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circuit breaker with all the items necessary for successful operation shall be
supplied, including but not limited to the following:
5.3.1 Breaker assemblies with bases, support structure for circuit breaker as well as for
control cabinet, central control cabinet and foundation bolts for main structure
(except concrete foundations), terminals and operating mechanisms are included
in the scope of supply.
5.3.3 In case of 220 kV circuit breakers one central control cabinet for each breaker,
and one control box for each pole shall be provided with all the required
electrical devices mounted therein and the necessary terminal blocks for
termination of inter pole wiring. The necessary inter pole cabling at site shall be
done by the Purchaser based on the schematic, wiring diagram and termination
schedule to be supplied by the successful Bidder.
5.3.4 Instruments, gauges and other devices for SF6 gas pressure, pneumatic/hydraulic
pressure supervision.
5.3.5 All necessary parts to provide a complete and operable circuit breaker
installation such as main equipment, terminal, control parts, connectors and other
devices, whether specifically called for herein or not.
5.4 The 220 kV SF6 circuit breaker shall be designed for high speed single and three
pole re-closing and 132 kV SF6 Circuit breakers and 33kV Vacuum Circuit
breakers shall be designed for high speed three pole re-closing with operating
sequence and timing as specified in clause 4.0 "Principal Parameters".
5.5 The support structure of circuit breaker as well as that of control cabinet shall be
hot dip galvanized. All other parts can be gray color painted as per shade 631 of
IS-5.
5.7 All breakers shall be supplied with terminal connectors. The exact requirement
of terminal clamps would be intimated to the successful bidder.
5.8 The current density adopted for the design of the terminal pads shall in no case
exceed the following values. For copper pads - 1.6 A/sq. mm. and others - 1.0
A/sq. mm.
5.9 CONTACTS:
5.9.1 All making and breaking contacts shall be sealed free from atmospheric effects.
Contacts shall be designed to have adequate thermal and current carrying
capacity for the duty specified and to have a life expectancy so that frequent
replacements due to excessive burning will not be necessary. Provision shall be
made for rapid dissipation of heat generated by the arc on opening.
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5.9.2 Main contacts shall be the first to open and the last to close so that there will be
little contact burning and wear.
5.9.3 If arcing contacts are used they shall be the first to close and the last to open.
These shall be easily accessible for inspection and replacement. If there are no
separately mounted arcing contacts the main contacts shall be easily accessible
for inspection and replacements. Tips of arcing contacts and main contacts shall
be silver plated or have tungsten alloy tipping.
5.9.4 Any device provided for voltage grading to damp oscillations or to prevent
restrict prior to the complete interruption of the circuit or to limit over-voltages
on closing shall have a life expectancy comparable to that of the breaker as a
whole.
5.9.5 Breakers shall be so designed that when operated within their specified rating,
the temperature of each part will be limited to values consistent with a long life
of the material used. The temperature shall not exceed that indicated in IEC-56
under specified ambient conditions.
5.9.6 Contacts shall be kept permanently under pressure of SF6 gas. The poles shall be
partially filled with SF6 gas at the time of dispatch and only topping upto
required pressure shall be permitted at site. The gap between the open contacts
shall be such that it can withstand atleast the rated phase to ground voltage
continuously at zero gauge pressure of SF6 gas due to its leakage.
5.9.7 Specific guarantee that the SF6 gas will not leak more than 1% per year from the
breaker for a minimum period of 10 years from supply or commissioning
whichever is later shall be given. If leakage of SF6 gas occurs beyond this limit
within 10 years the defects in the breaker shall be attended to by the company
free of cost and this shall be done irrespective of the number of leakages during
the period of 10 years. The defect shall be rectified within 7 days from the date
of intimation (by Fax, Cable, Telephone) including travel time of the service
personnel.
If the defects due to which the gas leak occurs, are not attended by the bidder
within 7 days, the cost towards the quantum of gas to be refilled due to the
defective system, shall be recovered from their running bills or shall be made
good by the bidder.
The bidder should give a special guarantee for vacuum bottle/interrupter for 5
years from the date of supply or commissioning whichever is later . Free
replacement, if fails during five years period.
The bidder would not confirm on Clause 5.9.7 and Clause 5.9.8 shall be treated
as non-responsive.
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5.10 PORCELAIN HOUSING:
5.10.1 The porcelain housing shall be of single piece construction without any joint or
coupling. It shall be made of homogeneous, vitreous porcelain of high
mechanical and dielectric strength. Glazing of porcelain shall be uniform brown
or dark brown colour with a smooth surface arranged to shed away rain water or
condensed water particles (fog), free from blisters, burns and similar other
defects.
5.11.1 a) The circuit breakers shall be single pressure type and single break. The
design and construction of the circuit breaker shall be such that there is
minimum possibility of gas leakage and entry of moisture. There should
not be any condensation of SF6 gas on the internal insulating surface of
220 kV and 132 kV SF6 circuit breakers.
d) Each pole of 220 kV and 132 kV SF6 Circuit Breakers shall form an
enclosure filled with SF6 gas independent of the other two poles. The
SF6 gas density of each pole shall be monitored and regulated by
pressure switches .
e) The SF6 gas density monitor of 220 kV and 132 kV SF6 Circuit Breakers
shall be adequately temperature compensated. The density monitor shall
meet the following requirements:
ii) It shall damp the pressure pulsation while filling the gas in
service so that the flickering of the pressure switch contacts does
not take place.
f) Means for pressure relief shall be provided in the gas chamber of circuit breaker
to avoid damages or distortion during occurrence of abnormal pressure increase
or shock waves generated by internal electrical faults, if required for the Circuit
Breakers design. The position of pressure relief devices shall be so arranged as
to minimize danger to the operators in the event of gas or vapour escaping under
pressure.
g) Sufficient SF6 gas for 220 kV and 132 kV SF6 Circuit Breakers shall be
provided to fill all the circuit breakers installed. In addition to this 20% of the
total gas requirement shall be supplied in separate cylinders as spare requirement.
5.12 SULPHUR HEXAFLUORIDE GAS (SF6 GAS ) : (220 kV and 132 kV SF6
Circuit Breakers)
a) The SF6 gas shall comply with IEC-376, 376A and 376B and be suitable
in all respects for use in the switch gear under the worst 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:
IS:7285 Seamless high carbon steel cylinders for permanent and high
pressure liquifiable gases.
c) Test: SF6 gas shall be tested for purity, dew point, breakdown voltage,
water contents as per IEC-376, 376A and 376B and test certificates shall
be furnished to Purchaser indicating all the tests as per IEC376 for each
lot of SF6 gas.
5.13.1 The circuit breakers shall be totally re-strike free under all duty conditions and
shall be capable of performing specified duties without opening resistors.
5.13.2 The circuit breakers shall meet the duty requirements for any type of fault or
fault location, for line charging and dropping when used on an effectively
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grounded system and perform make and break operations as per stipulated duty
cycles satisfactorily.
iii) Clearing short line faults (Kilometric faults) with source impedance
behind the bus, equivalent to symmetrical fault current specified.
v) Breaking 25% of the rated fault current at twice rated voltage under
phase opposition condition.
5.13.4 The critical current which gives the longest arc duration at lockout pressure of
extinguishing medium and the arc duration shall be indicated.
5.13.5 The breakers shall satisfactorily withstand the high stresses imposed on them
during fault clearing, load rejection and re-energisation of lines with trapped
charges. The breakers shall also withstand the voltage specified in clause 4.0
"Principal Parameters" of the specification.
5.14.1 The "Total Break Time" as specified in clause 4.0, "Principal Parameters" of this
section shall not be exceeded under any of the following duties:
5.14.2 The bidder may please note that there is only one specified break time of the
breaker which shall not be exceeded under any duty conditions specified such as
with the combined variation of the trip coil voltage, (70-110%) pneumatic,
hydraulic pressure and arc extinguishing medium pressure etc., the proof for the
total break time of complete circuit breaker shall be furnished.
5.14.3 The values guaranteed shall be supported with the type test reports.
5.15.1 The circuit breakers shall be designed for electrical local as well as remote
control. In addition there shall be provision for local mechanical control
(emergency trip).
5.15.2 The operating mechanism for 220 kV SF6 Circuit Breakers shall be pneumatic
type or hydraulic type or mechanical spring charging type and where as for 132
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kV Sf5 and 33 kV vacuum Circuit Breakers shall be spring charge type operated
by electrical control. The mechanism shall be adequately designed for the
specified tripping and re-closing duty. The entire operating mechanism control
circuitry, individual breaker compressor unit for pneumatically operating
mechanism Circuit Breaker, hydraulic pump for hydraulic mechanism Circuit
Breaker, spring charge motor for spring mechanism Circuit Breaker etc., as
required, shall be housed in an outdoor type, hot dip galvanized or painted steel
enclosure.
5.15.7 The Bidder shall furnish detailed operation and maintenance manual of the
mechanism along with operation manual for the circuit breakers.
5.16 CONTROL:
5.16.1 The close and trip circuits shall be designed to permit use of momentary contact
switches and push buttons.
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5.16.2 Each breaker pole shall be provided with two (2) independent tripping circuits,
valves and coils each connected to a different set of protective relays.
5.16.3 The breaker shall normally be operated by remote electrical control. Electrical
tripping shall be performed by shunt trip coils. However, provisions shall be
made for local electrical control. For this purpose a local/remote selector switch
and close and trip push buttons shall be provided in the breaker central control
cabinet. Remote located push buttons and indicating lamps shall be provided by
the Purchaser.
5.16.4 The trip coils shall be suitable for trip circuit supervision. The trip circuit
supervision relay would be provided by the Purchaser. Necessary terminals shall
be provided in the central control cabinet of the circuit breaker by the Bidder.
5.16.5 Closing coil shall operate correctly at all values of voltage between 85% and
110% of the rated voltage. Shunt trip shall operate correctly under all operating
conditions of the circuit breaker upto the rated breaking capacity of the circuit
breaker and at all values of supply voltage between 70% and 110% of rated
voltage.
5.16.6 Suitable relay for monitoring of DC supply voltage to the control cabinet shall be
provided. The pressure switches used for interlock purposes shall have adequate
contact ratings to be directly used in the closing and tripping circuits. In case the
contacts are not adequately rated and multiplying relays are used then the
interlock for closing/opening operation of breaker shall be with "NO" logic of the
relay i.e. if the DC supply to the interlock circuit fails then it is essential that
breaker trips in order to protect the switch gear and connected equipment like
transformers etc., for any possible faults at that time. Provision for automatic
tripping of the breaker shall be made along with the flag indication for non-
availability of DC supply. The connection must be such that capacitor provided
for this purpose gets charged from the DC source provided by the Board only
and the capacitor supply is released for the tripping circuit as soon as DC supply
fails. It must be possible to close the breaker only after restoration of DC supply.
The entire arrangement of CTD (Capacitor Tripping Device ) facility shall be
mounted on control cubicle for 220 kV and 132 kV SF6 Circuit Breakers.
5.16.7 A local manual closing device which can be easily operated manually by one
standing on the ground shall also be provided for maintenance purposes and
direction of motion of handle shall be clearly marked for the spring operating
mechanism of Circuit Breaker.
5.16.8 The auxiliary switch of the breaker shall be preferably positively driven by the
breaker operating rod and where due to construction features, same is not
possible a plug-in device shall be provided to simulate the opening and closing
operations of circuit breaker for the purpose of testing control circuits.
The spring mechanism shall be fitted with a local manual release, preferably
by a push button to avoid inadvertent operation. Means shall be provided for
discharging the spring when the circuit breaker is in the open position without
circuit breaker attempting to close.
b) The ICU shall be complete with air piping and accessories, all stop
valves, tees, pressure reducers etc., required for normal operation of the
breaker.
c) The breaker local receivers shall comply with the requirements in clause
5.28.
g) All hydraulic joints shall have no oil leakage under the site conditions
and joints shall be tested at factory against oil leakage.
5.21 INTERLOCKS:
1) The minimum vertical clearance from any energized metal part to the
bottom of the circuit breaker (structure) base, where it rests on the
foundation pad, shall be as per the principal parameters clause – 4 in this
specification.
2) The minimum vertical distance from the bottom of the lowest porcelain
part of the bushings, porcelain enclosures or supporting insulators to the
bottom of the circuit breaker base, where it rests on the foundation pad
shall be 2.55 meters for all voltages.
5.23.1 Following is the major fittings and accessories to be furnished by Bidder in the
central control cabinet.
a) Central control cabinet in accordance with clause No.5.31 complete with:
b) Anti-pumping relay.
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c) Rating and diagram plate in accordance with IEC incorporating year of
manufacture.
5.23.2 Additional fittings for pneumatically operated circuit breaker.
a) Unit compressed air system in accordance with clause No.5.29.
b) Breaker local air receivers.
c) Pressure gauge spring loaded safety valve, pressure switch with
adjustable contacts and explosion vents.
d) Pressure switch to initiate an alarm if the pressure in the aux. reservoir
remains below a preset level for longer than it is normally necessary to
refill the reservoir.
e) Stop, non-return and other control valves, pipings and all accessories
upto breaker mechanism housing.
5.25 GALVANISING:
All ferrous parts including all sizes of nuts, bolts, plain and spring washers,
support channels, structures, shall be hot dip galvanised conforming to latest
version of IS:2629 or any other equivalent authoritative standard.
5.26 EARTHING:
Circuit breaker and its operating device shall be provided with a rating plate or
plates marked with but not limited to following data:
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a) Manufacturer's or trade mark.
b) Serial number or type designation making it possible to get all the relevant
information from the manufacturer.
c) Year of manufacture.
d) Rated voltage.
e) Rated insulation level.
f) Rated frequency.
g) Rated normal current.
h) Rated short circuit breaking current.
i) First pole to clear factor.
j) Rated duration of short circuit.
k) Rated auxiliary DC supply voltage of closing and opening devices.
l) Rated pressure of compressed air gas for operation and interruption.
m) Rated out of phase breaking current.
n) Rated supply voltage of auxiliary circuits.
o) Rated supply frequency of auxiliary circuits.
The coils of operating devices shall have a reference mark permitting the data to
be obtained from the manufacturer.
The rating plate shall be visible in position of normal service and installation.
The rating plate shall be weather proof and corrosion proof.
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The temperature rise on any part of equipment shall not exceed the maximum
temperature rise specified below under the conditions specified in test clauses.
Notes: i) When applying the temperature rise of 55 deg.C. care should be taken
to ensure that no damage is caused to the surrounding insulating materials.
ii) The quality of the silver facing shall be such that a layer of silver remains
at the points of contact after the mechanical endurance test. Otherwise,
the contacts shall be regarded as "bare".
iii) The values of temperature and temperature rise are valid whether or not
the conductor connected to the terminals is silver faced.
iv) The temperature shall not reach a value where the elasticity of the
material is impaired. For pure copper, this implies a temperature limit of
75 deg.C.
5.29.1 Each circuit breaker shall be supplied with individual compressor unit. Each ICU
shall be provided with compressor, piping, piping accessories, local air receivers,
control valves, filters, coolers of adequate capacity, reducing valves, isolating
valves, drain ports etc.,
5.29.2 The capacity of local air receivers shall be sufficient for two CO operations of
the circuit breaker, at the lowest pressure for auto re-closing duty without
refilling.
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5.29.3 AIR COMPRESSOR:
a) The air compressor shall be of air cooled type complete with cylinder,
lubrication, drive motor and slide rails. Each compressor shall be rated
for the following duty:
d) The receiver shall be rated such that the compressor will not be required
to start within less than four hours for supplying the leakage of air from
the compressed air system.
Compressed air used shall be free of dust particles. Arrangement for conditioning
the compressed air shall be provided as an integral part of air compressor system.
a) The flow capacity of all valves shall be atleast 20% greater than the total
compressor capacity.
b) The high pressure pipe and air system shall be such that after one 0-0.3
sec. CO operation the breaker shall be capable of performing one CO-
operation within 3 minutes.
e) All joints and connections in the piping system shall be brazed or flared
as necessary.
f) All compressed air piping shall be carried out in accordance with latest
Indian Standard.
The 415 Volt motor control centres conforming to requirements for control
cabinets stipulated in clause 5.31 of this specification shall be fixed type and
fully sectionalized and shall be equipped with load break switches. Motor feeders
shall be provided with switch fuse unit and contactor with thermal overload relay
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and open phase protection. The motor contactor shall have one normally open
auxiliary contact for alarm purposes.
An ammeter shall be provided on the motor feeders. The motor control circuit
shall be independent from all other control circuits.
5.29.10 FUSES:
All fuses shall be of the HRC cartridge type, conforming to IS:2208 and suitable
for mounting on plug-in type of fuse bases. Fuses shall be provided with visible
operation indicators to show that they have operated. All accessible live
connections shall be adequately shrouded, and it shall be possible to change fuses
with the circuit live, without damage of contact with live conductor. Insulated
fuses pulling handle shall be supplied with each control cabinet.
5.30.1 The terminal connectors suitable for Zebra(28.62 mm)/Moose(31.77 mm) ACSR
conductor 6 Nos. per circuit breaker shall be supplied and shall meet the
following requirements.
a) Terminal connectors shall be manufactured and tested as per IS:5561.
b) All castings shall be free from blow holes, surface blisters, cracks and
cavities. All sharp edges and corners shall be blurred and rounded off.
1. Control cabinets shall be of the free standing floor mounting out door
type.
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2. Control cabinets shall be sheet steel enclosed and shall be dust, weather
and vermin proof. Sheet steel shall be atleast 3.0 mm. thick . 15 mm.
thick neoprene or better type of gaskets shall be provided to ensure
degree of protection of atleast IP 55 as per IS:2147. Control cabinets
shall be provided with hinged door and padlocking arrangement. The
door hinges shall be of union joint type to facilitate easy removal. Door
shall be properly braced to prevent wobbling. There shall be provision in
the bottom sheet for entrance of cables from below.
5. Motors rated 1 kW and above being controlled from the control cabinet
shall be suitable for operation on a 415 V, 3 phase 50 Hz. system.
Fractional kW motors shall be suitable for operation on a 240 V, 1-phase,
50 Hz. supply system.
7. Fuses shall be HRC cartridge link type having prospective current rating
of not less than 46 kA (rms). They shall be provided with visible
operation indicators to show when they have operated. One fuse pulling
handle shall be supplied for every ten fuses or a part thereof.
8. Push button shall be rated for not less than 6 Amps. 240 V AC or 2
Amps, 220 V DC and shall be flush mounted on the cabinet door and
provided with appropriate name plates. Red, Green and Amber indicating
lamps shall be flush mounted and provided with series resistors to
eliminate the possibility of short circuiting of control supply in the event
of fusing of lamps.
9. For motors upto 5 kW, contactor shall be direct-on-line, air break, single
throw type and shall be suitable for making and breaking the starting
current of the associated motor which shall be assumed equal to 6.5 times
the full load current of the motor at 0.2 p.f. For motors above 5 kW,
automatic star delta type starters shall be provided. 3 pole contactor shall
be furnished for 3 phase motors and 2 pole contactor for single phase
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motors. Reversing contactor shall be provided with electrical interlocks
between forward and reverse contactor. If possible, mechanical interlocks
shall also be provided. contactor shall be suitable for uninterrupted duty
and shall be of duty category class AC4 as defined in IS:2959. The main
contacts of the contactor shall be silver plated and the insulation class for
the coils shall be class E or better. The dropout voltage of the contactor
shall not exceed 70% of the rated voltage.
10. contactor shall be provided with a three element, positive acting, ambient
temperature compensated, time lagged, hand reset type thermal overload
relay with adjustable setting. Hand reset button shall be flush with the
front door of the cabinet and suitable for resetting with starter
compartment door closed. Relays shall be either direct connected or CT
operated depending on the rated motor current.
11. Single phasing preventor relay shall be provided for 3 phase motors to
provide positive protection against single phasing.
12. Mini starters shall be provided with no volt coils wherever required.
13. All necessary cable terminating accessories such as glands, crimp type
tinned copper lugs etc., for control cables shall be included in Bidder's
scope of supply. Suitable brass cable glands shall be provided for cable
entry.
14. Wiring for all control circuits shall be carried out with 1100/650 volts
grade PVC insulated tinned copper stranded conductors of sizes not
smaller than 2.5 sq.mm. Atleast 10% spare terminal blocks for control
wire terminations shall be provided on each panel.
16. Space heaters shall be provided inside each cabinet complete with
thermostat (preferably differential type) to prevent moisture
condensation. Heaters shall be controlled by suitably rated double pole
miniature circuit breakers.
17. Signal lamps provided shall be of neon screw type with series resistors,
enclosed in bake lite body. Each signal lamp shall be provided with a
fuse integrally mounted in the lamp body.
19. Items inside the cabinet made of organic material shall be coated with a
fungus resistant varnish.
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20. All doors, panels, removable covers and breaker openings shall be
gasketed all around. All louvers shall have screens and filters. Cabinets
shall be dust, moisture and vermin proof.
5.32 MOTORS:
5.32.1 Motors shall be "Squirrel Cage" three phase induction motors of sufficient size
capable of satisfactory operation for the application and duty as required for the
driven equipment.
6.0 TESTS:
6.1.1 All the equipment offered, shall be fully type tested by the bidder as per the
relevant standard. The bidder shall furnish one set of the following type test
reports for each equipment offered along with bid. The type tests must have
been conducted not earlier than five years form the date of bid opening.
6.1.2 The Bidder shall indicate the costs for conducting the following type tests. Cost
for each type test shall be indicated clearly.
6.2.1 All acceptance and routine tests as stipulated in the relevant standards shall be
carried out by the Supplier in the presence of Purchaser's representative.
6.2.2 In addition to the mechanical and electrical tests specified by IEC, the following
shall also be performed.
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Speed curves for each breaker shall be obtained with the help of a suitable
operation analyzer to determine the 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 tests shall
show the speed of contacts directly at various stages of operation, travel of
contacts, opening time, closing time, shortest time between separation and
meeting of contacts at break/make operation etc. This test shall also be
performed at site for which the necessary operation analyzer along with
necessary transducers, cables, console, etc., shall be furnished as mandatory
maintenance equipment.
The Purchaser reserves the right for carrying out any other tests of a reasonable
nature at the works of the Supplier/laboratory or at any other recognised
laboratory/research institute in addition to the above mentioned type, acceptance
and routine tests at the cost of the Purchaser to satisfy that the material complies
with the intent of this specification.
7.0 INSPECTION:
7.1 The inspection may be carried out by the Purchaser at any stage of manufacture.
The Supplier shall grant free access to the Purchaser's representative at a
reasonable time when the work is in progress. Inspection and acceptance of any
equipments under this specification by the Purchaser shall not relieve the
Supplier of his obligation of furnishing equipment in accordance with the
specification and shall not prevent subsequent rejection if the equipment is found
to be defective.
7.2 The supplier shall keep the Purchaser informed in advance, about the
manufacturing programme so that arrangement can be made for inspection.
7.3 The Purchaser reserves the right to insist on witnessing the acceptance/routine
testing of the bought out items.
7.4 No material shall be dispatched from its point of manufacture unless the material
has been satisfactorily inspected and tested.
7.5 The supplier shall give 15 days (for local supplies)/ 30 days. (In case of foreign
supplies) advance, intimation to enable the purchaser to depute his representative
for witnessing acceptance and routine tests.
8.1 The bidder shall invariably furnish the following information along with his
offer failing which the offer shall be liable for rejection. Information shall be
separately given for individual type of equipment offered.
ix) Level of automation achieved and list of areas where manual processing
exists.
xi) List of testing equipment available with the bidder for final testing
of equipment specified and test plant limitation, if any vis-a-vis the type. Special
acceptance and routine tests specified in the relevant standards. These
limitations shall be very clearly brought out in "Schedule of Deviations" from
the specified test requirements.
8.2 The Contractor shall within 30 days of placement of order, submit the
following information to the purchaser.
i) List of the raw material as well as bought out accessories and the names
of sub-suppliers selected from those furnished along with the offer.
ii) Type test certificates of the raw material and bought out accessories if
required by the purchaser.
iii) Quality Assurance Plan (QAP) with hold points for purchasers
inspection. QAP and purchasers hold points shall be discussed between
the purchaser and contractor before the QAP is finalised.
The contractor shall submit the routine test certificates of bought out accessories
and central excise asses for raw material at the time of routine testing if required
by the purchaser and ensure that the quality assurance requirements of
specification are followed by the sub-contractor.
8.3 The Quality Assurance Programme shall give a description of the Quality
System and Quality Plans with the following details.
i) Quality System:
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The Structure of the Organisation
The duties and responsibilities assigned to staff ensuring quality of work.
The system of purchasing, taking delivery of verification of materials.
The system of ensuring of quality workmanship.
The system of control of documentation.
The system of retention of records.
The arrangement of contractor internal auditing.
A list of Administrator and work procedures required to achieve contractors
quality requirements. These procedures shall be made readily available to the
purchaser for inspection on request.
The contractor shall provide necessary facilities for training personnel at their
works/principals works relating to design, manufacture, assembly and testing and
operation maintenance for six personnel free of cost. However, travel and
incidental charges of the personnel will be borne by the purchaser.
9.0 DOCUMENTATION:
9.1 All drawings shall conform to International Standards Organisation (ISO) 'A'
series of drawing sheet/Indian Standards Specification. All drawings shall be in
ink and suitable for micro filming. All dimensions and data shall be in S.I. Units.
The Bidder shall furnish four sets of relevant descriptive and illustrative
published literature pamphlets and the following drawings for preliminary study
along with the offer.
9.3 The Supplier shall within 2 weeks of placement of order submit four sets of final
version of all the above drawings for Purchaser's approval. The Purchaser shall
communicate his comments/approval on the drawings to the Supplier within two
weeks of receipt of drawings. The supplier shall, if necessary, modify the
drawings and resubmit four copies of the modified drawings for Purchaser's
approval .The purchaser shall communicate approval with in two weeks of
receipt of modified drawings. After receipt of Purchaser's approval, the Supplier
shall, within three weeks, submit 20 prints and two good quality re-producibles
of the approved drawings for Purchaser's use.
9.4 The Supplier shall also furnish twenty copies of bound manuals covering
erection, commissioning, operation and maintenance instructions in English
Language and all relevant information and drawings pertaining to the main
equipment as well as auxiliary devices. Marked erection drawings shall identify
the component parts of the equipment as shipped to enable Purchaser to carryout
erection with his own personnel. Each manual shall also contain one set of all the
approved drawings, type test reports as well as acceptance reports of the
corresponding consignment dispatched.
9.5 The manufacturing of the equipment shall be strictly in accordance with the
approved drawings and no deviation shall be permitted without the written
approval of the Purchaser. All manufacturing and fabrication work in connection
with the equipment prior to the approval of the drawing shall be at the supplier's
risk.
9.6 Approval of drawings by the Purchaser shall not relieve the supplier of any of his
responsibility and liability for ensuring correctness and correct interpretation of
the drawings for meeting the requirements of the latest revision of the applicable
standards, rules and codes of practices. The equipment shall conform in all
respects to high standards of engineering, design, workmanship and latest
revisions of relevant standards at the time of supply and Purchaser shall have the
power to reject any material which, in his judgment, is not in full accordance
therewith.
b) The temperature v/s pressure curves for each setting of density monitor,
along with details of density monitor.
e) Sectional view of non return couplings if used for SF6 pipes (for SF6
Circuit Breakers).
f) Details and type of filters used in interrupter assembly and also the
operating experience with such filters (for SF6 C.B.)
i) Curves supported by test data indicating the opening time under close
open operation with combined variation of trip coil voltage and
pneumatic/hydraulic pressure.
k) All duty requirements shall be proved with the support of adequate test
reports to be furnished along with the bid failing which the bid is likely to
be rejected.
The Supplier shall ensure that the packing list and bill of material are approved
by the Purchaser before despatch.
The Supplier shall arrange for unloading the material/equipment at his cost.
11.0 QUANTITY AND DELIVERY REQUIREMENTS:
i) This is set out in the proforma given in Price Schedule and the prices
shall be quoted accordingly.
ii) The scope of supply shall include supply of 25% extra-quantity of bolts,
nuts, washers, split pins, cotter pins and such other small loose items free
of cost.
S. Description Particulars
No
220 kV SF6 132 kV SF6 CBs 33 kV VCBs
CBs
1. a) Maker's name country
of manufacture.
b)Manufacturer's type
designation.
2. Applicable Technical Standards
4. Number of Poles
5. Class (Outdoor/Indoor)
6. Rated normal current: a)
Under site conditions
(Amps)
b) Rated (Amps)
b)Percentage DC component
e) Oscillogram no.
8. Rated short circuit making current
(kA)
9. First Pole to clear factor
10. Rated transient recovery voltage
for terminal faults (kV peak)
11. Rated characteristics for short
line faults.
12. Rated operating sequence .
13. Rated duration of short circuit
CB 34
(sec.)
14. Rated out of phase breaking
current (kA)
15. Opening time (ms)
16. Arcing time (ms)
a) At 10% rated breaking current
b) Closing (ms)
20. Rated line charging breaking
current (kA)
21. Maximum cable charging current
a) On supply side
b) On line side
22. Rated small inductive breaking
current (kA)
23. Max. rise of temperature over
ambient temperature for current
rating under clause 6.
24. Interrupting capacity based on
duty cycle as per clause 11.
a) AC Component (kA)
b) Percentage D.C.
Component
25. Latching current (kA)
26. No of breaks in series per pole
27. Length of contact travel (mm)
28. Total length of break per pole
CB 35
(mm)
29. Rate of contact travel :
a) At tripping (meters/sec.)
b) At closing (meters/sec.)
30. Type of devices, if any, usd to
obtain uniform voltage
distribution between breaks
31. Recovery voltage distribution
between breaks in percent of
rated voltage:
b) Arcing
c) Auxiliary
35. Whether contacts are silver plated
2.Spring closing/opening
i) Number of springs
ii) Type
iii) Number of turns
iv) Guage
v) External diameter mm.
vi) Stiffness
vii) Material
CB 39
viii) Force developed in full
charged position.
ix) Specification reference.
g) Compressor stops at
kg/sq.cm.
h) Alarm switch on receiver
closes at kg/sq.cm.
i) Lockout switch on
receiver operates at
i) From atmospheric to
pressure indicated in (g) above,
(minutes)
CB 40
ii) From pressure indicated in (g)
above to that in (h) above
(minutes)
57. Rated pressure of SF6 gas in the
circuit breaker (kg/sq.cm)
58. Rated pressure of SF6 gas in the
gas cylinders (kg./sq.cm.)
59. Quantity of SF6 gas required per
single pole unit (kg.) (3 pole unit
for 145 kV)
60. Quantity of SF6 gas per cylinder
(kg.)
61. Weight of empty cylinder (kg.)
62. Quantity of absorbent required
per pole (kg.)
63. Recommended interval for
renewal of absorbent in case of
outdoor circuit breakers
operating in tropical conditions.
64. Chemical composition of
absorbent
65. Quantity of absorbent covered in
the scope of supply (including spare quantity) (kg.)
66. Limits of gas pressure for
pressure operation of circuit
breaker (kg./sq.cm.)
67. Pressure and temperature at
which the temperature
compensated gas pressure switch
a) alarm (kg./sq.cm., deg.C)
b) Cut off (kg/sq.cm. deg.C)
68. Name of SF6 supplier and
country of origin
69. Quantity of SF6 gas supplied for
a) Actual use in breakers (kg.)
b) As spare (kg.)
Date ..............................
ACRONYMS