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GETCO/E/TS-ISO 011/R1/May09

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GUJARAT ENERGY TRANSMISSION

CORPORATION LTD.

TECHNICAL SPECIFICATIONTECHNICAL SPECIFICATIONTECHNICAL SPECIFICATIONTECHNICAL SPECIFICATION

OFOFOFOF

400400400400 KV KV KV KV P P P PAAAANTOGRAPH ISOLATORSNTOGRAPH ISOLATORSNTOGRAPH ISOLATORSNTOGRAPH ISOLATORS



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SPECIAL INSTRUCTIONS TO BIDDER Please read following instructions carefully before submitting your bid. 1. All the drawings, i.e. elevation, side view, plan, cross sectional view etc., in

AutoCAD format and manuals in PDF format, for offered item shall be submitted. Also the hard copies as per specification shall be submitted.

2. The bidder shall submit Quality Assurance Plan with the technical bid. 3. The bidder shall have to submit all the required type test reports for the

offered item. In absence of this, the evaluation shall be carried out accordingly as non-submission of type test reports.

4. The bidder must fill up all the points of GTP for offered item/s. Instead of

indicating “refer drawing, or as per IS/IEC”, the exact value/s must be filled in.

5. All the points other than GTP, which are asked to confirm in technical

specifications must be submitted separately with the bid. 6. The bidder is required to impart training in view of manufacture, assembly,

erection, operation and maintenance for offered item, at his works, to the person/s identified by GETCO, in the event of an order, free of cost. The cost of logistics will be bear by GETCO.

7. Please note that the evaluation will be carried out on the strength of

content of bid only. No further correspondence will be made. 8. The bidder shall bring out all the technical deviation/s only at the specified

annexure.


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QUALIFYING REQUIREMENT DATA (For Supply)

Bidder to satisfy all the following requirements. 1) The bidder shall be Original Equipment Manufacturer

(OEM). The offered equipment have to be designed, manufactured and tested as per relevant IS/IEC with latest amendments.

2) The minimum requirement of manufacturing capacity of

offered type, size and rating of equipment shall be FIVE (5) times tender/ bid quantity. The bidder should indicate manufacturing capacity by submitting latest updated certificate of a Chartered Engineer (CE).

3) Equipment proposed shall be of similar or higher rating

and in service for a minimum period of THREE (3) years and satisfactory performance certificate in respect of this is to be available and submitted.

4) The bidder should clearly indicate the quantity and Single

Value Contract executed during last FIVE (5) years, for the offered equipment. Bidder should have executed one single contract during last five years for the quantity equivalent to tender / bid.

The details are to be submitted in following format, Sr. No

ITEMS SUPPLIED TO

ORDER REFERENCE No. &

DATE

ITEMS QUANTITY

ORDER FULLY

EXECUTED. YES/NO

STATUS, IF ORDER UNDER

EXECUTION

REMARK

e) Equipment offered shall have Type Test Certificates from

accredited laboratory (accredited based on ISO/IEC Guide 25 / 17025 or EN 45001 by the National accredition body of the country where laboratory is located), as per IEC / IS / technical specification. The type test reports shall not be older than FIVE years and shall be valid up to expiry of validity of offer.


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INDEX

Clause No. Title Page

No.

1.0 Scope 5

2.0 Standards 6

3.0 Service Conditions 7

4.0 Principal Parameters 8

5.0 General Technical Requirement 10

6.0 Test 22

7.0 Inspection 24

8.0 Quality Assurance Plan 24

9.0 Documentation 26

10.0 Packing and Forwarding 28

11.0 Support structure 28

ANNEXURE

Annexure – I System Particulars 29

Annexure – II List of Mandatory Spares 30

Annexure – III Guaranteed Technical Particulars 31

Note:- All these sections are supplementary to each other and the particulars and

requirements contained herein shall govern the supply of all equipment and materials covered under this specification.


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TECHNICAL SPECIFICATION FOR AIR BREAK

PANTOGRAPH TYPE

DISCONNECTORS (ISOLATORS)

1.0 SCOPE:

1.1 This specification provides for design, engineering, manufacture,

production, stage testing, inspection and testing before dispatch, packing

and delivery at destination of 420 KV, class PANTOGRAPH Isolators

(Disconnectors), along with all accessories, auxiliary equipments and

mandatory spares and maintenance equipments and supporting structures

specified herein required for their satisfactory operation in various

substations. Also, at the discretion of the purchaser, bidder shall have to

undertake the scope of support structure, complete erection or supervision of

erection, testing and commissioning of the isolators as indicated in schedule- A

of respective tender. Design calculations along with bill of

Material for structure shall have to be submitted by the

successful bidder.

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

construction of equipment. However, the equipment shall conform in all

respects to high standards of engineering, design and workmanship and

shall be capable of performing in continuous commercial operation up to

the supplier’s guarantee acceptable to the purchaser, who will interpret in

a manner the meanings of drawings and specifications and shall have the

power to reject any work or material which in his judgment is not in

accordance therewith, The equipment offered shall be complete, with all

components necessary for its effective and trouble free operation along

with associated equipment interlocks, protection schemes etc. Such

components shall be deemed to be within the scope of supply, irrespective

of whether those are specifically brought out in this specification and/or

the commercial order or not. All similar parts particularly movable ones

shall be interchangeable.


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2.0 STANDARDS:

Unless otherwise specified, the rating as well as performance and testing

of the isolators shall conform to the latest revisions and amendments of the

following standards available at the time of opening of Technical Bid.

Sr. No.

Standard No.

Title

1 IS:9921 Alternating current isolators (Disconnectors) and earthing switches.

2 IEC-60129 Alternating current isolators (Disconnectors) and earthing switches.

3 IS:2544 Insulators

4 IS:13947 Low voltage switchgear and control gear.

5 IS:4691 Degree of protection provided by enclosure.

6 IS:325 Three phase induction motors.

7 IS:4722 Rotating electrical machines.

8 IS:2629 Recommended practice for hot dip galvanizing of iron and steel.

9 IS:4759 Hot dip galvanization coating on structural steel.

10 IS:2633 Method of testing weight thickness and uniformity of coating on fasteners.

11 IS:1573 Electroplated coating of zinc on iron & steel.

12 IS:6735 Spring Washers.

13 IS:2016 Plain Washers.

14 IS: 5561 Specification of electric power connector.

15 IS:5350 Solid core insulators or multi-core type insulators.

Equipment meeting with the requirements of other authoritative National or

International Standards, which ensure equal or better performance than the

standards mentioned above, shall also be considered. When the

equipment offered by the Bidder conforms to other standards salient points

of difference between standards adopted and the standards specified in

this specification shall be clearly brought out in the relevant schedule, four

copies of such standards with authentic translation in English shall be

furnished along with the offer.


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3.0 SERVICE CONDITIONS:

3.1 Climatic Conditions

Equipment to be supplied against this specification shall be suitable for

satisfactory continuous operation under the following tropical conditions:

i) Location: As per Annexure- I

enclosed

ii) Max. Ambient air temp. (°C) 50

iii) Min ambient air temp (°C) 3.5

iv) Average daily ambient air Temperature (°C) 35

v) Relative humidity (%) 95%

vi) Average annual rainfall (mm) 1150

vii) Max. wind pressure (kg/sq. m) 150

viii) Max. altitude above mean (meters) Not Exceeding

Sea level.... Not exceeding 1000 meters

ix) Ceraunic level (days/year) 15

x) Seismic level (horizontal acceleration) 0.5 g

xi) Max Yearly Avg.ambient Temp. 38 Degree Centi.

Note : Moderately hot and humid tropical climate conducive to rust and

fungus growth. The climatic conditions are also prone to wide

variations in ambient conditions. Smoke is also present in the

atmosphere. Heavy lightning also occurs during June to October.

3.2 Auxiliary Power Supply

The equipment offered under this specification shall be suitable for the

following auxiliary power supplies.

a) Power Devices (like drive motors) 440V, 3 phase, 4wire, 50 Hz

neutral grounded AC supply

b) Ac control and protective, devices

lighting fixtures, space heaters and

motors

-Do-

c) DC alarm, control and protective

devices

220 V, DC 2-wire


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Each of the foregoing supplies shall be made available by the purchaser at

the terminal point for each equipment for operation of accessories and

auxiliary equipment. Supplier’s scope shall include supply of

interconnecting cables, terminal boxes, HRC Fuses etc. The above supply

voltages may vary as below and all devices shall be suitable for continuous

operation over entire range of voltages.

i) AC Supply: Voltage ± 10%, frequency ± 5%

ii) DC Supply: -15% to + 20%

4.0 PRINCIPAL PARAMETERS:

The equipment covered in this specification shall meet the technical

requirements listed below:

Sr. No.

Technical Parameter Requirement 420 KV Isolators

1 Rated Frequency (Hz) 50

2 System Neutral Earthing Effectively Earthed

3 No. of Phases (Poles) 3

4 Temperature Rise As per relevant IS/IEC publication

5 Safe Duration of Overload

(a) 150% of Rated Current 5 minutes

(b) 120% of Rated Current 30 minutes

6 Rated Voltage (KV rms)/Highest System Voltage (KV rms)

400 / 420

7 Type of disconnector Pantograph

8 Rated Normal Current 2000 (Amp. RMS)

9 Rated short time withstand current (KA RMS) of MS & EB

for Duration

40 KA

3 Sec.

10 Rated dynamic withstand current (KA) 100

11 Rated short circuit making current of EB (KA peak)

100

12 Basic insulation level

A) 1.2/50 microsecond lightning impulse withstand voltage (+ve or –ve polarity)

a) To earth (KVP) 1425


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b) Across isolating distance 1665

- One terminal subjected to lighting impulse (KVP) and opposite terminal subjected to power frequency (KV rms) voltage of opposite polarity (as per IS) (KVP/KV rms)

B) 250/2500 microseconds switching impulse withstand voltage (+ve or –ve polarity)

a) To earth (KVP) 1050

b) Across isolating distance

One terminal subjected to lighting impulse (KVP) and opposite terminal subjected to power frequency voltage of opposite polarity (as per IS) (KVP/KV rms)

1245

C) Rated 1 minute power frequency withstand voltage (KV rms)

650

13 Min. creep age distance of support and operating Rod insulator (mm)

10500

14 Rated Mech. Terminal Load

(a) Straight load (Kg.) PG 408

(b) Across load (Kg.) PG 163.2

15 Rated magnetizing/capacitive current make and break (Amp. Rms)

0.7

16 Rated contact zone for PG isolator when fixed contacts are supported on flexible conductors:

(a) Horizontal deflection (Meters) 0.5

(b) Vertical deflection (Meters) 0.3

(c) Total amplitude of longitudinal movement with respect to conductor supporting fixed contact (meters)

0.4

17 Phase to phase spacing for installation (mm) 7000

18 Minimum Clearances:

(a) Phase to earth 3500

(b) Phase to Phase 4200

19 Height of centre line of terminal pad above PLINTH level (mm)

8000

20 Radio interference voltage at 1 MHz and at 1.1 times maxi. Phase to earth voltage (microvolt)

1000

21 Min. Corona extinction voltage (KV rms) 320


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22 Rating of auxiliary contacts 10 A at 220 Volts DC with breaking capacity of 2A DC with time constant

not less than 20 ms.

23 Seismic acceleration As specified against clause 3.1 (x)

24 Operating time 12 seconds or less

5.0 GENERAL TECHNICAL REQUIREMENT:

5.1 420 kV pantograph Isolators shall be individual pole operated, but suitable

for electrical gang operation.

The earth switches for 420 KV Isolators shall be motor operated.

Each Isolator shall be provided with operating handle for manual operation,

which shall be provided with pad locking arrangement, in close and open

position.

5.2 Purchaser reserves the right to choose all isolators of any one type

specified or any combination of the same with one/two earth switches or

without earth switches. Bids would however, be analysed based on

quantities of each type as specified in schedule of quantities.

5.3 Complete isolators with all necessary items for successful operation shall

be supplied including but not limited to the following:

5.3.1 Gang operated and individual pole operated Isolators assembled with

isolators blades (main and earth) complete base frame, linkages, operating

mechanism complete etc.

5.3.2 One control cabinet for each isolator with all the required electrical devices

mounted therein and the necessary terminal blocks for termination of wiring

to be done by purchaser for gang operated operating isolators.

For this purpose, one master control cabinet and slave control cabinets

with all the required electrical devices shall be provided.

5.4 Material of earthing blades and contacts shall be same as those of main

blades and contacts respectively. Cross sectional area of earthing blades

and contacts shall not be less than 50% of cross sectional area of main

blades and contacts. The earthing blade shall have the same short time

current rating (thermal and dynamic) as that of main blades.

5.5 Support insulators for all types of isolator’s shall be of solid core type.

The insulator supplier shall be GETCO’s approved vendor and shall have

supplied same to GETCO/GEB in the past

5.5.1 The insulator shall be made of homogeneous and vitreous porcelain of

high mechanical and die-electric strength, it shall have sufficient

mechanical strength to sustain electrical and mechanical loading on


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account of wind load, short circuit forces etc. glazing of the porcelain shall

be of uniform brown or dark brown colour with a smooth surface arranged

to shed away rain water. The porcelain shall be free from laminations and

other flaws or imperfections that might affect the mechanical or dielectric

quality. It shall be thoroughly vitrified, tough and impervious to moisture.

The porcelain and metal parts shall be assembled in such a manner and

with such material that any thermal differential expansion between the

metal and porcelain parts throughout the range of temperature specified in

this specification shall not loosen the parts or create undue internal stress

which may affect the mechanical or Electrical strength or rigidity. The

assembly shall not have excessive concentration of electrical stresses in

any section or across leakage surfaces. The cement used shall not give

rise to chemical reaction with metal fittings. The insulator shall be suitable

for water washing by rain or artificial means in service condition. The profile

of the insulator shall also conform to IEC-815. Insulator shall have

minimum cantilever strength of 8 KN, for 420 kV.

5.5.2 Cap to be provided on top of the insulator shall be of high-grade cast iron

of malleable steel casting. It shall be machine faced and hot dip

galvanized. The cap shall have four numbers of tapped holes spaced on a

pitch circle diameter of 127 mm. The holes shall be suitable for bolts with

threads having anticorrosive protection. The effective depth of threads shall

not be less than the nominal dia. of the bolt. The cap shall be so designed

that it shall be free from visible corona and shall have Radio Interference

Level within the limit specified in this specification. If corona-grading rings

are necessary to meet the above requirement, the same shall be in the

supplier’s scope of supply.

5.5.3 The casting shall be free from blowholes, cracks and such other defects.

5.5.4 All the ferrous metal parts shall be hot dip galvanised smoothly, as per IS:

2629 or any other equivalent authoritative standard. The material shall be

galvanised only after shop operations upon it have been completed. The

metal parts before galvanizing should be thoroughly cleaned of any paint,

grease, rust, scales or alkali or any foreign deposit, which are likely to

come in the way of galvanizing process. The metal parts coating shall

withstand minimum four one minute dips in copper sulphate solution as per

IEC-168.

5.5.5 The insulator unit shall be assembled in a suitable jig to ensure correct

positioning of the top and bottom metal fittings relative to one another. The

faces of the metal fittings shall be parallel and at right angles to the axis of

the insulator and the corresponding holes in the top vertical plane

containing the axis of the insulator.


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5.5.6 It shall be the sole responsibility of the supplier to carry out thorough

inspection and quality checks on the insulators at the insulator supplier’s

works, before offering the insulators for purchaser’s inspection at works.

5.5.7 The fixed contact of disconnector should be covered properly to avoid nest

building by birds.

5.5.8 Isolator design shall be such as to permit addition of earth switches at

future date. It should be possible to interchange position of earth

switch to either side.

5.5.9 Technical parameters for solid core insulators shall be as follow:

Solid core post insulator

Sr. No. Description Unit

400 kV 01 02 03 04 01 Highest system voltage KV 420 02 Height of unit mm 3910 03 Bending strength (approximate failing load):

a) Upright

Kgf

800 04 Tensile strength (Approximate) Kgf 17,000 05 Compression strength (Approximate) Kgf 33,000 06 Torsion strength (Approximate) KgfM. 460 07 a) Power frequency flashover voltage (dry)

b) -do- (wet) KV

KV

890

820 08 a) Impulse flashover voltage (Positive)

b) -do- (Negative) KV

KV

1850

1850 09 a) One min PF withstand voltage (dry)

b) -do- (wet) (w/o arcing horns ) KV KV

760 680

10 Impulse positive/negative withstand voltage KV 1550 11 Power frequency puncture voltage KV Puncture proof

12 RIV a) Test V to Ground KV rms b) at 1000 KHz with grading rings

KV

mV

266

<1000mV 13 (a) Visible discharge

(b) Switching surge withstand voltage KV KVp

320 with grading ring 1080

14 Creepage distance a) Total b) Protected

mm

10,500 5250

15 Top metal fitting PCD mm 4 holes of M16 PCD 127

16 Bottom metal fitting PCD mm 8 Holes of M18 PCD 300

17 All ferrous part should be hot dip galvanized to IS:2629/1966

Yes

18 Suitable for Hot line washing Yes 19 Corona Extinction device Corona ring provided 20 Dry Arcing Distance mm. 3400


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5.6 Operating Mechanism

5.6.1 3 ø/1 ø AC motor operated type operating mechanism shall be provided for

operation of main blades for all the Isolators. 420 KV pantographs shall be

individual pole operated but the same shall be suitable for simultaneous

electrical operation. For this purpose, one master control cabinets and two

slave control cabinets with all the required electrical devices shall be

provided.

The earth switches for 420 KV Isolators shall be motor operated.

Each motor operated isolator and earth switches shall be provided with

manual operating handle with padlocking arrangement. The height of

operating handle above the plinth shall be 1000 mm.

5.6.2 The operating mechanism shall provide quick, simple and effective

operation. The motor operated type operating mechanism shall be suitable

for remote operation of Isolator as well as local manual operation. The

design of manual operation shall be able to operate the isolator without

undue effort with about 20 (TWENTY) revolutions of the crank. The

operating mechanism shall be suitable to hold the disconnector in CLOSE

OR OPEN position and prevent operation by gravity, wind, short circuit

forces, seismic forces, vibration, shock, accidental touching etc.

5.6.3 Limit switches for control shall be fitted on the isolator/earth switch shaft

within the cabinet to sense the open and close positions of the isolators

and earth switches.

5.6.4 It shall not be possible, after final adjustment has been made, for any part

of the mechanism to be displaced at any point in the travel sufficient

enough to cause improper functioning of the isolator when the isolator is

opened or closed at any speed. All holes in cranks, linkage etc. having

moving pins shall be drilled accurately so as to maintain the minimum

amount of slack and lost-motion in the entire mechanism.

5.6.5 A “local/remote” selector switch and a set of open/close push buttons shall

be provided on the control cabinet of the isolator to permit its operation

through local or remote push buttons. The remote push buttons shall be

arranged by the purchaser.

5.6.6 Provision shall be made in the control cabinet to disconnect power supply

to prevent local/remote power operation.

5.6.7 Each motor operated mechanism shall be subjected to blocked rotor test.

5.7 Control Cabinet

The control cabinet shall be made of 3 mm Aluminum sheet with


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powder coating OR of 3 mm stainless steel sheet.

The size of mechanism box for main and earth switch shall not be less than 550 (H) x 550 (W) x 300 (D) mm. The height of operating handle shall be maintained at 1000 mm from plinth level.

Hinged door shall be provided with pad locking arrangement. Sloping rain

hood shall be provided to cover all sides. 15 mm thick neoprene or better

type of gaskets shall be provided to ensure degree of protection of at least

IP55 as per IS: 2147. The cabinet shall be suitable for mounting on support

structure with adjustment for vertical, horizontal and longitudinal alignment.

Details of these arrangements shall be furnished along with the tender.

5.8 Motor

The motor shall be squirrel cage type or PMDC type, suitable to operate on

3 phase/1-phase 440 V/A.C. supply with variations as specified in this

specification. It shall be totally enclosed type if mounted outside the control

cabinet. The motor shall withstand without damage-stalled torque for at

least three sec, in all other respects, conform to the requirement of IS-325.

If necessary, electromechanical brake shall be fitted on the higher

speed shaft to effect rapid breaking.

5.9 Gear

The disconnector may be required to operate occasionally, with

considerably long idle intervals. Special care shall be taken for selection of

material for gear and lubrication of gears to meet this requirement. The

gears shall be made out aluminium bronze or any other better material and

lubricated for life with graphite or better quality non-draining and non-

hardening type of grease. Wherever necessary automatic relieving

mechanism shall be provided. Complete details of components, material,

grade, self-lubricating arrangement, grade of used for quality check shall

be furnished by the supplier in his offer.

5.10 Gland Plate and Glands

A removable gland plate with double compression type brass cable glands

shall be provided with each operating mechanism for terminating all cables.

Exact quantity of glands to be provided, shall be intimated to the successful

bidder.

5.11 Control Circuits


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Control device shall store OPEN and CLOSE command even if the

corresponding switch is momentarily pressed until the command is fully

executed and the components get de energised after execution. Failure of

auxiliary power supply or loose contact shall not cause faulty operation.

5.12 Limit Switches

Limit switches shall be of reputed make. Auxiliary switch shall not be used

as limit switch. Details of make, rating and type of limit switch shall be

furnished in the offer.

5.13 Overload and Single Phasing Preventor

Suitable relay/device shall be provided to prevent overloading of the motor.

Single phase preventor for 3-phase motor shall be provided to operate on

open circuiting of any phase and shall trip off the motor. Complete details

of the devices shall be furnished in the offer.

5.14 Contactor

The contactor shall be suitable for making and breaking stalled motor

current. The contactor coil shall be suitable for 220 V D.C. or three phase

415 V A.C. with suitable interlocking D.C. relay to cut off A.C. supply to the

motor in accordance with the interlocking scheme. Two nos. of contactors

shall be provided for each motor for OPEN and CLOSE operation

respectively. Make, type, rating and details of the contactor shall be

furnished in the offer.

5.15 Auxiliary Switch

5.15.1 Each operating mechanism boxes shall be equipped with Ten & Six nos. of

NC and Ten/ Six nos. of NO separate and reliable auxiliary switches for

isolator and earthing switch respectively, exclusively for purchaser’s use,

direct or through contact multiplication relays for various protection

schemes. In addition, two/one pairs of make before break NO, NC contacts

shall be provided in the operating mechanism box for isolator and earthing

switch respectively.

5.15.2 The auxiliary switches and auxiliary circuits shall be capable of carrying the

current of at least 10 Amps continuously.

5.15.3 Auxiliary switches shall be capable of breaking at least 2A in a 220 V D.C.

circuit with a time constant of not less than 20 milliseconds.

5.15.4 Quick make and Break (QMB) type auxiliary shall have snap action built-in

within the switch.

5.15.5 The auxiliary switches shall be actuated by a cam type arrangement

directly mounted on the isolator and shall be without any intermediate

levels, linkages etc. to ensure fail safe operation. On pole mounted

auxiliary contacts are not acceptable.

5.16 Space Heaters


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Thermostat controlled space heater suitable for 1 phase 240 V AC supply

shall be provided for motor operated operating mechanism to prevent

condensation. A common switch and individual fuse/link shall be provided

in the operating mechanisms.

5.17 Terminal Block and Wirings

Each operating mechanism shall be provided with 1100 v grade stud type

terminal block. All auxiliary switches, interlocks and other terminals shall be

wired up to terminal block including spare. The terminal block shall have at

least 20% extra terminals. All wirings shall be carried out with 1100 v grade

insulated 2.5 sq. mm. copper wires.

5.18 Duty Requirements

5.18.1 Isolators and earth switches shall be capable of withstanding the dynamic

and thermic effects of the maximum possible short circuit current of the

systems in their closed position. They shall be constructed such that they

do not open under influence of short circuit current forces, gravity, wind

pressure, vibrations, reasonable shocks or accidental touching of the connecting

rods or their operating mechanisms. The reliability of current carrying capacity

shall not be impaired due to such forces.

5.18.2 The earth switches, wherever provided shall be constructionally interlocked

so that the earth switches can be operated only when the isolator is open

and vice-versa. The constructional castle key type interlocks shall be built-

in addition to the electrical and mechanical interlocks provided in the

operating mechanism.

5.18.3 In addition to the constructional interlock, isolator and earth switches shall

have provision to prevent their electrical and manual operation unless the

associated and other interlocking conditions are met. All these interlocks

shall be of fail safe type. Suitable individual interlocking coil arrangements

shall suitable for continuous operation from DC supply and within a

variation range stipulated in this volume.

5.18.4 The isolator shall be capable of making/breaking normal currents when no

voltage occurs across the terminals of each pole of isolator on account of

make/break operation.

5.18.5 The isolator shall be capable of making/breaking magnetizing current of 0.7

A at 0.15 power factor and capacitive current of 0.7 A at 0.15 power factor.

5.18.6 Isolator and earth switches shall be able to bear on the terminals the total

forces including wind loading and electrodynamics forces on the attached

conductor without impairing reliability or current carrying capacity.


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5.19 Interior Illumination

A switch, HRC fuse and holder suitable for a 240 V lamp shall be provided

in the motor operated mechanism.

5.20 Power Socket

A 1 Phase 240 V 15 A power socket and switch shall be provided in the

motor operated operating mechanisms.

5.21 Control and Auxiliary Supply

A 3 Phase switch with HRC fuses for phase and link for neutral shall be

provided for power supply and a 2 way switch with HRC fuses shall be

provided for control supply in the motor operated mechanisms.

5.22 Accessories

The accessories to be provided on the isolator shall include but not limited

to the following:

5.23 Position Indicator

A position indicator to indicate ON or OFF position of Isolator & earthing

switch shall be provided. It should be engraved on the operating

mechanism. Electrical ON or OFF position of Isolator & earthing switch

shall also be provided.

5.24 Counter Balance Springs

Counter balance springs, cushions etc. shall be provided to prevent impact

at the end of travel both on opening and closing of the isolator. The springs

shall be made of durable and non-rusting type alloy.

5.25 Name Plates

Isolator, earthing switches and their operating devices shall be provided

with a nameplate. The nameplate shall be of stainless steel of 2 mm

thickness. All the letters shall be engraved on the name plate. It shall be

mounted in such a position that it shall be visible in the position of normal


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service and installation. It shall carry the following information duly

engraved or punched on it.

5.25.1 Isolator Base

Name of Purchaser :

Name of Manufacturer :

A/T No. :

Type Designation :

Manufacturer’s serial number :

Rated Voltage :

Rated normal current :

Rated short time current (rms) and duration :

Rated short time peak current (KAP) :

Weight :

5.25.2 Earthing Switch

Name of Purchaser :


A/T No. :

Type Designation :

Manufacturer’s serial number :

Rated Voltage :

Rated short time current (rms) and duration :

Rated short time peak current (KAP) :

Weight :

5.25.3 Operating Device

Name of Purchaser :


A/T No. :

Type Designation :

Reduction gear ratio :

A. C. Motor

i) Rated auxiliary voltage :

ii) Starting current :

iii) Designation of AC motor as per IS:4722:

iv) Starting torque at 80 % of supply voltage :


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v) Over travel in degrees after cutting off supply:

Total operating time in seconds

i) CLOSE operation - electrical

ii) OPEN operation – electrical

iii) –Do- manual

Space Heater

Rated voltage and power

Auxiliary contacts

i) Rated current (Amps)

ii) Time constant (ms)

iii) No. of contacts used (NC &NO)

iv) No. of free contacts (NC &NO)

v) Terminal blocks and wiring

vi) Rated current

vii) Voltage grade and type

5.26 Padlocking Device

All Isolator and earthing switch shall be provided with padlocking device to

permit locking of the isolator and earthing switch in both fully open and fully

closed positions. Power driven isolator and earthing switch shall be

arranged to be interlocked electrically also.

5.27 Signaling

5.27.1 Signaling of the close position shall not take place unless the movable

contact has set in a position in which the rated normal current, the peak

withstand current and the short time withstand current can be carried

safely.

5.27.2 Signaling of the open position shall not take place unless the movable

contact has reached the position such that the clearance between the

movable and fixed contacts is at least 80 % of the isolating distance.

5.28 Earthing

5.28.1 Flexible copper connections shall be provided between rotating earth

blades and the frame, which shall have a cross-section of least 50 sq. mm

and shall be tinned or suitably treated against corrosion.


20

5.28.2 The frame of each disconnect and earthing switch shall be provided with

two reliable earthing terminals for connection to the purchaser’s earthing

conductor/flat so also clamping screws suitable for carrying specified short

time current. Flexible ground connections shall be provided for connecting

operating handle to the earthing flat. The diameter of clamping screw shall

be at least 12 mm. The connecting point shall be marked with earth

symbol.

5.29 Hot dip galvanized steel structures for mounting the pantograph isolators

shall be in supplier’s scope of supply. The base shall be rigid and self

supporting and shall require no gauging or cross bracing between phases.

The pantograph Isolator shall be mounted on tubular structures with rigid

base frame.

5.30 Design and Construction

5.30.1 The supplier shall have sufficient experience in the design, manufacture

and supply of the equipment offered. Full particulars of design,

manufacture, jig template and quality control devices developed for

manufacture of the equipment offered in respect of but not limited to the

following shall be furnished with drawings and descriptions along with the

tender.

i) Contacts, material, current density etc.

ii) Design of contact pressure.

iii) Contact support and fixing arrangement on isolators.

iv) Operating mechanism, clamps locks etc.

v) Bearings, housing of bearings, bushes etc.

vi) Balancing of heights

vii) Coupling pipes, joints, connection adjustments.

viii) Base plates

ix) Down pipe guides joints

x) Brass bushes and bearings at various joints

xi) Operating mechanism, type of gear motor, limit switch, aux. switch,

timers, size and thickness of box, degree of protection, gland plate,

gland etc.

xii) Nuts, bolts and fasteners

xiii) Interlocking devices

5.30.2 Offers without the above information or with incomplete information shall

not be considered.


21

5.30.3 All live parts shall be designed to have smooth surfaces without any edge,

sharp point or other corona producing surfaces so as to eliminate corona at

specified extinction voltage or at 1.1 x rated voltage, if extinction voltage is

not specified. All current carrying parts excluding contacts shall be made of

high strength copper or Aluminum Alloy.

5.30.4 Fasteners

Nuts, bolts and washers of 5/8" and higher size shall be hot dip galvanised.

The bolts used on tapped holes of insulator cap shall be galvanised by

centrifuge process to avoid excess deposition of zinc on threads. Nuts,

bolts and washers of less than 5/8" size shall be of stainless steel when

used on live parts and nickle-plated brass in other parts.

5.30.5 Contacts

Contacts shall be made out of hard drawn electrolytic grade copper. The

contact surface shall be silver-plated. Fabrication of contact shall be made

with suitable jig to avoid deviations during production. Details of size and

shape of contacts, springs, back plate, fixing arrangements design of

contact pressure, life of contacts, limit of temperature rise etc. shall be

furnished along with the tender. No undue wear or stuffing shall be

evident during mechanical endurance tests. Contacts & spring

shall be so designed that readjustment in contact pressure shall

not be necessary throughout the life of Isolator or earthing

switch.

5.30.6 Mounting of Contacts

The contacts shall rest on a brass block and with initial tension. Suitable

device shall be provided to prevent dashing, fabrication, welding etc. shall

be done in suitable jig to avoid deviations during production. The contact

shall be self aligning & self cleaning & so designed that binding

cannot occur after remaining closed for prolonged period of time

in a heavily polluted atmosphere.

5.30.7 Terminal Pad

The terminal pad shall be suitable for connection to aluminum terminal

connector through bimetallic plate wherever necessary. It shall be made

out of electrolytic copper heavily silver-plated. Dimension of the terminal

pad shall be furnished with the tender.

5.30.8 Moving Blade

Contact surface of moving blade shall be heavily silver-plated. The surface

shall be wiped during closing and opening operations to remove any film,

oxide coating etc. wiping action shall not cause scouring or abrasion of

surfaces.


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5.30.9 The rotating insulator shall be mounted on housing with bearing; the

housing shall be made of gravity die cast aluminum with smooth surfaces

suitably machined for seating the bearings. Two nos. of bearings with

adequate shaft diameter and distance between the bearings shall be

provided to avoid wobbling bearing operations. The bearings shall be of at

least 75 mm more than shaft diameter. The bearings shall be of reputed

make e.g. SKF, HMT, NBC, TATA and lubricated for life. Provision of

continuous adjustment/alignment of insulator shall be there which is

required to compensate permitted tolerances of insulator and

structure or base frame assembly. Adjustment/alignment using shim

washers is not allowed. All other friction location shall be provided with

suitable bearings or stainless steel or brass bushes. The bearings bushes

joints springs etc. shall be so designed that no lubrication shall be required

during service. Complete details of bearings, bushes, housing, greasing

etc. shall furnished with the tender.

5.30.10 50 MM ID class B pipe shall be provided for operating

disconnectors. The pipe shall be terminated into a suitable swivel or

universal type joint between the insulator bottom bearing and the operating

mechanism to take care of marginal angular misalignment at site.

5.30.11 Each isolator shall be provided with a rigid base fabricated from

steel sections. The base shall be suitable for mounting on support

structures. Fabrication, welding etc. shall be done by suitable jig, power

press, templates to avoid deviations during production, Details of

dimensions of sections, jig templates and device used for production of the

base shall be furnished with the tender.

5.31 Terminal Connectors

5.31.1 All disconnectors shall be provided with terminal connectors of type and

quantity, which are specified in the respective schedule.

5.31.2 The terminal connectors shall meet following requirements:

i) Terminal connectors shall be manufactured and tested as per

IS:5561

ii) All castings shall be free from blow holes, surface blisters, cracks

and cavities. All sharp edges and corners shall be blurred and

rounded off.

iii) No part of a clamp shall be less than 15 mm thick

iv) All ferrous parts shall be hot dip galvanised conforming to IS:2629

v) For bimetallic connectors, copper alloy liner of minimum thickness of

2 mm shall be cast integral with aluminum body.


23

vi) Flexible connectors shall be made from tinned copper/aluminium

sheets.

vii) All current carrying parts shall be designed and manufactured to

have minimum contact resistance.

viii) Connectors shall be designed to be corona free in accordance with

the requirements stipulated in IS:5561.

ix) Terminal connectors preferably shall be compression less/bolt type.

x) Terminal shall be suitable for twin ACSR moose conductor/4” IPS

pipe.

xi) Terminal connector shall be having STC of 40 KA/3 seconds.

xii) Type test report for STC of 40 KA/3 seconds shall be submitted, not

older than 5 yrs.

5.31.3 Exact quantities of rigid & expansion type terminal connectors required

shall be intimated to the successful supplier. The purchaser reserves the

right to procure terminal connector from the Bidder or make his own

separate arrangement for balance quantity or full requirement.

5.31.4 Wherever necessary bimetallic strip of standard quality shall be used to

avoid galvanic corrosion.

5.32 Assembly

The disconnector shall be fully assembled at the work of the supplier and

operations shall be carried out on it to ascertain that all parts fit correctly

and function satisfactorily.

5.33 Painting Galvanizing and climate proofing:

5.33.1 All interiors and exteriors of enclosures, cabinets, and other metal parts

shall be thoroughly cleaned to remove all rust, scales, corrosion, grease

and other adhering foreign matter and the surfaces treated by recognized

phosphating (e.g. seven tank phosphating sequence), After such

preparation of surfaces, two coats of zinc oxide primer shall be given by

suitable stoving and air drying before final painting. Colour of the final

paints shall be of shade no. 631 of IS:5. The finally painted cubicle shall

present aesthetically pleasing appearance free from any dent or uneven

surface.

5.33.2 Paint inside the metallic housing shall be of anti condensation type and the

paint on outside surfaces shall be suitable for outdoor installation.

5.33.3 All components shall be given adequate treatment of climate proofing as

per IS:3202 so as to withstand corrosive and severe service conditions.

5.33.4 All metal parts not suitable for painting such as structural steel, pipes, rods,

levers, linkages, nuts, and bolts used in other than current path etc. shall

be hot dip galvanized and shall be capable to prevent corrosion in view of

the severe climatic conditions.


24

5.33.5 Complete details of painting, galvanizing and climate proofing of the

equipment shall be furnished in the tender.

5.34 Current Density:

Current density to be adopted for all part of the Pantograph Isolator and

terminal connector shall not exceed the following limits:

(a) Hollow tube section : Copper – 2.0 A/mm2

Aluminum–1.25 A/mm2

(b) Other sections & terminal connectors : Copper – 1.60A/mm2

Aluminum – 1.0 A/mm2

6.0 TESTS

6.1 Type Tests

All equipments offered shall be fully type tested as per the relevant standards. In case the equipment of the type and design offered has already been type tested, the bidder shall furnish four sets of the type test reports along with the offer. However, the type test reports shall not be older than five years and shall be valid up to expiry of validity of offer.

6.1.1 The purchaser reserves the right to demand repetition of some or all the

type test in the presence of purchaser’s representative. For this purpose

the bidder may quote unit rates for carrying out each type test. For any

change in the design/type already type tested and the design/type offered

against this specification the purchaser reserves the right to demand

repetition of tests without any extra cost.

6.1.2 During type tests the disconnector shall be mounted on its own support

structure or equivalent support structure and installed with its own

operating mechanism to make the type tests representative. Drawing of

equivalent support structure and mounting arrangements shall be furnished

for purchaser’s approval before conducting the type tests.

6.1.3 The type tests shall be conducted on the disconnector alongwith approved

insulators and terminal connectors.

6.2 Acceptance and Routine Test

For isolator/earthing switch to be supplied with structure, all the acceptance tests shall be performed on offered structure only. For isolator/earthing switch to be supplied without structure, all the acceptance tests shall be performed on dummy structure. All the acceptance tests shall be performed in

presence of purchaser’s representative.

Following Routine / Acceptance tests shall be carried out on isolators

and isolators-cum-earthing switches along with insulators offered for supply.

i) Power frequency voltage dry withstand test on main circuit with offered insulators

ii) Voltage tests on control and auxiliary circuits iii) Measurement of resistance of main circuit iv) Mechanical operation test on isolator and earthing switch (50 operating


25

cycles at rated auxiliary supply or hand operated & 10 operating cycles each at maximum and minimum auxiliary supply)

v) Block rotor test

vi) List of additional tests on insulator

(1) Bending load test in four direction of 50% min bending load guaranteed on all insulators as routine test

(2) Bending load test in four directions at 100 % of min bending load

guaranteed as special test on sample of insulator selected from each lot.

(3) Tensional test on sample of insulator selected from each lot. (4) Ultrasonic test as routine test

6.2.1 Successful bidder shall offer PROTO isolator for inspection.

On approval of this manufacturing clearance shall be given.

The purchaser reserve right of having at his own expense any other test(s) of

responsible nature carried out at supplier’s works or at site or in any other place in

addition to the aforesaid type and routine tests, to satisfy that the material

confirms to with this specification.

6.2.2 Mechanical operation test (routine test) shall be conducted on disconnector

(main switch and earth switch) at the supplier’s works or purchaser’s

substation site.

6.3 Immediately after finalization of the programme of type /acceptance,

routine testing, the supplier shall give sufficient advance intimation to the

purchaser to enable him to depute his representative for witnessing the

tests.

6.4 Test certificates of various items including but not limited to the following

shall be furnished at the time of routine tests.

a) Chemical analysis of copper along with a copy of excise certificate

indicating genuine source of procurement of electrolytic grade

copper.

b) Bearings

c) Fasteners

d) Universal/swivel joint coupling

e) Insulators

f) Motor

g) Gears

h) Auxiliary switch

i) Limit switch

j) Timer

k) Overload/single phase prevented relay

l) Interlocking devices


26

m) Terminal block

n) Any other item.

6.5 Type Test Reports

6.5.1 Bidder shall submit the following Type test reports along with the Technical

bid

i) Lightning Impulse Voltage withstand test

ii) Switching Impulse Voltage withstand test (for 400 kV)

iii) Power Frequency Voltage withstand test on main circuit.

iv) Power Frequency Voltage withstand test on auxiliary circuit

v) Temperature rise test on main isolator

vi) Short Time Current & peak withstand current test on isolator and earthing

switch.

vii) Short Circuit making performance test of earthing switch

viii) Operating and mechanical endurance test on isolator and earthing switch

ix) Measurement of Radio Interference level

x) Corona Inception & extinction test

xi) STC test on terminal connector

xii) Degree of protection test on cubicle

xiii) Blocked rotor test

xiv) Seismic test

xv) Mech & Elect Endurance test on Auxiliary switch

xvi) Tests on insulator (Dielectric and mechanical load tests)

xvii) Galvanizing test

xviii) Dielectric tests on insulating sleeve provided on operating handle.

7.0 INSPECTION

i) The purchaser shall have access at all times to the works and all

other places of manufacture, where the disconnectors, earth

switches and associated equipment are being manufactured and the

supplier shall provide all facilities for unrestricted inspection of the

works, raw materials, manufacture of all the accessories and for

conducting necessary tests as detailed herein.

ii) The successful bidder shall keep the purchaser informed in advance

of the time of starting and of the progress of manufacture of

equipment in its various stages so that arrangements could be made

for inspection.

iii) No material shall be dispatched from its point of manufacture unless

the material has been satisfactorily inspected and tested.

iv) The acceptance of any quantity of the equipment shall in no way

relieve the successful bidder of his responsibility for meeting all the


27

requirement of this specification and shall not prevent subsequent

rejection if such equipment are later found to be defective.

8.0 QUALITY ASSURANCE PLAN:

The bidder shall invariably furnish following information along with his offer,

Information shall be separately given for each type of the disconnector.

i) Statement giving list of important raw materials, including but not

limited to:

a) Copper

b) Steel

c) Springs

d) Bearings

e) Nuts & bolts

f) Grease

g) Operating mechanism and its components such as motor, gear,

contactor, timer, relays, aux. Switch, limit switch, interlocks,

terminal block etc.

ii) Names of sub suppliers for the raw materials, list of standards

according to which the raw materials are tested, list of tests normally

carried out on raw materials in presence of supplier’s representative,

copies of test certificates.

iii) Information and copies of test certificates as in (i) and (ii) above in

respect of bought out accessories.

iv) List of manufacturing facilities available.

v) Level of automation achieved and lists of areas where manual

processing still exists.

vi) List of areas in manufacturing process, where stage inspection are

normally carried out for quality control and details of such tests and

inspections.

vii) List of testing equipments available with supplier for final testing

equipment and test plant limitation if any, vis-à-vis the type, special,

acceptance and routine test specified in the relevant standards.

These limitations shall be very clearly brought out in the specified

test requirements.

8.1 The successful bidder shall within 30 days of placement of order, submit

following information to the purchaser.


28

i) List of raw material as well as bought out accessories and the

names of sub-suppliers selected from the lists furnished along with

offer.

ii) Type test certificates of the raw material and both bought out

accessories.

iii) Quality Assurance Plan (QAP) with hold points for purchaser’s

inspection. The quality assurance plan and hold points shall be

discussed between the purchaser and supplier before the QAP is

finalized.

iv) Field Quality Plan (FQP) with hold points for storage, erection &

maintenance. The field quality plan and hold points shall be

discussed between the purchaser and supplier before the FQP is

finalized.

8.2 The successful bidder shall submit the routine test certificates of bought

out accessories and central excise passes for raw material viz. copper,

aluminum conductors, lubricating material, gear material etc. at the time of

routine testing of the fully assembled disconnector.

9.0 DOCUMENTATION

All drawings shall conform to international organization for standards (ISO)

‘A’ series of drawing sheet/Indian standards specification IS:11065. All

drawings shall be in ink and suitable for microfilming. All dimensions and

data shall be in S.I. Units.

9.1 List of drawings and documents

The bidder shall furnish four sets of following drawings along with his offer:

a) General outline and assembly drawings of the disconnector

operating mechanism, structure, insulator and terminal connector.

b) Sectional views and descriptive details of items such as moving

blades, contacts, arms contact pressure, contact support bearing

housing of bearings, balancing of heights, phase coupling pipes,

base plate, operating shaft, guides, swivel joint operating

mechanism and its components etc.

c) Loading diagram.

d) Drawings with structure for the purpose of type tests.


29

e) Name plate

f) Schematic drawing

g) Type test reports in case the equipment has already been type

tested.

h) Test reports, literature, pamphlets of the bought out items and raw

material.

9.2 The successful bidder shall within 2 weeks of placement of order, submit

four sets of final version of all the above said drawings for purchaser’s

approval. The purchaser shall communicate his comments/approval on the

drawings to the supplier. The supplier shall, if necessary, modify the

drawings for purchaser’s approval, the supplier shall within three weeks,

submit 10 prints and two good quality reproducible of the approved

drawings for purchaser’s use. One copy of approved drawings shall also be

sent along with each set of isolator. One copy of the routine test report and

operation/maintenance manual shall be sent with each set of isolators

dispatched for the use by field engineer.

9.3 Six sets of the type test reports if required to be carried out duly approved

by the purchaser shall be submitted by the supplier for distribution, before

commencement of supply. Adequate copies of acceptance and routing test

certificates, duly approved by the purchaser shall accompany the

dispatched consignment.

9.4 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.

9.5 Approval of drawings/work by purchaser shall not relieve the supplier of his

responsibility and liability for ensuring correctness and correct

interpretation of the latest revision of applicable standards, rules and codes

of practices.

9.6 Instruction Manuals

Six copies of the erection and maintenance manuals in English shall be

supplied for each type of disconnector one month prior to dispatch of the

equipment. The manual shall be spiral bound volumes and shall contain all

drawings and information required for erection, operation and maintenance

of the disconnector including but not limited to the following particulars:


30

a) Marked erection prints identifying the component parts of the

disconnector as shipped with assembly drawings.

b) Detailed dimensions and description of all auxiliaries.

c) Detailed views of the insulator stacks, metallics, operating

mechanism, structure, interlocks, spare parts etc.

10.0 PACKING AND FORWARDING

10.1 The equipment shall be packed in M.S. crates suitable for

vertical/horizontal transport, as the case may be and suitable to withstand

handling during transport and outdoor storage during transit. The easily

damageable material shall be carefully packed in M.S. container and

marked with the appropriate caution symbols. Wherever necessary, proper

arrangement for lifting, any material found short inside the packing cases

shall be supplied by supplier without any extra cost.

10.2 Each consignment shall be accompanied by a detailed packing list

containing the following information:

a) Name of the consignee.

b) Details of consignment.

c) Destination.

d) Total weight of consignment.

e) Handling and unpacking instructions.

f) Bill of material indicating contents of each package.

10.3 The supplier shall ensure that the packing list and bill of material are

approved by the purchaser before dispatch.

11.0 The support structure required for pantograph types of disconnector

(isolators) shall be supplied by the successful Bidder.

The support structure shall be tubular type made out mild steel pipe of

suitable size and completely hot dip galvanized for Pantograph. Design

calculations along with bill of Material for structure shall

have to be submitted by the successful bidder. The foundation

bolt of appropriate size and at least 550 mm in length shall be supplied

along with the structure. The foundation bolt shall be galvanized for 175

mm from the top threaded portion; the rest of it will be blank.

The support structure will be provided with fastening arrangement for

connection of the structure to the earthing arrangement.


31

The cost of the support structures and foundation bolts shall be deemed to

be included in the cost of equipment.

12 Erection and commissioning

12.1 The Bidder shall quote for the services of an Erection Engineer who shall assure

full responsibility for the erection, testing and commissioning of isolator. Skilled

and unskilled labour and normal erection tools would be provided by the

purchaser. All special erection tools required for the erection, testing and

commissioning of the isolators, shall be provided by the bidder.

12.2 “After erection as required in clause NO 2.14.1 the supplier shall demonstrate &

perform 50 Nos. of consecutive successful open close operation of isolator with

motor operated mechanism on at least one isolator at every place of erection.

If during above 50No of operation any abnormality or difficulty is observed then

after due rectification again 50 Nos of consecutive operations will be

performed. This may be repeated till 50 Nos of consecutive operations are

successful.”

12.3 Purchaser shall provide local workman as well as all ordinary tools required for

erection, at his own expense. Apart from the above, the purchaser shall not be

responsible for any other expenses incurred by the Bidder and expenses such

Erector’s salary, insurance against personnel injuries to the Erector etc. which

shall be to the Bidder’s account.

12.4 Bidder shall not be liable for any loss, damage or injury to property or person at

the installation site unless such damage or injury is caused by any act or

negligence of the supervising Erector.


32

ANNEXURE – I

(Isolators)

SYSTEM PARTICULARS

Electrical system Data :

a) System voltage (KV rms) 400

b) Max. voltage (KV rms) 420

c) Lightning impulse withstand voltage (dry & wet)

(Kvp)

1425

d) Power frequency withstand voltage (wet) (kvp) 650

e) Short circuit level (kA) for 3 sec. 40

f) Switching surge withstand voltage (wet) KVP 1050

g) Radio interference voltage at 1 MHz (micro volt) 1000 at 1.1 times

maxm. phase to

ground voltage

h) Min corona extinction voltage @ 50 Hz AC system

dry condition (KV rms)

320


33

Annexure – II

(Isolator)

LIST OF MANDATORY SPARES

Sr. No.

Item Quantity per each type of

isolator (Total)

1 Copper contact fingers for female contact

6 sets

2 Support insulator stack for one pole of isolator

1 stack

3 Rotary bearings for isolator 6 sets

4 Hinge pin 6 nos.

5 Limit switch and aux. Switch 1 set

6 Terminal connectors 1 no. of each type


34

(To be filled in by the Bidders)

GUARANTEED TECHNICAL PARTICULARS FOR PANTOGRAPH

DISCONNECTOR (ISOLATORS) – 420 KV

1) Type/Installation P.G.

2) Manufacturer’s Name and Country of Manufacture

3) Standard/s according to which the isolators are

manufactured

4) Maximum design voltage at which the isolator can

operate (kV)

5) Frequency (Hz)

6) Rated voltage (KV)

7) Max. current that can be safely interrupted by the

isolator

Inductive (A & % PF)

Capacitive (A & % PF)

8) Continuous current rating

Nominal (Amps)

Under site conditions (Amps)

9) Rated short time current (for main & E/S)

i) For 3 Seconds (KA rms)

ii) Rated peak short time current (KVP)

10) Material & Current density at the minimum cross-

section of main & E/S

a) Moving blade (Amps/Sq. mm.)

b) Terminal pad (Amps/Sq. mm.)

c) Contacts (Amps/Sq. mm.)

d) Terminal Connector (Amps/Sq. mm.)

e) Fixed contact (Amp./sq. mm.)

11) Max. temp. rise of current carrying parts when

carrying rated current continuously (°C)


35

12) Seismic level

13) Insulation levels

i) Impulse withstand voltage (kV peak)

Phase to Earth

Isolating Distance

ii) Switching surge withstand voltage

(kVpeak)

Phase to Earth

Isolating Distance

iii) Power frequency withstand voltage (kVrms)

Phase to Earth

Isolating Distance

iv) Radio interference voltage at 266 kV rms

(micro volts)

v) Corona inception voltage (kV rms)

vi) Corona extinction voltage (kV rms)

14) Minimum clearance in air :

i) Between poles (mm)

ii) Between live parts and earth (mm)

iii) Between live parts when switch is open:

a) On the same pole (mm)

b) Between adjacent Poles (mm)

15) Rated mechanical terminal load

i) Load along the terminal connector side

(kg.)

ii) Load across the terminal connector side

(kg.)

16) Torque required to operate the switch in kg-m

17) Contact Zone

i) Horizontal deflection (mm)

ii) Vertical deflection (mm)


36

iii) Total amplitude of longitudinal movement

with respect to conductor supporting fixed

contact (mm)

18) Design and Construction

i) No. of insulators per pole

ii) No. of breaks per pole

iii) Type of closing/opening mechanism

iv) Contacts:

a) Material and grade

b) Cross-sectional area in sq. mm.

v) Moving Blades:

a) Material and grade

b) Cross-sectional area in sq. mm.

vi) Contact Support:

a) Material and size of Channel/block

b) Material and size of plate

vii) Rain hood –Material grade and size

viii) Total weight of isolator excluding structure

ix) Nuts and Bolts:

a) Size, material and grade in the live

parts

b) Size, material and grade in other parts

x) Insulator base plate

Material and size of plate below insulators

xi) Bearings:

a) Material and size of housing

b) No. of bearing, location and size

xii) Tandem pipe:

a) Size class and no. of pipes

b) Size of shackle, screw

c) No. of bearings/bush and its material


37

and size

xiii) Type of interlock

xiv) Down pipe size and class

xv) Type of universal/swivel joint

a) Between bearing and down pipe

b) Between down pipe and operating

mechanism

xvi) Operating mechanism:

a) Control cabinet

Material and thickness

Degree of protection

Type size and no. of cable glands

Whether removable gland plate

provided

b) Make type, rating and qty. of:

Motors

Gears

Limit switches

Contactors

Over load relay

Single phase preventor

Auxiliary switch

Terminal blocks

Insulator wires

HRC fuses

Pole discrepancy relay

Timer

Space Heater

Interlocks

Thermostat

xvii) Insulators:

a) Type


38

b) No. of units per insulator

c) Rating of insulators (kV)

d) Height of each insulator stack (mm)

e) Bolt circle diameter (mm)

TOP

BOTTOM

f) Tensile strength (Kg.)

g) Compressive strength

h) Torsional strength (kg. Cm.)

i) Cantilever strength upright

j) Power frequency dry flash over voltage

(kV)

k) Power frequency puncture Voltage (kV)

l) Impulse flash over voltage (positive

wave) (kV) peak

m) Impulse withstand voltage (kV) peak

n) Power frequency puncture voltage (kV)

o) Visual discharge voltage level (kv) rms

p) Cree page distance:

Total (mm)

Protected (mm)

q) Dry arcing distance (mm)

xviii) Base:

a) Size of steel section used

b) Overall size

c) Total weight

xix) Terminal Connectors:

a) Clamp Body:

Alloy composition

Plating if any Area at min. cross-section


39

b) Bolts and nuts size

Alloy composition

Tensile strength

c) Type of washers used

d) Materials of braids

e) Temperature rise when carrying rated

current at 50°C ambient (°C)

f) Weight of each type of clamp (kg.)

g) Make of bolt less type connector

h) Length of tube of compression type

connector for the length of conductor

being compressed

18a Time of opening and closing of

Main isolator

Earthing switch

19) List of bought out items

20) List of test certificates furnished

21) List of drawings furnished

Signature of Bidder: _______________ Designation & Seal: _____________________ Date: ________________________

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