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SPECIFICATION FOR 11 KV ANTIFOG STRAIN DISC INSULTOR 120 KN
11 KV porcelain disc Insulator of size 305 mm dia and 145 mm in
height, ball and socket
type made of best quality H.T.porcelain, sound free from
defects, thoroughly vitrified and
smoothly glazed suitable for use in 110 KV transmission lines.
The glaze shall be brown incolour. The glaze shall cover all the
porcelain parts of the Insulator except those areas whichserve as
supports during firing or left unglazed for purpose of assembly.
The insulator should be
suitable for using in the 110 KV tower line in tension
tower.
The design of the insulator shall be such that stress due to
expansion and contraction in
any part of the insulator shall not lead to deterioration. The
porcelain shall not engage directlywith hard metal. Cement used in
the construction of the insulator shall not cause fracture by
expansion or loosening by contraction and proper care shall be
taken to locate individual partcorrectly during cementing.
The cement shall not give rise to chemical reaction with metal
fittings and its thicknessshall be uniform. The insulator shall be
suitable for heavily polluted area and the minimumcreepage distance
shall be 460 mm and the minimum failing load should be 120 KN.
Each insulator shall be legibly and indelibly marked to show the
following:-
a) Name and trade mark of the manufacturer,b) Month and year of
manufacture,
c) Minimum failing load
d) Country of manufacture.
Marking on porcelain shall be printed and applied before firing.
The insulator shall be
marked with ISI certification mark.
The 11 KV antifog disc insulator should have the following
specification:-
Rated voltage : 12 KV
Ball and Socket size : 20 mmMin. Power Frequency Dry : 90 KV
Min. Power Frequency Wet : 55 KV
Flash over voltage 50% impulse positive : 140 KV (peak)
Flash over voltage 50% impulse negative : 150 KV (peak)Power
Frequency Dry withstand voltage : 85 KV
Power Frequency wet withstand voltage : 50 KV
Impulse withstand voltage positive : 135 KV (Peak)
Impulse withstand voltage negative : 135 KV (Peak)Puncture
withstand voltage : 130 KV
Visible discharge voltage : 18 KV
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The Insulator shall generally conform to IS:731/1971 and
IS:3188/1980 for dimension,
IS:2486(Part-II)/1974 for ball and socket IS:2486(Part III)/1974
for R shaped locking devicemade of steel, all with latest
amendments, and as per drawing enclosed for style No.1-027-OA
with net weight of 8.7 Kgs.
Necessary type test certificate obtained from Government
approved laboratory should be
submitted along with tender.
Necessary routine electrical and mechanical test certificate in
duplicate as per relevantIS should be furnished along with
supply.
Quantity: 1250 Nos.
Delivery: within 30 days.
SUPERINTENDING ENGINEERIELECTRICITY DEPARTMENT
PUDUCHERRY
