remote control equipment - Indian Railways Institute of Electrical ...
remote control equipment - Indian Railways Institute of Electrical ...
remote control equipment - Indian Railways Institute of Electrical ...
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5.9.5 A single shot reclosing relay to work in conjunction with MasterTrip relay shall<br />
be provided.The auto-reclosing relay shall have an adjustable time setting between 0.5 sec. to<br />
30 sec for the reclosure <strong>of</strong> the feeder circuit breaker.After single auto-reclose <strong>of</strong> the breaker it<br />
shall be possible to operate the same either manually or on <strong>remote</strong> <strong>control</strong> without any<br />
necessity for manual reset in auto-reclosing relay.This requirement as essential in view <strong>of</strong> the<br />
sub-station being unattended.<br />
5.9.6 Suitable operation counter shall also be provided individually for distance protection<br />
adittance(Mho) relay,wrong phase coupling admittance(Mho) relay, instantaneous over<br />
current relays and also for the auto-reclosing scheme.<br />
5.9.7 In addition to the above protection an instantaneous acting undervoltage relay<br />
is provided by the purchaser to trip the bridging interruptor at the neutral section in case <strong>of</strong><br />
undervoltage during emergency feed condition.<br />
5.9.8 The relays shall be suitable for operation from 25KV current transformer and<br />
25KV potential transformer to the following particulars :<br />
Rating CT PT<br />
i) Rated system voltage 25KV rising upto 30KV<br />
ii) Rated transformation 1000-500/5A 25KV/110V<br />
ratio<br />
iii) Rated burden 60VA 100VA<br />
iv) Rated accuracy limit<br />
lactor 15 --<br />
iv) Accuracy class 5P as per 1.0/3P as<br />
IS:2705 PER IS:3156<br />
(PTIII) (pt.II & III)<br />
1981 1978<br />
5.9.9 The relay shall conform to the accuracy class 15 as per IS 3231-1965<br />
5.9.10 The operating time for the Mho relay shall be as small as possible and shall<br />
not exceed 20ms for a source to line impedance ratio <strong>of</strong> 1:1 in case <strong>of</strong> earth fault relays. The<br />
operating times for minimum and maximum setting <strong>of</strong> the relays in term <strong>of</strong> distance shall be<br />
furnished by the tenderer together with the variation in operating time for various fault positions<br />
expressed as percentage <strong>of</strong> relay settings.<br />
5.9.11 The polarizing input for relays shall have a tuned memory circuit ,so that it is<br />
possible to maintain a polarizing signal even after a fault occur , for a sufficiently long time for<br />
the operation <strong>of</strong> relay to operate in case <strong>of</strong> a fault close to the sub-station, when the<br />
restaining voltage disappears.<br />
5.9.12 The relays shall be insensitive to power swing, heavy overload and transient<br />
condition including magnetizing in rush current <strong>of</strong> locomotive to transformers and shall be<br />
suitably designed to compensate the effect <strong>of</strong> fault arc resistance.<br />
107
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