220-66-kv-xmer-on-line-nifes-r4-sept-08 - Gujarat Electricity Board
220-66-kv-xmer-on-line-nifes-r4-sept-08 - Gujarat Electricity Board
220-66-kv-xmer-on-line-nifes-r4-sept-08 - Gujarat Electricity Board
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GETCO/E/TS – XMER01power/R4 Sept <strong>08</strong><br />
from mixing with the oil in the transformer tank. A buchholz relay shall be provided<br />
to indicate accumulati<strong>on</strong> of gas and alarm thereof.<br />
1.17.1.3 The tap changer shall be capable of permitting parallel operati<strong>on</strong> with other<br />
transformer of the same type.<br />
1.17.1.4 The transformer shall give full load out-put <strong>on</strong> all taps. The manual operating device<br />
shall be so located <strong>on</strong> the transformer that it can be operated by an operator standing<br />
at the level of the transformer track. It shall be str<strong>on</strong>g and robust in c<strong>on</strong>structi<strong>on</strong>.<br />
1.17.1.5 The c<strong>on</strong>trol scheme for the tap changer shall be provided for independent c<strong>on</strong>trol of<br />
the tap changers, when the transformers are in independent service. In additi<strong>on</strong>,<br />
provisi<strong>on</strong> shall be made to enable parallel c<strong>on</strong>trol also at times so that the tap<br />
changers will be operated. Simultaneously, when <strong>on</strong>e unit is in parallel with another<br />
so that under normal c<strong>on</strong>diti<strong>on</strong>s the tap changer will not become out of step and this<br />
will eliminate circulating currents. Additi<strong>on</strong>al features like master followers and<br />
visual indicati<strong>on</strong> during the operati<strong>on</strong> of motor shall also be incorporated.<br />
1.17.1.6 Necessary interlock, blocking independent, c<strong>on</strong>trol, must be provided when the units<br />
are in parallel shall be provided.<br />
1.17.1.7 Under abnormal c<strong>on</strong>diti<strong>on</strong>s such as may occur, if the c<strong>on</strong>tactor c<strong>on</strong>trolling <strong>on</strong>e tap<br />
changer sticks, the arrangement must be such as to switch off supply, to the motor<br />
so that an out of step c<strong>on</strong>diti<strong>on</strong> is limited to <strong>on</strong>e tap difference between the units.<br />
Details of out of step protecti<strong>on</strong> provided for the taps should be furnished in the bid.<br />
1.17.1.8 The c<strong>on</strong>tactors and associated gear for the tap change driving motors shall be housed<br />
in a local kiosk mounted adjacent to or <strong>on</strong> the transformer. The motor shall be<br />
suitable for operati<strong>on</strong> with 3 phase, 415 Volts, 50 Cycles external power supply with<br />
MCB / fuse and single phasing preventi<strong>on</strong>.<br />
1.17.1.9 In additi<strong>on</strong> to the above equipment, the supplier shall supply a separate panel for<br />
installati<strong>on</strong> in purchaser’s c<strong>on</strong>trol room for remote operati<strong>on</strong> with the following<br />
accessories.<br />
<br />
<br />
<br />
<br />
<br />
<br />
Raise and lower functi<strong>on</strong>.<br />
Remote tap positi<strong>on</strong> Indicator of digital type<br />
Remote tap positi<strong>on</strong> indicati<strong>on</strong> of digital type, device for indicating ‘ON’ &<br />
‘OFF’ positi<strong>on</strong> of fan / motor / pump of cooler c<strong>on</strong>trol.<br />
Microprocessor based Annunciati<strong>on</strong><br />
Out of step relay and indicati<strong>on</strong>.<br />
Name-plate for each comp<strong>on</strong>ent. An alarm indicati<strong>on</strong> lamps showing tap<br />
changing in progress.<br />
Sign and Seal of Bidder Page 17 of 87
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