Give the details of switchyard 220 kV CB, Isolator, CT, CVT and lightning arrestor.
220 kV SF6 Circuit Breaker
1. Make – ABB
2. Air pressure blocking a. Close Block – 17.3 bar.
b. Open block – 16.7 bar.
c. Auto reclose block – 19 bar.
3. SF6 pressure block a. Alarm – 5.2 bar.
b. Rated – 6 bar.
c. Limit – 5 to 6 bar.
d. Open block – 5 bar
4. Weight of gas / pole : 20 kgs.
5. Closing time : 130-milli sec.
6. Method of closing : Electro-pneumatic.
7. Compressor pressure : 20.5 kg/cm2.
Isolator
1. Type : High-pressure pressure relieving isolator (HPPR) central pole double
break.
2. CB and Isolator clearances : Phase to Phase – 4500 mm.
Phase to earth – 2300 mm.