MGVCL Exam Paper (30-07-2021 Shift 2)
Consider the following statements associated with Buchholz's relays. Statement 1: Buchholz's relay is a current operated device. Statement 2 : Buchholz's relay is placed between the transformer tank and the conservator.
Buchholz relay is gas operated relay. It will operate when internal fault occurs in transformer. It is placed between tank to main conservator. It has two contacts trip and alarm. Use of Buchholz relay in distribution transformer is not economical.
The capacity of reactor = 50 MVAr when it is operated at 415 kV. Impedance of reactor = V2/MVAr = (415*415)2/50 = 3444.5 Ω For 400 kV, Reactive power observed = (400*400)/3444.5 = 46.45 MVAR
Or
VAr capacity of capacitor or reactor is proportional to V²