My utility recently commissioned a zig-zag earthing transformer with the following rating: 33kV, 2000A for 10 seconds, 19.4 ohms on one of its 33kV network. Two days after commissioning, it was detected that oil was dripping from the transformer as a result of overheating. The grounding of the...
The distribution network in my country is a 4-wire star system. Most of the load in the system are single phase, 230V. The system loss figure is estimated at 25% consisting of both technical and commercial. We have tried to bring down this figure but our efforts have not yielded much. I want to...
I attended an interview on Monday and one of the questions asked was that I should tell why star-star transformers are usually not used. According to the questioner, there is a particilar problem with them that makes their use not advisable. I have read a lot about transformers but have not come...
Does the duty cycle of a circuit breaker have anything to do with autoreclosing? We have a CB with duty cycle of CO-15s-CO. We are to implement an autoreclosing scheme consisting of one fast reclosing of 0.5sec and one delayed reclosing of 15sec. I have been wondering whether the CB is suitable...
