Recent content by haisa

Hello All. We are installing a 150MVA 330/132/33kV Y/Y/D Transformer. Is using an Earthing Transformer and Earthing Reactor together appropriate on the Tertiary winding for protection?

What I want to know is whether the fault level of a substation has any effect on the choice of transformer to be installed at that substation. In this case the fault level of this substation according to my calculation is about 35KA while the short circuit withstand current rating of the...

The Short Circuit MVA level of a 132/33kv substation is 20.31pu on 100MVA base. 2 x 60MVA Transformers were installed in the substation and the two packed up within a very short time. What factors do we consider in choosing a transformer for this substation please.

Thanx a lot

Yes it is removed.

Hello everyone, We conducted a magnetic balance test on a 30MVA, 132/33KV transformer on all the taps at both primary and secondary. The results showed that the sum of the two voltages are different from the applied voltage by about 6V to 10V. Is this acceptable? What could be wrong please.

Hello Engrs We conducted a tan delta test on a 30MVA, 132/33KV transformer recently using OMICRON CPC 100. At different voltages we had values like -6%, 0.5 % and 23%. What can we deduce from these. Iread that for good insulation the value should be around 0.007% what does the minus sign imply.

Hello, I am please looking for a detailed wiring drawing of a Hawker Siddeley 36KV Horizon Circuit Breaker. I could not find on their website.

Hello, What are the possible faults on transmission lines apart from long trees grounding the line? We have a 330KV line that keeps tripping but continue in service once closed back. We have cleared all vegetations under the line and all terminal equipment have passed insulation resistance test...

We have wired a siprotec relay on a 60MVA, 132/33KV Transformer. All readings looks okay but the differential current is too high and the differential current on blue phase is twice the other phases. What could be the possible reasons please.

The relay is micom p 422. Is it possible to change its direction by changing the star point of the CT or the phase rotation of VT?

Hello My distance relay at a 132/33kV terminnal sub-station is tripping due to faults on 33KV feeders. My suspicion is that it is looking at the wrong side. How do I confirm and correct this please?

Please guide me How to conduct TAn DELTA test for power transformer.Pls give me some documents related

Is it Possible to apply a low voltage of say 415V and then short the Secondary, so that the little current flowing keeps it warm?

What I am actually after is the KVA Rating. So How do I find the Rated output Current of the Transformer?