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?
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.
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,
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.
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?
Hello Everybody
We have a 30MVA, 132/33KV transformer that is tripping on bucholtz. We carried out Insulation resistance, magnitisation and short circuit tests which all shows a satisfactory result. The magnitisation and short circuit tests were carried out using 415V and the Insulation...
We have a 30MVA, 132/33KV Transformer that was removed from service due to leakage, for about 3years and the oil was beign removed and used elsewhere. Recently, the leakages were sealed and it was filled with oil and energised without picking any load for five days. On the fifth day the primary...