132/33kV Trafo vector group - Dy or Yd
132/33kV Trafo vector group - Dy or Yd
(OP)
Is Dy connection common for 132/33kV transformers. Delta on 132kV side means more insulation cost, on the otherhand, the Star on 33kV provides neutral for solid earthing of 33kV system.
Any views.
Thanks in anticipation.
Any views.
Thanks in anticipation.






RE: 132/33kV Trafo vector group - Dy or Yd
RE: 132/33kV Trafo vector group - Dy or Yd
How about 132/33kV transformers in Indian power distribution system. Are these Yd connected or Yy. If it is Yy connected, is the reflection of 33kV earth faults on to 132kV system not an issue (and how is it addressed).
Dy connection for 132/33kV - J&P transformer Handbook has some discussion (hope I am right about the reference, remember to have seen long back) and says that if the source end 132kV winding has neutral for solid earthing at receiveing substations, delta connected 132kV windings are used and allowed in British power system.
RE: 132/33kV Trafo vector group - Dy or Yd
How they are taking care of fault currents.... our protection gurus may take over.
RE: 132/33kV Trafo vector group - Dy or Yd
One of the ways to reduce fault current of YY grounded transformers could be by specifing high positive and zero seq impedance.
RE: 132/33kV Trafo vector group - Dy or Yd
RE: 132/33kV Trafo vector group - Dy or Yd
The vendors seem to be deliberately limiting the earth fault current by choosing higher zero sequence impedance for the zigzag transformer.
The spec calls for 5 Ohm impedance but vendors say there is limitation in design (to meet the stipulation).