In network, a 132/33KV YY0 T/F is in series with Ynd1 33/13.8KV T/F. What should be the vector group of a 132/13.8KV T/F required to be operated in parallel with the above two T/Fs?
Responding to MA Husain’s 20-May-08 (01:02) query... tagging the 132/33kV transformer 'A', the 33/13.8kV transformer 'B', and the new 132/13.8kV transformer 'C'. Then:
1) Transformer ‘C’ must have the same Vector group as the transformer ‘B’, that is, Ynd1.
2) Caveat... to eliminate disproportionate loading, the impedance of transformer 'C' should be approximately equal to the sum of transformer 'A' and 'B' impedances, when converted to a common base.
