Reason of Vector Group Selection of Transformer YNd11

Reason of vector group selection of transformer YNd11 & YNyn0 for unit aux transformer & Station transformer. The phase shift in the Transformers needs to be grouped at New TPP, for that a combination of YNd11 (GT) & YNd11 (UAT) ensures Phase Reference: GRID at 6.6kV Service Bus at TPP Also note that YNyn0 Trafo introduces ZERO phase Shift, Hence Phase Reference shall remains the same.

132 kV Bus Phase Ref: GRID

60/80 MVA YNd11 ( New Trafo ) GT

35 MW YNyn0

Phase Ref: GRID 11 kV Service Bus at Existing TPP

10/12.5 MVA YNd11 ( New Trafo ) UAT 60 MW

YNyn0 ( New Trafo ) ST

Phase Ref: GRID 6.6 kV Service Bus at TPP

Synchronizing Breaker