what is the criterion for selecting vector group of Transformers ? i mean how to decide vector group of Generator transformer, substation trasformer and transformer at consumer end?
The winding (delta or star) depends on the type of electrical system. The phase shift is selected so that transformer interconnections are synchronised.
im working in marine field , in single line diagram it is mentioned as 0 deg,+7,5 deg,-7,5 deg for the phase shift transformers for the seismic compressors,
is it has any relation with vector group ,then what is 0,+7.5 & -7.5 degrees and also this was any relation with leading or lagging angles voltage & current
pls clarify very soon
I don't think this is anything to do with vector groups.
These figures may related to a special transformer where a specified phase shift is introduced to cancel out harmonics.