Zig Zag Transformer - Phasing 1

[tefaber]

Hi all,

I will be installing a Zig-Zag transformer to provide a ground reference for a 69kV delta system. This Zig-Zag TR will be installed in conjuction with a two-winding power transformer where the phasing into the power transformer is Phase 1 into the H1 bushing, Phase 2 into the H2 bushing, and Phase 3 into the H3 bushing. Based upon the layout of the substation, it is most convienient to connect the grounding transformer such that Phase 3 is connected to the H1 bushing, Phase 2 is connected to the H2 bushing, and Phase 1 is connected to the H3 bushing.

My question/concern (valid or not) is whether there will be a problem connecting a Zig-Zag in this fashion such that the phasing into it (3-2-1) is opposite that of the power transformer (1-2-3)?

Any input is greatly appreciated.

Thanks!

 

[pwrtran]

It doesn't matter. All a zig-zag grounding transformer does is to provide a low impedance path for the zero sequence current.