SLG Fault Contribution From 3 Winding Transformer 2

[3winding]

Scenario. Mulitiple generators connected to the grid through a Wye/Wye transformer with a Delta Tertiary (buried).

For a SLG fault on the HV side of the transformer, will the grid contribute SLG current through the transformer?

The SKM model I am running shows a higher SLG current on the HV side of the transformer than the LV side (after turns ratio applied), so I assume the transformer is acting as a source to the fault?

 

[davidbeach]

If it is a grounded wye-grounded wye, yes there is a zero sequence connection through the transformer as well as the ability to source ground fault current. If ungrounded, the zero sequence connection would be open.

 

[RAgrawal]

Yes, Yn0Yn0d Transformers act as source to the griund fault current and what you are experiencing is correct.