Ground Fault Currents in delta connected circuits

[zing22]

Hi all,
how would be the distribution of positive, negative and zero sequence currents for a single line to ground fault in a delta connected circuit at say 35kV?
would the zero sequence dominate or otherwise?
The upstream circuit has a delta-star(high impedance grounded) transformer feeding this faulted delta on the LV bus. The ground fault current will return to the high impedance grounding connection in the transformer LV.
thanks!

 

[slavag]

Hi Zing22.
Ground fault in the isolated system ( that menat delta connection w/o any grounding trafo)=0.
Actually is equl to capacitance current of all elements.
Upstream system maybe fill some unbalance.
Regards.
Slava

 

[dpc]

If you have a resitance grounded wye winding supplying this system, then you don't have a delta circuit. You may have delta connected loads, but that is not a factor.

If you have ground fault, the current will have to get back to the transformer neutral point, via whatever path it can find and then through the resistor.

It is a straightforward line-to-ground fault in terms of symmetrical component analysis, except that you must include the grounding resistance in the zero sequence impedance or the fault impedance.

But maybe I'm not understanding what you are trying to ask.

 

[jghrist]

I₁=I₂=I₀