Voltage During SLG and DLG faults
Voltage During SLG and DLG faults
(OP)
I was wondering if it is possible for the voltage of the healthy phase to a double line to ground fault to be higher than the voltage of the healthy phases to a single line to ground fault. The fault is considered to happen on the low voltage side of a transformer feeding a grid.






RE: Voltage During SLG and DLG faults
There's a series of curves of maximum voltage to ground for arrester application. These are plotted as a function of X0/X1 and R0/X1. The values (voltage on unfaulted phase) are based on both a single line-to-ground fault as well as a double line-to-ground. The double line to ground fault does influence a portion but not the majority of the curve.
I'll try to post a copy of one of the curves if someone else doesn't do it.
RE: Voltage During SLG and DLG faults
Regards,
Reynaldo Salcedo
RE: Voltage During SLG and DLG faults
If the sequence impedance parameters could be available, the maximum voltage could be calculated after determine the coefficient of grounding (Eath Fault Factor for the IEC marketplaces).
Check this post: http://www.eng-tips.com/viewthread.cfm?qid=237503
RE: Voltage During SLG and DLG faults
For the most part, you can come pretty close to this curve if you base it on a single line-to-ground fault. However, there is a small area where a double line-to-ground fault is more limiting.
This is really the same curve that cuky referred to.
RE: Voltage During SLG and DLG faults
RE: Voltage During SLG and DLG faults
Regards,
Reynaldo Salcedo