Earth Fault Scale

[SRA007]

Could anyone please provide a range of typical values for GPR(Ground potential Rise).Touch and Step Potentail that should be expected within an 11kV/0.4kV distribution substation i.e i am looking foa a scale for example 0-1kV.

 

[7anoter4]

The GPR, Touch and Step voltage you may calculate yourself following Annex B of IEEE Std. 80/2000.
The system fault level at 11 kV will be around of 500 MVA. Since, the transformer stands on the grounding grid and the supplied premise [installation] stands on the same grounding grid, the fault current flows only through the grounding grid conductors and not through the Earth and then the low voltage fault current does not produce GPR

 

[cherryg]

7anoter..Am I correct in saying that fault on the HV side will be the cause for GPR...again, all the fault current may not enter the earth, but partly flow back to the source S/S by means of earth wire which accompanies the overhead lines supplying this S/S....