I am looking at the results for an earth grid study for a 50Hz substation.
- Primary Voltage (Vp) = 11,000V
- Secondary Voltage (Vs) = 415V
- Secondary Fault Current (If)= 24kA
- Secondary Grid Current (Ig)= 2.4kA
- Ground Resistance (Rg) = 1.7 Ohm
- Calculated Ground Potential Rise (GPR) = 4080V
I understand that GPR = Ig x Rg, but
What is the relationship between Vp/Vs and GPR? If 4000+V is available at the earth grid, wouldn't current flow back up the faulted conductor to the source?
Is it related to different reference points?
Appreciate it anyone could help me get my head around this one?