Hi Please refer to attached pdf. C

[hhhansen]

Hi
Please refer to attached pdf. Can anyone tell me what is wrong considering my calculation of U2 potential when there is a single phase fault on HV in secondary substation. I am considering a TT-system with RE and RB not connected.

IEC 60364-4-442 table 44.A1 says U2=U0, however I reach the result U2=U0+(2x RE x IE).

Best Regards

hhhansen

 

[RedSnake]

U[sub]0[/sub] is the potential between L1 and N, PEN

So the potential on the HV cabinet at a short circuit is U[sub]E[/sub] = I[sub]E[/sub]* R[sub]E[/sub]
so U[sub]1[/sub] = I[sub]E[/sub]* R[sub]E[/sub]+ U[sub]0[/sub]
And the potential U[sub]2[/sub] when R[sub]E[/sub] and R[sub]B[/sub] are not connected is the same as U[sub]0[/sub].

Best Regard A