DC Hi-pot voltage buildup
DC Hi-pot voltage buildup
(OP)
Hello,
I encountered a voltage increase during the DC hi-pot test for our ESP (electrical submersible pump) power cable. Normally when doing a DC test at 10kV for 1 min, it'd stay there and pass the test...or drop back down to fail. However, in this instance, when testing this 4kV rated cable, after setting the test at 10kV, it'd keep gradually increasing to more than 12.5kV by itself. What could be the reason for this voltage buildup?
Help appreciated!
I encountered a voltage increase during the DC hi-pot test for our ESP (electrical submersible pump) power cable. Normally when doing a DC test at 10kV for 1 min, it'd stay there and pass the test...or drop back down to fail. However, in this instance, when testing this 4kV rated cable, after setting the test at 10kV, it'd keep gradually increasing to more than 12.5kV by itself. What could be the reason for this voltage buildup?
Help appreciated!






RE: DC Hi-pot voltage buildup
Thank you
RE: DC Hi-pot voltage buildup
RE: DC Hi-pot voltage buildup
RE: DC Hi-pot voltage buildup
That particular hi-pot set I think was home-made. It had several different pieces.
I have also seen factory made ac hi-pot sets nicely packaged in a tall cabinet - worked like a charm and voltage was perfectly stable.
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RE: DC Hi-pot voltage buildup
The voltage build up could be a number things. I think eletricpete's idea is a valid one. Is the AC voltage source a resonant transformer? It is possible that at higher voltages the charging current can effect the gap in the magnetic circuit of the transformer. This then changes the resonance circuit. It is plausible that the circuit actually became more in tune during the test and therefore caused an increase in voltage.
RE: DC Hi-pot voltage buildup
I am not an expert in AC hi-pot test equipment.
RE: DC Hi-pot voltage buildup