Equipment Over-Voltage

[rowb...@666telusplanet.net]

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Earlier I had posted a question about operating with a ground fault on a
system where the capacitance and inductance vectorially added up to a
value that would cause ringing.

I suggested that it should be possible to calculate the values of
capacitance and Induction so that the system characteristics would not add
vectorially to a magnitude that would cause problems for the system..

We did a calculation and it appears that under the circumstances of a
phase to ground fault the voltage that would appear upon the system would
be 7.8 kV for a 4.16kV system.

Now while this may be acceptable for a small duration of time, I am not
certain of the consequences of impressing this over voltage upon a system
where the first phase to ground fault may stay on the system for a matter
of weeks... What would happen to a motor if it had that magnitude of over
voltage impressed upon it for a week or two?

Thanks again, gentlemen.

HR.
--
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