Operation at frequency higher than rated frequency

1 reply [Last post]
Muhammad916's picture
Joined: 2017-05-18

Hi everyone! I have a few questions that I could not the find answers. I would really appreciate it if anybody can help me.

I have a 15kV ANSI standard switchgear. I have to operate it at 16kV and 285 Hz. I am trying to figure out what is going to be the effect of high frequency on the following:

1. On continuous current rating. (I think it should increase because of increase in resistance due to skin effect)

2. On basic impluse level (BIL). ( I think it should remain same because it is not dependent on frequency)

3. On rated withstand voltage. (I think it should remain same because RMS value of sine wave does not depend on frequency)

4. Rated maximum voltage.


Also what is going to be the effect of higher operation voltage than rated voltage at

1. continuous current rating

2. BIL

3. Rated with stand voltage.

Thank you!

ekras's picture
Joined: 2013-11-08

Think about this: if the resistance goes up, power loss (in heat) will go up in the gear. The same is true if the current remains the same and the voltage is increased. That would dictate a reduction in the continuous current rating. The effects of both the increased voltage and frequency will affect the nature of the arc that occurs with make and break operations, perhaps to a catastrophic degree. These and the other questions can only really be addressed by the manufacturer, which probably only tested the gear for operation at the intended rating and won't be willing to tell you it would be OK to use it for your intended purpose.

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