GE SURGE CAPACITOR CALCULATION -101N171

[arjun_athi]

Dear Colleagues,

I am looking for technical advice on the below

As per the client request While doing AC dielectric test for the surge capacitor (4.16 KV P-P, 1.5 Micro farad 3 Phase, CAT# 18L0015WH, GE Make) , we have found 100 mA for 450 V P-Ground and we were not able to inject more due to high leakage current.

Can you please advice whether Tan delta test can be performed to confirm the integrity of the capacitor as we don't have dielectric tester with more than 100 mA capacity?

Kindly advice is there any other tests that can confirm the capacitor integrity,

we have done the IR test at 5 KV DC and measured the capacitance per phase (0.5 Micro farad per phase) and the values are found satisfactory.

Client would like to confirm us the capacitor is working good and there is no issue in the unit.

Anticipating your support at the earliest..

Regards,

Arjun @ Alex

 

[petersonra]

You might want to contact GE and see what they think.

 

[tom baker]

Yes that is a very specific question, we may not be able to answer, not really an NEC question.

 

[synchro]

It's not surprising that you see leakage because this surge capacitor incorporates an internal discharge resistor in parallel with the capacitor.

What's most important for the application of this device is the equivalent series resistance of the capacitor (aka ESR). Because of the presence of a shunt resistor, to extract the the series resistance you'd have to measure the impedance of the device at more than one frequency (preferably widely separated). At low frequencies the shunt resistor is the dominant loss mechanism because the reactance of the capacitor is high. At higher frequencies the series resistor is dominant because the reactance of the capacitor is low.

Not knowing what test equipment you have, it's difficult to make any recommendations. As was mentioned contacting GE would be a good idea.