Polarity Testing of 15 KV Wound Type Current Transformer

[kibz]

Hi Guys,
We have a "15 KV Wound Type" Current Transformer, I want to perform Polarity Test. Can we use the Kick Method using 6 volts Battery? In the net, examples of Battery Kick Method are only Ring or Doughnut type. Are there any safety concerns during testing?
Thanks.. Kibz

 

[Skogsgurra]

If you mean Kick-back, you may need to think about the possible very high primary voltage if you test from secondary. I do not do the classical kick-back for many reasons - if anything looks bad anytime after you done the test, you can be dead sure that some one will remember and you will have a much bigger problem than finding out polarity ever was.

I use a version of the test where I discharge a capacitor with a diode parallel to the capacitor. By doing that, I do not risk DC saturating the core and I do not risk a very high kick-back when I disconnect the source, since it is already discharged by then. The parallel diode works as a free-wheeling diode and prevents the circuit from oscillating so there will be only one deflection of the needle/trace and there will be no ambiguity. It also prevents the capacitor from being charged wrong way if you use an electrolytic capacitor, which I recommend.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[krisys]

Kick Method using 6 volts Battery is accepted at majority of the sites. As the energy level and the exposure time duration is minimal, the saturation would be very shallow, which may be negligible for all the practical purposes. So far I have not heard anyone complaining about any problem due to Kick Method testing.

As you are aware, this is very simple to understand. So in my view, you should go ahead with the testing using the Kick Method.

The caveat is that, if it is a laboratory level precision CT probably, you may further review the testing method, which I am not aware of the requirement.

 

[scottf]

In short, yes, you can use the "kick" method on any type of CT that I can think of.

 

[kibz]

Hi Guys,
Thank you very much for sharing your knowledge on this subject & also your time.
Regards.Kibz