Ring Current Transformer direction test

[pauliethegull]

Hi,

Obviously a RING type CT has be correctly fitted for KWh metering, but how can a CT that is inaccessible be tested to verify that its direction is correct prior to energizing?

I heard that connecting a battery to one side of the CT leads and a analogue needle ammeter to the other (making a circuit) would deflect the ammeter one way then bounce the other way showing the direction of a CT. I have tried this but its not clear at all.

any ideas?

regards

 

[SG-1]

Can you gain access to the primary conductor that is routed through the CT ?

This is a video of the test ( Inductive Kick Method ) you are trying to perform on the CT.
http://www.youtube.com/watch?v=1AutEjVa-VQ

You can connect the meter to the CT secondary ( maybe at the watt meter, which must be disconnected for the test ) . Inject the DC through the primary conductor. You need access to the primary conductor on both sides of the CT. One side could be grounded & the frame used for the return path.

 

[pauliethegull]

Hi SG-1,

Thanks for the link, I can see now what we were doing wrong on the test bench whilst trying to find a way to test the CT direction:ashamed1:

Unfortunately we are unable to get to the primary conductor routed through the CT's nor can we get to the CT's !!! The numerous CT's were previously connected (with no markings on the CT) on a cable joint that is inaccessible. (not the best practice, but has now been changed).

As commissioning has to take place, we are trying to find a way to check that the CT's have been correctly installed before energising. Obviously, after commissioning we can easily tell if the H1/X1 and H2/X2 is facing the wrong way and simply switch the wires if necessary but we really wanted to check them all out first.

We just cant think of a way, not even the manufacturer can help us.

 

[SG-1]

Good luck with your project. I am glad the video helped.