zero sequence current transformer

Thread Starter


Joined Feb 4, 2009
Hi, I'm doing a senior design project for a company that will remain nameless. They produce a ground fault relay, and my task is to re-design it.

The GFR uses a zero sequence current transformer. I would like to learn as much as possible about these CT's. Can someone recommend good books or articles or websites that give a detailed explanation of these CT's?

Are there models of them in spice or other circuit sims? I would like to play around with simulations before I play around with real 1200amps, cough cough.

In my design im going to use ZC CT's that the company makes and use their output to control a micro-controller.

Thanks guys


Joined Mar 6, 2009
Try Googling something along the lines "fault detection / protection using transformer tertiary delta windings...."

If you've not studied symmetrical components you may need to get your head around that as well.