Series: Subject:
Question: 12 of 463

star/Delta transformer

What is neutral transformer?
Asked by: s_balwant | Member Since Jan-2014 | Asked on: Feb 5th, 2014

View all questions by s_balwant

Showing Answers 1 - 1 of 1 Answers
Alok Behera

Answered On : Feb 12th, 2014

If the earthing transformer on the Delta Side is outsides the Zone of protection the Earth Fault(E/F)in the delta system outside Current Transformer(CT) locations would produce current distributions as shown which circulate within the differential CT secondaries and is kept out of operating coils.

Zig-Zag or inter connected star grounding transformer has normal magnetizing impedance of high value but for E/F, currents flow in windings of the same - core in such a manner that the ampere turn cancel and hence offer lower impedance.

In cases where the neutral point of three phase system is not accessible like the system connected to the delta connected side of a electrical power transformer, an artificial neutral point may be created with help of a zigzag connected earthing transformer.

zigzag star connected earthing transformer

This is a core type transformer with three limbs. Every phase winding in zigzag connection is divided into two equal halves. One half of which is wound on one limb and other half is wound on another limb of the core of transformer.

1st half of Red phase winding is wound on the 1st limb of the core and 2nd half of same Red phase is wound on 3rd limb.

Yes  1 User has rated as useful.
Login to rate this answer.

Give your answer:

If you think the above answer is not correct, Please select a reason and add your answer below.

Related Open Questions



twitter fb Linkedin GPlus RSS


Interview Question

 Ask Interview Question?


Latest Questions

Interview & Career Tips

Get invaluable Interview and Career Tips delivered directly to your inbox. Get your news alert set up today, Once you confirm your Email subscription, you will be able to download Job Inteview Questions Ebook . Please contact me if you there is any issue with the download.