×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Sizing zig-zag transformers

Sizing zig-zag transformers

Sizing zig-zag transformers

(OP)
I would like to know a proper guide to size grounding transformer for a wind farm (ohms and MVA rating, continuous rating for 10 sec and short time rating for 3 seconds).

Following is assumed data: 34.5kV bus (line to line voltage at a switchgear bus), like to ground fault current given as I = 3000A. Charging current on the a 34.5kV feeder where zig-zag is to be installed is 120A.

thank you.

bozz

RE: Sizing zig-zag transformers

If you are going to solidly ground the zig-zag transformer it will need to be able to withstand 3000 Amps for 10 Seconds.
If you are going to limit the fault current then the transformer may be a lot smaller.
If you cannot find published specs for zig-zag transformers then call a manufacturer with your requirements.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Sizing zig-zag transformers

In some systems, you may want to consider the unbalance current

RE: Sizing zig-zag transformers

Further to Hamid's post;
If there are phase to neutral connected loads, then:
A/ The zig-zag transformer must be solidly grounded by many codes.
B/ It must be capable of carrying the neutral load continuously.
C/ It must be capable of carrying the short circuit current until the circuit is disconnected.
But this probably does not apply in your case.

Bill
--------------------
"Why not the best?"
Jimmy Carter

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources