×
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

Better protection for a delta circuit

Better protection for a delta circuit

Better protection for a delta circuit

(OP)
We have a delta configured circuit, that is several miles long. It runs through a mountainous area, so conversion to a wye isen't much of an option.

The problem is to detect ground faults, currents are close to zero (There is a wye connected generation source that sometimes runs).
At issue is if we use neutral voltage detection, we may see more third harmonic under normal conditions, then we may see during a fault.

Any better ground protection ideas?

RE: Better protection for a delta circuit

Grounding transformers exist just for this purpose. You can also use 59G relay.

Rafiq Bulsara
http://www.srengineersct.com

RE: Better protection for a delta circuit

I don't see how running through a mountainous area precludes a wye source.  No need for a fourth wire, just grounded wye transformer at the end.

RE: Better protection for a delta circuit

(OP)
Actually I think we have a forth wire for the first 5 miles. At the generator at that point, we don't have a good ground connection, despite being tied to the steel water pipes connecting to the plant.

We are considering a wye transformer, or a zig-zag, however we wanted to know what other options might be available.

RE: Better protection for a delta circuit

I imagine that you have a radial system ?

Is the design for a delta network related for continued production for a phase-groud type fault ?

A zero sequence voltage detector network can work in most instances for a single phase to ground type fault. Basically consist of a Y-D set of PT's with open corner secondary connected to an UV relay or a voltage operated type inverse-time relay. Can also be used for ground alarm functions.

Loading resistor on the secodary a necesity for the circuit to operate realiably.

 

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