×
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

Ungrouded Wye Capacitor Bank Protection

Ungrouded Wye Capacitor Bank Protection

Ungrouded Wye Capacitor Bank Protection

(OP)
We are going to purchase the PF correction capacitor banks 13.8kV, 4800kVAR) with ungrounded wye configuration (single wye) with unbalanced voltage protection, and the system grounding is low impedance grounding (400A).

MY client have a concern that capacitive charging currents (circulating current) would be resulting in misoperation of ground OC relay.

I belive it would not be a problem since GF relay setting of 10% of 400A (40A), and the capacitive charging current on system would be ignorable.

Would anybody advise on the GF protection on ungrounded wye capacitor bank?

Thanks in advance.

RE: Ungrouded Wye Capacitor Bank Protection

(OP)
In addition to this, do you think circulating currents could be a problem with this arrangement?

Thanks in advance for any advices.

RE: Ungrouded Wye Capacitor Bank Protection

You don't ground the wye point of the PF correction capacitors. If you do, this becomes a parallel path for ground currents during line to gorund faults! The GF protection may miss the fault.

respectfully

RE: Ungrouded Wye Capacitor Bank Protection

sykimk,

The Star point is not grounded when you don't want to burden the capacitors with hamonic load.

The neutral displacement protection works but needs to be time delayed sufficiently to prevent operation during earth faults elsewhere in the system.

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