×
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

Blocking Pilot POTT schemes for GOAB switching
2

Blocking Pilot POTT schemes for GOAB switching

Blocking Pilot POTT schemes for GOAB switching

(OP)
For a 138KV fiber optic POTT scheme on network lines with a POTT instanteous O/C ground setting of about 300 amps, does your utility block the scheme during GOAB (group operated air break switching) on the lines?
thanks JIM

 

RE: Blocking Pilot POTT schemes for GOAB switching

After a false trip on a scheme like that, we moved the instantaneous ground overcurrent setting up above the largest possible ground current due to one or two poles open.  That project was a good example of how using every available element when upgrading from electro-mechanical relays to microprocessor based relays can lead to new types of incorrect trips.  Also be sure any negative sequence elements are secure during GOAB.

RE: Blocking Pilot POTT schemes for GOAB switching

So, then how do you detect open conductor "faults"?  As we change from ground overcurrent to ground distance we tend to loose sensitivity to open conductors and I'm not always sure that is a good thing.

RE: Blocking Pilot POTT schemes for GOAB switching

I don't think we have coverage for all open conductor situations.  It is a parallel line from a remote generation site that also has tapped load, so the flow is often zero at some point on the line.  

The instantaneous elements are set above the pole disagreement level with some more sensitive elements set to trip on a time delay.

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