×
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

PQ Meter on a delta feeder

PQ Meter on a delta feeder

PQ Meter on a delta feeder

(OP)
Are there ramifications as to Power Quality metering performance on a 3-phase / 3-Wire MV line, comparing Delta connected PT's & CT's "corner" grounded, or Wye connected PT's & CT's, Star grounded, or some combination of the two. Technically this line is resistance grounded, but many miles away. There is no neutral conductor. Three instrument  transformers are planned for each (6-total).

I am not to much up on the triplen harmonics and such, the meter rep, did not give me much confidence in his answer delta-delta arrangement.

RE: PQ Meter on a delta feeder

 
Seems like the question of PT quantity and configuration cannot be addressed without knowing capabilities of the ”meter.”  

If the meter is intended to measure phase-to-ground quantities, consider three wye-grounded PTs with primaries rated for ø-ø voltage, but running at 0.58 per-unit voltage under normal conditions, similar to IEEE C57.13 §7 group 2 VT application.
  

RE: PQ Meter on a delta feeder

Have you considered how well the instrument transformers will pass through harmonics? Up to what harmonic are you interested in measuring?

RE: PQ Meter on a delta feeder

(OP)
The meter is a name brand 4-voltage channels and 5 current channels meter. It can be "enabled" wye or delta mode.

The customer said put the meter here (at this particular location). Since all of the downstream transformers are delta-wye (secondary distribution MV level) w/neutral resistance or transformer grounding), which in turn feed the utilization level delta-wye transformers i.e. 208-480v. My thought is that the odd harmonics generated at the utilization level will not even make it to the PQ meter. What will make it back to the meter? or is this going to be in essence a voltage and current recorder? An advantage to the star connections is the PT's will have sqrt3 less voltage across them and may be more reliable.

RE: PQ Meter on a delta feeder

GOTWW-

I don't believe there is any reliability issues associated with using the VTs with L-L connection (2-bushing) or L-G connection (1 bushing). Each is designed for its application.

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