×
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

Current abnormal increase on paralleling generator with DECS200 regul

Current abnormal increase on paralleling generator with DECS200 regul

Current abnormal increase on paralleling generator with DECS200 regul

(OP)
I'm commissioning installation of a DECS200 regulator on a 380Vac rated vapor turbine driven generator. When trying to parallel the generators, current outrushed to abnormal level (over 6kA on a 4345A nominal generator) but it's voltage seemed to stagnate to the setpoint (400). I'm in VAR mode. Another generator is already on the bus. The online gen's active power didn't vary but the current of the bus incomming generator goes to 6 000 A. What would be the explanation to that current outrush of the generator ? Your answers would be very helpful.

See attached parameters for the DECS200.

Toudom

RE: Current abnormal increase on paralleling generator with DECS200 regul

It sounds like the voltage droop characteristic of the AVR is incorrect. The AVR droop setting should provide a falling voltage characteristic for increasing lagging reactive power. If the droop CT is either in the wrong phase or wrong polarity the AVR output will increase instead of decrease when lagging reactive power is produced. The effect is dramatic and very quick resulting in a high level of reactive power flowing between paralled machines.
Check the AVR CT and voltage sensing is as per the manufacturers schematic.

RE: Current abnormal increase on paralleling generator with DECS200 regul

(OP)
Thank you glendale.
Of course CT wrong phase and wrong polarity were detected. This change was made before and was not reported.
CT had to be wired on B phase but it was wired on phase A. That caused a false calculation of real power that was negative. The wrong polarity caused the increase of reactive power flowing across the two generators. The two problems were solved.

Thanks,
Toudom

RE: Current abnormal increase on paralleling generator with DECS200 regul

toudom-

You make me feel good.  Your subsequent explanation described what I was expecting.

Good luck in the future.  You've just had a valuable bit of experience.

old field guy

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