Hi All

Problem - Frame 5 machine MVAR suddenly dropped from 6.5 MVAR to -20.6 MVAR.

Details:
Total 3 GAS turbines were in service at 09:00 and one of the machine MVAR dropped from 6.5 MVAR to -20 MVAR, and it was observed other machines MVAR increased to compensate the VAR.

 

Djafer,

Likely Cause:
Excitation regulator went to "minimum" on the GT that went to -20.6 MVAr.

Likely Reason:
Problem with Generator PT (Potential Transformer) feedback, or if the unit was operating in VAr or Power Factor control, a problem with the VAr transducer input.

Please write back to let us know what you discover.

 

What were the system voltage and Generator Terminal voltage at that time?

any action with transformer tap position lower or raise carried out?
Did you check the Excitation any lower or raise manually initiated
mvar shifted to GT's value?