we have two synchronised turbogenerator of 16.5 and 20 MW each with unitrol 1000 and F avr and running on .93 and .93 pf. we are observing that all of a sudden pf become unbalance in the order of .97 and .88. and keep on fluctuating for some 2-3 hrs. At that time load and freq being more or less same. what could be the reason.

 

Anon... faced with a similar problem before SERs or SOEs were available I used a camcorder trained on the instrumentation panel.

Its frame/sec rate was increased some 5-10 times normal. It never failed to determine the cause of the disturbance.

Regards, Phil Corso (cepsicon[at]aol[dot]com}