Synchronous generator to the grid. Having issues with exciter field breaker. The breaker gets its signal to close and occasionally (1, 2 times monthly), it rejects closing and unit trips, no alarms on the excitation panel, 64f trips, 86g trips. i have noticed higher than normal generator terminal voltage during failures any possibilities would help. We have megger generator and field breaker and found nothing, just reset and go for another start and works fine? Thanks

 

Erache11... please provide some details such as manufacturer, V & A rating, operating mechanism (magnetic, spring & motor, pneumatic, hydraulic, solenoid), ambient temperature, age, last time maintenance/testing was carried-out, etc.

Regards, Phil Corso

 

Check for governor/load hunting due to high frequency oscillation. It caused the AVR to overshoot upper regulation limit. In this case AVR should change to manual. Normally it ends up tripping the generator.

Another thing you can investigate is whether you speed droop set point is well tuned to voltage drooping of AVR. I give you an example, if your speed droop set point is 5% and voltage regulation is 4% then your generator can have higher no load voltage than it should.