Flutuation in Main Generator parameters

[iamazeb]

Hi,
02 Power plants (#1 & #2)are running in parallel, All grid parameters are normal but internal le we are facing some fluctuation in the generator parameters as mentioned below:
* Excitation Current & Voltage of 100HZ.
* DC Voltage & Current of Generator rotor.
* Generator Phase A/B/C currents.
* Generator Reactive Power.
* Generator Terminal voltage.
* Volt balance of AVR.
* Generator Active Power, correspondingly GV’s position/impulse pressure also varies during the fluctuations & impulse loop out.
Normally the fluctuations of #1 are in positive direction & of #2 are in negative direction, the amplitude of #1 is slightly larger than #2.
The generator terminal voltage of #1 was Set at 20. 08 KV, after manual decrease & afterword increase of plant power the gen terminal voltage became 20.50 kV (Without any adjustment.
No obvious abnormality has been observed in the AVRs of both plants.
What should I check to pin point the problem, please help if someone has faced similar experience.
Thanks

 

[waross]

Possibly a failing quadrature CT or a failing resistor in a quadrature circuit. Possibly a failed diode in an exciter loop.

Bill
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"Why not the best?"
Jimmy Carter