voltage variation in a generator
voltage variation in a generator
(OP)
Hi guys,
I work for a local refinery. I am looking after the operations and maitainance of diesel power plant. We have 4 1.2MW 1577kVA diesel gensets. We run three at a time and we are facing problem as one of our gensets after synchoronizing to main busbar produces voltage varaitions and produces powerfactor and kA swings keeping the kW constant. We have checked its exciter winding its resistance is 8ohm and meggar results also found ok. Changed AVR card many times but problem remains same. Sometimes it automatically remains calm and other times it is very distrubtive. Please need help.
Thanks
I work for a local refinery. I am looking after the operations and maitainance of diesel power plant. We have 4 1.2MW 1577kVA diesel gensets. We run three at a time and we are facing problem as one of our gensets after synchoronizing to main busbar produces voltage varaitions and produces powerfactor and kA swings keeping the kW constant. We have checked its exciter winding its resistance is 8ohm and meggar results also found ok. Changed AVR card many times but problem remains same. Sometimes it automatically remains calm and other times it is very distrubtive. Please need help.
Thanks





RE: voltage variation in a generator
If the AVR has terminals for connection of the quadrature CT the resistor will have been changed with the AVR. If the resistor is external to the AVR it may be failing.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: voltage variation in a generator
rasevskii
RE: voltage variation in a generator
@ waroos: do you mean droop ct by saying quadrature ct? and the avr i using is beslers aec63-7, and no external resistor is available, only we have to connect the wires to the avr card. is there a possibility that quadrature (droop) ct, got faulty? what do u say.
@rasevskii: boss, we are generating at 460V, no pt, taking voltage directly. only cts are available.
RE: voltage variation in a generator
When the power factor is unity this voltage is a right angles to the sense voltage and has little effect on the sensed voltage. However any reactive current will develop a voltage component that is in phase with the sense voltage and either add or subtract from the sensed voltage to adjust the excitation for proper VAR sharing between machines. Any intermittent faults in this circuit including the single/parallel switch will result in voltage instability.
Bill
--------------------
"Why not the best?"
Jimmy Carter