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#1

# how power factors of GT and DG are inversely proportional to each other

Hi everyone.. I am working in a power plant which has both gas turbines and diesel engines are synchronised internally not to the outside grid. When GT running in parallel /kw control mode and DG running in Isle/speed(directly connected to load) control mode, how the power factors of GT and DG are inversely proportional to each other.
If I raise GT power factor then reduces the DG power factor. how??
08-20-2014 10:17 AM
Top #2

You are describing exactly the situation when you have an isolated system with two generators feeding the same load, with AVRs that do not have their cross current or reactive droop compensation set properly.

As you raise the excitation level on one generator its terminal voltage rises, at the same time the other generator's AVR sees the voltage rising and tries to lower it to its setpoint by lowering the excitation. It's pure logic, your load only requires a certain amount of VARs and it doesn't care which machine provides them. The net sendout is always the same, but one machine will be absorbing the excess the other one delivers to the bus.

Alan
08-20-2014 01:14 PM
Top #3
Very well explained by Mr, Alan Maltz.
08-20-2014 03:43 PM
Top #4
I agree with Mr. Maltz
08-20-2014 06:21 PM
Top #5

I have checked GT generator parameters and noticed that with the decrease in power factor followed by increase in reactive power and apparent power but not much change in terminal voltage.
08-20-2014 09:02 PM
Top #6