06-05-2016 01:36 PM
Well, the first thing we would need to know is exactly what is controlling your power factor while the generator is grid connected. It is likely one of two things, you have a voltage regulator, (such as a DVR or CDVR) that has the ability to control power factor if properly setup and wired, or you have a load control device (such as a Woodward controller like a DSLC) that has the ability to interface with your AVR and control the power factor.
Next thing, if you have a "-0.92" power factor at the generator metering (assumes all is properly connected and commissioned) then are in a "lagging" power factor and your generator is exporting VAR's into the system. This is the normal condition as you would prefer to export rather than import VAR's.
Now, what is the electrical rating of your generator in kVA? If your generator is rated at 800 ekW and has a kVA rating of 1000 then the rated power factor is 0.8 lagging. This means you should be able to operate the unit at a 0.8 lagging power factor continuously at full rated ekW load.
Your poor power factor at the utility metering is likely due to the fact you are providing most of the kW (real power) load but not enough or the kVAR (apparent power) load in the facility, so while the site imports less kW it has to import a higher ratio of kVAR's, this is why your power factor at the utility metering is low. What you did not indicate but I am assuming is that the power factor at the utility meter is leading (importing kVAR's to the site)
You may be able to change your generator's power factor to provide more kVAR up the rating of the machine, but two things to keep in mind,
1. What does your utility interconnect agreement allow for a power factor setpoint?
2. Does increasing the kVAR output of the generator increase the system voltage? Not all utilities are "stiff", a "soft" utility service may increase in voltage as kVAR's are imported into the system.
Without knowing more details about your system this is likelyt he best answers you can get unless you provide more details like,
What kind of voltage regualtor do you have?
What is the serial number of your unit?
What is the method of power factor control?
What are the limits imposed by your interconnect agreement with the utility?
Knowing where you are at in the world may get you answers from folks who are familiar with the particular requirements in your area.
Hope that helps, MikeL.
06-05-2016 01:12 PM
Agree, it is not a normal behavior i think. It should be in the positive side from 0.5 to 0.9 in the best conditions. I do not know if it is a problem with the meter or something else.
06-05-2016 12:56 PM
is not normal we can not this in italy , we go to 099 in paralleling with national network, not are possible different, we start and we go at sun to real power, and absoluty not less 60% of load
06-04-2016 11:40 PM
Our plant has a G3520C engine working with biogas from a landfill. In this moment the gen set is working at 800 kW and recently we have noticed it always show a -0.92 PF. Can anyone explain me why are we working with a negative PF. Dealer says it is been set during the comissioning but for me it's not a valid answer.
As we are supplying our power generated to the grid, the Electric company has charged us a low PF (past month 57.99%) and we want to improve this as soon as possible to make it efficient if possible.
Thanks in advance.