Power Factor

[jadams84]

I am trying to calculate savings on our power bill at a mining facility by installing power factor correction. When I use rkvah and the kwh and figure my kVAh in the power factor triangle. I come up with a great power factor of .878.
I know this is incorrect because we had a power factor study done 5 years before I arrived and the metering we have installed doesn't come close to my calculated power factor from the power bill. Any thoughts are appreciated.

 

[Meterman Eng]

Not all power factor is created equal. Different meters can calculate different power factors in different ways, which will change the result. There are different methods for calulating displacement power factor, distortion power factor, and true power factor. I think this is a pretty good intro into methods to calulate pf, and general info about power factor.
http://users.ece.utexas.edu/~grady/POWERFAC.pdf

I think you should first ask: are you correcting for poor displacement power factor or poor distortion power factor, and what was previousely metered?

 

[iwire]

I am trying to calculate savings on our power bill at a mining facility by installing power factor correction. When I use rkvah and the kwh and figure my kVAh in the power factor triangle. I come up with a great power factor of .878.
I know this is incorrect because we had a power factor study done 5 years before I arrived and the metering we have installed doesn't come close to my calculated power factor from the power bill. Any thoughts are appreciated.

I would not try to calculate any savings till I put power quality recording meter on the service for at least 30 days and find out what the true PF is.

 

[don_resqcapt19]

In most cases the costs on the bill are in the form of low power factor penalties. You should be able to get all of the needed information from the bill.