Micro-Farad Calculation

It would be better to give that data to someone who can, then, rather than struggle with it one's self.

Corrected KVA x 10^9
C = ----------------------------
2 pi x f x e^2


Where;
C = required capacitance in microfarads
f = frequency of applied voltage
e = applied voltage

You could use Tau instead of 2Pi, but that would only hasten Pi's death.

I'm not sure why you're looking for the value in μF, when most of the power factor caps I've seen are rated & sold by kVAR. Take a look at the following site which gives a LOAD of assorted on-line calculators for electrical applications. The first page (check out all 8 pages - lots of good stuff!) gives 2 different ones to calculate kVAR of caps needed based on your existing and desired power factor. Beware of trying to correct to a PF of 1.0 - Not a good idea. Better to correct to 0.95 or so.

http://www.electricsmarts.com/container.aspx?tab=tools&distid=19542&showresults=1&limit=&ph=calculators&aw=&anw=&ew=&page=1

Here's a site that gives a good practical explanation of PF correction and does example calculations:

http://home.earthlink.net/~jimlux/hv/pfc.htm

Try searching...

http://home.earthlink.net/~jimlux/hv/pfc.htm

And it is professional job, cannot be a fixed values connected permanently until ensured that does not reach unity and beyond. Damage to Powerlines or equipment may occur.

I have never heard of anyone warning off of unity for power factor. Why would you not want that?

If you try to correct to get 1.0 PF, changes in load can drive the system "past" unity to capacitive power factor. Then you run the distinct likelihood of getting into a resonant condition. The resulting overvoltages are well-documented to be destructive for electrical equipment.

I see what you are saying. I shoot for the best I can, but I have a very stable load running 24/7 on an UPS which manages a 1.00 for the provider. On the supply side of the UPS we average about .96 pf.

We monitor for destructive harmonics regularly to prevent such unfortunate occurrences.

If V is the phase voltage and call it U in a 3 phase supply, f is the frequency.

And required KVAR = Q

And Cd = Capacitor Value for each phase In Delta connection

And Cs = Capacitor Value for each phase to Neutral in Star connection

Then Cd = [(Q*1000) / (2*∏*f*U²*√3)]*10^6

And Cs = 3*Cd