Proper Sizing of Power Factor Capacitors

[strongone]

I'm currently performing a power factor correction on a plant, and I've calculated that I need to install 2400 kVAR reactive power correction. I have decided that I would install 5 banks of 500kVAR capacitors. The problem I now face is that I have received quotes on 150kVAR single phase capacitors. I don't know how to apply these single phase capacitors to this problem. Any adive will be helpful.

 

[jghrist]

Capacitors are single phase devices that generally come in multiples of 50 kvar. You have to have banks where the total bank kvar divided by three is a multiple of 50. A 3Ø banks of 150 kvar 1Ø capacitors is the closest the bidder can come to your specified 500 kvar.

What you probably need is four banks of 600 kvar, made up of 200 kvar 1Ø capacitors.

 

[Dopler]

Single phase capacitors connected un Y.
You add the capacitances to have total capacitance.
Take care of harmonics in the circuit and resonance.

 

[jbartos]

Suggestion: Reference:
Donald Beeman "Industrial Power Systems Handbook," 1st Ed., McGraw-Hill Book Co., 1955
Chapter 8 Power Factor Improvement

 

[CJFlatters]

As jghrist mentions, the UK PFC industry certainly works on multiple contactor controlled, 50kVAr delta connected capacitor banks.

This allows for greater control of the final power factor, certainly you will need to consider harmonics and the use of detuned capacitor banks ie fitted with rejection reactors.


_______________________________________
Colin J Flatters BSc(Hons) IEng MIEE MIIE
Electrical Engineer / Project Manager
Email - cflatters@colin7.demon.co.uk.