Eng.Moawad Consultant

You need to know what is the present power factor.

I assume that you have ,( like most people), a lagging power factor , which means that your inductive loads are higher than your capacitive loads.

While there are a couple ways of correcting power factor, by far the most popular is the use of power factor correction capacitors.

After you have assessed your power factor, your will have to decide what equipment are the main causes of your lagging power factor.

Are these equipment on constantly or are they on for intermittent periods.

If they are on constantly, then connecting your correction capacitors permanently is aceptable and will give a good result.

If for instance , they are motors run intermittently, then you may have to use an "at the load" type application e.g. using a contactor slaved off the motor contactor to turn the capacitor on and off.

You can also connect the capacitor in parallel to the motor but extreme caution must be used to avaiod resonance durng motor coast down due the the varying frequency of the residual induction in the motor.

Power factor correction capacitors comes ( conveniently) in KVA ratings just for this type of application so that you do not have to do the calculations yourself.

There are three methods for improve power factore

1- By Capictor

2- Syncronus Condenssor

3- Phase Advancer

To find KVAR required to improve power factor following equation use

KVAR = P (tan1-tan2)

P= Power of Circut in KW

KVAR= Rating of PFI Plant/KVAR supplied by Capicitor or any equipment

If you connect the capicitor in the parallel of circuit the power factor must be improve