A factory draws 100 kW at 0.8 p.f. lagging from a 3-phase, 11 kV supply. It is desired to raise the p.f. to unity using the capacitor bank. The total power rating of the capacitor bank is
A factory draws 100 kW at 0.8 p.f. lagging from a 3-phase, 11 kV supply. It is desired to raise the p.f. to unity using the capacitor bank. The total power rating of the capacitor bank is
Right Answer is:
75 kVAR
SOLUTION
Reactive Power of capacitor bank required for power factor correction is given by
$Q = P\left( {\tan {\phi _1} – \tan {\phi _2}} \right)$
Where, φ1 = power factor angle before compensation
φ2 = power factor angle after compensation
P = Real Power
Given that cos φ1 = 0.8
⇒ φ1 = 36.86 degrees
Cos φ2 = 1
⇒ φ2 = 0 degrees
Now,
Q = P(tan(36.86) − tan(0)) = 74.87 kVAR