Question

A 400 V, 50 Hz 3-$\varphi$ balanced source supplies to a star connected load whose rating is S= (300 + j400) KVA. The rating of the delta connected capacitor bank necessary to bring the power factor to 0.9 lagging is _______ kVAR.

• A. 254.72

Answer 1

The correct option is A 254.72
Load rating,

S = (300 + j400) KVA

Active power, P = 300 kW

$Powerfactor=\cos \left[ta{n}^{-1}\left(\frac{400}{300}\right)\right]=0.6lagging$

Required capacitor bank rating,

$Q_c=P_{1}tan{\theta }_1-P_{1}tan{\theta }_2$

$=300[\tan {53.13}^o-\tan {25.84}^o]$

$=254.72kVAR$