Question

Calculate the compensator rating required for cos(Φ)=.35.

(a) .936 P.U

(b) .154 P.U

(c) .481 P.U

(d) .289 P.U

The question was posed to me in my homework.

My question is taken from Solid-State Devices in portion Introduction to Solid-State Devices of Electric Drives

Answer 1

Right answer is (a) .936 P.U

Easiest explanation: The compensator rating can be calculated using the relation QP.U=√1-cos^2(∅)=√1-.1225=.936. This per unit value VAR compensator is required to improve the power factor of the system.