Question

Calculate the compensator rating required for cos(Φ)=.1.

(a) 0.91 P.U

(b) 0.99 P.U

(c) 0.97 P.U

(d) 0.92 P.U

The question was posed to me during an interview for a job.

This question is from Solid State Controlled Drives in chapter Introduction to Solid State Controlled Drives of Electric Drives

Answer 1

Right answer is (b) 0.99 P.U

The best explanation: The compensator rating can be calculated using the relation QP.U=√1-cos^2(∅)=√1-.01=.99. This per unit value VAR compensator is required to improve the power factor of the system.