Question

What should be the capacitor power to be used for compensation of the 100kVA transformer?​

Answer 1

It depends on power factor of the load and degree of compensation you want to implement.

Suppose your loaf p.f is cos (theta)

and you want k% compensation

and Q is the MVA rating of the transformer.

then Q/sin(theta) is the MVar of load and k*Q/100*sin(theta) is the reactive power to be compensated total.

then per phase compensation for a 3-phase transformer will be k*Q/3*100(sin(theta)=L

and per phase capacitor will be calculated from V2/Zc =L equation

Where V is the input voltage for the side where capacitor is kept

and Zc = 1/wc = capacitive reactance

w=2*pi*f

f=system frequency.