A three phase synchronous generator delivers 10 mvA, at

A three phase synchronous generator delivers 10 mvA, at a voltage of 10.5 kV. The line impedance is 5Ω. What is the voltage drop in the line in per unit and in volts ? Use the reference base as 12 mVA at 11 kV.

1. 549.36A, 1.25 kV
2. 539.46A, 2.81 kV
3. 549.36A, 2746.8 kV
4. 549.36A, 2.0 kV

S_3φ = √3 V_L. I_L V_A

∴ I_L =	S_3φ
	√3V_L

Here, S_3φ = 10 mVA = 10 × 10⁶ VA,
VL = 10.5 kV = 10.5 × 10³V

∴ I_L =	10 × 10⁶	= 549.36 amp
	√3 10.5 × 10³

I_ph = I_L = 549.36 A
Voltage drop in the line per base = Z_ph. I_ph
= 5 × 549.36 = 2.749 k V.