Question

A three-phase voltage source with a terminal voltage of 22kV is connected to a three-phase transformer rated 5MVA 22kV/220V. The transformer has a per-phase series impedance of 0.05 pu and is connected to a distribution line with series impedance of 0.01+0.05Ω per phase. The line supplies a balanced three-phase load rated 1MVA, 220V with 0.8 lagging power factor.

a. Draw the one-line diagram of the system described.
b. Draw the equivalent per phase circuit of the system indicating all impedances in per unit. Use 1MVA, 220V as the base at the load.
c. Calculate the real losses in the transmission line in kW.

Answer 1

A) See Attachment B) See Attachment C) 186.153

Step-by-step explanation:

C) Per phase Voltage= 220/∛3

= 6.037

S=V²/Z

= (6.037)²/(0.01+i0.05)

= 62051.282-i310256.41

Active power losses per phase= 62.051kW

total Active power losses= 62.051×3

=186.153kW