2- Calculate the values of Ro, X,, Reg1 and Xeg1 of the equivalent circuit of a 1-ph, 4KVA, 200/400V, 50HZ transformer of which the following are test results: open-circuit: 200V, 0.7A and 70W on low-voltage (primary) side. Short-circuit: 15V, 10A and 80W on high-voltage (secondary) side.

- A 150 KVA, 0.4/250 kV testing transformer has 10% leakage reactance and 4% resistance on 150 kVA base. A cable has to be tested for 500 kV using this transformer at a resonant frequency of 50 Hz. If the charging current of the cable at 500 kV is 0.4 A. Assuming 1.5% resistance for the inductor to be used and the connecting leads and neglecting dielectric loss of the cable, calculate: 1.2.1 The series inductance required 1.2.2 The input voltage of the transformer and power (kW).

Fast do...

A 200/400V, 50Hz, 1-ohm draws a current of 0.7A and power of 70W when rated voltage is applied to the LV side and HV side isleft open. It draws a current of 10A and consumes 80W power when a reduced voltage of 15V is applied to the HV side and LVterminals are short circuited. Determine the equivalent circuit parameters of the transformer.