Question

a) A three-phase overhead line has a load of 30MW, the line voltage is 33kV and power factor is0.85 lagging. The receiving end has a synchronous compensator, 33kV is maintained at both ends of the line. (i) Calculate the MVAR of the compensator given that the line resistance is 6.50 per phase and inductance reactance is xy2 per phase. (ii) Repeat your calculation using the short-circuit current at node method. Compare and explain the difference between the results. b) Explain with the aid of diagrams both overcurrent and residual earth fault relay circuits, how they are employed to monitor overhead lines. Then explain their operational use and benefits.

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