Impact of MOV models on asymmetrical fault current calculations in fixed series compensated lines

Abstract

The investigation carried out in the paper addresses the effect of series compensation on short circuit calculations in Extra High Voltage (EHV) system. Whenever the fault occurs, the Metal Oxide Varistor (MOV) bypasses the series capacitor in that particular phase causing unbalance in the network. The sequence matrix representing the network becomes coupled and makes the calculation of fault current difficult as compared to normal fault analysis method. The work presented in this paper, proposed a new method for calculating short circuit current for different asymmetrical faults in the network. Different models of MOV are considered in the study. Based on the investigations, appropriateness of the proposed method has been justified.