A modified wide-area backup protection scheme for shunt-compensated transmission lines

Abstract

In this paper, a new modified methodology has been proposed to protect shunt-compensated transmission lines as properly as uncompensated lines. The proposed scheme initially selects the nearest buses to the fault location based on data provided by the phasor measurement units (PMUs). Three buses with the minimum magnitude of the positive-sequence voltages or maximum magnitude of negative (or zero)-sequence voltages are selected as the nearest buses to the fault location. All connected lines to these buses are designated as suspected. Afterward, the suspected line with the maximum absolute difference of positive (or negative)-sequence current angle is concluded as the faulted line. The effectiveness of the proposed technique has been evaluated under various fault scenarios in WSCC 9-bus and IEEE 39-bus test systems in MATLAB/SIMULINK platform. The outputs clearly reveal that the recommended scheme finds the faulted line precisely under different fault types, fault locations, fault resistances, and shunt-compensator types within 3 ms. The modified scheme can also detect high-resistance asymmetrical faults accurately exploiting negative-sequence current angles instead of the positive ones.