Performance Assessment of Distance Relay Owing To Uncertain Source Impedance Disparity With Large Wind Power Integration

Abstract

Large wind farms are frequently utilized to generate renewable energy that is incorporated into the grid. The total source impedance of a large wind farm is uncertain as the number of units varies with wind speed. These wind farms use doubly-fed induction generators (DFIG) to produce electricity. The uncertain source impedance of DFIG has a negative impact on the distance relays, used to protect high-voltage transmission lines, especially in abnormal operating conditions. In this paper, the distance relay performance connected under large wind power generation is assessed during various faulty conditions. On a modified New England 39-bus test system, various simulations are performed with changes in the source impedance during faulty conditions at different locations using MATLAB/Simulink platform, and effects of uncertain source impedance are investigated to note the mal-operation of distance relay. It is observed that distance relays are adversely affected due to the uncertain source impedance caused by the presence of intermittent wind generation.