A New Distance Protection Scheme for SCIG-based Wind Farms

This paper presents a new algorithm for a distance relay located at the terminal of a squirrel cage induction generator (SCIG)-based wind farm (WF). The proposed relaying algorithm addresses the line protection challenges which stem from the particular characteristics of the current fed from a SCIG-based WF. The fault current of a SCIG-based WF decreases immediately after a balanced fault and results in the apparent impedance trajectory leaving zone 2 before the distance relay operates. The proposed method uses the impedance measured by the relay together with the damping characteristics of the phase fault current injected by the SCIG-based WF to detect faults in the protection zones of the relay and to generate the proper trip signal. The performance of the proposed algorithm is verified on a 4-bus test system. The obtained results demonstrate the reliability of the proposed protection scheme and its robustness to the fault impedance.