Research on the impact of large capacity synchronous condenser on distance protection and its countermeasures

Abstract

This paper analyses the impact of large capacity synchronous condenser (SC) on distance protection. A two-machine system model with SC is established in PSCAD, and numerous simulations in various conditions are carried out. The simulation results show that the installation of SC has adverse impacts on the measured impedance. Aiming at the problem that distance protection can not operate correctly, a new line protection scheme adapted to SC access is proposed. In this scheme, the fault distance is estimated based on two-terminal data and a new root identification method is employed. The new scheme can judge inner and outer faults correctly, and improve the reliability of line protection in the presence of large capacity SC.