Power system transmission section security protection control program

The removal of overload lines can cause power flow transferring, which may give rise to some transmission lines overload. By analysis of available methods of determining transmission sections with shortcomings, this paper proposes a new way to determine transmissions section based on real-time power flows, and then deduce a new criterion of transmission section security protection based on the redundancy of normal line´s power flows. A new transmission section security protection control scheme based on wide area measurement system (WAMS) is also proposed. When there is line overload, we should make a decision according to the protection criterion, if the transmission lines are safe after the overload removal, allow the backup protection to cut off the overload line; if not, block the protection. Therefore, it can avoid cascading overload tripping. At last, the validity of proposed algorithm is verified by the simulation results of CEPRI 36-bus system.