Power system transient instability detection based on wide area measurement system

Abstract

The instability detection method of a power system by directly analyzing the transient response of the electric power system is not only useful for stopping the time domain simulation of system trajectory to reduce CPU time for preventive control program, but also can be used to trigger transient stability emergency control and system splitting based on wide area measurement system. Reliability, speediness and computational simplicity are of primary importance in developing online instability detection method. With regard to these requirements, a novel method for instability detection based on generator angle and angular velocities is proposed in this paper. System instability or out-of-step condition is detected by the characteristics concave or convex of the critical machine trajectory of the post-fault system. The generalized transient energy function method is applied to analysis reliability and robustness of the proposed method. The proposed method was successfully tested on several different power systems varying in size from Single-Machine-Infinite-Bus system and IEEE 50 generator systems. The method is shown to be a potential tool for initiating online emergency control. (7 pages)