Synchrophasor-Based Online Modal Analysis to Mitigate Power System Interarea Oscillation

Power system interarea oscillations constrain the amount of power that can be transferred through some parts of interconnected power grids. Interarea oscillations without proper remedial action can result in power system separation or a major blackout. This paper reports on a new technology that can automatically mitigate unstable power system oscillations. The system consists of real-time modal analysis based on power system synchrophasor measurements, interarea oscillation identification logic, and remedial action logic. The oscillation identification logic indentifies the interarea oscillation modes across the power system and detects any unstable oscillation mode. The identification logic and control logic are implemented in standard IEC 61131 programming language. With minimal configuration, the system can provide automatic early warning of unwanted power system oscillations and trigger appropriate remedial actions. Real-time digital simulation (with hardware in the loop) test results demonstrate the feasibility of this new technology.