Adaptive System Integrity Protection Scheme Constrained by Minimum Loss of Service Using PMU Data

The modern power system is operated at the maximum possible operating point. So, robust defence mechanisms are needed to safeguard its integrity. The System Integrity Protection Scheme (SIPS) is one such scheme that is designed to safeguard system integrity and avoid blackout scenarios. An outage of a fully loaded critical line due to a circuit breaker’s operation to isolate fault, or a misoperation often leads to an overload of multiple lines. The overloading of these lines may cause maloperation of their protection system. These maloperations can occur in a cascaded manner and can lead to a blackout. This paper proposes a System Integrity Protection Scheme to continously monitor the transmission line loading and alleviate the overload to avoid cascade tripping. The overload is alleviated by mitigating the best and least combination of loads chosen based on Generation Shift Sensitivity Factors (GSSF) and real-time data from the Phasor Measurement Units (PMU). At any given instant, the least combination that would sufficiently relieve the overload is chosen, so unnecessary load shedding is avoided. The performance of the proposed SIPS is validated through case studies on IEEE 24 Bus System in DIgSILENT PowerFactory and MATLAB environments. The proposed SIPS can adaptively choose the least and best combination and alleviate the overloaded condition with minimal loss of service.