New predictive analytic-aided response-based system integrity protection scheme
The ever-increasing power demand coupled with limited power transfer corridors and minimum redundancy have forced power system operation close to its security limits. Further, increase in renewable penetration, market deregulation, and mal-operation of protective devices under stressed conditions has imposed serious threats to power system stability. To overcome these operational challenges, a new response-based system integrity protection scheme (SIPS) is proposed here. The proposed scheme works towards preserving system integrity in two ways. First, an apparent impedance-based relay security index (RSI) is introduced to prevent the zone 3 mal-operations of distance relays under stressed situations and achieve accelerated zone 3 operation during faults. Second, a system stability index (SSI) computed from the generator rotor angles is forecasted using a predictive analytic to foresee system instability, if any, and take corrective actions in real time. The scheme can be used for area-based monitoring and control of system stability, does not require coherency group identification, remains unaffected by changes in network topology, and can effectively function for first swing stable contingencies. The scheme is tested on IEEE 39-bus New England system and the results obtained validate the reliability of scheme in maintaining system integrity.