A Synchrophasor Assisted Frequency and Voltage Stability Based Load Shedding Scheme for Self-Healing of Power System

This paper presents a new scheme for load curtailment in the power system required for its self-healing under critical contingencies, which may pose a threat to frequency as well as the voltage stability of the system. The load shedding requirement in the system has been calculated based on the computed disturbance power as well as the voltage stability condition of the system, with the aid of real-time data, assumed to be available from the synchrophasor based wide area monitoring and control system (WAMCS). This scheme assesses voltage stability based on a dynamic voltage stability criterion, formulated using a Voltage Stability Risk Index (VSRI). Suitable locations for the load curtailments have been chosen according to the VSRI, calculated at each load bus. Performance of the proposed scheme has been tested on New England 39-bus system and a practical 246-bus Indian system. The results are compared with a conventional under frequency load shedding scheme and an adaptive load shedding scheme.