A synchrophasor measurements based adaptive underfrequency load shedding scheme

Abstract

This paper presents a new Synchrophasor-assisted scheme for Underfrequency load shedding (Sy-UFLS) in the events of severe generation-load mismatch. Such a mismatch may pose a threat to the frequency stability of the power system. The proposed scheme focuses mainly on three aspects of load shedding, viz., when, how-much and where to shed the load. The load shedding requirement is assessed by computing the disturbance power, utilizing the synchrophasor measurements. Next, by selecting the total real power generation, total real power demand, rate of change of frequency, and real power reserves in the system as the input neurons to an Artificial Neural Network, the minimum amount of load shedding is determined to maintain the stability of the system. Lastly, the load shedding amount is effectively distributed among various load buses, based on the novel concept of electrical distance, in order to arrest the situation. The effectiveness of the proposed Sy-UFLS scheme is demonstrated on New England 39-bus system under various test cases and found to be superior than the conventional UFLS scheme.