WAMS Based Intelligent Under Frequency Load Shedding Considering Online Disturbance Estimation

The use of wide area measurements at a central monitoring and control center has brought greater flexibility in the monitoring, control and protection of modern power systems. Under frequency load shedding (UFLS) is one of the many areas experiencing the advantages involved with using wide area measurement systems (WAMS). Conventional UFLS techniques follow a pre-set and rigid threshold of frequency to shed loads at dedicated load buses in the network without considering the magnitude of the disturbance. In this paper, based on the wide area phasor measurements, the actual disturbance in the system is determined a few seconds before performing load shedding. Time domain simulations on an analytic system frequency response model of wide area power system verify the efficiency of the proposed method.