A New Load Shedding Scheme for Limiting Underfrequency

Abstract

Under-frequency load shedding acts to alleviate load-generation imbalance following a sudden loss of large amounts of generation. Loads are shed at pre-scheduled locations throughout the power system. This, unfortunately, does not adequately correct for the effects of the location of the disturbance on the power system. It would be better if load shedding were to occur at locations close to the lost generation so reducing the reactive power losses associated with transmitting larger amounts of power to the disturbed location. A new hierarchical load shedding scheme is proposed, based on frequency, voltage and rate of frequency decline, which utilizes a distributed intelligence to shed load according to the actual system state at each locality.