The Method of Design an Optimal Under-Frequency Load Shedding Scheme

There is a significant risk of instability, which may lead to wide-spread blackout if power system is stressed towards their stability limit under any unexpected serious disturbances. Frequency is a reliable indicator for identification of power system instability. Therefore, under-frequency load shedding technique is used to stable the power system by reduce the load. This article is focused on determining the frequency of UFLS scheme to ensure the optimal sequence of switching off consumers. For this goal it is proposed to use the optimization method. A developed method upgrades the UFLS model for assessment of optimal load capacity and load disconnection sequence during a power system emergency. The simulation results prove that proposed method is an effective approach to improve power system reliability.