Coordinated strategy for under-voltage and under-frequency load shedding

Network operation is being increasingly impacted by the changing load dynamics served by distribution utilities, and increasing dependence on generation that is located remotely from load centers. Investigations following recent blackouts, point out that the main reason for many of the major power system instabilities is voltage collapse. This paper proposes a co-ordination method for load shedding techniques using both frequency and voltage. Parameters of the suggested schemes are also selected adaptively based on the magnitude of the disturbance. The proposed method is illustrated by simulation on the IEEE-39 bus test system. The post recovery voltage characteristic is also assessed following load shedding.