WAMS-based Load Shedding for Systems Suffering Power Deficit

As the last resort, UFLS (under frequency load shedding) was introduced to recover system frequency and is widely deployed in present power systems. With the lessons learned from blackouts, this paper reveals that fast and precise load shedding to efficiently rebalance the power between generation and load has crucial significance. But conventional UFLS often fails to realize this function. Further the disadvantages of UFLS are illustrated with a specific example and explained according to the factors affecting frequency dynamics. Then the concept of WAMS(Wide Area Measurement System)-based load shedding is proposed. Preliminary work on this area is described with load shedding optimization problem constrained by frequency and voltage recovery requirements. It is further approximately reformulated as linear programming problem by utilizing load shedding sensitivities. Promising simulation results of proposed method compared with conventional UFLS are provided. Work to be extended for real time implementation is briefly discussed.