The Application of Electrical Dissection Theory in the Occurrence of Large-Scale Power Loss

When the tie-line of an ultra-high voltage (UHV) power grid is removed on account of accidents, large-scale power loss will arise in the receiving-end grid. In order to restore the balance between the power generated and the power consumed, appropriate emergency control measures should be taken in the system. In both aspects of load shedding and unit output regulating, this paper presents an emergency control strategy based on source-flow coupling factors. Firstly, obtain the coupling factors related to the tie-line by dissecting the system using the power flow data at the moment before accidents. The associated loads to be shed and the associated generators to be adjusted can be determined by the coupling factors. Then, calculate the coupling coefficients between the tie-line and its associated loads, and between the associated loads and their associated generators. Finally, the load to be shed on each associated loads and the power to be increased on each associated generators can be calculated by using the coupling coefficients. We apply the proposed method on a modified 39-bus New England test system. The results show that by using this method, the power flow deviation caused by emergency control is small, which indicates the scope of the accident is significantly reduced. The method we have proposed is effective.