A New Risk Indices Based Under Voltage Load Shedding Scheme

This paper proposes a risk based method to design under voltage load shedding scheme. Different with traditional methods, the proposed method employs a series of risk indices, which are obtained based on a full-scale contingencies analysis, to determine the operating parameters of load shedding. According to this method, the load bus with the highest risk level of voltage instability is selected as the first candidate to execute load shedding. And the amount of loads to be shed is identified though a relationship between risk values and shedding amount. The selection of shedding time conforms to the principle that the compound risk brought by failed shedding and unexpected shedding must be the minimum. Experiments conducted for IEEE 39-bus system reveal that the proposed method is a practical tool for identifying the location, amount and time of load shedding while taking into account a great deal of uncertain factors in voltage collapse mitigation