Transient stability emergency control based on critical generator pairs

To control the transient stability emergency effectively, starting with the information of critical generator pairs a generator tripping/load shedding control strategy based on sensitivity of stability indices of critical generator pairs is proposed. Firstly, the expression of the sensitivity of stability indices of critical generator pairs to control variables is derived and applied to construct constraints of transient stability, and then by means of optimization algorithm the amounts of both tripped generators and shed load needed for emergency control as well as corresponding substations to perform the measures are achieved. Only part of generator information is needed for the proposed method, so the calculation is simple and by means of the sensitivity of stability indices of critical generator pairs the control ability of control quantity to each instable generator can be expressed and its physical meaning is clearer. Simulation results show that the amount of generator tripping and load shedding by the proposed method is less than that by the method based on the sensitivity of margin sensitivity of the whole system.