Novel model for optimal coordinated voltage emergency control against voltage collapse

A novel optimal coordinated voltage emergency control (OCVEC) model is proposed in this paper. The model, which takes into account the dynamics of loads and discrete/continuous nature of controls, can coordinate dissimilar controls at different geographical locations in order to keep voltage stability against voltage collapse globally during an emergency. A heuristic integration index of the load bus voltage deviation is used as the voltage stability performance index. Based on the optimal control theory, the sensitivities of the performance index with respect to controls are derived rigorously. The sensitivities can be calculated out based on the quasi-steady-state (QSS) fast time domain simulation. The intractable OCVEC model can then be converted into a problem of mixed-integer linear programming. The effectiveness of the proposed model is validated with numerical tests on the New England test power system.