A novel preventive control approach for mitigating voltage collapse

A novel preventive control approach for mitigating the voltage unstable contingencies is proposed in this paper. The contingencies for which there are no post-fault equilibrium points are called unstable contingencies. The preventive control problem is decomposed into two sub-problems and solved iteratively and alternately. One sub-problem is that the stability bifurcation points in contingency parameter space are computed by using the contingency parameterization continuation power flow and the sensitivities of contingency instability margin with respect to controls are obtained. Another sub-problem is that a sensitivity-based linear programming is constructed and solved to obtain the preventive control actions. In latter one several heuristic strategies are used to improve the computational efficiency of the LP problem. Case studies with a practical 3000-bus power system indicate that the proposed approach is effective and suitable for on-line applications in a large scale power system