An Optimal Power Flow Model and Approach with Static Voltage Stability Constraints

A multiple contingency optimal power flow problem incorporating static voltage stability constraints is proposed. The distance in term of load MW between the current operating point and the point of collapse is used as the index for evaluating the voltage stability. A new decomposition and iteration method for solving the proposed MC-VSCOPF problem is presented. The continuation power flow is used as a module to obtain the voltage collapse points and check the voltage stability constraints while the sensitivities of the violated constraints with respect to any controls are used to construct the reduced OPF sub-problems. It provides the optimal solution both minimizing control costs and guaranteeing the voltage security level. Case studies with a practical 640-bus power system indicate that the proposed methods are effective and suitable for on-line applications in a large scale power system.