Security enhancement using an optimal switching power flow

The method presented allows the determination of the optimal and n-1 secure power system state by switching operations. A linear switching model is applied in an active way to model the control actions and in a more passive way to set up contingency constraints. Using the switching model in a dual role permits the integration of contingencies and control actions into one optimization algorithm. Thus, with exactly one optimization step the power system can be improved considering various security levels. A comparison is made between preventive conservative and postcontingency rescheduling. The main difference lies in the time-dependent performance of the topology changes in establishing a normal undisturbed system state if any contingency occurs. The preventive way of rescheduling has the advantage that there are no limit violations produced by a contingency. In postcontingency rescheduling short-term overloads are tolerated. This system state has the advantage of lower production costs. The performance of the algorithm is shown in a test case