Co-optimization of unit commitment and transmission switching with short-circuit current constraints

Abstract

Abstract Excessive short-circuit current (SCC) has been a common problem in power systems with the enhancement of the transmission network. In this paper, a co-optimization model of unit commitment and transmission switching (UC-TS) with SCC limitation is proposed. By jointly optimizing UC and TS, the solution of the model includes both the generation schedule and the network topology that can more easily constrain the SCC below the limitation. Due to the complexity of the proposed model, which is difficult to solve directly, it is first simplified by giving only one topology for a day according to the requirements of real-world operations, and then the nonlinear SCC constraints are replaced with linearized SCC cuts obtained by a sensitivity-based approach. Moreover, the model is decomposed into a master problem and a smaller subproblem by a step-by-step solving strategy, which can be solved iteratively to obtain the final solution within a reasonable time. An effective anti-island measure is further proposed to completely prevent the occurrence of isolated buses or islands. The computational results based on IEEE 118-bus, 300-bus and 699-bus systems demonstrate that using the combination of UC and TS to limit SCC has distinct advantages over conventional approaches.