Optimal Operation for Hybrid AC and DC Systems Considering Branch Switching and VSC Control

This article presents an optimal N−1 security constrained operation model for hybrid ac and dc power systems with voltage source converters (VSC). In the proposed model, the fast VSC power control and the branch switching-based topology optimization are utilized together to achieve a more economic and secure operation. Also, the postcontingency short-term operation security and the wind power uncertainty are considered in the proposed optimal operation model. The proposed model is formulated as a mixed integer convex optimization model. To efficiently solve this model, a two-stage optimization approach is proposed to improve the computational speed by finding the effective branch switches. Results of two hybrid ac and dc power systems validate that the economy and security level can be enhanced by simultaneously considering the topology optimization and the grid-coupling VSC control. Also, the results demonstrate that the proposed two-stage optimization method is much faster than the direct optimization in solving the proposed model.