Maximizing the feed-in of renewable energy into high-voltage grids by seasonal topology measures — a german case study

The German Renewable Energy Act obliges power grid operators to connect renewable generation units to their grids, even when the transfer capacity is temporarily insufficient. During times of excessive renewable energy generation, the grid operator often has to reduce the feed-in of renewable generation units to preserve a secure system state. This paper assesses the potential of seasonal topology measures to maximize the feed-in of renewable generation units in a real 110 kV grid. The mixed-integer nonlinear programming problem (MINLP) is solved by a binary Particle Swarm Optimization (PSO) algorithm. A novel bus coupler modeling strategy for multiple-busbar stations is proposed, which reduces the number of control variables in the optimization process. The results show the efficiency of the proposed method and the significance of seasonal transmission switching in power system operation.