Maximizing the feed-in of renewable energy into 110 kV distribution grids — a German case study

In Germany, the 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 topology measures to maximize the feed-in of renewable generation units in a realistic 110 kV grid. In this context a new modeling strategy for switchgears in multiple-busbar stations is proposed, which overcomes the disadvantages of existing topology modeling strategies. The mixed-integer nonlinear programming problem (MINLP) is solved by a novel binary Particle Swarm Optimization (PSO) algorithm. The influence of different penalty function modeling strategies on the solution space is also analyzed. The results illustrate the performance and efficiency of the proposed method.