Improving power system efficiency: a case study on optimized reactive power management in high-voltage grids

The increasing installed capacity of renewable energy systems is changing the traditional supply of ancillary services by displacing synchronous generators. On the one hand, this creates the need to develop alternative sources, on the other hand, it also opens up opportunities for flexible and cost-efficient solutions. Against this background, this paper investigates the future role of renewable energy resources in the context of reactive power management using a simulation model of a real German high-voltage grid. Both the potentials of reactive power provision in the high-voltage grid and different strategies for reactive power control are analysed. In addition to conventional characteristic driven controls, an optimisation-based approach using the particle swarm optimisation is also considered. The simulation results underline the considerable potential increases through an extension of the operating ranges of renewable energy plants. Furthermore, it is shown that optimised use of these sources can improve grid stability and reduce overall system costs. In this context, optimised operation can have advantages for both the grid operator and the operator of the renewable energy system.