Wind turbines voltage support in weak grids

This paper investigates how Full-Scale Converter (FSC) wind turbines can contribute to voltage support in weak grids. A novel voltage support strategy is proposed, which optimizes the voltage support during the fault. This strategy is compared to the voltage support required by two grid codes, the Danish and the German E.ON ones. The influence of a number of parameters, as the network X/R ratio, the voltage support controller gain and the post-fault power ramp is investigated. A sensitivity analysis with regard to uncertainties in the knowledge of the X/R ratio is performed. Finally, the voltage support provided by a wind power plant (WPP) is compared to that provided by a conventional power plant with synchronous generation. Simulation results indicate that a FSC WPP if properly controlled is able to provide a post-fault voltage support comparable to the one provided by a synchronous generator.