Comparison of wind turbine power control strategies to provide power reserves

Due to an increasing amount of wind turbines in the power system, which have a volatile power output, the need for flexibility increases. This flexibility can be obtained by ancillary services. Therefore, the provision of ancillary services with wind turbines is gaining interest. As they currently do not participate in the frequency control, this might compromise the proper functioning of the power system. The modern turbines are equipped with a power-electronic converter, so they can be used to provide a variety of ancillary services when the appropriate control strategies are used. In this paper, the provision of active power reserves for frequency control is considered. Three state-of-the-art power control strategies, i.e., constant power control, linear slope control and percentage control are compared to determine their ability to maintain reserves. It is concluded that all the strategies are able to provide reserves, but linear slope control and percentage control perform the best, especially when the wind turbines are aggregated in wind farms.