Evaluation of Efficient Frequency Control Strategies in a Wind-Hydro Dominated Power System

This paper aims to investigate the possibility of providing a joint service of coordinated frequency support from hydro units and wind turbines (WTs) in a low inertia power system. While WTs can arrest the initial frequency dip (IFD) by providing fast support using their converter controllers, hydro turbines are capable of mitigating the second frequency dip (SFD) resulting from the restoration phase of WTs by increasing their production accordingly. Furthermore, a recently-issued grid-code for fast frequency reserve (FFR) provision in the Nordic synchronous area (NSA) is analysed and compared with the proposed method. Results show that the proposed coordinated frequency support strategy can mitigate both the IFD and the SFD with less energy requirements compared to the grid-code characteristics.