Impacts of Large-Scale Wind Power Integration on Subsynchronous Resonance

Renewable energy sources, especially wind power, are considered as important generation alternatives in electric power systems due to their nonexhausted nature and benign environmental effects. This trend will inevitably lead to large wind turbine generators being integrated into electric power grids, which challenges the existent network. It is all known that subsynchronous resonance (SSR) is a highly destructive phenomenon in a series compensated conventional system. Therefore, it is worth studying the SSR in the wind power system. Based on IEEE first benchmark system in PSCAD/EMTDC, this paper firstly analyzed SSR in an asynchronous wind power system, and then discussed the influences of the grid-connected power and series compensation level on SSR. Finally, the impacts of both thyristor controlled series capacitor (TCSC) and fixed series capacitor (FSC) on SSR were compared. Extensive simulations show that the system is more prone to SSR either with the large-scale of grid-connected power or with the high level of series compensation. Compared with FSC, TCSC with open loop control can mitigate SSR to some degree.