Frequency Performance Assessment of Future Grids

Abstract

Future grids security will be challenged by the increasing penetration of non-synchronous renewable energy sources (NS-RES). Studies of future grids with high penetration of NS-RES suggest that along with other issues, system frequency control will become a challenging task. Therefore, this thesis first, studies the impact of high penetration of NS-RES and different penetration levels of prosumers on the performance and frequency stability of the Australian national electricity market (NEM). By doing this, the connection between the NS-RES and the system frequency performance, as well as different penetration levels of prosumers and the system frequency performance are quantified. Second, we propose a frequency performance assessment framework based on a timeseries approach that facilitates the analysis of a large number of scenarios. This framework is utilised to assess the frequency performance of the Australian future grid by considering a large number of future scenarios and sensitivity of different parameters. By doing this, we identify a maximum non-synchronous instantaneous penetration range for the system from the frequency performance point of view. Then, to improve the frequency performance of the system with high penetration levels of NS-RES, we evaluate the contribution of different resources, such as synchronous condensers, wind farm’s synthetic inertia and a governor-like response from the de-loaded wind farms, on frequency control. The results show that the last one adds more flexibility to the system for frequency control. Finally, a coordinated operation strategy for wind farms is proposed. It is shown that by operating the wind farm in a coordinated way, we can increase both the output power and the rotational kinetic energy of the wind farm. Time-domain simulations show that the proposed operation strategies noticeably improve the wind farm’s performance in frequency control.