Modal interaction of power systems with high penetration of renewable energy and BES systems

Integration of renewable energy sources (RESs) at transmission level is getting popular in the recent years. RESs have advantages of generating clean and environmentally friendly electricity. However, due to the uncertainty and less inertia characteristic of the RESs based power plant, it can bring negative impacts on small signal stability which is also known as low-frequency oscillatory stability. Hence, utilizing an additional device, such as battery energy storage (BES) in power system with high penetration of RESs is inevitable. BES system could provide additional active power to the grid to overcome the shortfall energy from RESs. Conversely, BES installation may also introduce negative impact on system dynamic in terms of possible interaction with other elements of the power system. Therefore, proper gain control setting of BES is required to avoid undesirable interaction and make sure system stability. This paper investigates the impact of gain variation in BES controller to oscillatory stability and modal interaction on the power system. Eigenvalue trajectories, participation factor and time domain simulation of the critical modes are thoroughly investigated. Influence of the capacity of BES and its location on damping ratio of weak modes is also examined in the paper. Moreover, the mitigation of modal interaction occurrence through BES gain tuning using metaheuristic algorithms is proposed in this paper. From the simulation results, it was found that increasing BES's gain controller could lead to the interaction events. It was also reported that the proposed tuning method is feasible to mitigate the occurrence of modal interaction.