Optimal sitting, sizing and control of battery energy storage to enhance dynamic stability of low-inertia grids

Abstract

As inverter-based resources like wind turbines increase, grid inertia and stability decrease. Optimal placement and control of energy storage systems can stablise low-inertia grids. This paper investigates how optimal battery energy storage systems (BESS) enhance stability in low-inertia grids after sudden generation loss. The sitting, sizing and control of BESS are determined simultaneously in each genetic algorithm (GA) population, then voltage and frequency stability is evaluated based on the network simulation. This continues until the optimal solution is found. A network based on Kundur's four-machine system is modelled for the first study and two of the four synchronous generators (SGs) have been replaced with wind farms. Then, the production of the third SG has been decreased by 13%. According to the results, addition of wind farms causes the frequency drop below 49.6 Hz for more than 5 min, indicating instability. It is also demonstrated that with optimal control parameters and placement, a 60 MW BESS can alleviate the voltage and frequency fluctuations, leading to enhanced stability. This method has also been tested on the IEEE 39-bus network, where the installation of a BESS with a capacity of 9 MVA could restore the frequency stability.