Adaptability Analysis of Grid-Following and Grid-Forming Energy Storage Systems Under Different Grid Conditions

In recent years, the installed capacity of energy storage systems (ESS) has shown explosive growth, which has had a certain impact on the characteristics of the grid. This paper analyzes the adaptability of the grid-following and the grid-forming ESS. The grid-following control strategy, utilizing a phase-locked loop (PLL) to synchronize with the grid voltage phase. It is equivalent to a current source, which poses a higher risk of instability under weak grid conditions. The grid-forming ESS operates in a self-synchronous mode, thus being free from the influence of PLL and able to provide frequency and voltage support, making it more suitable for operation in weak grid conditions. It is found that by adjusting the proportion of grid-forming ESS, it is possible to adapt to different grid conditions and achieve stable operation. Simulation results validate the analysis.