Performance Evaluation of Islanding Detection for Distributed Energy Resources With Grid-Forming Control

With the proliferation of Distributed Energy Resources (DER), advanced inverter functions such as Gridforming (GFM) have been developed. With the main object to maintain the frequency and voltage stability during the grid- connected operation, such functions, however, has raised great concerns on the effectiveness degradation of islanding prevention. Focusing on it, this paper evaluates the performance of the widely used Slip-Mode Frequency Shift (SMS) islanding detection method operating together with the classic droop based GFM control. First, the small-signal model for such control combination is derived, and their interaction mechanism is then thoroughly investigated. Accordingly, the desirable range of SMS coefficient is characterized to guarantee a successful islanding detection during the islanded condition and a stable operation during the grid-connected condition. It is observed that several key parameters, especially the SMS coefficient and Q-V coefficient of droop control, jointly dominate the effectiveness of the islanding detection and should be well designed. Finally, simulations and experiments are performed to validate the above analysis.