Stability Improvement Strategy of Distribution Network Based on Grid-Forming Mode Switching

Distributed photovoltaic is generally connected to the distribution network through grid-following inverter, which may cause a series of stability problems when the connection ratio is high. The dual-mode inverter with grid-following and grid-forming can ensure the stable access to the grid of distributed photovoltaic by mode switching. Nowadays, the research mainly focuses on the switching strategy of grid-following/islanding, and there is little research on how to choose the optimal switching scheme when the distributed photovoltaic is connected to multiple points. In this regard, this paper focuses on the distribution system with dual-mode inverter access, and proposes a mode switching strategy that integrates the stability margin and voltage deviation requirements of the system to improve the power quality and stable operation when the system parameters change. The simulation results verify the effectiveness of the proposed mode switching strategy.