Overvoltage Suppression Strategy after Short Circuit Faults Applied to PV Systems

The worldwide transition to renewable-based energy systems is continuing to speed up due to the strong demand on pollutant gas emission reduction and the supportive policies of the governments. In recent decades, the share of photovoltaic (PV) in renewable energy has steadily increased. Nevertheless, the voltage stability of the PV system faces several difficulties when it is connected to the distribution network (DN). The features of the PV system may worsen the voltage profile of the DN, particularly in the event of a short circuit fault. After the short circuit fault is fixed, the overvoltage issue would appear in the DN due to the inertia of PI (proportional-integral control) in the PV inverter, which might have a major impact on the stability of the DN's operation. This paper proposes an overvoltage suppression strategy after AC short circuit faults for PV systems, which can be used after the short circuit faults in the grid-connected PV system's AC line are cleared. To achieve the integration with the PV system, a novel overvoltage suppression control framework is designed based on the overvoltage suppression strategy. The effectiveness of the suggested overvoltage suppression strategy is tested in Simulink using a model constructed based on a real village DN data in Shandong, China. The findings show that the overvoltage issue can be resolved, and voltage stability can be significantly increased by 60 percent in some cases.