Design of Flexible Arc Suppression System for Ground Fault in Distribution Network Based on Proportional Integral Control

When a single-phase grounding fault occurs in the distribution network, it may lead to fire accidents if the fault arc cannot be suppressed in time. The active arc suppression device can effectively suppress the grounding fault current. Based on this, the basic principle of flexible arc suppression in the distribution network is analyzed, and the magnitude of the current that needs to be injected to achieve fault arc suppression when a single-phase grounding fault occurs in the distribution network has been derived. It is verified that the magnitude of the injected current is independent of the resistance value of the grounding fault. Aiming at controlling the fault phase voltage to $\mathbf{0}$, a dual-closed-loop PI control method based on a voltage outer loop and a current inner loop is proposed, which does not require measuring the grounding parameters of the distribution network, thus improving the system’s response speed. The amplitude-frequency curve and root locus method are used to analyze the suppression effect and stability of the system. Under the premise of ensuring system stability, the parameters of the dual-loop controller with optimal arc suppression effect are obtained.