An active current arc suppression scheme using PI and repetitive control strategy for distribution networks

Abstract

Active arc suppression devices can not accurately issue compensation current during single-phase grounding faults in the distribution network. Thus, an active current arc suppression scheme based on PI and repetitive control strategy was proposed on the basis of the analysis of the active current arc suppression principle. Based on the use of voltage feedforward links to eliminate neutral voltage disturbances, the PI and repetitive control strategy was introduced into the current closed-loop system to achieve fine-grained processing of the grounding residual current through the static-free tracking of the frequency as well as the 5 and 7 times commanded current. Compared with the traditional PI control strategy, this method used a parallel structure of PI and repetitive control to achieve accurate output compensation current by using the fast response of PI control to command current and the static-free tracking performance of repetitive control to multi-frequency AC signals. The simulation and experimental results show that compared to PI control, the PI+repeat control strategy can reduce the deviation of the injected current from the commanded current from 14.85% to 3.27%; the compensation rate of single-phase earth fault residual current under different earth resistances is improved, for example, the compensation rate increasing from 79.67% to 94.74% for an earth fault 1.4 Ω resistances, which can better achieve the goal of full compensation of earth residual current.

Keywords

• distribution network
• pi+ repetitive control
• active arc suppression
• current injection
• the fault arc suppression
• closed-loop control