Research on Line Selection for Switch-type Arc Suppression Devices in Ungrounded Neutral Systems

摘要

In neutral point ungrounded power distribution system, the control strategy of arc suppression with bus grounding device is still a lot of room for improvement, such as low phase selection accuracy and resonance. In order to solve the aforementioned problems, in this paper, the key technology applied to operating principle and characteristics of the switch-type arc-suppression device in a neutral point ungrounded system is studied, phase selection method based on phase voltage differences and line selection method based on zero-sequence current variations are proposed, the difference between bus faults and feeder faults, and the design of judging procedure. Finally, by using the PSCAD/EMTDC software, we model and simulate the single-phase ground fault. The simulation indicates that phase selection method and line selection method we designed has a high degree of accuracy, verifying the rationality and effectiveness of the proposed method and process in this paper.