High Sensitivity Protection Method of Low-resistance Grounding System Based on 5G Technology

Abstract—In order to resolve the problem about weak sensitivity of high-resistance ground fault in low-resistance grounding system, this paper analyzes the characteristics of zero-sequence (ZS) network when single phase grounding fault occurs in distribution network. It can be concluded that neutral point ZS current is approximately equal to ZS current of fault feeder and always much larger than ZS current of non-fault feeder. And the phase angle difference between neutral point ZS current and fault feeder ZS current is greater than that between neutral point ZS current and non-fault feeder ZS current. Based on this, a comparison method of ZS current with double judgement based on 5G technology is proposed. This method ensures that the information of the ZS current of the neutral point can be accurately transmitted to each protection device on time, forming a local protection. Through theoretical and simulation analysis, this method improves the sensitivity and reliability of high resistance grounding fault protection without changing the existing protection devices.