608 / 2019-03-12 11:04:22

Summary and adaptability analysis of implementation schemes about single-phase-to-ground fault diagnosis in distribution system

Single-phase-to-ground fault, fault diagnosis, neutral grounding, distribution system, adaptability analysis

Single-phase-to-ground fault accounts for about 80% of faults in distribution system, which will easily cause system overvoltage and multi-point-grounded short-circuit fault. Therefore, fault location should be accurately and quickly determined after single-phase-to-grounded (SPG) fault occurs. Due to different neutral grounding modes in distribution system, the fault characteristics are various when SPG fault occurs. Therefore, the fault detection methods are different under different neutral grounding modes of the system, and the acquired data and configured equipments may also be different. According to the types of monitoring devices applied, SPG fault diagnosis solutions could be divided into three categories: fault-indicator scheme, intelligent-monitoring-terminal scheme and boundary-switch scheme. According to diagnosis principle, the solutions are further subdivided into transient-recording method, directional-adaptive method, signal-injection method, multilevel- directional protection method, phase-asymmetry detection method and so on. This paper firstly summarizes the existing implementation schemes for SPG fault diagnosis including the principle, implementation method and application scope of each scheme. Secondly, analysis about technical and economical comparison is done among different schemes. Finally, suitable SPG fault handling schemes for different neutral grounding systems are put forward, including the processing pattern and required equipment, which will effectively promote the level of safe and reliable operation in distribution system.