Study On Fault Location Of Distribution Feeders Based On Transient Traveling Waves

Many countries including China adopt non-effective grounding (isolated, Petersen coil compensated or high resistance earthed) neutral in medium voltage distribution network to reduce outages caused by single phase earth fault(small current earth fault).When single phase earth fault occurs, it is difficult to locate the fault position due to weak current and unstable fault arc. On the other hand, when inter-phase short circuit fault occurs, there is little auto-located function among inter-phase short circuit fault location methods. Therefore, locating fault position fastly and automatically is significant to improve the power supply reliability and reduce the outage loss.This paper uses double terminal method of travelling waves generated by fault to locate single phase earth fault and inter-phase short circuit fault .The main researches are as follows:(1) Transient characteristics of travelling waves for different type of faults, especially for single phase earth fault, are analyzed systemaatically. Meanwhile, propagation characteristic of travelling waves in distribution feeders are also analyzed. The results show that transient process of single-phase earth fault in neutral non-effective grounding system produce aerial mode component of travelling waves, though stable state of line-to-line voltage and load current kept constant after fault occurred. Similarly, aerial mode component of travelling waves was also generated by inter-phase short circuit fault. Therefore, either single-phase earth fault or short circuit fault can use aerial mode component of traveling waves with steady-parameter as measurement signals. Traveling waves refract and reflect complexly in distribution feeders mixed with overhead lines and underground cables segments when it transmits in them, so single terminal method of travelling waves was unsuitable for the fault location.(2) Double terminal method of travelling waves is affirmed for fault location...