The study of single line to ground fault line selection in non-direct ground power system based on DSP device

The middle-low voltage distribution networks mostly adopt neuter point not-valid grounding(be so called to the small current groundding system).The distribution wire fault particularly the fast and accurate location that the single grounding fault, not only to the repair wire and promise dependable power supply, and circulate to the safe stability and economy that promises the whole electric power system to all have a very important function. With reference of actual conditions for single phase earthing fault, the paper puts forward the principle on single phase earthing faulty line selection, and with the support of digital signal processing device(DSP)capable in floating point computation, to design a new type of low current single phase earthing faulty line selection device for power distribution system.