Aiming at the problem of low power supply reliability caused by long time-consuming manual line inspection after single-phase grounding faults of low-resistance grounding systems

a fault location method based on zero-sequence voltage projection gradient is proposed to determine the accurate fault location.Firstly

the distribution characteristics of zero-sequence current and zero-sequence voltage after single-phase grounding of low resistance grounding system are analyzed by using a zero-sequence equivalent circuit diagram. Secondly

the distribution characteristics of zero-sequence voltage projections of single-type lines and hybrid lines are analyzed by the phasor diagram of zero-sequence voltage changes of fault lines.It is found that after the hybrid lines are equivalent

the projections of both are linear functions of the distance to the bus.Finally

on the basis of accurately obtaining the location results of the section

a ranging method based on the gradient of zerosequence voltage projection is proposed. A 10 kV small resistance grounding distribution network is built by MATLAB/Simulink

and simulation experiments are carried out on different line types.The results show that the method has high ranging accuracy and can effectively overcome the influence of inaccurate parameters of a single type of line on ranging results.