Accurate and reliable single-phase grounding fault location in distribution networks is of great significance for reducing fault search time and rapidly restoring power supply. To address the issue of existing methods for low location accuracy caused by the inconspicuous characteristics of single-phase grounding faults in distribution networks
a fault location method that injects dual-frequency signals via a flexible grounding device to enhance fault characteristics is proposed. First
the influence of load current is eliminated by combining the fault-phase network with the zero-sequence network. Second
a fault location equation is established using the electrical quantities at the line head end
and the equation is solved by injecting two non-power-frequency signals through the flexible grounding device. Furthermore
corresponding fault location equations are derived for lines with branches and overhead line–cable hybrid lines
enabling fault section identification and precise location based on the proposed criteria. Finally
simulation and experimental verification demonstrate that the proposed method achieves high location accuracy and is less affected by transition resistance.
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