Fault sensing method, device and equipment of power distribution network resonance grounding system and medium

The embodiment of the invention discloses a fault sensing method and device for a power distribution network resonance grounding system, equipment and a medium. The method comprises the steps of obtaining a target frequency of a detection current; determining reference power distribution network impedance under the detection current of the target frequency during normal operation of the power distribution network and grounding power distribution network impedance under the detection current of the target frequency during single-phase grounding of the system by injecting the detection current of the target frequency; determining the parallel impedance of the capacitance converted to the secondary side of the PT from the ground distributed capacitance of the arc suppression coil inductor of the power distribution network to the ground and the grounding transition resistor; further determining a to-ground dielectric loss tangent value of the power distribution network under the detection current of the injection