The invention is suitable for the technical field of
arc extinction of a power distribution network, and provides a self-adaptive composite
arc extinction method based on a zero-sequence
voltage threshold value of the power distribution network, which comprises the following steps: monitoring the
neutral point voltage of the power distribution network, and judging whether the power distribution network has a single-phase earth fault or not; when the single-phase earth fault does not occur in the power distribution network, injecting a first current into the neutral point of the power distribution network, and calculating an earth parameter of the power distribution network and an earth
capacitance current when the
voltage of the neutral point of the power distribution network is zero; when a single-phase earth fault occurs in the power distribution network, injecting a second current into the neutral point of the power distribution network, and calculating a fault point offset
voltage of the power distribution network; and calculating a voltage threshold value and a corrected current
arc extinction reference value based on the ground parameter, the ground
capacitance current and the fault point offset voltage, if the
neutral point voltage of the power distribution network is smaller than the voltage threshold value when the single-phase ground fault occurs, adopting voltage arc
extinction, otherwise, adopting the corrected current arc
extinction reference value to implement current arc
extinction. According to the invention, the reliability of single-phase earth fault arc extinction can be improved.