Method for implementing earthing distance measurement element based on negative sequence fault current component

The invention discloses an implement method of an element for measuring a grounding distance unrelated to the loading current and the grounding resistance, which is based on a negative sequence fault current component. When a high-voltage/ ultra-high-voltage/extra-high-voltage has a single-phase grounding fault, the current in a relay location is IPhi, and the voltage is UPhi; the distance from the fault point to the relay location is x; the voltage at the fault point is UPhif; the grounding current is IPhif; and the break current IPhi2 of negative sequence in the relay location is measured. Since the grounding is ohmic, IPhif is in the same phase with IPhif; as for the single-phase grounding fault, since IPhi2 has the same phase angle with IPhif, UPhif has the same phase angle as IPhi2, so as to calculate and obtain a formula of the distance from the fault point to the relay location; since the formula is unrelated to the loading current and the grounding resistance, as a distance protective impedance measuring element, the element has high measuring accuracy, and is not affected by the loading current or the high resistance grounding fault. Theoretical analyses and simulation results show that the proposed principle has very high practicability and computational accuracy.