Method for implementing earthing distance measurement element

The invention discloses a high-accuracy implement method of an element for measuring a grounding distance unrelated to the loading current and the grounding resistance. 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 DeltaIPhin of positive sequence and negative sequence in the relay location is measured. Since the grounding is ohmic, UPhif is in the same phase with IPhif; and since DeltaIPhin has the same phase angle as IPhif, UPhif has the same phase angle as the DeltaIPhin, thereby further obtaining a fault distance formula which is unrelated to the loading current and the grounding resistance, wherein Phi is equal to a, b or c, and n is equal to 1 or 2. Since the formula itself is unrelated to the loading current and the grounding resistance, and DeltaIPhin and IPhif have the same phase angle, 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.