Method for implementing element for measuring distance between phases without relevance to load current and ground resistance

The invention discloses an implement method of an element for measuring a phase distance unrelated to the loading current and the fault resistance. When a high-voltage/ ultra-high-voltage/extra-high-voltage has a phase fault, the current in a relay location is IPhiPhi, and the voltage is UPhiPhi; the distance from the fault point to the relay location is x; the voltage at the fault point is UPhiPhif, and the current is IPhiPhif; and the break current DeltaIPhiPhi in the relay location is measured. Since the fault is phase-to-phase, UPhiPhif has the same phase asss IPhiPhif; and since DeltaIPhiPhi has the same phase angle as IPhiPhif, UPhiPhif has the same phase angle as DeltaIPhiPhi, wherein UPhiPhif is equal to UPhiPhiPhi minus xZ1IPhiPhi, DeltaIPhiPhi and UPhiPhif are changed into plural forms; since DeltaIPhiPhi and UPhiPhif have the same phase angle, the ratio of the imaginary part to the real part of DeltaIPhiPhi is equal to the ratio of the imaginary part to the real part of UPhiPhif, which is shown in formula (II), so as to calculate and obtain the fault distance x unrelated to the loading current and the fault resistance, which is shown in formula (I); since the formula is unrelated to loading current and the fault resistance, the element can be used as a distance protective impedance measuring element. Theoretical analyses and simulation results show that the proposed principle has very high practicability and computational accuracy.