Supertension line fault phase selection method based on voltage fault component

The invention provides a supertension line fault phase selection method based on a voltage fault component in the technical field of high voltage power grids. Three-phase voltage signals at a protective installation position at the time of a line fault are collected to calculate a three-phase voltage fault component, and an obtained proportional relation is used as a fault phase recognition coefficient; logical judgment is conducted according to the relation between the three-phase voltage signals, the three-phase voltage fault component and the fault phase recognition coefficient, namely a single-phase earth fault is judged first, a phase-to-phase fault between two phases is judged if the single-phase earth fault does not exist, and a three-phase earth fault is judged if the phase-to-phase fault does not exist; if the three-phase earth fault does not exist, a two-phase earth fault is judged finally to realize supertension line fault phase selection. The supertension line fault phase selection method based on the voltage fault component has quite high sensitivity and reliability under different fault conditions including fault positions, fault types, transition resistances and initial phase angles, and can select a fault phase quickly and accurately in a latter half cycle of the fault; meanwhile, the scheme of the supertension line fault phase selection method has sufficient sensitivity both on a strong power supply side and on a weak power supply side.