A phase selection method for transmission line ground faults against the influence of distributed capacitive current and transition resistance

Abstract

The invention discloses a power transmission line grounding fault selection method capable of resisting distributed capacitive current and transition resistance effect. According to the power transmission line grounding fault selection method, a distributed parameter model is used as a physical model; phase relationship between a zero-sequence voltage difference and an A-phase negative-sequence current vector sum and phase relationship between the zero-sequence voltage difference and the A-phase positive-sequence current vector sum are utilized for forming a power transmission line grounding fault phase selection criteria, thereby accurately determining the type of a power transmission line grounding shortcircuit fault. According to the method of the invention, a distributed parameter model is used as the physical model; the method of the invention has natural capability for resisting the distributed capacitive current effect, and is suitable for superhigh-voltage and ultrahigh-voltage power transmission line. When high-resistance grounding shortcircuit fault occurs on condition that relatively large change of a weak power supply side and a system operation mode occurs. According to the method of the invention, a high-enough phase selection sensitivity is realized in the whole fault process of power transmission line grounding fault. A particular grounding fault phase can be accurately determined. Accurate and reliable fault phase information can be supplied for distance protection and correct action of an autoreclose circuit breaker.

Description

technical field [0001] The invention relates to the technical field of relay protection for power systems, in particular to a phase selection method for transmission line grounding faults against the influence of distributed capacitive currents and transition resistances. Background technique [0002] Phase selection methods for transmission line faults mainly include phase selection of phase current mutation, phase selection of phase voltage mutation and comprehensive phase selection of voltage and current mutation. On the weak power supply side, the phase selection sensitivity of phase current mutation is not high enough; on the strong power supply side, the phase selection sensitivity of phase voltage mutation is insufficient; although the comprehensive phase selection method of voltage and current mutation has relatively high The sensitivity of phase selection is good, but the sensitivity of three-phase short-circuit fault phase selection and high-resistance grounding sh...

AI Technical Summary

Problems solved by technology

On the weak power supply side, the phase selection sensitivity of phase current mutation is not high enough; on the strong power supply side, the phase selection sensitivity of phase voltage mutation is insufficient; although the comprehensive phase selection method of voltage and current mutation has relatively high Good phase selection sensitivity, but insufficient sensitivity in phase selection for three-phase short-circuit faults and high-resistance grounding short-circuit faults

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