Phase Selection Method for Grounding Fault of Transmission Line

Abstract

The invention discloses a power transmission line grounding fault phase selection method. According to the method of the invention, a distributed parameter model is used as a physical model; phase relationship between a zero-sequence voltage difference and one end A-phase negative-sequence current of a power transmission line and phase relationship between the zero-sequence voltage difference and one end A-phase positive-sequence current of the power transmission line are used for forming a power transmission line grounding fault phase selection criteria, thereby accurately determining the type of power transmission line grounding shortcircuit fault. According to the method of the invention, the distributed parameter model is used as the physical model. The method has natural capability of resisting influence of distributed capacitive current and is suitable for superhigh-voltage and ultrahigh-voltage power transmission lines. When high-resistance grounding shortcircuit fault of the power transmission line occurs on condition that relatively large change of a weak power supply side and system operation mode is generated, the method of the invention has advantages of realizing high-enough phase selection sensitivity, accurately determining a particular grounding fault phase and supplying accurate and reliable fault phase information for distance protection and accurate action of an autoreclose circuit breaker.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a phase selection method for grounding faults of transmission lines. 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 short-circuit fault is insufficient. [0003] Whether the transmission line f...

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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