Method of realizing line-to-ground fault phase selection by using sequence voltage phase characteristic

Abstract

The invention discloses a method of realizing line-to-ground fault phase selection by using a sequence voltage phase characteristic. The method comprises the steps of firstly using the phase relation between zero-sequence voltage and A phase negative sequence voltage to form a criterion and accurately judging whether a transmission line fault is a grounded short circuit fault; secondarily using the magnitude relation between interphase fault impedance and setting impedance to form a criterion; and differentiating a single-phase grounded short circuit fault and a two-phase grounded short circuit fault. When a high impedance grounded short circuit fault occurs on a transmission line at a weak power source side and under the condition that the system operation mode is changed greatly, the method is high enough in phase selection sensitivity, the specific grounded fault phase can be accurately judged, the method is applicable to the fault phase selection of the whole fault process of the transmission line grounded short circuit fault, and is applicable to the fault phase selection of a climbing transmission line high impedance grounded short circuit, and accurate and reliable fault phase information can be provided for distance protection and automatic reclosing lock correct operation.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for realizing line grounding fault phase selection by utilizing sequence voltage phase characteristics. 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 Good phase selection sensitivity, but there is insufficient sensitivity in phase selection for three-phase short-circuit faults. Since the methods of phase-current sudden change ...

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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

Since the methods of phase-current sudden change phase selection, phase voltage sudden change phase selection and voltage-current sudden change comprehensive phase selection methods all use power frequency sudden change to participate in the calculation, power frequency change only exists within two cycles after the transmission line fault, so , phase current mutation phase selection, phase voltage mutation phase selection and voltage current mutation comprehensive phase selection methods are only suitable for the fault phase selection within two cycles after the transmission line fault, and cannot be applied to the climbing transmission line high Phase selection for resistance to ground short circuit fault

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