Method for locating single-phase disconnection non-ground fault of power distribution network

Abstract

The invention relates to a method for locating a single-phase disconnection non-ground fault of a power distribution network. After the single-phase disconnection non-ground fault occurs, the positive sequence voltage of the high-voltage side of each distribution transformer after a fault point is far lower than the positive sequence voltage of the high-voltage side of each distribution transformer before the fault point and the positive sequence voltage of the high-voltage side of each distribution transformer of a non-faulty line, and the positive sequence voltage of the low-voltage side of each distribution transformer after the fault point also correspondingly becomes about 50 percent of the positive sequence voltage before the fault point. For three-phase voltage information acquired by different types of measuring devices installed at load points, the positive-sequence component of the voltage of each load point is calculated in real time; and if the positive sequence voltage of a certain load point and the positive sequence voltages of all downstream load points of the load point are obviously reduced at one point, and the positive sequence voltages of upstream load points of the load point are constant, the single-phase disconnection non-ground fault can be determined in an upstream adjacent line connected with the load point. According to the method for locating the single-phase disconnection non-ground fault of the power distribution network disclosed by the invention, new equipment does not need to be equipped; the calculation is simple; and the fault can be located between two load points to realize the diagnosis and the location of the single-phase disconnection non-ground fault.

Description

technical field [0001] The invention relates to the technical field of power system operation, in particular to a method for locating a single-phase disconnection and non-ground fault in a distribution network. Background technique [0002] The distribution network is directly oriented to users, with wide coverage and different operating environments. Affected by operating equipment defects, human error, external damage, and meteorological disasters, especially overhead lines, disconnection faults are prone to occur. Among them, the disconnection ground fault can be judged according to the ground fault transient component and harmonic characteristics, and the impedance method or traveling wave method can be used for positioning. For ungrounded faults after disconnection, there is no obvious fault feature and it is difficult to locate. [0003] After searching the existing technologies, it is found that technology 1 ([1] You Yi, Liu Dong, Li Liang, et al. Judgment of 10kV o...

AI Technical Summary

Problems solved by technology

However, for medium-voltage distribution networks, the number of measuring devices arranged along the feeder is often small. Therefore, based on fault diagnosis and location, it can only be located between two measuring devices, and the positioning accuracy is low.

And limited measuring devices can usually only measure one or two phase-to-phase values, and cannot obtain the voltage and current information of each phase. Fault diagnosis based on incomplete information may cause misjudgment or missed judgment

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