Detection method and detection device of three-phase AC circuit phase loss fault

Abstract

The present invention discloses a detection method of a three-phase AC circuit phase loss fault. According to a sampling period ts and a phase voltage period T, the sampling number N in a phase voltage period is calculated. The point of each Delta Theta before and after a zero-crossing point is selected as a reference point, the absolute value Y of the phase voltage of the reference point is calculated, and the absolute value Y is taken as the reference value of the judgment counting. The maximum sampling number Nmax in a 2 Delta Theta interval is calculated. According to the sampling period ts, the continuous sampling of each phase voltage of a three-phase AC circuit is carried out, and after taking the absolute value of the sampling data, the absolute value and a reference value Y are compared. If the absolute value of the sampling data is smaller than or equal to the reference value Y, 1 is added to a corresponding counting value, if the absolute value of the sampling data is larger than the reference value Y, 1 is subtracted from the corresponding counting value, and the minimum value of the counting value is defined as zero. Whether the counting value of each phase satisfies a condition that Nx is larger than or equal to k*Nmax, and if so, a condition that the phase corresponding to the corresponding counting value in the three-phase AC circuit is lost is judged.

Description

technical field [0001] The invention relates to a detection method and a detection device for a phase loss fault of a three-phase AC circuit. Background technique [0002] Three-phase AC circuit phase loss detection has a wide range of applications in the field of power systems and industrial automation. All kinds of power distribution and safety protection equipment in the power system need to have the ability of phase loss detection and failure alarm; electrical equipment such as frequency converters and inverters in the field of industrial automation also need to integrate the ability of phase loss detection and failure alarm. Function. [0003] There are many detection methods for phase loss faults in three-phase AC circuits, but most of the detection methods currently in use are hardware detection, such as high-impedance isolation rectification method, double-limit comparison method, and phase voltage difference comparison method. In recent years, with the continuous ...

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Problems solved by technology

[0006] Aiming at the problems of cumbersome implementation, potential safety hazards and low real-time performance in the actual application of the prior art, especially the limitations of the application, the present invention provides a detection method and detection device suitable for phase loss faults of three-phase AC circuits , adopting the present invention can eliminate the disadvantages of cumbersome implementation and potential safety hazards, can quickly and accurately detect phase-lack faults, and has no strict requirements on the symmetry of three-phase circuits, which improves the universality of application

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