Diagnosis method for diode open-circuit fault of metro rectifier unit based on waveform characteristics

Abstract

The invention relates to a diagnosis method for a diode open-circuit fault of a metro rectifier unit based on waveform characteristics, which mainly comprises the steps of A, respectively performing real-time acquisition on output voltage of the rectifier unit and A-phase input current of four rectifier bridges; B, performing normalization processing to obtain normalized output voltage; C, solvinga minimum value set of the normalized voltage signal within a period between a sampling moment t to a sampling moment (t-T+1); D, determining that a fault occurs when the absolute value of the difference between two adjacent minimum values in the minimum value set is greater than 0.1; E, comparing the A-phase input current with set positive and negative thresholds to determine the rectifier bridge where the failure diode is located; and F, determining the specific position of the failure diode according to the A-phase input current waveforms corresponding to diodes at different positions whenbeing conducted. The diagnosis method realizes recognition and positioning for the diode open-circuit fault quickly and effectively, reduces the diagnosis cost, facilitates timely maintenance and more effectively avoids the expansion of losses and the occurrence of accidents.

Description

technical field [0001] The invention relates to a method for diagnosing open-circuit faults of diodes of subway rectifier units based on input current. Background technique [0002] The subway rectifier unit is the core equipment of the traction power supply system, and its working performance and operational reliability are directly related to the operation of the entire system. In order to reduce the impact of the grid-side harmonic current of the rectifier substation on the urban power grid, most of the traction rectifier substations in urban subway rail transit in my country adopt the equivalent 24-pulse rectification method, namely: two axially split traction transformers and four sets of full-wave rectifiers. Composition of uncontrolled rectifier bridge. The primary side of each transformer adopts the Yanbian delta connection method to achieve a phase shift of ±7.5°, and the two sets of windings on the secondary side adopt star connection and delta connection methods r...

AI Technical Summary

Problems solved by technology

If the open-circuit fault of the diode cannot be detected and taken measures in time, the rectifier circuit still works. This kind of sick work will cause serious distortion of the rectifier waveform, so that the load cannot operate normally, and also increases the harmonic interference to the power grid.

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