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

A technology of rectifier units and waveform characteristics, applied in the direction of instruments, measuring devices, measuring electricity, etc., can solve the problems of increasing the harmonic interference of the power grid, the distortion of the rectifier waveform, and the abnormal operation of the load, so as to avoid accidents, avoid missed detection, The effect of high diagnostic efficiency

Active Publication Date: 2019-07-23
SOUTHWEST JIAOTONG UNIV
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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.

Method used

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  • Diagnosis method of diode open-circuit fault of subway rectifier unit based on waveform characteristics
  • Diagnosis method of diode open-circuit fault of subway rectifier unit based on waveform characteristics
  • Diagnosis method of diode open-circuit fault of subway rectifier unit based on waveform characteristics

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Embodiment

[0034] figure 1 It is shown that a method for diagnosing the diode open-circuit fault of the subway rectifier unit based on the waveform characteristics, the steps are as follows:

[0035] A. Collect the output voltage of the subway rectifier unit and the A-phase input current of the four rectifier bridge network sides of the subway rectifier unit in real time, and obtain the output voltage signal u(t) of the subway rectifier unit and the input current signal i of the rectifier bridge A-phase n (t), wherein, t represents the sampling time, the subscript n is the serial number of the rectifier bridge, and the value is 1, 2, 3 or 4, which respectively represent No. 1, No. 2, No. 3 or No. 4 rectifier bridges;

[0036] B. The value u(t), u(t-1)...,u(t-T+1) of the output voltage signal u(t) from the sampling time t to the time t-T+1 constitutes the sampling time t The output voltage set U(t), U(t)=[u(t),u(t-1)...,u(t-T+1)], where T represents an AC power frequency cycle that is 0....

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Abstract

A method for diagnosing the diode open-circuit fault of the subway rectifier unit based on waveform characteristics. The steps are mainly: A. Real-time acquisition of the output voltage of the rectifier unit and the A-phase input current of 4 rectifier bridges respectively; B. Normalization processing, Obtain the normalized output voltage: C, obtain the minimum value set of the normalized voltage signal in the sampling time t to t-T+1 moment; D, when the difference between two adjacent minimum values ​​in the minimum value set When the absolute value of is greater than 0.1, it is determined that a fault has occurred; E. Compare the input current of phase A with the set positive threshold and negative threshold to determine the rectifier bridge where the faulty diode is located; F. The corresponding phase A when the diode is turned on according to different positions Input the current waveform to determine the specific location of the faulty diode. The invention quickly and effectively realizes the identification and location of the diode open-circuit fault, 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 method re...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/02
CPCG01R31/50
Inventor 林圣黄宇剑黄迪王爱民
Owner SOUTHWEST JIAOTONG UNIV
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