CN108983025A - The diagnostic method of subway Rectification Power Factor diode open-circuit failure based on wave character - Google Patents
The diagnostic method of subway Rectification Power Factor diode open-circuit failure based on wave character Download PDFInfo
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Abstract
A kind of diagnostic method of the subway Rectification Power Factor diode open-circuit failure based on wave character, step are main are as follows: A, are acquired in real time to Rectification Power Factor output voltage and 4 rectifier bridge A phase input currents respectively；B, it is normalized, obtains normalized output voltage: C, the minimum value set for finding out the normalized voltage signal within sampling instant t to the t-T+1 moment；D, when minimum absolute value of the difference two neighboring in minimum value set is greater than 0.1, determine failure；E, by A phase input current compared with the positive threshold value of setting, negative threshold value, the rectifier bridge where failure diode is determined；F, corresponding A phase input current waveform when according to different location diode current flow determines the diode specific location that is out of order.The present invention fast and effeciently realizes the identification and positioning of diode open-circuit failure, reduces diagnosis cost, is conducive to repair in time, more effectively avoids the expansion of loss and the generation of accident.
Description
Technical field
The diagnostic method for the subway Rectification Power Factor diode open-circuit failure based on input current that the present invention relates to a kind of.
Background technique
Subway Rectification Power Factor is the core equipment of tractive power supply system, and working performance and operational reliability are directly concerning whole
The traffic-operating period of a system.In order to reduce influence of the side harmonics electric current at rectification transformer station to urban distribution network, China city
The traction rectifier substation of iron rail traffic mostly uses greatly equivalent 24 pulse wave rectifier mode, it may be assumed that two axial split formula tractions become
Depressor and four groups of all-wave uncontrollable rectifier bridge compositions.Every transformer primary side realizes ± 7.5 ° of shifting using extend-triangle connection
Phase, secondary side double winding be respectively adopted star connect with connection delta connection, make poor 30 ° of the phase of its line voltage phase vector.It is formed in this way
15 ° of phases of line voltage vector mutual deviation of four sleeving valve side windings of two transformers, respectively after full-wave rectification, in DC side parallel
Operation exports along the confession of 24 pulse wave DC voltages needed for train operation.Its advantage is that the side harmonics electric current at rectification transformer station is small,
The power supply quality for exporting direct current is high, but consequent is that diode required for equipment is at least 4 × 6=24, so
More diodes causes the accident rate height and more difficult diagnosis after the accident.The failure of diode has open-circuit fault and short circuit event
Hinder two kinds of situations.There is preferable protection scheme for the short trouble of diode: one fast fast thawing of each rectifier diode series connection
Disconnected device, works as shorted diode, when losing one-way conduction performance, short circuit current will be generated in circuit, is melted at this time by diode fuses
Break and carry out protection diode, and converts open-circuit fault for short trouble.And diode open-circuit failure is also required to can be timely
It was found that and taking measures.If the open-circuit fault of diode can not find and take measures in time, rectification circuit still works, this
Kind, which goes to work braving one's illness, will lead to rectified waveform generation Severe distortion, be not normally functioning load, while also increasing to power grid
Harmonic wave interference.So needing to fast implement fault diagnosis, positioning and exclusion, it is effectively prevented from the expansion of loss and the hair of accident
It is raw.
Summary of the invention
The diagnosis for the subway Rectification Power Factor diode open-circuit failure based on wave character that the purpose of the present invention is to propose to a kind of
Method, this method can judge whether the diode of subway Rectification Power Factor occurs open-circuit fault, and realize determining for failure diode
Position effectively avoids the expansion of loss and the generation of accident, improves the efficiency and effect of subway circulation in order to repair in time
Benefit.
The present invention realizes its goal of the invention, and used technical solution is: a kind of subway motor-generator set based on wave character
The diagnostic method of group diode open-circuit failure, its step are as follows:
A, electricity is inputted with four rectifier bridge net side A phases of subway Rectification Power Factor to the output voltage of subway Rectification Power Factor respectively
Stream is acquired in real time, and sample frequency 48kHz obtains output voltage signal u (t) and rectifier bridge the A phase of subway Rectification Power Factor
Input current signal in(t), wherein t indicates sampling instant, and subscript n is the serial number of rectifier bridge, value 1,2,3 or 4, difference
Indicate No. 1, No. 2, No. 3 or No. 4 rectifier bridge；
B, the value u (t) by output voltage signal u (t) at sampling instant t to the t-T+1 moment, u (t-1) ..., u (t-T+1)
The output voltage set U (t) of sampling instant t is constituted, U (t)=[u (t), u (t-1) ..., u (t-T+1)], wherein T represents one
Sampling number in AC power frequency period, that is, 0.02s, value 960；
The output voltage signal u (t) of sampling instant t is normalized, the normalized output of sampling instant t is obtained
Voltage u'(t):
Wherein, umaxFor the maximum value of the element in the output voltage set U (t) of sampling instant t, uminFor sampling instant t
Output voltage set U (t) in element minimum value；
C, by normalized output voltage u'(t) in the value u'(t at sampling instant t to t-T+1 moment), u'(t-1) ..., u'
(t-T+1) the normalized output voltage curve U'(t of sampling instant t is formed), the normalized output voltage for finding out sampling instant t is bent
Line U'(t) all minimums, obtain the normalized voltage signal u'(t of sampling instant t) minimum value set minV (t)；
D, the normalized voltage signal u'(t of sampling instant t) minimum value set minV (t) in, such as it is two neighboring minimum
The absolute value of the difference of value is less than or equal to 0.1, executes the operation of A step；Otherwise, sampling instant t=t at this time is enabled0, execute E step
Operation；
E, the operation for executing A step, carries out following operation immediately:
N=n' is enabled, such as n' rectifier bridge A phase input current signal, in moment t0To t0The value i at-T/3+1 momentn'(t0),
in'(t0+1)...,in'(t0+ T/3+1), it is all larger than the conducting negative threshold value of setting, is also respectively less than the positive threshold value of conducting of setting；Then sentence
It is scheduled on moment t0N-th ' number rectifier bridge has diode either open failure, executes the operation of F step；Otherwise, the operation of A step is executed；
If F, n'=1, by No. 3 rectifier bridge A phase input current signal i3(t) in moment t0+ T/24 arrives t0+ 9T/24+1's
Value i3(t0+T/24),i3(t0+T/24+1)...,i3(t0+ 9T/24+1) formed curve, judge waveform as diode location；
If n'=2, by No. 3 rectifier bridge A phase input current signal i3(t) in moment t0- T/24 arrives t0The value of+7T/24+1
i3(t0-T/24),i3(t0-T/24+1)...,i3(t0+ 7T/24+1) formed curve, judge waveform as diode location；
If n'=3, by No. 1 rectifier bridge A phase input current signal i1(t) in moment t0- T/24 arrives t0The value of+7T/24+1
i1(t0-T/24),i1(t0-T/24+1)...,i1(t0+ 7T/24+1) formed curve, judge waveform as diode location；
If n'=4, by No. 2 rectifier bridge A phase input current signal i2(t) in moment t0- T/24 arrives t0The value of+7T/24+1
i2(t0-T/24),i2(t0-T/24+1)...,i2(t0+ 7T/24+1) formed curve, judge waveform as diode location；
G, the diode location according to obtained in F-step judges the feature of waveform, the corresponding relationship of according to the form below:
Must be out of order specific location of the diode in n' rectifier bridge.
The principle of the present invention are as follows:
When normal operation, the current waveform of subway Rectification Power Factor output is pulsed 4 times within an industrial frequency AC period, is inputted
Monophase current it is positive within an industrial frequency AC period, reversed each conducting is twice.It can be made when diode open-circuit failure occurs
Decline at Rectification Power Factor output voltage amplitude in the failure diode operation period, place rectifier bridge input current wave head disappears
The phenomenon that, input current waveform distortion phenomenon occurs for remaining rectifier bridge.Time to be declined according to output voltage amplitude is come really
Determine time of failure, then finding out the rectifier bridge that input current wave head disappears in fault time section is two that open-circuit fault occurs
Rectifier bridge where pole pipe.
Meanwhile when operating normally, four rectifier bridge A phase input current waveforms are identical, only occur on a timeline
Translation；Furthermore, the A phase input current waveform in each rectifier bridge when different location diode current flow is different, and different
A phase input current waveform in rectifier bridge when same position diode current flow is identical, only translates on a timeline.Work as generation
When diode open-circuit failure, with failure rectifier bridge be not at the rectifier bridge wave distortion situation of same 12 pulse wave rectifier unit compared with
Gently, thereon the diode current flow of each position when wave character with normal operation when it is identical.By to lighter whole of distortion situation
The translation for flowing bridge A phase input current waveform, can obtain the expectation waveform in the failure diode operation period namely diode position
Judgement waveform is set, the feature of waveform and corresponding relationship you can get it the failure of failure diode location are judged by diode location
The position of diode.
Compared with prior art, the beneficial effects of the present invention are:
One, the present invention can have found in real time, determine that open-circuit fault has occurred in subway Rectification Power Factor diode, and can provide event
Hinder the accurate location of diode, convenient for the open-circuit fault of on-call maintenance, exclusion diode；After avoiding diode open-circuit failure
Rectification circuit still goes to work braving one's illness, and causes rectified waveform that Severe distortion occurs, big to the harmonic wave interference of power grid, makes load cannot be just
Often the problem of operation, the expansion of loss and the generation of accident are efficiently avoided.
Two, output voltage and a phase (A phase) input current sampled signal, which is used only, in the present invention realizes diode open-circuit
The identification and positioning of failure.The input of its signal and calculation amount are small, and diagnosis efficiency is high, diagnose at low cost.Diode open-circuit occurs
When failure, Diagnostic Time needed for the present invention is less than 0.01s.
Further, the present invention is to the output voltage of subway Rectification Power Factor and four rectifier bridge net side A of subway Rectification Power Factor
The sample frequency that phase input current is acquired in real time is 48kHz, the sampling number T in an AC power frequency period, that is, 0.02s
Value be 960；The positive threshold value of the conducting is 500A, conducting negative threshold value is -500A.
Sample frequency selects 48kHz to can guarantee that sampling is accurate, and the waveform and original waveform of record are close；An exchange simultaneously
The integral multiple that the sampling number 960 of input current signal is 24 in the power frequency period time, diode location judge 7.5 ° of waveform
The endpoint that phase angle corresponds to the period can be overlapped with sampling.The accurate of fault diagnosis of the present invention and can is thereby further ensured that
It leans on.
The conducting negative threshold value that positive threshold value, -500A is connected of 500A, the input current being slightly less than under rated load operation operating condition
Amplitude, erroneous detection caused by output voltage fluctuation interference, was also avoided that missing inspection improved inspection caused by both having can be reduced due to load variation
The efficiency of survey further ensures the reliable and effective of fault diagnosis of the present invention.
Present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.
Detailed description of the invention
Fig. 1 is the circuit diagram for the subway Rectification Power Factor that the method for the present invention is applicable in.
Fig. 2 is the corresponding relationship that diode location of the invention judges waveform Yu failure diode location.
Specific embodiment
Embodiment
Fig. 1 is shown, a kind of diagnostic method of the subway Rectification Power Factor diode open-circuit failure based on wave character, step
It is as follows:
A, electricity is inputted with four rectifier bridge net side A phases of subway Rectification Power Factor to the output voltage of subway Rectification Power Factor respectively
Stream is acquired in real time, obtains output voltage signal u (t) and rectifier bridge A phase the input current signal i of subway Rectification Power Factorn
(t), wherein t indicates sampling instant, and subscript n is the serial number of rectifier bridge, value 1,2,3 or 4, respectively indicates No. 1, No. 2, No. 3
Or No. 4 rectifier bridges；
B, the value u (t) by output voltage signal u (t) at sampling instant t to the t-T+1 moment, u (t-1) ..., u (t-T+1)
The output voltage set U (t) of sampling instant t is constituted, U (t)=[u (t), u (t-1) ..., u (t-T+1)], wherein T represents one
Sampling number in AC power frequency period, that is, 0.02s；
The output voltage signal u (t) of sampling instant t is normalized, the normalized output of sampling instant t is obtained
Voltage u'(t):
Wherein, umaxFor the maximum value of the element in the output voltage set U (t) of sampling instant t, uminFor sampling instant t
Output voltage set U (t) in element minimum value；
C, by normalized output voltage u'(t) in the value u'(t at sampling instant t to t-T+1 moment), u'(t-1) ..., u'
(t-T+1) the normalized output voltage curve U'(t of sampling instant t is formed), the normalized output voltage for finding out sampling instant t is bent
Line U'(t) all minimums, obtain the normalized voltage signal u'(t of sampling instant t) minimum value set minV (t)；
D, the normalized output voltage u'(t of sampling instant t) minimum value set minV (t) in, such as it is two neighboring minimum
The absolute value of the difference of value is less than or equal to 0.1, executes the operation of A step；Otherwise, sampling instant t=t at this time is enabled0, execute E step
Operation；
E, the operation for executing A step, carries out following operation immediately:
N=n' is enabled, such as n' rectifier bridge A phase input current signal in'(t) in moment t0To t0The value i at-T/3+1 momentn'
(t0),in'(t0+1)...,in'(t0+ T/3+1), it is all larger than the conducting negative threshold value of setting, is also respectively less than the positive threshold of conducting of setting
Value；Then determine in moment t0N-th ' number rectifier bridge has diode either open failure, executes the operation of F step；Otherwise, A step is executed
Operation；
If F, n'=1, by No. 3 rectifier bridge A phase input current signal i3(t) in moment t0+ T/24 arrives t0+ 9T/24+1's
Value i3(t0+T/24),i3(t0+T/24+1)...,i3(t0+ 9T/24+1) formed curve, judge waveform as diode location；
If n'=2, by No. 3 rectifier bridge A phase input current signal i3(t) in moment t0- T/24 arrives t0The value of+7T/24+1
i3(t0-T/24),i3(t0-T/24+1)...,i3(t0+ 7T/24+1) formed curve, judge waveform as diode location；
If n'=3, by No. 1 rectifier bridge A phase input current signal i1(t) in moment t0- T/24 arrives t0The value of+7T/24+1
i1(t0-T/24),i1(t0-T/24+1)...,i1(t0+ 7T/24+1) formed curve, judge waveform as diode location；
If n'=4, by No. 2 rectifier bridge A phase input current signal i2(t) in moment t0- T/24 arrives t0The value of+7T/24+1
i2(t0-T/24),i2(t0-T/24+1)...,i2(t0+ 7T/24+1) formed curve, judge waveform as diode location；
G, the diode location according to obtained in F-step judges the feature of waveform, the corresponding relationship of according to the form below:
Must be out of order specific location of the diode in n' rectifier bridge.
Diode location of the invention judges the corresponding relationship of waveform and failure diode location referring to fig. 2.
This example is to the output voltage of subway Rectification Power Factor and four rectifier bridge net side A phase input currents of subway Rectification Power Factor
The sample frequency acquired in real time is 48kHz, and the value of the sampling number T in an AC power frequency period, that is, 0.02s is
960；The positive threshold value of the conducting is 500A, conducting negative threshold value is -500A.
Emulation experiment
For the validity for verifying the method for the present invention, following emulation experiment is carried out.
Rectification Power Factor model is built using MATLAB/Simulink software, power supply 33kV is reduced to 1180V through transformer
Connect 4 three-phase rectification bridges, final output 1500V direct current.Transformer primary side, which connects, realizes ± 7.5 ° using delta connection
Phase shift, secondary side are respectively adopted star and connect the phase shift for connecting 30 ° of realization with triangle.The circuit diagram of Rectification Power Factor is shown in Fig. 1.
In nominal load 2200kW, No. 4 rectifier bridges are set using single-phase circuit breaker and are located at the diode in B phase at bridge arm
VD3Open-circuit fault occurs, Rectification Power Factor output voltage signal and A phase input current signal are acquired in real time, sample frequency
For 48kHz.
Normalized output voltage pattern obtained in emulation experiment, in sampling instant t0=3350 (the 3350th sampled points)
When, occur two neighboring minimum absolute value of the difference in set minV greater than 0.1.In moment t0To moment t0In+T/3+1, No. 4
Rectifier bridge A phase input current i4(t) always between positive negative threshold value, therefore determine that failure diode is located at No. 4 rectifier bridge.
No. 2 rectifier bridges of 15 ° of phases of advanced No. 4 rectifier bridges are obtained in moment t0- T/24 to moment t0The A phase of+7T/24+1
Input current signal i2(t) waveform, as the expectation waveform in the failure diode operation period, (diode location is sentenced
Disconnected waveform), control diode location judges the feature of waveform and the mapping table (diode of Fig. 2 of failure diode location
Position judges the corresponding relationship of waveform Yu failure diode location), it can determine that bridge arm diode VD in the B phase of No. 4 rectifier bridges3
Open-circuit fault occurs.The failure diode location VD being diagnosed to be3It is consistent with the failure diode location of setting.
Claims (2)
1. a kind of diagnostic method of the subway Rectification Power Factor diode open-circuit failure based on wave character, its step are as follows:
A, respectively the output voltage to subway Rectification Power Factor and four rectifier bridge net side A phase input currents of subway Rectification Power Factor into
Row acquisition in real time, obtains output voltage signal u (t) and rectifier bridge A phase the input current signal i of subway Rectification Power Factorn(t),
In, t indicates sampling instant, and subscript n is the serial number of rectifier bridge, value 1,2,3 or 4, respectively indicates No. 1, No. 2, No. 3 or No. 4
Rectifier bridge；
B, the value u (t) by output voltage signal u (t) at sampling instant t to the t-T+1 moment, u (t-1) ..., u (t-T+1) are constituted
The output voltage set U (t) of sampling instant t, U (t)=[u (t), u (t-1) ..., u (t-T+1)], wherein T represents an exchange
Sampling number in power frequency period, that is, 0.02s；
The output voltage signal u (t) of sampling instant t is normalized, the normalized output voltage of sampling instant t is obtained
U'(t):
Wherein, umaxFor the maximum value of the element in the output voltage set U (t) of sampling instant t, uminFor the defeated of sampling instant t
The minimum value of element in voltage set U (t) out；
C, by normalized output voltage u'(t) in the value u'(t at sampling instant t to t-T+1 moment), u'(t-1) ..., u'(t-T+
1) the normalized output voltage curve U'(t of sampling instant t is formed), find out the normalized output voltage curve U ' of sampling instant t
(t) all minimums obtain the normalized voltage signal u'(t of sampling instant t) minimum value set minV (t)；
D, the normalized voltage signal u'(t of sampling instant t) minimum value set minV (t) in, such as two neighboring minimum
Absolute value of the difference is less than or equal to 0.1, executes the operation of A step；Otherwise, sampling instant t=t at this time is enabled0, execute the operation of E step；
E, the operation for executing A step, carries out following operation immediately:
N=n' is enabled, such as n' rectifier bridge A phase input current signal in'(t) in moment t0To t0The value i at-T/3+1 momentn'(t0),
in'(t0+1)...,in'(t0+ T/3+1), it is all larger than the conducting negative threshold value of setting, is also respectively less than the positive threshold value of conducting of setting；Then sentence
It is scheduled on moment t0N-th ' number rectifier bridge has diode either open failure, executes the operation of F step；Otherwise, the operation of A step is executed；
If F, n'=1, by No. 3 rectifier bridge A phase input current signal i3(t) in moment t0+ T/24 arrives t0The value i of+9T/24+13
(t0+T/24),i3(t0+T/24+1)...,i3(t0+ 9T/24+1) formed curve, judge waveform as diode location；
If n'=2, by No. 3 rectifier bridge A phase input current signal i3(t) in moment t0- T/24 arrives t0The value i of+7T/24+13
(t0-T/24),i3(t0-T/24+1)...,i3(t0+ 7T/24+1) formed curve, judge waveform as diode location；
If n'=3, by No. 1 rectifier bridge A phase input current signal i1(t) in moment t0- T/24 arrives t0The value i of+7T/24+11
(t0-T/24),i1(t0-T/24+1)...,i1(t0+ 7T/24+1) formed curve, judge waveform as diode location；
If n'=4, by No. 2 rectifier bridge A phase input current signal i2(t) in moment t0- T/24 arrives t0The value i of+7T/24+12
(t0-T/24),i2(t0-T/24+1)...,i2(t0+ 7T/24+1) formed curve, judge waveform as diode location；
G, the diode location according to obtained in F-step judges the feature of waveform, the corresponding relationship of according to the form below,
Must be out of order specific location of the diode in n' rectifier bridge.
2. the diagnosis side of the subway Rectification Power Factor diode open-circuit failure according to claim 1 based on wave character
Method, it is characterised in that: described to the output voltage of subway Rectification Power Factor and four rectifier bridge net side A phases of subway Rectification Power Factor
The sample frequency that input current is acquired in real time is 48kHz, the sampling number T's in an AC power frequency period, that is, 0.02s
Value is 960；The positive threshold value of the conducting is 500A, conducting negative threshold value is -500A.
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| CN113376496A (en) * | 2021-05-21 | 2021-09-10 | 南京航空航天大学 | Self-coupling transformer rectifier diode fault diagnosis method based on Hausdorff distance |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016035355A1 (en) * | 2014-09-03 | 2016-03-10 | オムロン株式会社 | Inspection device for solar power system and solar power system inspection method |
| CN108196154A (en) * | 2017-12-04 | 2018-06-22 | 西北工业大学 | Aviation three-level formula synchronous motor rotating rectifier faults monitoring and Fault Locating Method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2016035355A1 (en) * | 2014-09-03 | 2016-03-10 | オムロン株式会社 | Inspection device for solar power system and solar power system inspection method |
| CN108196154A (en) * | 2017-12-04 | 2018-06-22 | 西北工业大学 | Aviation three-level formula synchronous motor rotating rectifier faults monitoring and Fault Locating Method |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113376496A (en) * | 2021-05-21 | 2021-09-10 | 南京航空航天大学 | Self-coupling transformer rectifier diode fault diagnosis method based on Hausdorff distance |
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