CN109581211A - A kind of load ratio bridging switch mechanical breakdown on-line monitoring method based on current of electric - Google Patents
A kind of load ratio bridging switch mechanical breakdown on-line monitoring method based on current of electric Download PDFInfo
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- CN109581211A CN109581211A CN201811345233.XA CN201811345233A CN109581211A CN 109581211 A CN109581211 A CN 109581211A CN 201811345233 A CN201811345233 A CN 201811345233A CN 109581211 A CN109581211 A CN 109581211A
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- 238000012544 monitoring process Methods 0.000 title claims abstract description 20
- 238000010338 mechanical breakdown Methods 0.000 title claims abstract description 19
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- 238000005314 correlation function Methods 0.000 claims description 10
- 230000007246 mechanism Effects 0.000 claims description 9
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/327—Testing of circuit interrupters, switches or circuit-breakers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0046—Arrangements for measuring currents or voltages or for indicating presence or sign thereof characterised by a specific application or detail not covered by any other subgroup of G01R19/00
- G01R19/0053—Noise discrimination; Analog sampling; Measuring transients
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/34—Testing dynamo-electric machines
- G01R31/343—Testing dynamo-electric machines in operation
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Abstract
The present invention relates to a kind of load ratio bridging switch mechanical breakdown on-line monitoring method based on current of electric.This method comprises: acquisition signal, denoising, determining characteristic coefficient, reconstruct and judgement.The present invention overcomes needing to be manually set the problem of parameter brush selects IMF component in EEMD decomposable process, have the shortcomings that huge contingency and limitation；In the principle very good solution EEMD decomposable process combined using cross-correlation analysis and EEMD algorithm the problems such as the interference of modal overlap phenomenon and effective inhibition power frequency and harmonic wave.
Description
Technical field
The present invention relates to a kind of load ratio bridging switch mechanical breakdown on-line monitoring method based on current of electric, belongs to electric power
Systems technology field.
Background technique
Load ratio bridging switch (OLTC) is an important component of power transformer, and operation conditions is directly related to
The stability and security of transformer and system.OLTC is one of transformer fault rate highest component, and failure not only directly affects change
Depressor operation, and influence power grid quality and operation of power networks.According to domestic statistics, the accident as caused by OLTC failure accounts for about
28% or so and fault type of the total accident of transformer are essentially mechanical breakdown, such as contact slap, contact fall off, mechanism card
Puckery, slide piece, tripping etc..Mechanical breakdown can directly damage OLTC and transformer itself, and then cause other more serious electrical events
Barrier, so that causing serious consequence.Therefore, the mechanical performance of running OLTC is monitored, finds that its failure is hidden early
Suffer from, has very great meaning to the safe operation of transformer and electric system.
Existing OLTC method for diagnosing faults mainly has two major classes: one kind is off-line maintenance, and off-line maintenance will generally have a power failure,
It dismantles transformer tank manually to be overhauled, and interruption maintenance influences transformer and operates normally, and needs to expend a large amount of human and material resources
And financial resources.Another kind is on-line monitoring, and on-line monitoring method mainly has the online prison based on thermal noise diagnosis and based on vibration
Survey etc..Based on thermal noise poor anti jamming capability, it is difficult have stronger practical engineering application.Existed based on vibratory drilling method on-line monitoring key
In the characteristic quantity of trouble-shooting, but signal after and monitoring method and monitoring bigger based on the contingency that vibratory drilling method is monitored on-line
Analysis method also influences the accuracy of fault diagnosis.
Summary of the invention
The invention solves technical problems to be: the shortcomings that overcoming above-mentioned technology, provides a kind of nothing based on current of electric method
The load ratio bridging switch mechanical breakdown on-line monitoring method of interference.
In order to solve the above-mentioned technical problem, technical solution proposed by the present invention is: a kind of to have load point based on current of electric
Connect the mechanical On-line Fault monitoring method of switch, which comprises the steps of:
(1) current signal of the motor of transmission mechanism in load ratio bridging switch action process is acquired；And by collected electricity
Stream signal carries out wavelet threshold denoising and is decomposed into several IMF using EEMDiComponent；
(2) signal after denoising in each IMF component and upper step mutually close and be analyzed, determine that characteristic coefficient is greater than
The number of plies of the 0.2 IMF component less than 0.5；
(3) IMF between the number of plies determined in step (2) is reconstructed, obtains reconstruction signal and use to seek reconstruction signal
The envelope of waveform；
(4) judge the comparison normal tooling state lower envelope line of load ratio bridging switch of envelope obtained by step (3) to have load
The mechanical breakdown of tap switch.
Above scheme is further improvement is that the step (1) acquires load ratio bridging switch action process with current clamp
The current signal of the motor of middle transmission mechanism.
Above scheme is further improvement is that use sym8 wavelet basis, by the collected electric current of institute in the step (1)
Signal carries out wavelet threshold denoising, and threshold value uses the unbiased evaluation of risk of adaptive Stein.
Above scheme is further improvement is that the signal in definition step (1) after denoising is w*(t), white Gaussian is added
Noise hi(t) it obtains: wI(t)=w*(t)+hi(t)；The signal w of white Gaussian noise will be addedⅠ(t) empirical mode decomposition is carried out to obtain
To several intrinsic intrinsic mode function IMFi。
Above scheme further improvement is that the step (2) in denoising after signal w*(t) and IMFiCross-correlation
Function R (τ) is defined as:U in formulaiIt (t) is IMFi；N is the sampling length of signal；J is
The time difference, j=0,1,2 ...；The characteristic coefficient of cross-correlation function is further obtained according to the cross-correlation function of the two:
Above scheme will be further improvement is that the step (3) will filter out 0.2 < ρ of characteristic coefficient in step (2)
The IMF of < 0.5iCarry out signal reconstruction:In formula: N is sampled point, and M is characterized 0.2 < ρ of coefficient
The IMF of < 0.5iTotal number of plies.
Load ratio bridging switch mechanical breakdown on-line monitoring method provided by the invention based on current of electric, use based on
The monitoring method of current of electric can generate distinctive vibration, and by system when some components of OLTC break down
Coupling generates corresponding influence to the current signal of motor.The shortcomings that the present invention overcomes existing methods, current signal is easy
Acquisition, signal-to-noise ratio is high, has very strong engineer application.Meanwhile it overcoming and needing that parameter brush is manually set in EEMD decomposable process
The problem of selecting IMF component has the shortcomings that huge contingency and limitation；It is combined using cross-correlation analysis and EEMD algorithm
Principle very good solution EEMD decomposable process in modal overlap phenomenon and effective power frequency and the interference of harmonic wave etc. is inhibited to ask
Topic.
Detailed description of the invention
Fig. 1 is flow diagram of the invention.
Fig. 2 is the motor current signal schematic diagram for collecting OLTC.
Fig. 3 is the schematic diagram of motor current signal after denoising.
Fig. 4 is each IMF schematic diagram that motor current signal passes through that EEMD is decomposed.
Fig. 5 is the envelope schematic diagram under OLTC nominal situation.
Fig. 6 is the corresponding envelope schematic diagram of different faults.
Specific embodiment
Embodiment
The load ratio bridging switch mechanical breakdown on-line monitoring method based on current of electric of the present embodiment, such as Fig. 1, including such as
Lower step:
(1) current signal of the motor of transmission mechanism in load ratio bridging switch action process is acquired；
(2) and by collected current signal it carries out wavelet threshold denoising and decomposes (i.e. set empirical modal using EEMD
Decompose) it is several IMFiComponent；
(3) signal after denoising in each IMF component and upper step mutually close and be analyzed, determine that characteristic coefficient is greater than
The number of plies of the 0.2 IMF component less than 0.5；
(4) IMF between the number of plies determined in step (3) is reconstructed, obtains reconstruction signal and use to seek reconstruction signal
The envelope of waveform；
(5) judge the comparison normal tooling state lower envelope line of load ratio bridging switch of envelope obtained by step (4) to have load
The mechanical breakdown of tap switch.
Wherein, the electric current that step (1) current clamp acquires the motor of transmission mechanism in load ratio bridging switch action process is believed
Number.
Wherein, sym8 wavelet basis is used in step (2), and the collected current signal of institute is subjected to wavelet threshold denoising, threshold
Value uses the unbiased evaluation of risk of adaptive Stein.
Wherein, the signal in definition step (2) after denoising is w*(t), white Gaussian noise h is addedi(t) it obtains: wI(t)=
w*(t)+hi(t)；The signal w of white Gaussian noise will be addedⅠ(t) it carries out empirical mode decomposition and obtains several intrinsic empirical modals
Function IMFi。
Wherein, the signal w in step (3) after denoising*(t) and IMFiCross-correlation function R (τ) is defined as:U in formulaiIt (t) is IMFi；N is the sampling length of signal；J is the time difference, j=0,1,
2,…；The characteristic coefficient of cross-correlation function is further obtained according to the cross-correlation function of the two:
Wherein, step (4) will filter out the IMF of 0.2 < ρ < 0.5 of characteristic coefficient in step (3)iCarry out signal reconstruction:In formula: N is sampled point, and M is characterized the IMF of 0.2 < ρ < 0.5 of coefficientiTotal number of plies.
The present embodiment selects the III -500-63B-10193W type of CM of Shanghai Huaming Utilities Electric Co., Ltd. production to have load to disassemble
It closes and is used as research object, the current signal of acquisition OLTC nominal situation lower transmission mechanism motor will be as shown in Fig. 2, will collect first
Motor current signal carry out select sym8 wavelet basis, threshold value use adaptive Stein unbiased evaluation of risk, carry out it is 4 layers small
Wave Decomposition, shown in the waveform diagram 3 after denoising.
EEMD decomposition is carried out to the waveform after denoising, that is to say and white Gaussian noise is added and then is obtained into empirical mode decomposition
The intrinsic mode function IMF of some column is as shown in Figure 4.
According to cross-correlation function formula and characteristic coefficient formula, corresponding characteristic coefficient is calculated.
Current signal characteristic coefficient after obtained some column IMF and denoising the result is as follows:
| IMF1 | IMF2 | IMF3 | IMF4 | |
| ρ | 0.652 | 0.432 | 0.361 | 0.225 |
| IMF5 | IMF6 | IMF7 | IMF8 | |
| ρ | 0.211 | 0.089 | 0.006 | 0.002 |
The characteristic coefficient of signal after illustrating each IMF in table and denoising.
If ρ > 0.5, illustrate too big by power frequency 50Hz frequency influence；ρ < 0.2 illustrates comprising being that characteristic information very little may be used
It ignores.Remaining IMF2~IMF5 is carried out signal reconstruction, believed after making reconstruct by the IMF for removing ρ < 0.2 and ρ > 0.5
Number envelope, as shown in Figure 5.
OLTC mechanical breakdown generally comprises, the slight bite of transmission mechanism, serious bite, spring failure etc..Different mechanical events
The envelope comparison of current of electric is as shown in Figure 6 when barrier acts.
The present invention is not limited to the above embodiment.All technical solutions formed using equivalent replacement, are all fallen within the present invention and wanted
The protection scope asked.
Claims (6)
1. a kind of load ratio bridging switch mechanical breakdown on-line monitoring method based on current of electric, which is characterized in that including as follows
Step:
(1) current signal of the motor of transmission mechanism in load ratio bridging switch action process is acquired；And collected electric current is believed
It number carries out wavelet threshold denoising and being decomposed into several IMF using EEMDiComponent；
(2) signal after denoising in each IMF component and upper step mutually close and be analyzed, it is small to determine that characteristic coefficient is greater than 0.2
In the number of plies of 0.5 IMF component；
(3) IMF between the number of plies determined in step (2) is reconstructed, obtains reconstruction signal and use to seek reconstruction signal waveform
Envelope；
(4) the comparison normal tooling state lower envelope line of load ratio bridging switch of envelope obtained by step (3) is judged into loaded tap-off
The mechanical breakdown of switch.
2. the load ratio bridging switch mechanical breakdown on-line monitoring method according to claim 1 based on current of electric, special
Sign is: the step (1) acquires the current signal of the motor of transmission mechanism in load ratio bridging switch action process with current clamp.
3. the load ratio bridging switch mechanical breakdown on-line monitoring method according to claim 1 based on current of electric, special
Sign is: using sym8 wavelet basis in the step (1), the collected current signal of institute is carried out wavelet threshold denoising, threshold value
Using the unbiased evaluation of risk of adaptive Stein.
4. the load ratio bridging switch mechanical breakdown on-line monitoring method according to claim 3 based on current of electric, special
Sign is: the signal in definition step (1) after denoising is w*(t), white Gaussian noise h is addedi(t) it obtains: wI(t)=w*(t)+hi
(t)；The signal w of white Gaussian noise will be addedⅠ(t) it carries out empirical mode decomposition and obtains several intrinsic intrinsic mode function IMFi。
5. the load ratio bridging switch mechanical breakdown on-line monitoring method according to claim 1 based on current of electric, special
Sign is: the signal w in the step (2) after denoising*(t) and IMFiCross-correlation function R (τ) is defined as:U in formulaiIt (t) is IMFi；N is the sampling length of signal；J is the time difference, j=0,1,
2,…；The characteristic coefficient of cross-correlation function is further obtained according to the cross-correlation function of the two:
6. the load ratio bridging switch mechanical breakdown on-line monitoring method according to claim 1 based on current of electric, special
Sign is: the step (3) will filter out the IMF of 0.2 < ρ < 0.5 of characteristic coefficient in step (2)iCarry out signal reconstruction:In formula: N is sampled point, and M is characterized the IMF of 0.2 < ρ < 0.5 of coefficientiTotal number of plies.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113553930A (en) * | 2021-07-14 | 2021-10-26 | 董跃周 | Method for diagnosing mechanical fault of on-load tap-changer of transformer |
| CN114382718A (en) * | 2022-01-05 | 2022-04-22 | 杭州老板电器股份有限公司 | Fan fault identification method and system of central range hood |
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| CN108761332A (en) * | 2018-05-08 | 2018-11-06 | 郑州轻工业学院 | A kind of set empirical mode decomposition current diagnostic method of motor broken bar fault |
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Patent Citations (5)
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| KR101539896B1 (en) * | 2014-10-14 | 2015-08-06 | 울산대학교 산학협력단 | Method for diagnosis of induction motor fault |
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| CN114382718A (en) * | 2022-01-05 | 2022-04-22 | 杭州老板电器股份有限公司 | Fan fault identification method and system of central range hood |
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Application publication date: 20190405 |