CN107422235A - A kind of cable local discharge Signal Pre-Processing Method - Google Patents
A kind of cable local discharge Signal Pre-Processing Method Download PDFInfo
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- CN107422235A CN107422235A CN201710764592.8A CN201710764592A CN107422235A CN 107422235 A CN107422235 A CN 107422235A CN 201710764592 A CN201710764592 A CN 201710764592A CN 107422235 A CN107422235 A CN 107422235A
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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
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
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Abstract
The present invention provides a kind of cable local discharge Signal Pre-Processing Method.A kind of cable local discharge Signal Pre-Processing Method, wherein, comprise the following steps：Step 1：Input pending cable local discharge signal；Step 2：Empirical mode decomposition is carried out to cable local discharge signal, obtains each intrinsic mode function component；Step 3：For each intrinsic mode function component, its energy is calculated respectively, and all intrinsic mode function components are divided into active constituent and the class of reactive component two according to energy size；Step 4：For reactive component, zero setting is directly carried out, for active constituent, denoising, the active constituent after being handled are carried out using wavelet thresholding method；Step 5：Reactive component after step processing and active constituent are reconstructed, obtain pretreated cable local discharge signal.Method provided by the invention is effectively combined wavelet analysis method and ensemble empirical mode decomposition method, combines both advantages, can obtain more preferable denoising effect.
Description
Technical field
The present invention relates to cable local discharge on-line monitoring technique field, more particularly, to a kind of cable local discharge
Signal Pre-Processing Method.
Background technology
In cable local discharge on-line monitoring, during cable local discharge on-line checking, because equipment is in operation
There is serious electromagnetic interference in state, scene, these interference can be overlapped with original local discharge signal, cause original part
The Severe distortion of discharge signal, the O＆M that defect type judges and defective locations position is carried out to by local discharge signal waveform
Personnel bring extreme difficulties.Therefore, it is significant to the local discharge signal progress noise suppression preprocessing detected.
In terms of local discharge signal denoising, wavelet analysis method due to good local time-frequency characteristic, extensively should
For the denoising of local discharge signal, but it easily receives the influence of noise, and mother wavelet is difficult to select.And empirical mode
Local feature time scale of (empirical mode decomposition, the EMD) method based on signal is decomposed, can be non-flat
Steady signal decomposition is limited basic friction angle component (intrinsic modefunction, IMF) sum, is a kind of adaptive
Signal processing method, it is adapted to non-linear and non-stationary process.
The content of the invention
It is an object of the invention to provide a kind of cable local discharge Signal Pre-Processing Method, this method is by wavelet analysis method
Effectively combined with EMD methods, combine both advantages, more preferable denoising effect can be obtained.
In order to solve the above technical problems, the technical solution adopted by the present invention is：A kind of cable local discharge Signal Pretreatment
Method, wherein, comprise the following steps：
Step 1：Input pending cable local discharge signal；
Step 2：Empirical mode decomposition is carried out to cable local discharge signal, obtains each intrinsic mode function component；
Step 3：The each intrinsic mode function component obtained for step 2, calculates its energy respectively, and big according to energy
It is small that all intrinsic mode function components are divided into active constituent and the class of reactive component two；
Step 4：The reactive component obtained for step 3, zero setting is directly carried out, the active constituent obtained for step 3, made
Denoising is carried out with wavelet thresholding method, the active constituent after being handled；
Step 5：Reactive component and active constituent after the processing obtained to step 4 are reconstructed, and obtain pretreated
Cable local discharge signal.
Further, in the step 2, empirical mode decomposition is carried out to cable local discharge signal, obtained each intrinsic
The step of mode function component is：
To cable local discharge signal x (t), after empirical mode decomposition, it is represented by：
In formula, IMFi(t) intrinsic mode function component, r are representedn(t) remainder is represented.
Further, in the step 3, each intrinsic mode function component for being obtained for step 2 calculates its energy respectively
Amount, and be the step of all intrinsic mode function components are divided into two class of active constituent and reactive component according to energy size：
(1) for each intrinsic mode function component, its energy is calculated according to the following formula：
In formula, EiFor i-th of intrinsic mode function component IMFi(t) energy, T are each intrinsic mode function component
Signal length；
(2) for each Ei, handled according to the following formula：
In formula, eiRepresent after treatment, EiCorresponding value；
(3) given threshold λ, above or equal to λ eiCorresponding intrinsic mode function component is designated as active constituent, is less than
λ eiCorresponding intrinsic mode function component is designated as reactive component.
Further, in the step 4, the reactive component that is obtained for step 3 directly carries out zero setting, for step 3
The active constituent arrived, denoising is carried out using wavelet thresholding method, be the step of active constituent after being handled：
(1) for reactive component, zero setting is directly carried out；
(2) for active constituent, denoising, the active constituent after being handled are carried out using wavelet thresholding method.
Further, in the step 5, reactive component and active constituent after the processing obtained to step 4 are reconstructed,
The step of obtaining pretreated cable local discharge signal be：
For the intrinsic mode function component IMF after processingi(t) ', it is reconstructed, obtains pretreated according to the following formula
Cable local discharge signal：
In formula, x ' (t) is pretreated cable local discharge signal.
Compared with prior art, its advantage is the present invention：
Method provided by the invention is effectively combined wavelet analysis method and ensemble empirical mode decomposition method, combines two
The advantage of person, more preferable denoising effect can be obtained.
Brief description of the drawings
Fig. 1 is the principle process schematic diagram of the present invention.
Embodiment
Accompanying drawing being given for example only property explanation, it is impossible to be interpreted as the limitation to this patent；It is attached in order to more preferably illustrate the present embodiment
Scheme some parts to have omission, zoom in or out, do not represent the size of actual product；To those skilled in the art,
Some known features and its explanation may be omitted and will be understood by accompanying drawing.Being given for example only property of position relationship described in accompanying drawing
Explanation, it is impossible to be interpreted as the limitation to this patent.
As shown in figure 1, a kind of cable local discharge Signal Pre-Processing Method, wherein, comprise the following steps：
Step 1：Input pending cable local discharge signal.
Step 2：Empirical mode decomposition is carried out to cable local discharge signal, obtains each intrinsic mode function component.Tool
Body, comprise the following steps：
To cable local discharge signal x (t), after empirical mode decomposition, it is represented by：
In formula, IMFi(t) intrinsic mode function component, r are representedn(t) remainder is represented.
Step 3：The each intrinsic mode function component obtained for step 2, calculates its energy respectively, and big according to energy
It is small that all intrinsic mode function components are divided into active constituent and the class of reactive component two.Specifically, comprise the following steps：
(1) for each intrinsic mode function component, its energy is calculated according to the following formula：
In formula, EiFor i-th of intrinsic mode function component IMFi(t) energy, T are each intrinsic mode function component
Signal length；
(2) for each Ei, handled according to the following formula：
In formula, eiRepresent after treatment, EiCorresponding value；
(3) given threshold λ, above or equal to λ eiCorresponding intrinsic mode function component is designated as active constituent, is less than
λ eiCorresponding intrinsic mode function component is designated as reactive component.
Step 4：The reactive component obtained for step 3, zero setting is directly carried out, the active constituent obtained for step 3, made
Denoising is carried out with wavelet thresholding method, the active constituent after being handled.Specifically, comprise the following steps：
(1) for reactive component, zero setting is directly carried out；
(2) for active constituent, denoising, the active constituent after being handled are carried out using wavelet thresholding method.
Step 5：Reactive component and active constituent after the processing obtained to step 4 are reconstructed, and obtain pretreated
Cable local discharge signal.Specifically, comprise the following steps：
For the intrinsic mode function component IMF after processingi(t) ', it is reconstructed, obtains pretreated according to the following formula
Cable local discharge signal：
In formula, x ' (t) is pretreated cable local discharge signal.
Obviously, the above embodiment of the present invention is just for the sake of clearly demonstrating example of the present invention, and is not
Restriction to embodiments of the present invention.For those of ordinary skill in the field, on the basis of the above description also
It can make other changes in different forms.There is no necessity and possibility to exhaust all the enbodiments.It is all
All any modification, equivalent and improvement made within the spirit and principles in the present invention etc., should be included in right of the present invention will
Within the protection domain asked.
Claims (5)
1. a kind of cable local discharge Signal Pre-Processing Method, it is characterised in that comprise the following steps：
Step 1：Input pending cable local discharge signal；
Step 2：Empirical mode decomposition is carried out to cable local discharge signal, obtains each intrinsic mode function component；
Step 3：The each intrinsic mode function component obtained for step 2, its energy is calculated respectively, and will according to energy size
All intrinsic mode function components are divided into active constituent and the class of reactive component two；
Step 4：The reactive component obtained for step 3, zero setting is directly carried out, the active constituent obtained for step 3, use is small
Ripple threshold method carries out denoising, the active constituent after being handled；
Step 5：Reactive component and active constituent after the processing obtained to step 4 are reconstructed, and obtain pretreated cable
Local discharge signal.
A kind of 2. cable local discharge Signal Pre-Processing Method according to claim 1, it is characterised in that the step 2
In, empirical mode decomposition is carried out to cable local discharge signal, the step of obtaining each intrinsic mode function component is：
To cable local discharge signal x (t), after empirical mode decomposition, it is represented by：
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<mo>(</mo>
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</mrow>
</mrow>
In formula, IMFi(t) intrinsic mode function component, r are representedn(t) remainder is represented.
A kind of 3. cable local discharge Signal Pre-Processing Method according to claim 1, it is characterised in that the step 3
In, each intrinsic mode function component for being obtained for step 2 calculates its energy respectively, and will be all solid according to energy size
There is the step of mode function component is divided into two class of active constituent and reactive component to be：
(1) for each intrinsic mode function component, its energy is calculated according to the following formula：
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In formula, EiFor i-th of intrinsic mode function component IMFi(t) energy, T are the signal of each intrinsic mode function component
Length；
(2) for each Ei, handled according to the following formula：
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<mi>e</mi>
<mi>i</mi>
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<mo>...</mo>
<mo>,</mo>
<mi>n</mi>
</mrow>
In formula, eiRepresent after treatment, EiCorresponding value；
(3) given threshold λ, above or equal to λ eiCorresponding intrinsic mode function component is designated as active constituent, the e less than λi
Corresponding intrinsic mode function component is designated as reactive component.
A kind of 4. cable local discharge Signal Pre-Processing Method according to claim 1, it is characterised in that the step 4
In, the reactive component that is obtained for step 3 directly carries out zero setting, the active constituent obtained for step 3, uses wavelet threshold
Method carries out denoising, is the step of active constituent after being handled：
(1) for reactive component, zero setting is directly carried out；
(2) for active constituent, denoising, the active constituent after being handled are carried out using wavelet thresholding method.
A kind of 5. cable local discharge Signal Pre-Processing Method according to claim 1, it is characterised in that the step 5
In, reactive component and active constituent after the processing obtained to step 4 are reconstructed, and obtain pretreated cable local discharge
The step of signal is：
For the intrinsic mode function component IMF after processingi(t) ', it is reconstructed according to the following formula, obtains pretreated cable office
Portion's discharge signal：
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<mi>IMF</mi>
<mi>i</mi>
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</mrow>
<mo>&prime;</mo>
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<mo>,</mo>
<mn>2</mn>
<mo>...</mo>
<mi>n</mi>
</mrow>
In formula, x ' (t) is pretreated cable local discharge signal.
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| CN201710764592.8A CN107422235A (en) | 2017-08-30 | 2017-08-30 | A kind of cable local discharge Signal Pre-Processing Method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112213561A (en) * | 2020-09-25 | 2021-01-12 | 清华大学 | Measurement data preprocessing method and device for leading load parameter noise identification |
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|---|---|---|---|---|
| CN104777410A (en) * | 2015-04-22 | 2015-07-15 | 东北电力大学 | Partial discharge pattern identification method for crosslinked polyethylene cable |
| CN105973618A (en) * | 2016-08-03 | 2016-09-28 | 南京理工大学 | Preliminary assessment method for security domain of wheel service state |
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2017
- 2017-08-30 CN CN201710764592.8A patent/CN107422235A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104777410A (en) * | 2015-04-22 | 2015-07-15 | 东北电力大学 | Partial discharge pattern identification method for crosslinked polyethylene cable |
| CN105973618A (en) * | 2016-08-03 | 2016-09-28 | 南京理工大学 | Preliminary assessment method for security domain of wheel service state |
Non-Patent Citations (1)
| Title |
|---|
| 徐艳春等: ""EMD自相关阈值去噪法在水电机组振动信号中的研究"", 《中国农村水利水电》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112213561A (en) * | 2020-09-25 | 2021-01-12 | 清华大学 | Measurement data preprocessing method and device for leading load parameter noise identification |
| CN112213561B (en) * | 2020-09-25 | 2022-01-18 | 清华大学 | Measurement data preprocessing method and device for leading load parameter noise identification |
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