CN109814005A - A kind of cable insulation defect recognition and localization method and system - Google Patents
A kind of cable insulation defect recognition and localization method and system Download PDFInfo
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- CN109814005A CN109814005A CN201711160682.2A CN201711160682A CN109814005A CN 109814005 A CN109814005 A CN 109814005A CN 201711160682 A CN201711160682 A CN 201711160682A CN 109814005 A CN109814005 A CN 109814005A
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Abstract
The invention discloses a kind of cable insulation defect recognition and localization method and system, method includes: to inject the increased frequency signal of ladder to cable under test；From the voltage signal and current signal of the corresponding each frequency signal of injection phase acquisition；According to the increased frequency signal of the ladder and the corresponding voltage signal of each frequency signal and current signal, the impedance spectrum of cable under test is obtained；According to the impedance spectrum discrimination cable under test got with the presence or absence of insulation defect and positioning defective locations.The present invention can be tested without destroying cable, not cause secondary damage to cable；It is not necessarily limited by the constraint of cable length, breaks through the fault location of long-distance cable and the technical bottleneck of Aging Assessment, realizes the integrated testing and evaluation of the cable of multistage connection；It can be used for accurate fault location, it can be achieved that multiple spot accurate positioning, convenient for searching multiple defect points, and assesses the severity of different defect points.
Description
Technical field
The present invention relates to electrical network field more particularly to a kind of cable insulation defect recognition and localization method and systems.
Background technique
Cable capacitive reactance frequency domain derivative analysis routine more early originates from Northern Europe, and at present in North America, there is an application in Australia, but due to
The hardware cost of capacitive reactance frequency domain differential is higher, commonly used in accurate fault identification and accurate positioning, the appearance of degree of precision at present
Anti- frequency domain differential technology can be used for the positioning of 1cm failure length, be the rebasing basis of insulation defect identification of cable.Hold
Anti- frequency domain differential is usually required installation reflection bridge or is carried out using two-port, for the power failure of cable test, reflection
The frequency band of electric bridge is restricted, and is typically only used for the reflection of 1MHz or more, and long-distance cable may need kilohertz
Output frequency, therefore the use of reflection bridge is simply possible to use in the detection of 100 meters or less cables.And two-port can obtain preferably
Transmission characteristic, transfer impedance catastrophe point can analyze according to the frequency spectrum of transmission characteristic, and frequency conversion to time domain realized it is fixed
Position, but for field erected cable, double-end measurement is unrealistic, though using wireless network, for wideband frequency clock synchronization not
Height is required nothing more than, is also difficult to obtain satisfied required precision.
Summary of the invention
The technical problem to be solved in the present invention is that in view of the above drawbacks of the prior art, it is scarce to provide a kind of cable insulation
Fall into identification and localization method and system.
The technical solution adopted by the present invention to solve the technical problems is: constructing a kind of cable insulation defect recognition and positioning
Method, method include:
The increased frequency signal of ladder is injected to cable under test；
From the voltage signal and current signal of the corresponding each frequency signal of injection phase acquisition；
Believed according to the increased frequency signal of the ladder and the corresponding voltage signal of each frequency signal and electric current
Number, obtain the impedance spectrum of cable under test；
According to the impedance spectrum discrimination cable under test got with the presence or absence of insulation defect and positioning defective locations.
In cable insulation defect recognition of the present invention and localization method, the impedance spectrum of the acquisition cable under test
Include:
According to the corresponding voltage signal of each frequency signal and current signal, the corresponding impedance letter of each frequency signal is determined
Number；
According to all impedance signals corresponding to the increased frequency signal of ladder, obtain between reaction impedance signal and frequency
Relationship impedance spectrum.
In cable insulation defect recognition of the present invention and localization method, the impedance spectrum that the basis is got is known
Other cable under test whether there is insulation defect and positioning defective locations include:
The impedance spectrum of cable under test is subjected to integral transformation, obtain characterization cable distribution coefficient with cable position change to
Survey the distance state function of cable；
The distance state function of cable under test is compared to obtain diagnosis function with the distance state function of reference cable,
If variation of the diagnosis function at some position is more than threshold value, it is determined that there are local damages for the position.
In cable insulation defect recognition of the present invention and localization method, method further includes carrying out again to cable under test
Before detection, the distance state function of reference cable is obtained；
Wherein, the distance state function of the acquisition reference cable specifically includes:
The increased frequency signal of ladder is injected to reference cable；
From the voltage signal and current signal of the corresponding each frequency signal of injection phase acquisition；
Believed according to the increased frequency signal of the ladder and the corresponding voltage signal of each frequency signal and electric current
Number, obtain the impedance spectrum of reference cable；
The impedance spectrum of reference cable is subjected to integral transformation, obtains the ginseng that characterization cable distribution coefficient changes with cable position
Examine the distance state function of cable.
In cable insulation defect recognition of the present invention and localization method, method further includes carrying out again to cable under test
Before detection, the distance state function of reference cable is obtained；
The distance state function of the acquisition reference cable specifically includes: being obtained based on what following formula calculated with reference to electricity
The impedance spectrum of cable:The impedance spectrum of reference cable is subjected to integral transformation, is obtained
The distance state function for the reference cable that cable distribution coefficient changes with cable position must be characterized；
In formula, ZhIt (w) is the impedance spectrum of reference cable, ZLFor load impedance, Z0In normal state for reference cable
Characteristic impedance, ΓLFor the reflection coefficient of load end, γ is the propagation coefficient of reference cable, and l is total cable length；Wherein, Z0With
γ can be calculated according to the resistance R (ω) of reference cable, inductance L (ω), conductance G (ω), capacitor C (ω):
Wherein, rcAnd rsThe respectively conductor radius of cable core and metal screen layer inside radius, δcAnd δsRespectively core wire and metal
The skin depth of shielded layer, γcAnd γsRespectively corresponding conductivity, μ0For space permeability, εeFor electric cable compound insulation etc.
Imitate complex dielectric permittivity.
In cable insulation defect recognition of the present invention and localization method, the frequency signal injected to cable is to apply
To between cable insulation conductor and shielded layer or being applied between multiple-core cable conductor, cable is light condition, output short-circuit shape
State or bringing onto load state；The frequency range of the frequency signal of injection is 0.1Hz-10GHz, the increased step-length model of frequency signal ladder
It encloses for 1Hz-10MHz.
The invention also discloses a kind of cable insulation defect recognition and positioning systems, comprising:
Signal injection module, for injecting the increased frequency signal of ladder to cable；
Signal acquisition module, for the voltage signal and current signal from the corresponding each frequency signal of injection phase acquisition；
Impedance spectrum obtains module, for according to the increased frequency signal of the ladder and the corresponding institute of each frequency signal
Voltage signal and current signal are stated, the impedance spectrum of cable is obtained；
Defect recognition locating module, for the presence or absence of insulation defect and being determined according to the impedance spectrum discrimination cable got
Position defective locations.
In cable insulation defect recognition of the present invention and positioning system, the impedance spectrum obtains module and includes:
Impedance signal acquiring unit, for determining every according to the corresponding voltage signal of each frequency signal and current signal
The corresponding impedance signal of a frequency signal；
Impedance spectrum acquiring unit obtains anti-for all impedance signals according to corresponding to the increased frequency signal of ladder
Answer the impedance spectrum of the relationship between impedance signal and frequency.
In cable insulation defect recognition of the present invention and positioning system, the defect recognition locating module includes:
Integral transformation unit obtains characterization cable distribution coefficient with electricity for the impedance spectrum of cable to be carried out integral transformation
The distance state function of the cable of cable change in location；
Defect recognition positioning unit, for by the distance state function of the distance state function of cable under test and reference cable
It is compared to obtain diagnosis function, if variation of the diagnosis function at some position is more than threshold value, it is determined that there are offices for the position
Portion's damage.
Preferably, system further includes reference cable impedance spectrum computing unit, is joined for what is calculated based on following formula
Examine the impedance spectrum of cable:
In formula, ZhIt (w) is the impedance spectrum of reference cable, ZLFor load impedance, Z0In normal state for reference cable
Characteristic impedance, ΓLFor the reflection coefficient of load end, γ is the propagation coefficient of reference cable, and l is total cable length；Wherein, Z0With
γ can be calculated according to the resistance R (ω) of reference cable, inductance L (ω), conductance G (ω), capacitor C (ω):
Wherein, rcAnd rsThe respectively conductor radius of cable core and metal screen layer inside radius, δcAnd δsRespectively core wire and metal
The skin depth of shielded layer, γcAnd γsRespectively corresponding conductivity, μ0For space permeability, εeFor electric cable compound insulation etc.
Imitate complex dielectric permittivity.
Implement cable insulation defect recognition and localization method and system of the invention, has the advantages that this hair
It is bright to be tested without destroying cable, secondary damage is not caused to cable；It need to only be adopted at the position of injected frequency signal
Collect signal, it is not necessary to it is limited to the constraint of cable length, breaks through the fault location of long-distance cable and the technical bottleneck of Aging Assessment,
Realize the integrated testing and evaluation of the cable of multistage connection；It is lacked according to the impedance spectrum discrimination cable got with the presence or absence of insulation
It falls into and positioning defective locations, can be used for accurate fault location, it can be achieved that multiple spot is accurately positioned, convenient for searching multiple defect points,
And assess the severity of different defect points.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
The embodiment of invention for those of ordinary skill in the art without creative efforts, can also basis
The attached drawing of offer obtains other attached drawings:
Fig. 1 is the flow chart of cable insulation defect recognition of the present invention and localization method；
Impedance magnitude spectrogram when Fig. 2 is cable normal condition；
Impedance phase spectrogram when Fig. 3 is cable normal condition；
Impedance magnitude spectrogram when Fig. 4 is cable fault state；
Impedance phase spectrogram when Fig. 5 is cable fault state.
Specific embodiment
To facilitate the understanding of the present invention, a more comprehensive description of the invention is given in the following sections with reference to the relevant attached drawings.In attached drawing
Give exemplary embodiments of the invention.But the invention can be realized in many different forms, however it is not limited to this paper institute
The embodiment of description.On the contrary, purpose of providing these embodiments is make it is more thorough and comprehensive to the disclosure.
Unless otherwise defined, all technical and scientific terms used herein and belong to technical field of the invention
The normally understood meaning of technical staff is identical.Term as used herein in the specification of the present invention is intended merely to description tool
The purpose of the embodiment of body, it is not intended that in the limitation present invention.
With reference to Fig. 1, the total thinking of the present invention is:
S100, the increased frequency signal of ladder is injected to cable；
S200, the voltage signal and current signal that each frequency signal is corresponded to from injection phase acquisition；
S300, according to the increased frequency signal of the ladder and the corresponding voltage signal of each frequency signal and electricity
Signal is flowed, the impedance spectrum of cable is obtained；
S400, defective locations with the presence or absence of insulation defect and are positioned according to the impedance spectrum discrimination cable got.
In order to better understand the above technical scheme, in conjunction with appended figures and specific embodiments to upper
It states technical solution to be described in detail, it should be understood that the specific features in the embodiment of the present invention and embodiment are to the application
The detailed description of technical solution, rather than the restriction to technical scheme, in the absence of conflict, the present invention are implemented
Technical characteristic in example and embodiment can be combined with each other.
The cable insulation defect recognition and localization method that preferred embodiment provides, specifically include；
S100, the increased frequency signal of ladder is injected to cable；
The frequency signal injected to cable is applied between cable insulation conductor and shielded layer or is applied to multicore cable
Between conductor；
Cable is light condition, output short-circuit state or bringing onto load state；
The frequency range of the frequency signal of injection is 0.1Hz-10GHz, and the increased step-length range of frequency signal ladder is
1Hz-10MHz。
S200, the voltage signal and current signal that each frequency signal is corresponded to from injection phase acquisition；
The voltage signal of acquisition is time-domain digital signal, amplitude and phase including voltage, when the current signal of acquisition is
Domain digital signal, amplitude and phase including electric current.
S300, according to the increased frequency signal of the ladder and the corresponding voltage signal of each frequency signal and electricity
Signal is flowed, the impedance spectrum of cable is obtained.Specifically: according to the corresponding voltage signal of each frequency signal and current signal, determine
The corresponding impedance signal of each frequency signal；According to all impedance signals corresponding to the increased frequency signal of ladder, obtain anti-
Answer the impedance spectrum of the relationship between impedance signal and frequency.
It should be noted that impedance spectrum includes impedance magnitude spectrum and impedance phase spectrogram.Believed by voltage signal and electric current
Number impedance signal is calculated, impedance signal is carried out to handle available impedance magnitude signal and impedance phase signal, in turn
It can be obtained by impedance magnitude signal relationship varying with frequency and impedance phase signal relationship varying with frequency, obtain cable
Wideband impedance modal data.Impedance magnitude spectrogram when such as Fig. 2 being cable normal condition, resistance when Fig. 3 is cable normal condition
Anti- phase spectrogram, impedance magnitude spectrogram when Fig. 4 is cable fault state, impedance phase spectrum when Fig. 5 is cable fault state
Figure.
S400, defective locations with the presence or absence of insulation defect and are positioned according to the impedance spectrum discrimination cable got.
There is cyclically-varying in the impedance spectrum of input impedance, mainly reflects the characteristic of cable itself, the period of impedance spectrum
Property is by operatorIt is determined.Portion's defective section point of setting a trap is set to ld, propagation coefficient γd, its resistance of the cable of local defect section
The periodical operator by defective section of anti-spectrumIt is influenced, the main character of the cable resistance spectrum of the section containing local defect is available
Orthogonal functionIt expresses, wherein γhAnd γdRespectively the intact part of cable and lack
Fall into the propagation coefficient of section.γdWith ldIt is unknown number, but γhIt can be obtained ahead of time by measuring or calculating, and γhFor the letter of frequency
Number, therefore the impedance spectrum basic function of characterization local defect feature can be constructed:
The integral function of local defect positioning is realized according to function g (x) are as follows:
Work as x=ldWhen, due to the propagation coefficient γ of cable local defect sectionh≠γd, lead to above-mentioned integrated value a and b difference
It is very big, therefore, the changed point of cable distribution coefficient can be found out by Integral Transformation Method, to realize local defect
The positioning of point.Cable serviceable condition can be used as a reference state, and impedance spectrum can be before cable puts into operation or to same model electricity
Cable measures acquisition.
Therefore, step S400 of the invention specifically:
S410, the impedance spectrum of cable under test is subjected to integral transformation, obtains characterization cable distribution coefficient and becomes with cable position
The distance state function Z of the cable under test of changed(x)；
For example, if the impedance spectrum of cable under test is Zd(ω) then carries out following integral transformation to it:The signal of frequency domain can be transformed in spatial domain.γ in integration type is that cable is intact
Propagation coefficient, calculation method will be discussed in detail subsequent.
S420, the distance state function Z by cable under testd(x) with the distance state function Z of reference cableh(x) compared
Relatively obtain diagnosis function VA (x)=| Zh(x)|/|Zd(x) |, under normal circumstances cable everywhere propagation coefficient be it is equal, not with position
It sets and changes, therefore, if VA (x) shows at cable different location when being constantly equal to (error range in scientific meaning) 1.0
Propagation coefficient is identical, i.e., cable is in serviceable condition, does not occur local defect in cable.If diagnosis function VA (x) is in some position
Set xdApparent mutation occurs, such as the variation (such as variation of VA (x) fluctuating range) of diagnosis function VA (x) is more than threshold value,
Show cable in this position xdPlace's propagation coefficient is substantially change, it is determined that the position is there are local damage, according further to examining
The degree that disconnected function VA (x) changes, it can be determined that the severity of insulation defect, the severity and diagnosis function of insulation defect
The degree that VA (x) changes is directly proportional.
Herein it should be noted that diagnosis function VA (x) is not limited to form as described above, it can also be that other compare
The function of form.Reference cable refers to intact cable identical with the specifications parameter of cable under test.
Wherein, the distance state function Z of reference cableh(x) it needs to obtain before again detecting cable under test, obtain
It takes there are two types of methods.
First method, the distance state function Z with cable under testd(x) acquisition methods are just the same, i.e., for reference
Cable executes the impedance spectrum Z that step S100-S300 obtains reference cableh(ω), then integrate to obtain apart from shape by step S410
State function Zh(x), specifically: the increased frequency signal of ladder is injected to reference cable, from the corresponding each frequency of injection phase acquisition
The voltage signal and current signal of rate signal, according to the increased frequency signal of the ladder and the corresponding institute of each frequency signal
Voltage signal and current signal are stated, the impedance spectrum Z of reference cable is obtainedh(ω), by the impedance spectrum Z of reference cableh(ω) is carried out such as
Lower integral transformationObtain the reference electricity that characterization cable distribution coefficient changes with cable position
The distance state function Z of cableh(x)。
Second method the difference is that, the impedance spectrum Z of reference cable is obtained by calculating with first methodh
(ω), then again by impedance spectrum Zh(ω) carries out following integral transformationObtain characterization cable
The distance state function Z for the reference cable that propagation coefficient changes with cable positionh(x).Wherein, ZhThe calculation method of (ω) is as follows:
Wherein, ZhIt (w) is the impedance spectrum of reference cable, ZLFor load impedance, Z0For the spy of reference cable in normal state
Levy impedance, ΓLFor the reflection coefficient of load end, γ is the propagation coefficient of reference cable, and l is total cable length；
In formula, Z0It can be according to the resistance R (ω) of reference cable, inductance L (ω), conductance G (ω), capacitor C (ω) with γ
It is calculated:
Wherein, rcAnd rsThe respectively conductor radius of cable core and metal screen layer inside radius, δcAnd δsRespectively core
The skin depth of line and metal screen layer, γcAnd γsRespectively corresponding conductivity, μ0For space permeability, εeIt is multiple for cable
Close the equivalent complex dielectric permittivity that insulate.Above-mentioned parameter can be obtained by the technical parameter that cable producer provides.
Due to needing to draw impedance frequency curve and phase frequency curve in the present invention, the experiment power supply of frequency signal is generated
Output has a certain frequency bandwidth, and cable insulation is in capacitive state, and in low frequency in resistive, capacitive or sense is presented in when high frequency
Property, therefore it is directed to different test voltage frequencies, the electric current for flowing through insulating layer is also different, when insulation fault occurs for cable, no
Occur inside shielded layer or sheath or cable center conductor or between cable conductor and shielded layer by failure or cable is more
Between core conductor, no matter also whether cable distal end is short-circuit, opens a way or is connected with load, the resistance that can be tested, and drawn
Anti- frequency curve and phase frequency curve had both included the frequency characteristic of cable inherent characteristic impedance, also included insulating layer failure
Or the impedance frequency characteristic of defect, further comprise load characteristic (load of open circuit, short circuit or output connection).
In addition, it is necessary to explanation, the present invention is not limited the terminal connection method of subject cable, does not also limit list
Core cable or multicore cable, do not limit yet injecting voltage frequency response test output voltage (different rated operational voltages are different,
Dielectric strength is different), but since the insulating layer of cable is in generally capacitive, and with the increase of cable length, capacitance
Increase, i.e., the electric current that output is tested under same frequency increases also with cable length and increased, therefore detects the electricity of test output
Stream may cover several mA (such as several meters) to several amperes (A) (number kilometers length), it is only necessary to Injection Current frequency response test
Output provides the impedance frequency curve and phase frequency curve that lower voltage (several volts arrive tens of volts) can measure cable.
Based on the same inventive concept, the invention also discloses a kind of cable insulation defect recognition and positioning system, system packets
It includes:
Signal injection module, for injecting the increased frequency signal of ladder to cable；
Signal acquisition module, for the voltage signal and current signal from the corresponding each frequency signal of injection phase acquisition；
Impedance spectrum obtains module, for according to the increased frequency signal of the ladder and the corresponding institute of each frequency signal
Voltage signal and current signal are stated, the impedance spectrum of cable is obtained；
Defect recognition locating module, for the presence or absence of insulation defect and being determined according to the impedance spectrum discrimination cable got
Position defective locations.
Specifically, the impedance spectrum acquisition module includes:
Impedance signal acquiring unit, for determining every according to the corresponding voltage signal of each frequency signal and current signal
The corresponding impedance signal of a frequency signal；
Impedance spectrum acquiring unit obtains anti-for all impedance signals according to corresponding to the increased frequency signal of ladder
Answer the impedance spectrum of the relationship between impedance signal and frequency.
Specifically, the defect recognition locating module includes:
Integral transformation unit obtains characterization cable distribution coefficient with electricity for the impedance spectrum of cable to be carried out integral transformation
The distance state function of the cable of cable change in location；
Defect recognition positioning unit, for by the distance state function of the distance state function of cable under test and reference cable
It is compared to obtain diagnosis function, if variation of the diagnosis function at some position is more than threshold value, it is determined that there are offices for the position
Portion's damage.
Other specific implementations of system refer to the above-mentioned elaboration about method, and details are not described herein again.Correspondingly, reference cable
Impedance spectrum Zh(ω) if using calculate obtain, system further includes reference cable impedance spectrum computing unit, for based on
What lower formula calculated obtains the impedance spectrum of reference cable:
In formula, ZhIt (w) is the impedance spectrum of reference cable, ZLFor load impedance, Z0In normal state for reference cable
Characteristic impedance, ΓLFor the reflection coefficient of load end, γ is the propagation coefficient of reference cable, and l is total cable length；Wherein, Z0With
γ can be calculated according to the resistance R (ω) of reference cable, inductance L (ω), conductance G (ω), capacitor C (ω):
Wherein, rcAnd rsThe respectively conductor radius of cable core and metal screen layer inside radius, δcAnd δsRespectively core wire and metal
The skin depth of shielded layer, γcAnd γsRespectively corresponding conductivity, μ0For space permeability, εeFor electric cable compound insulation etc.
Imitate complex dielectric permittivity.
In conclusion implementing cable insulation defect recognition and localization method and system of the invention, have beneficial below
Effect: the present invention can be tested without destroying cable, not cause secondary damage to cable；It only need to be in injected frequency signal
Signal is acquired at position, it is not necessary to be limited to the constraint of cable length, break through the fault location and Aging Assessment of long-distance cable
Technical bottleneck realizes the integrated testing and evaluation of the cable of multistage connection；According to the impedance spectrum discrimination cable got whether
There are insulation defect and positioning defective locations, it can be used for accurate fault location, it can be achieved that multiple spot accurate positioning, more convenient for searching
A defect point, and assess the severity of different defect points.
The embodiment of the present invention is described with above attached drawing, but the invention is not limited to above-mentioned specific
Embodiment, the above mentioned embodiment is only schematical, rather than restrictive, those skilled in the art
Under the inspiration of the present invention, without breaking away from the scope protected by the purposes and claims of the present invention, it can also make very much
Form, all of these belong to the protection of the present invention.
Claims (10)
1. a kind of cable insulation defect recognition and localization method, which is characterized in that method includes:
The increased frequency signal of ladder is injected to cable under test；
From the voltage signal and current signal of the corresponding each frequency signal of injection phase acquisition；
According to the increased frequency signal of the ladder and the corresponding voltage signal of each frequency signal and current signal, obtain
Take the impedance spectrum of cable under test；
According to the impedance spectrum discrimination cable under test got with the presence or absence of insulation defect and positioning defective locations.
2. cable insulation defect recognition according to claim 1 and localization method, which is characterized in that the acquisition is to be measured
The impedance spectrum of cable includes:
According to the corresponding voltage signal of each frequency signal and current signal, the corresponding impedance signal of each frequency signal is determined；
According to all impedance signals corresponding to the increased frequency signal of ladder, the pass between reaction impedance signal and frequency is obtained
The impedance spectrum of system.
3. cable insulation defect recognition according to claim 1 and localization method, which is characterized in that described according to acquisition
To impedance spectrum discrimination cable under test with the presence or absence of insulation defect and positioning defective locations include:
The impedance spectrum of cable under test is subjected to integral transformation, obtains the electricity to be measured that characterization cable distribution coefficient changes with cable position
The distance state function of cable；
The distance state function of cable under test is compared to obtain diagnosis function with the distance state function of reference cable, if examining
Disconnected variation of the function at some position is more than threshold value, it is determined that there are local damages for the position.
4. cable insulation defect recognition according to claim 3 and localization method, which is characterized in that method further includes right again
Before cable under test is detected, the distance state function of reference cable is obtained；
Wherein, the distance state function of the acquisition reference cable specifically includes:
The increased frequency signal of ladder is injected to reference cable；
From the voltage signal and current signal of the corresponding each frequency signal of injection phase acquisition；
According to the increased frequency signal of the ladder and the corresponding voltage signal of each frequency signal and current signal, obtain
Take the impedance spectrum of reference cable；
The impedance spectrum of reference cable is subjected to integral transformation, obtains the reference electricity that characterization cable distribution coefficient changes with cable position
The distance state function of cable.
5. cable insulation defect recognition according to claim 3 and localization method, which is characterized in that method further includes right again
Before cable under test is detected, the distance state function of reference cable is obtained；
The distance state function of the acquisition reference cable specifically includes: obtaining reference cable based on what following formula calculated
Impedance spectrum:The impedance spectrum of reference cable is subjected to integral transformation, obtains table
The distance state function for the reference cable that sign cable distribution coefficient changes with cable position；
In formula, ZhIt (w) is the impedance spectrum of reference cable, ZLFor load impedance, Z0For the feature of reference cable in normal state
Impedance, ΓLFor the reflection coefficient of load end, γ is the propagation coefficient of reference cable, and l is total cable length；Wherein, Z0It can with γ
It is calculated according to the resistance R (ω) of reference cable, inductance L (ω), conductance G (ω), capacitor C (ω):
Wherein, rcAnd rsThe respectively conductor radius of cable core and metal screen layer inside radius, δcAnd δsRespectively core wire with
The skin depth of metal screen layer, γcAnd γsRespectively corresponding conductivity, μ0For space permeability, εeIt is compound absolutely for cable
The equivalent complex dielectric permittivity of edge.
6. cable insulation defect recognition according to claim 1 and localization method, which is characterized in that the frequency injected to cable
Rate signal is applied between cable insulation conductor and shielded layer or is applied between multiple-core cable conductor, and cable is unloaded shape
State, output short-circuit state or bringing onto load state；The frequency range of the frequency signal of injection is 0.1Hz-10GHz, frequency signal rank
The increased step-length range of ladder is 1Hz-10MHz.
7. a kind of cable insulation defect recognition and positioning system characterized by comprising
Signal injection module, for injecting the increased frequency signal of ladder to cable；
Signal acquisition module, for the voltage signal and current signal from the corresponding each frequency signal of injection phase acquisition；
Impedance spectrum obtains module, for according to the increased frequency signal of the ladder and the corresponding electricity of each frequency signal
Signal and current signal are pressed, the impedance spectrum of cable is obtained；
Defect recognition locating module, for being lacked according to the impedance spectrum discrimination cable got with the presence or absence of insulation defect and positioning
Fall into position.
8. cable insulation defect recognition according to claim 7 and positioning system, which is characterized in that the impedance spectrum obtains
Module includes:
Impedance signal acquiring unit, for determining each frequency according to the corresponding voltage signal of each frequency signal and current signal
The corresponding impedance signal of rate signal；
Impedance spectrum acquiring unit obtains reaction resistance for all impedance signals according to corresponding to the increased frequency signal of ladder
The impedance spectrum of relationship between antinoise signal and frequency.
9. cable insulation defect recognition according to claim 7 and positioning system, which is characterized in that the defect recognition is fixed
Position module include:
Integral transformation unit obtains characterization cable distribution coefficient with cable position for the impedance spectrum of cable to be carried out integral transformation
Set the distance state function of the cable of variation；
Defect recognition positioning unit, for carrying out the distance state function of the distance state function of cable under test and reference cable
Compare to obtain diagnosis function, if variation of the diagnosis function at some position is more than threshold value, it is determined that the position has part damage
Wound.
10. cable insulation defect recognition according to claim 7 and positioning system, which is characterized in that system further includes ginseng
Cable resistance spectrum computing unit is examined, obtains the impedance spectrum of reference cable for what is calculated based on following formula:
In formula, ZhIt (w) is the impedance spectrum of reference cable, ZLFor load impedance, Z0For the feature of reference cable in normal state
Impedance, ΓLFor the reflection coefficient of load end, γ is the propagation coefficient of reference cable, and l is total cable length；Wherein, Z0It can with γ
It is calculated according to the resistance R (ω) of reference cable, inductance L (ω), conductance G (ω), capacitor C (ω):
Wherein, rcAnd rsThe respectively conductor radius of cable core and metal screen layer inside radius, δcAnd δsRespectively core wire with
The skin depth of metal screen layer, γcAnd γsRespectively corresponding conductivity, μ0For space permeability, εeIt is compound absolutely for cable
The equivalent complex dielectric permittivity of edge.
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Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110082656A (en) * | 2019-05-29 | 2019-08-02 | 成都高斯电子技术有限公司 | A kind of method and device thereof of cable aging dealing monitoring |
| CN110320446A (en) * | 2019-07-18 | 2019-10-11 | 国网重庆市电力公司江北供电分公司 | Power cable defect location and diagnostic method based on return loss spectrometry |
| CN111679184A (en) * | 2020-07-06 | 2020-09-18 | 国家电网有限公司 | Method for evaluating performance of isolating switch through motor current |
| CN112816915A (en) * | 2020-12-24 | 2021-05-18 | 深圳供电局有限公司 | Cable breakage detection method and device, computer equipment and storage medium |
| CN112881806A (en) * | 2020-12-21 | 2021-06-01 | 四川大学 | Medium-voltage cable insulation online monitoring method based on impulse impedance spectroscopy |
| CN112881862A (en) * | 2021-01-18 | 2021-06-01 | 国网浙江省电力有限公司电力科学研究院 | Three-core cable fault positioning method and device based on relative impedance spectrum |
| CN112946426A (en) * | 2021-03-15 | 2021-06-11 | 哈尔滨理工大学 | Cable fault positioning system based on frequency response |
| CN113075501A (en) * | 2021-03-26 | 2021-07-06 | 华中科技大学 | Cable fault positioning method and system based on impedance spectrum periodic characteristics |
| CN113253046A (en) * | 2021-04-14 | 2021-08-13 | 国网江苏省电力有限公司淮安供电分公司 | Cable water tree fault positioning method based on impedance spectroscopy technology |
| CN113702450A (en) * | 2020-05-22 | 2021-11-26 | 新疆金风科技股份有限公司 | Method and device for detecting defects of magnetic pole coating |
| CN113740661A (en) * | 2021-07-19 | 2021-12-03 | 深圳供电局有限公司 | Cable defect positioning method and device, computer equipment and storage medium |
| CN114047409A (en) * | 2021-08-23 | 2022-02-15 | 四川大学 | Power cable local defect online positioning method based on electromagnetic coupling injection |
| CN114384383A (en) * | 2022-03-22 | 2022-04-22 | 东华理工大学南昌校区 | Circuit and method for positioning ultrahigh frequency partial discharge point |
| CN114441606A (en) * | 2021-12-28 | 2022-05-06 | 国网河北省电力有限公司电力科学研究院 | Method for positioning aging defect of cable water tree branch and test method and equipment thereof |
| CN115639500A (en) * | 2022-12-21 | 2023-01-24 | 哈尔滨理工大学 | Cable detection system and identification method based on variable-frequency pulse frequency modulation excitation |
| CN117031357A (en) * | 2023-10-08 | 2023-11-10 | 江苏省电力试验研究院有限公司 | Method and device for positioning grounding defect of single-core cable metal sheath with single-end grounded |
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Cited By (20)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110082656A (en) * | 2019-05-29 | 2019-08-02 | 成都高斯电子技术有限公司 | A kind of method and device thereof of cable aging dealing monitoring |
| CN110320446A (en) * | 2019-07-18 | 2019-10-11 | 国网重庆市电力公司江北供电分公司 | Power cable defect location and diagnostic method based on return loss spectrometry |
| CN113702450A (en) * | 2020-05-22 | 2021-11-26 | 新疆金风科技股份有限公司 | Method and device for detecting defects of magnetic pole coating |
| CN111679184A (en) * | 2020-07-06 | 2020-09-18 | 国家电网有限公司 | Method for evaluating performance of isolating switch through motor current |
| CN112881806A (en) * | 2020-12-21 | 2021-06-01 | 四川大学 | Medium-voltage cable insulation online monitoring method based on impulse impedance spectroscopy |
| CN112816915A (en) * | 2020-12-24 | 2021-05-18 | 深圳供电局有限公司 | Cable breakage detection method and device, computer equipment and storage medium |
| CN112881862A (en) * | 2021-01-18 | 2021-06-01 | 国网浙江省电力有限公司电力科学研究院 | Three-core cable fault positioning method and device based on relative impedance spectrum |
| CN112946426A (en) * | 2021-03-15 | 2021-06-11 | 哈尔滨理工大学 | Cable fault positioning system based on frequency response |
| CN113075501B (en) * | 2021-03-26 | 2021-12-17 | 华中科技大学 | Cable fault positioning method and system based on impedance spectrum periodic characteristics |
| CN113075501A (en) * | 2021-03-26 | 2021-07-06 | 华中科技大学 | Cable fault positioning method and system based on impedance spectrum periodic characteristics |
| CN113253046B (en) * | 2021-04-14 | 2022-07-26 | 国网江苏省电力有限公司淮安供电分公司 | Cable water tree fault positioning method based on impedance spectroscopy technology |
| CN113253046A (en) * | 2021-04-14 | 2021-08-13 | 国网江苏省电力有限公司淮安供电分公司 | Cable water tree fault positioning method based on impedance spectroscopy technology |
| CN113740661A (en) * | 2021-07-19 | 2021-12-03 | 深圳供电局有限公司 | Cable defect positioning method and device, computer equipment and storage medium |
| CN114047409A (en) * | 2021-08-23 | 2022-02-15 | 四川大学 | Power cable local defect online positioning method based on electromagnetic coupling injection |
| CN114441606A (en) * | 2021-12-28 | 2022-05-06 | 国网河北省电力有限公司电力科学研究院 | Method for positioning aging defect of cable water tree branch and test method and equipment thereof |
| CN114441606B (en) * | 2021-12-28 | 2023-11-24 | 国网河北省电力有限公司电力科学研究院 | Positioning method for ageing defect of cable water branch, testing method and testing equipment thereof |
| CN114384383A (en) * | 2022-03-22 | 2022-04-22 | 东华理工大学南昌校区 | Circuit and method for positioning ultrahigh frequency partial discharge point |
| CN115639500A (en) * | 2022-12-21 | 2023-01-24 | 哈尔滨理工大学 | Cable detection system and identification method based on variable-frequency pulse frequency modulation excitation |
| CN117031357A (en) * | 2023-10-08 | 2023-11-10 | 江苏省电力试验研究院有限公司 | Method and device for positioning grounding defect of single-core cable metal sheath with single-end grounded |
| CN117031357B (en) * | 2023-10-08 | 2024-01-19 | 江苏省电力试验研究院有限公司 | Method and device for positioning grounding defect of single-core cable metal sheath with single-end grounded |
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