CN109342883A - A kind of local ageing fault detecting and positioning method for cable - Google Patents
A kind of local ageing fault detecting and positioning method for cable Download PDFInfo
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- CN109342883A CN109342883A CN201811324845.0A CN201811324845A CN109342883A CN 109342883 A CN109342883 A CN 109342883A CN 201811324845 A CN201811324845 A CN 201811324845A CN 109342883 A CN109342883 A CN 109342883A
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- cable
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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
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/083—Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground
Abstract
The present invention relates to a kind of local ageing fault detecting and positioning method for cable, step includes: S1, the spectrum information database for establishing cable；S2, the transmission speed of light wave in the cable is determined；S3, cable under test is detected and analyzed.The present invention can learn state of insulation in the analysis of cable insulation in advance, handle convenient for orderly, planned aging cable, economic loss caused by avoiding because of loss of outage caused by burst cable fault and emergency maintenance.
Description
Technical field
The invention belongs to electric power safety monitoring technical fields, are related to the local ageing fault detection of cable, especially a kind of
Local ageing fault detecting and positioning method for cable.
Background technique
Under the electric power facility environment of current high speed development, cable is widely applied.Cable belongs to weak isolating equipment, can be because
Various mechanical factors, electricabsorption agent lead to insulation ag(e)ing and cause failure.Test for cable, including insulating performance of cable are surveyed
The position of examination and positioning insulation degradation.
Currently our location technologies to cable fault, belong to TDR time domain reflectometry, are carried out using time domain reflectometry TDR
There are some defects, one is that positioning cable length is shorter, is typically only used for 3 kilometers of fault location below for test；Second is that TDR
Time domain reflectometry may obtain tens of secondary reflections, be difficult to calculate abort situation, therefore practical application system；Third is that time domain is anti-
It is obvious for short circuit and open-circuit fault reflection to penetrate method, but both probability of failure very littles, when most high resistive fault can not
It is directly directly positioned with time domain reflectometry, it is also necessary to carry out high-voltage breakdown positioning, which adds work difficulties and danger
Property, also there is certain damage to cable.
In terms of insulating performance of cable, the mode of conventional inspection cable insulation defect is pressure test, since most
DC break down voltage develops to industrial frequency AC pressure resistance, ultralow frequency and series resonance pressure resistance, and technological means constantly improve, but has one
The defect damage without solution-detection process to cable insulation always.There is several defects for these types of scheme: first is that cable
The aging of early stage not easily passs through destructive means and directly finds, that is, pressure test is all gone well, and the aging for initial stage is resistance to
Pressure test can not be detected effectively；Second is that pressure test belongs to destructive testing, destructive means itself can accelerate fragile position
Aging, it is more likely that pressure test passes through, but due to the destructiveness of test, so that insulation weak spot or insulation defect are trying
Expand after testing, cause using middle cable insulation failure or again power transmission when cable fault；Third is that the position that local ageing occurs is very
Hardly possible carries out positioning searching.
Therefore, developing a kind of cable nondestructiving detecting means is very important.
Summary of the invention
It is an object of the invention to provide a kind of local ageing failure for cable in place of overcome the deficiencies in the prior art
Localization method is detected, lossless insulation assessment can be carried out to cable, degradation failure detects and positions, raising cable detection water
It is flat.
The present invention solves its technical problem and adopts the following technical solutions to achieve:
A kind of local ageing fault detecting and positioning method for cable, step include:
S1, the spectrum information database for establishing cable；
S2, the transmission speed of light wave in the cable is determined；
S3, cable under test is detected and analyzed.
The fault-free cable of several unlike materials, different length is selected to carry out spectrum measurement moreover, the S1 is specifically included,
Determine the impedance of every kind of cable and the resonance spectrum characteristic of phase.
Moreover, the resonance spectrum characteristic includes the amplitude range and radio frequency light of each each point of collection point resonance spectrum of cable
The attenuation data that wave transmits in the cable.
Moreover, the S2 particular content includes: that selection has different electric lead core materials, insulating layer material, electric lead
The fault-free cable of core diameter, insulation thickness, environment temperature, frequency and/or conductance core quantity carries out rf wave transmission
The measurement of speed.
Moreover, the quantity of each cable of the measurement for carrying out rf wave transmission speed is no less than 10.
Moreover, the S3 particular content includes:
S31, spectrum measurement is carried out to cable under test；
S32, it will survey and correspond to cable the spectrum information that prestores in spectrum information and database and compare, and judge to survey frequently
Spectrum information with whether prestore spectrum information consistent；If so, cable under test fault-free；If it is not, then determining that cable under test has event
Barrier；
S33, the generation time of transmission speed and fault spectrum in cable is being corresponded to failure according to acquisition light wave in S2
Point is positioned；
S34, judge fault point degree of aging.
Moreover, the judgment criteria of the S34 are as follows: when the impedance resonance characteristic of actual measurement frequency spectrum is constant, oscillation amplitude reduction reaches
When to threshold value, it is determined as the slight aging of cable；When exponential function feature is presented in the impedance spectrum of actual measurement frequency spectrum, oscillatory occurences disappears
When, it is determined as serious aging；Other are determined as failure to be determined.
Moreover, including: to carry out two to corresponding cable to survey detection to the processing of the failure to be determined, if secondary detection result
It is still failure to be determined, then determines cable fault-free；If secondary detection result be different from the new of failure to be determined as a result,
Then handled by new result.
The advantages and positive effects of the present invention are:
(1) cost that can greatly save cable insulation test, avoids the danger of high-potting；
(2) it in the lookup of Method of Cable Trouble Point, can quickly position, accelerate recovery time；
(3) in the analysis of cable insulation, state of insulation can be learnt in advance, convenient for orderly, planned to aging electricity
Cable is handled, economic loss caused by avoiding because of loss of outage caused by burst cable fault and emergency maintenance.
Detailed description of the invention
Fig. 1 is the flow chart for cable local ageing fault detecting and positioning method；
Fig. 2 is cable resistance spectrum vector performance plot；
Fig. 3 is micro- ageing state vector impedance spectrogram；
Fig. 4 is mittlere alterung state impedance spectrum vector figure.
Specific embodiment
The invention will be further described with reference to the accompanying drawing and by specific embodiment, and following embodiment is descriptive
, it is not restrictive, this does not limit the scope of protection of the present invention.
A kind of local ageing fault detecting and positioning method for cable (is referred to as frequency using radio frequency spectroscopic technique
Domain resonance impedance technology) it realizes.Radio frequency spectroscopic technique is substantially the unit lengths cable such as to obtain by non-destructive means
Impedance continuity feature, the technology analyzed and positioned by continuity vector characteristics.
Experimental study discovery, when cable insulation breaks down, equivalent impedance at least can be in the external examination of a characteristic frequency
It tests environment and generates resonance, which can be captured by the frequency domain characteristic of vector impedance.Pass through the frequency of detection cable
Domain vector impedance characteristic, the continuous feature by analyzing frequency domain vector impedance carry out fault location and Ageing Diagnosis.
In general, it includes core wire resistance that the factor for influencing cable aging, which has mechanical factor (squeezing deformation etc.), electricabsorption agent,
(high temperature change conductivity), inductance (local hole), leakage reactance (water-treeing etc.), capacitance (whole aging, extruding etc.).Machine
Tool factor will lead to the change of (part) electric parameter, and electric parameter change will lead to transmission characteristic change, such as: 1) spy of cable
Property wave impedance with frequency be presented nonlinear function, 2) change of cable equivalent parameters will affect velocity of wave.It is surveyed in radio frequency wave spectrum
It will appear discontinuous point in examination.Discontinuous point refers to the power reflection point of frequency domain or time domain, when apparatus insulated appearance is abnormal, meeting
Signal reflex is generated on some branch current, which can be distributed be added on entire frequency band (frequency domain scattering), including
Original transmitted signal and loop response signal, this feature such as show as at the discontinuous point of unit lengths impedance on equivalent circuit.
This discontinuous point is exactly the position of insulation defect.
The analysis for realizing frequency domain impedance insulation characterisitic first has to the impedance resonance spectral model for obtaining test product.Due to reality
Cable machinery length be it is uncertain, the cable resonance characteristic of different materials is also not fixed, thus need obtain examination
The resonance spectrum of product and cable resistance continuity Characteristics are modeled.
A kind of specific steps of the local ageing fault detecting and positioning method for cable include:
S1, the database for establishing impedance resonance frequency spectrum；
It selects the cable of several unlike materials, different length to carry out spectrum measurement, determines the impedance resonance frequency of every kind of cable
The attenuation degree of spectral property and radio frequency light wave its impedance and phase-amplitude after the cable transmission of different length, further according to each
The length computation of a cable goes out attenuation rate when radio frequency light wave transmits in same cable with length.By actual test obtain
The impedance resonance spectrum information that is transmitted in unlike material, different length cable and to calculate frequency spectrum according to these spectrum informations each
The amplitude range storage of point in the database, then by the corresponding radio frequency light wave of the cable in the dampening information wherein transmitted and
Attenuation range also is stored in database, obtains the frequency domain vector impedance characteristic of each cable, to sentence when constituting follow-up test
Determine contrast standard whether aging.
It is found in actual experiment, impedance magnitude attenuation characteristic is obvious, and phase-amplitude attenuation characteristic is lighter, in precise requirements
It is not high, can only consider resistive degeneration when hardware configuration is relatively low, can save and calculate time and memory.
The cable of unlike material said herein refers to the cable with different electric lead core materials, diameter or quantity, tool
There is the cable of different insulating layer material and thickness.Each ten, cable or more of each cable different length, length 2m,
5m, 10m, 15m, 20m, 30m, 50m etc..
Radiofrequency signal is generated using radio-frequency signal generator, Spectrum Analyzer receives the letter of the frequency spectrum after cable transmission
Number.
S2, transmission speed of the light wave in every kind of cable is determined；
Since velocity of wave is a complex process affected by many factors, and the principal element for influencing velocity of wave has conductance core
Material, insulating layer material, the diameter of conductance core, the thickness of insulating materials, environment temperature, frequency, the quantity of conductance core
Deng.Therefore, selection has different electric lead core materials, insulating layer material, conductance wire core diameter, insulation thickness, environment
Temperature, frequency, conductance core quantity cable respectively be no less than 10, carry out rf wave transmission speed measurement.Test cable is long
Degree is consistent, preferably the length of 50m or more, further according to the transmission speed of transmission time and length computation radio frequency light wave in the cable
Degree.
Environment temperature mentioned here refers to the temperature that environment is measured locating for cable, is also possible to the temperature of cable itself
Degree.
S3, cable under test is detected and analyzed；
Spectrum measurement, radio frequency wave frequency rate are carried out to cable under test using radio-frequency signal generator and radio spectrum receiving device
Used frequency is consistent in Database and when wave velocity measurement with this kind of cable.Acquire each acquisition point of cable
The impedance resonance frequency spectrum set.According to environment feelings locating for the material of cable under test conductance core, diameter and quantity and the cable
Condition selects matched impedance resonance frequency spectrum from database, and actual measurement frequency spectrum is compared analysis with standard frequency spectrum, exceeds amplitude model
What is enclosed is aging point, and the position of aging point is calculated according to velocity of wave and time, realizes localization of fault.Fault point degree of aging
Judgment basis it is as follows.
Fig. 2 is micro- loss (G=0) cable resistance spectrum vector characteristic under the conditions of cable short-circuit condition, 3MHz spectral bandwidth
Curve.It can analyze out from characteristic curve, in frequency domain, the periodic counterpart impedance peak value of the zero of impedance phase, because
There are natural resonance characteristics for this cable frequency domain impedance.It when cable properties are there are micro- aging, is simulated by leakage reactance, obtains G
Vector impedance frequency spectrum under the conditions of=0.000015, as shown in figure 3, can analyze out from this part of spectrum curve, when cable exists
When micro- aging, resonance characteristic is still remained, but great changes have occurred in its resonance amplitude.Continue simulation and increases insulation loss
Frequency domain spectral profile.Leakage reactance G=0.00003 is set, is 2 times of initial aged state, in the input impedance of 100MHz bandwidth
Under the conditions of radio spectrum be Fig. 4 shown in.
By Fig. 2, Fig. 3, Fig. 4 it was found that, normal cable is under certain frequency spectrum, and there are resonance characteristics；When cable is light
When micro- aging, impedance resonance characteristic is constant, but oscillation amplitude reduces.When serious aging, index is presented in the impedance spectrum of cable
Function feature, oscillatory occurences disappear.Accordingly can according to period of oscillation, the amplitude comprehensive analysis cable degree of aging of oscillation, and
Arrangement is repaired to it with this.
Determine that the threshold value that one oscillation amplitude of setting reduces when slight aging, reduction amplitude are more than that the threshold value is then determined as gently
Micro- aging, reduction amplitude are no more than the threshold value and are then determined as failure to be determined.Processing to failure to be determined includes: to corresponding electricity
Cable carries out two and surveys detection, if secondary detection result is still failure to be determined, determines cable fault-free；If secondary detection result
It is new as a result, then being handled by new result different from failure to be determined.
Although disclosing the embodiment of the present invention and attached drawing for the purpose of illustration, those skilled in the art can be managed
Solution: do not departing from the present invention and spirit and scope of the appended claims in, various substitutions, changes and modifications be all it is possible,
Therefore, the scope of the present invention is not limited to the embodiment and attached drawing disclosure of that.
Claims (8)
1. a kind of local ageing fault detecting and positioning method for cable, it is characterised in that: step includes:
S1, the spectrum information database for establishing cable；
S2, the transmission speed of light wave in the cable is determined；
S3, cable under test is detected and analyzed.
2. the local ageing fault detecting and positioning method according to claim 1 for cable, it is characterised in that: the S1
It specifically includes and the fault-free cable of several unlike materials, different length is selected to carry out spectrum measurement, determine the impedance of every kind of cable
With the resonance spectrum characteristic of phase.
3. the local ageing fault detecting and positioning method according to claim 2 for cable, it is characterised in that: described humorous
Vibration spectral characteristic includes the amplitude range of each each point of collection point resonance spectrum of cable and what radio frequency light wave transmitted in the cable decline
Subtrahend evidence.
4. the local ageing fault detecting and positioning method according to claim 1 for cable, it is characterised in that: the S2
Particular content include: selection have different electric lead core materials, insulating layer material, conductance wire core diameter, insulation thickness,
The fault-free cable of environment temperature, frequency and/or conductance core quantity carries out the measurement of rf wave transmission speed.
5. the local ageing fault detecting and positioning method according to claim 4 for cable, it is characterised in that: for into
The quantity of each cable of the measurement of row rf wave transmission speed is no less than 10.
6. the local ageing fault detecting and positioning method according to claim 1 for cable, it is characterised in that: the S3
Particular content includes:
S31, spectrum measurement is carried out to cable under test；
S32, it will survey and correspond to cable the spectrum information that prestores in spectrum information and database and compare, and judge that actual measurement frequency spectrum will be believed
It ceases and whether prestore spectrum information consistent；If so, cable under test fault-free；If it is not, then determining cable under test, there are failures；
S33, failure is clicked through according to the generation time for obtaining transmission speed and fault spectrum of the light wave in corresponding cable in S2
Row positioning；
S34, judge fault point degree of aging.
7. the local ageing fault detecting and positioning method according to claim 6 for cable, it is characterised in that: described
The judgment criteria of S34 are as follows: when the impedance resonance characteristic for surveying frequency spectrum is constant, and oscillation amplitude reduction reaches threshold value, be determined as electricity
The slight aging of cable；When exponential function feature is presented in the impedance spectrum of actual measurement frequency spectrum, when oscillatory occurences disappears, it is determined as serious old
Change；Other are determined as failure to be determined.
8. the local ageing fault detecting and positioning method according to claim 7 for cable, it is characterised in that: to described
The processing of failure to be determined includes: to carry out two to corresponding cable to survey detection, if secondary detection result is still failure to be determined,
Determine cable fault-free；If secondary detection result be different from the new of failure to be determined as a result, if handled by new result.
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Cited By (8)
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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 |
| CN110146784A (en) * | 2019-05-22 | 2019-08-20 | 河海大学 | A kind of cable local defect localization method based on impedance phase changing ratio |
| CN110766264A (en) * | 2019-07-31 | 2020-02-07 | 贵州电网有限责任公司 | Transmission cable health state monitoring and evaluating method |
| CN111077406A (en) * | 2019-11-27 | 2020-04-28 | 西安交通大学 | Direct-current arc fault detection and positioning method based on pulse polarity characteristic distribution spectrogram |
| CN111650479A (en) * | 2020-04-03 | 2020-09-11 | 国网吉林省电力有限公司长春供电公司 | IRC (infrared radiation correlation) and electrothermal accelerated aging test method |
| CN112763842A (en) * | 2020-12-21 | 2021-05-07 | 西安交通大学 | Cable local aging degree judging method and device based on impedance spectrum |
| 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 |
| 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 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| 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 |
| 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 |
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