CN116381358A - Online detection method and device for local defects of high-voltage power cable - Google Patents
Online detection method and device for local defects of high-voltage power cable Download PDFInfo
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- CN116381358A CN116381358A CN202310387516.5A CN202310387516A CN116381358A CN 116381358 A CN116381358 A CN 116381358A CN 202310387516 A CN202310387516 A CN 202310387516A CN 116381358 A CN116381358 A CN 116381358A
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- 238000001514 detection method Methods 0.000 title claims abstract description 64
- 230000007547 defect Effects 0.000 title claims abstract description 49
- 239000000523 sample Substances 0.000 claims abstract description 51
- 238000002347 injection Methods 0.000 claims abstract description 28
- 239000007924 injection Substances 0.000 claims abstract description 28
- 238000000034 method Methods 0.000 claims abstract description 15
- 239000002184 metal Substances 0.000 claims description 21
- 239000003990 capacitor Substances 0.000 claims description 17
- 239000004020 conductor Substances 0.000 claims description 14
- 230000001012 protector Effects 0.000 claims description 7
- 238000005259 measurement Methods 0.000 claims description 6
- 238000004891 communication Methods 0.000 claims description 3
- 238000001228 spectrum Methods 0.000 claims description 3
- 238000012360 testing method Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000032683 aging Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000005670 electromagnetic radiation Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 210000001503 joint Anatomy 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/28—Measuring attenuation, gain, phase shift or derived characteristics of electric four pole networks, i.e. two-port networks; Measuring transient response
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/04—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant in circuits having distributed constants, e.g. having very long conductors or involving high frequencies
- G01R27/06—Measuring reflection coefficients; Measuring standing-wave ratio
-
- 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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
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- General Physics & Mathematics (AREA)
- Testing Relating To Insulation (AREA)
Abstract
The invention discloses a method and a device for detecting local defects of a high-voltage power cable on line. The high-frequency signal of the injected sweep frequency signal at the local defect of the cable is scattered, part of signal energy is reflected back to the signal injection end, the signal is measured through the detection probe, the vector network analyzer calculates to obtain the equivalent scattering parameter of the cable system to be detected according to the measured signal, and the local defect of the cable can be detected and positioned under the cable running state through the measured scattering parameter.
Description
Technical Field
The invention belongs to the technical field of cable detection, and particularly relates to a method and a device for detecting local defects of a high-voltage power cable on line.
Background
The cable is widely applied to various fields of national economy development and is an indispensable power transmission device. In the long-term operation process of the cable, the cable is easy to be subjected to local ageing and damage caused by the actions of external mechanical stress, electromagnetic radiation, chemical corrosion, high-temperature heat effect and the like, the local defects gradually develop into hard faults of the cable along with the increase of the operation time of the cable, great challenges are formed on the power supply stability and the safety of a power system, fire and explosion accidents possibly caused by the faults of the cable form great threats on the life and property safety of people, if the local defects of the cable can be detected and accurately positioned at the initial stage of forming, and then the local defect sections of the cable are repaired or replaced, so that the occurrence of safety accidents can be avoided to a great extent, and the cable has important significance in guaranteeing the safety stability of the whole system and reducing the operation and maintenance cost.
However, in the existing cable local defect detection method, offline detection is mostly adopted, the cable needs to be powered off before detection, the cable is separated from an original connection system, detection can be performed only by connecting detection equipment, and the offline detection is complex in procedure and high in detection cost. At present, the detection mode of the local defect of the cable is developing towards the on-line detection direction, and the aim is to realize the detection and the accurate positioning of the local defect under the cable running state, so that the research results in the field are few and mostly in the theoretical stage at present, and an effective detection method and a detection technology are lacked.
Disclosure of Invention
In order to solve the technical problems, the invention provides an online detection method and device for local defects of a high-voltage power cable, which are used for solving the problems of lack of an effective detection method and detection technology for the local defects of the cable in the prior art.
In order to achieve the above object, the present invention provides an on-line detection device for local defects of a high-voltage power cable, comprising:
the wiring module is used for constructing a measuring environment;
the coaxial cable is connected with the wiring module and used for introducing a metal sheath of the cable to be tested into the wiring module;
the measuring module is connected with the wiring module and used for detecting high-frequency signals of the cable system to be tested;
the vector network analyzer is connected with the measuring module and is used for acquiring scattering parameters of the cable system to be measured based on the high-frequency signals;
the upper computer is connected with the vector network analyzer and used for controlling the vector network analyzer to measure scattering parameters and obtaining the local defect position of the cable to be tested according to the scattering parameters.
Preferably, the wiring module comprises a cross-header, a high frequency capacitor and a calibration fixture;
the cross interconnection box is used for providing a measuring frame;
the high-frequency capacitor is connected in parallel with the metal sheath protector of the cross-connection box and is used for preventing high-frequency signals from flowing to the metal sheath of the cable which is not to be tested;
and one end of the calibration clamp is connected with the coaxial cable, and the other end of the calibration clamp is connected with the high-frequency capacitor and used for loading the measurement module.
Preferably, the measurement module comprises an injection probe and a detection probe;
the injection probe is used for transmitting high-frequency signals;
the detection probe is used for receiving the reflected high-frequency signals.
Preferably, the injection probe and the detection probe are of a caliper type structure.
Preferably, the cable system comprises a cable under test, a coaxial cable, a calibration jig, an injection probe and a detection probe.
The invention also provides an online detection method for the local defect of the high-voltage power cable, which comprises the following steps:
segmenting the cable through a wiring module, and clamping the injection probe and the detection probe on an inner conductor of the calibration clamp;
connecting an upper computer with an injection probe and a detection probe through a vector network analyzer;
and measuring scattering parameters of the cable system to be measured by using an upper computer control vector network analyzer, uploading the scattering parameters to the upper computer, and judging whether a local defect exists in the cable section to be measured by using a power cable local defect detection method based on reflection coefficient spectrum after compensating the influence of the injection probe and the detection probe on the attenuation and distortion of signals, and if the local defect exists, positioning the local defect.
Preferably, the internal connection method of the wiring module includes: and connecting the high-frequency capacitor to two ends of a metal sheath protector of the cross-connection box, wherein one end of an inner conductor of the calibration clamp is connected with the high-frequency capacitor, and the other end of the inner conductor is connected with a metal sheath of the cable section to be tested through a coaxial cable.
Preferably, the method for connecting through the vector network analyzer comprises the following steps: the method comprises the steps of connecting a Part1 end of a vector network analyzer to an injection probe by using a standard cable, connecting a Part2 end of the vector network analyzer to a detection probe, connecting the vector network analyzer to an upper computer by using a USB bus, and establishing a communication channel with the upper computer.
Compared with the prior art, the invention has the following advantages and technical effects:
the invention fully considers the laying characteristics of the high-voltage power cable, uses the injection probe and the detection probe to inject high-frequency signals into the cable metal sheath at the cable cross-connection box and measure the high-frequency signals, and can realize the online detection of the local defects of the high-voltage cable; the calibration clamp is used as an auxiliary injection tool of the signal, so that the signal injection and measurement efficiency is improved; the sectional detection of the high-voltage cable is realized by connecting high-frequency capacitors in parallel at the two ends of the metal sheath protector, so that the requirement on the power of the injected signal is reduced.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application, illustrate and explain the application and are not to be construed as limiting the application. In the drawings:
FIG. 1 is a diagram showing a structure of an on-line detecting device for a local defect of a high-voltage power cable according to an embodiment of the present invention;
FIG. 2 is an equivalent measurement model diagram of a single-segment cable according to an embodiment of the present invention;
fig. 3 is a graph of experimental results of an embodiment of the present invention, in which (a) is a graph of 9.945 m cable detection results and (b) is a graph of 9.83 m cable detection results.
Detailed Description
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
It should be noted that the steps illustrated in the flowcharts of the figures may be performed in a computer system such as a set of computer executable instructions, and that although a logical order is illustrated in the flowcharts, in some cases the steps illustrated or described may be performed in an order other than that illustrated herein.
Example 1
As shown in fig. 1, the present invention provides an online detection device for local defects of a high-voltage power cable, wherein A, B, C is a phase number of a high-voltage three-phase cable, A1 represents a first section of an a-phase cable, A2 and A3 represent a second section and a third section of the a-phase cable, the numbers of B-phase and C-phase cables have the same meaning, and CC represents a coaxial cable. In accordance with the common high-voltage power cable laying mode, at the middle joint of the cable, the metal sheaths on the left and right sides of the joint are respectively led out into a cross-connecting box through the inner conductor and the outer conductor of the coaxial cable, and are connected in a cross-connecting mode shown in fig. 1.
In order to reduce the magnitude of the induced current in the metal sheath, the cable is equally divided into three sections, two intermediate connectors and two cross-headers need to be installed. The two ends of each metal sheath protector in the cross-connection box are connected with high-frequency capacitors in parallel to form a high-frequency signal path so as to achieve the purpose of detecting local defects of the cable in a segmented mode. And a signal injection probe and a signal detection probe are arranged on each coaxial cable inner conductor and each metal sheet for cross interconnection in the cross interconnection boxes, and six sets of probes are required to be arranged in each cross interconnection box. The injection probe and the detection probe are respectively connected with a Part1 port and a Part2 port of the vector network analyzer and are used for measuring scattering parameters (S parameters) of a cable system to be tested, and in order to improve signal injection efficiency and detection efficiency, a calibration clamp matched with the probe is used as a tool for injecting signals and detecting signals, as shown in fig. 2. The injection probe and the detection probe are mounted on the inner conductor of the calibration fixture, and two ends of the inner conductor of the calibration fixture are respectively connected with the cable metal sheath and the high-frequency capacitor.
The vector network analyzer is connected with the upper computer through the USB bus, the upper computer sends an instruction to the vector network analyzer, the vector network analyzer is controlled to measure data, the data are transmitted to the upper computer, and the local defect information of the cable section to be measured is extracted through a detection algorithm.
Example 2
The invention also provides an online detection method for the local defects of the high-voltage power cable, which comprises the following steps:
segmenting the cable through a wiring module, and clamping the injection probe and the detection probe on an inner conductor of the calibration clamp;
connecting an upper computer with an injection probe and a detection probe through a vector network analyzer;
and measuring scattering parameters of the cable system to be measured by using an upper computer control vector network analyzer, uploading the scattering parameters to the upper computer, and judging whether a local defect exists in the cable section to be measured by using a power cable local defect detection method based on reflection coefficient spectrum after compensating the influence of the injection probe and the detection probe on the attenuation and distortion of signals, and if the local defect exists, positioning the local defect.
Further, the internal connection method of the wiring module comprises the following steps: and connecting the high-frequency capacitor to two ends of a metal sheath protector of the cross-connection box, wherein one end of an inner conductor of the calibration clamp is connected with the high-frequency capacitor, and the other end of the inner conductor is connected with a metal sheath of the cable section to be tested through a coaxial cable.
Further optimizing the scheme, the method for connecting through the vector network analyzer comprises the following steps: the method comprises the steps of connecting a Part1 end of a vector network analyzer to an injection probe by using a standard cable, connecting a Part2 end of the vector network analyzer to a detection probe, connecting the vector network analyzer to an upper computer by using a USB bus, and establishing a communication channel with the upper computer.
Example 3
The test simulates that two sections of cable metal jackets are directly connected, and the sectional detection is realized by connecting a high-frequency capacitor, and the test setting is the simulation of detecting the local defect of the cable with any two sections of metal jackets which are directly connected in fig. 1. The cable 1 had a length of 9.945 meters, the local defect was located at 6 meters, the cable 2 had a length of 9.83 meters, and the local defect was located at 6 meters. High-frequency capacitor C 1 、C 2 、C 3 The capacitance values are 0.1 mu F, and the grounding resistance R 1 、R 2 、R 3 The resistances are 22 omega, and the grounding wire is simulated by using enameled wires with the same length as the cable to be tested.
As shown in fig. 3, in the detection result of the 9.945 m cable, there are two obvious peaks at 6.012 m and 10.458 m, which respectively represent the local defect position and the cable terminal position of the cable; in the detection result of the 9.83 m cable, two obvious peaks are respectively represented by the local defect position and the cable terminal position of the cable at 6.126 m and 10.128 m, and the test result proves the effectiveness of the invention.
The foregoing is merely a preferred embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions easily conceivable by those skilled in the art within the technical scope of the present application should be covered in the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (8)
1. The utility model provides a high voltage power cable local defect on-line measuring device which characterized in that includes:
the wiring module is used for constructing a measuring environment;
the coaxial cable is connected with the wiring module and used for introducing a metal sheath of the cable to be tested into the wiring module;
the measuring module is connected with the wiring module and used for detecting high-frequency signals of the cable system to be tested;
the vector network analyzer is connected with the measuring module and is used for acquiring scattering parameters of the cable system to be measured based on the high-frequency signals;
the upper computer is connected with the vector network analyzer and used for controlling the vector network analyzer to measure scattering parameters and obtaining the local defect position of the cable to be tested according to the scattering parameters.
2. The high voltage power cable local defect online detection device according to claim 1, wherein the wiring module comprises a cross-connection box, a high frequency capacitor and a calibration fixture;
the cross interconnection box is used for providing a measuring frame;
the high-frequency capacitor is connected in parallel with the metal sheath protector of the cross-connection box and is used for preventing high-frequency signals from flowing to the metal sheath of the cable which is not to be tested;
and one end of the calibration clamp is connected with the coaxial cable, and the other end of the calibration clamp is connected with the high-frequency capacitor and used for loading the measurement module.
3. The high voltage power cable local defect online detection device according to claim 1, wherein the measurement module comprises an injection probe and a detection probe;
the injection probe is used for transmitting high-frequency signals;
the detection probe is used for receiving the reflected high-frequency signals.
4. The high voltage power cable partial defect on-line detecting device according to claim 3, wherein,
the injection probe and the detection probe are of caliper type structures.
5. The high voltage power cable partial defect on-line detecting device according to claim 1, wherein,
the cable system comprises a cable to be tested, a coaxial cable, a calibration clamp, an injection probe and a detection probe.
6. The online detection method for the local defects of the high-voltage power cable is characterized by comprising the following steps of:
segmenting the cable through a wiring module, and clamping the injection probe and the detection probe on an inner conductor of the calibration clamp;
connecting an upper computer with an injection probe and a detection probe through a vector network analyzer;
and measuring scattering parameters of the cable system to be measured by using an upper computer control vector network analyzer, uploading the scattering parameters to the upper computer, and judging whether a local defect exists in the cable section to be measured by using a power cable local defect detection method based on reflection coefficient spectrum after compensating attenuation and distortion influences of the injection probe and the detection probe on signals, and if the local defect exists, positioning the local defect.
7. The method for on-line detection of local defects of a high voltage power cable according to claim 6, wherein,
the internal connection method of the wiring module comprises the following steps: and connecting the high-frequency capacitor to two ends of a metal sheath protector of the cross-connection box, wherein one end of an inner conductor of the calibration clamp is connected with the high-frequency capacitor, and the other end of the inner conductor is connected with a metal sheath of the cable section to be tested through a coaxial cable.
8. The method for on-line detection of local defects of a high voltage power cable according to claim 6, wherein,
the method for connecting through the vector network analyzer comprises the following steps: the method comprises the steps of connecting a Part1 end of a vector network analyzer to an injection probe by using a standard cable, connecting a Part2 end of the vector network analyzer to a detection probe, connecting the vector network analyzer to an upper computer by using a USB bus, and establishing a communication channel with the upper computer.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310387516.5A CN116381358A (en) | 2023-04-12 | 2023-04-12 | Online detection method and device for local defects of high-voltage power cable |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310387516.5A CN116381358A (en) | 2023-04-12 | 2023-04-12 | Online detection method and device for local defects of high-voltage power cable |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103344889A (en) * | 2013-07-02 | 2013-10-09 | 华北电力大学 | Method for measuring cable partial discharge by means of capacitor wire jumper |
| CN103954894A (en) * | 2014-05-12 | 2014-07-30 | 国家电网公司 | Partial discharge locating method for three-phase crossed and interconnected cables |
| WO2021023606A1 (en) * | 2019-08-08 | 2021-02-11 | Lisa Dräxlmaier GmbH | Test apparatus for testing an antenna |
| CN114217166A (en) * | 2021-12-01 | 2022-03-22 | 国网山西省电力公司晋中供电公司 | FDR frequency domain waveform-based transformer substation low-voltage cable local defect positioning method |
| CN115128403A (en) * | 2022-07-27 | 2022-09-30 | 哈尔滨工业大学 | Online signal measurement method for power cable |
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2023
- 2023-04-12 CN CN202310387516.5A patent/CN116381358A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103344889A (en) * | 2013-07-02 | 2013-10-09 | 华北电力大学 | Method for measuring cable partial discharge by means of capacitor wire jumper |
| CN103954894A (en) * | 2014-05-12 | 2014-07-30 | 国家电网公司 | Partial discharge locating method for three-phase crossed and interconnected cables |
| WO2021023606A1 (en) * | 2019-08-08 | 2021-02-11 | Lisa Dräxlmaier GmbH | Test apparatus for testing an antenna |
| CN114217166A (en) * | 2021-12-01 | 2022-03-22 | 国网山西省电力公司晋中供电公司 | FDR frequency domain waveform-based transformer substation low-voltage cable local defect positioning method |
| CN115128403A (en) * | 2022-07-27 | 2022-09-30 | 哈尔滨工业大学 | Online signal measurement method for power cable |
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