CN116125215A - Distribution cable state detection method based on partial discharge - Google Patents
Distribution cable state detection method based on partial discharge Download PDFInfo
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- CN116125215A CN116125215A CN202211092084.7A CN202211092084A CN116125215A CN 116125215 A CN116125215 A CN 116125215A CN 202211092084 A CN202211092084 A CN 202211092084A CN 116125215 A CN116125215 A CN 116125215A
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- partial discharge
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- 238000001514 detection method Methods 0.000 title claims abstract description 18
- 238000005315 distribution function Methods 0.000 claims abstract description 27
- 230000007547 defect Effects 0.000 claims abstract description 14
- 238000007619 statistical method Methods 0.000 claims abstract description 7
- 238000005070 sampling Methods 0.000 claims abstract description 4
- 230000002159 abnormal effect Effects 0.000 claims description 18
- 206010048669 Terminal state Diseases 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 5
- 238000012423 maintenance Methods 0.000 abstract 1
- 238000012512 characterization method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002459 sustained effect Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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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 relates to a distribution cable state detection method based on partial discharge, which comprises the following steps: carrying out a cable partial discharge detection test to obtain partial discharge data; the partial discharge data comprises partial discharge amounts of a plurality of discrete sampling points; carrying out statistical analysis on the partial discharge data, and fitting a probability distribution function f(s) of cable stress and a probability distribution function h(s) of cable strength; the stress is the maximum discharge amount of the current defect of the cable, and the strength is the maximum partial discharge amount of the cable with serious partial discharge defect; calculating a fault index F according to the partial discharge data, the probability distribution function F(s) and the probability distribution function h(s); reversely pushing the maximum partial discharge amount s according to the fault index F; and determining the cable state according to the comparison result of the maximum partial discharge amount s and a preset threshold value. The invention can prepare and detect the cable state and is convenient for maintenance and replacement of the cable according to the cable state.
Description
Technical Field
The invention relates to the technical field of cable detection, in particular to a distribution cable state detection method based on partial discharge.
Background
Power distribution cable faults have become one of the important problems affecting the power supply reliability of the power grid, and in order to improve the power supply reliability of the power grid, state detection needs to be performed on the power distribution cable regularly so as to maintain and replace the cable according to the cable state.
Disclosure of Invention
The invention aims to provide a distribution cable state detection method based on partial discharge so as to improve the power supply reliability of a power grid.
In order to achieve the above object, the present invention provides a method for detecting a state of a distribution cable based on partial discharge, comprising the steps of:
carrying out a cable partial discharge detection test to obtain partial discharge data; the partial discharge data comprises partial discharge amounts of a plurality of discrete sampling points;
carrying out statistical analysis on the partial discharge data, and fitting a probability distribution function f(s) of cable stress and a probability distribution function h(s) of cable strength; the stress is the maximum discharge amount of the current defect of the cable, and the strength is the maximum partial discharge amount of the cable with serious partial discharge defect;
calculating a fault index F according to the partial discharge data, the probability distribution function F(s) and the probability distribution function h(s);
reversely pushing the maximum partial discharge amount s according to the fault index F;
and determining the cable state according to the comparison result of the maximum partial discharge amount s and a preset threshold value.
Preferably, the probability distribution function h(s) of the cable strength is:
the probability distribution function f(s) of the cable stress is:
wherein the parameter mu can be obtained by statistical analysis of the partial discharge data 1 、σ 1 、μ 2 、σ 2 。
Preferably, said calculating a fault indicator F from said partial discharge data, said probability distribution function F(s) and probability distribution function h(s) comprises:
according to the partial discharge data and the formula
And calculating a fault index F.
Preferably, the step of back-pushing the maximum partial discharge amount s according to the fault index F includes:
according to the formula
And the fault index F reversely pushes the maximum partial discharge quantity s.
Preferably, the determining the cable status according to the comparison result of the maximum local discharge amount s and a preset threshold value includes:
for a common cable, if the maximum local discharge amount s of the body is less than or equal to 100pC, the body state is normal, otherwise, the body state is abnormal; if the maximum partial discharge amount s of the joint is less than or equal to 200pC, the joint state is normal, otherwise, the joint state is abnormal; if the maximum partial discharge amount s of the terminal is less than or equal to 2000pC, the terminal state is normal, otherwise, the terminal state is abnormal.
Preferably, the determining the cable status according to the comparison result of the maximum local discharge amount s and a preset threshold value includes:
for old cables, if the maximum partial discharge amount s of the body is less than or equal to 100pC, the body state is normal, otherwise, the body state is abnormal; if the maximum partial discharge amount s of the joint is less than or equal to 300pC, the joint state is normal, otherwise, the joint state is abnormal; if the maximum partial discharge amount s of the terminal is less than or equal to 3000pC, the terminal state is normal, otherwise, the terminal state is abnormal.
The invention has the following advantages:
the invention refers to a stress-intensity interference model commonly used in the field of mechanical reliability, calculates the fault index of the cable partial discharge defect under a certain partial discharge by utilizing the partial discharge data of the fault cable actually measured on site, and provides a more accurate defect severity measuring and calculating technology, so that a state evaluation result can be more accurate and quantitative by taking the fault index as a characterization parameter, and meanwhile, the distribution cable partial discharge detection criterion obtained according to the fault index realizes scientific and reasonable balance selection in reliability and operation detection cost.
Additional features and advantages of the invention will be set forth in the description which follows.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a flowchart of a method for detecting a state of a distribution cable based on partial discharge according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating the relationship between stress and intensity interference in an embodiment of the present invention.
Detailed Description
Various exemplary embodiments, features and aspects of the disclosure will be described in detail below with reference to the drawings. In addition, numerous specific details are set forth in the following examples in order to provide a better illustration of the invention. It will be understood by those skilled in the art that the present invention may be practiced without some of these specific details. In some instances, well known means have not been described in detail in order to not obscure the present invention.
Referring to fig. 1, an embodiment of the present invention provides a method for detecting a state of a distribution cable based on partial discharge, including the following steps:
step S1, carrying out a cable partial discharge detection test to obtain partial discharge data; the partial discharge data comprises partial discharge amounts s of a plurality of discrete sampling points;
s2, carrying out statistical analysis on the partial discharge data, and fitting a probability distribution function f (S) of cable stress and a probability distribution function h (S) of cable strength; the stress is the maximum discharge amount of the current defect of the cable, and the strength is the maximum partial discharge amount of the cable with serious partial discharge defect;
specifically, in this embodiment, the stress-intensity interference model is applied to circuit detection, where "intensity" is the maximum partial discharge of a cable (at the end of life edge) in which a serious partial discharge defect occurs, and represents the level of the maximum partial discharge that can be sustained by the cable, and the probability distribution is denoted by f (S); the "stress" in the model is the maximum discharge of the current defect, and the probability distribution of the maximum discharge is expressed by h(s); the maximum partial discharge of the cable with serious partial discharge defects approximately obeys the lognormal distribution, and the current maximum discharge of the defects also obeys the lognormal distribution; as shown in fig. 2; the area under the p(s) curve is numerically equal to the fault index F of the cable;
specifically, the probability distribution function h(s) of the cable strength is:
the probability distribution function f(s) of the cable stress is:
wherein the parameter mu can be obtained by statistical analysis of the partial discharge data 1 、σ 1 、μ 2 、σ 2 。
S3, calculating a fault index F according to the partial discharge data, the probability distribution function F (S) and the probability distribution function h (S);
specifically, according to the partial discharge data and the formula
And calculating a fault index F.
S4, reversely pushing the maximum partial discharge amount S according to the fault index F;
specifically, according to the formula
And the fault index F reversely pushes the maximum partial discharge quantity s.
And S5, determining the cable state according to a comparison result of the maximum partial discharge amount S and a preset threshold value.
For a common cable, if the maximum local discharge amount s of the body is less than or equal to 100pC, the body state is normal, otherwise, the body state is abnormal; if the maximum partial discharge amount s of the joint is less than or equal to 200pC, the joint state is normal, otherwise, the joint state is abnormal; if the maximum partial discharge amount s of the terminal is less than or equal to 2000pC, the terminal state is normal, otherwise, the terminal state is abnormal.
For old cables, if the maximum partial discharge amount s of the body is less than or equal to 100pC, the body state is normal, otherwise, the body state is abnormal; if the maximum partial discharge amount s of the joint is less than or equal to 300pC, the joint state is normal, otherwise, the joint state is abnormal; if the maximum partial discharge amount s of the terminal is less than or equal to 3000pC, the terminal state is normal, otherwise, the terminal state is abnormal.
It should be noted that, in the embodiment of the present invention, the probability density distribution function is fitted by using as many sample points as possible, and thus the F obtained in step S3 is not continuous, so that it is necessary to obtain the F and the formula according to step S3
The maximum partial discharge s is back-pushed and is considered to be continuous during the back-pushing.
The foregoing description of embodiments of the invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the technical improvements in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
Claims (6)
1. The power distribution cable state detection method based on partial discharge is characterized by comprising the following steps of:
carrying out a cable partial discharge detection test to obtain partial discharge data; the partial discharge data comprises partial discharge amounts of a plurality of discrete sampling points;
carrying out statistical analysis on the partial discharge data, and fitting a probability distribution function f(s) of cable stress and a probability distribution function h(s) of cable strength; the stress is the maximum discharge amount of the current defect of the cable, and the strength is the maximum partial discharge amount of the cable with serious partial discharge defect;
calculating a fault index F according to the partial discharge data, the probability distribution function F(s) and the probability distribution function h(s);
reversely pushing the maximum partial discharge amount s according to the fault index F;
and determining the cable state according to the comparison result of the maximum partial discharge amount s and a preset threshold value.
2. The partial discharge based distribution cable state detection method according to claim 1, wherein the probability distribution function h(s) of the cable strength is:
the probability distribution function f(s) of the cable stress is:
wherein the parameter mu can be obtained by statistical analysis of the partial discharge data 1 、σ 1 、μ 2 、σ 2 。
3. The partial discharge based distribution cable state detection method according to claim 2, wherein said calculating a fault index F from the partial discharge data, the probability distribution function F(s) and the probability distribution function h(s) comprises:
according to the partial discharge data and the formula
And calculating a fault index F.
4. The partial discharge-based distribution cable state detection method according to claim 3, wherein said back-pushing the maximum partial discharge amount s according to the failure index F comprises:
according to the formula
And the fault index F reversely pushes the maximum partial discharge quantity s.
5. The method for detecting the state of a distribution cable based on partial discharge according to claim 4, wherein determining the state of the cable according to the comparison result between the maximum partial discharge s and a preset threshold value comprises:
for a common cable, if the maximum local discharge amount s of the body is less than or equal to 100pC, the body state is normal, otherwise, the body state is abnormal; if the maximum partial discharge amount s of the joint is less than or equal to 200pC, the joint state is normal, otherwise, the joint state is abnormal; if the maximum partial discharge amount s of the terminal is less than or equal to 2000pC, the terminal state is normal, otherwise, the terminal state is abnormal.
6. The method for detecting the state of a distribution cable based on partial discharge according to claim 4, wherein determining the state of the cable according to the comparison result between the maximum partial discharge s and a preset threshold value comprises:
for old cables, if the maximum partial discharge amount s of the body is less than or equal to 100pC, the body state is normal, otherwise, the body state is abnormal; if the maximum partial discharge amount s of the joint is less than or equal to 300pC, the joint state is normal, otherwise, the joint state is abnormal; if the maximum partial discharge amount s of the terminal is less than or equal to 3000pC, the terminal state is normal, otherwise, the terminal state is abnormal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211092084.7A CN116125215A (en) | 2022-09-08 | 2022-09-08 | Distribution cable state detection method based on partial discharge |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211092084.7A CN116125215A (en) | 2022-09-08 | 2022-09-08 | Distribution cable state detection method based on partial discharge |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116125215A true CN116125215A (en) | 2023-05-16 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202211092084.7A Pending CN116125215A (en) | 2022-09-08 | 2022-09-08 | Distribution cable state detection method based on partial discharge |
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| Country | Link |
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| CN (1) | CN116125215A (en) |
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2022
- 2022-09-08 CN CN202211092084.7A patent/CN116125215A/en active Pending
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