CN112834885A - Evaluation of Power Supply Line Insulation Condition Based on Identification of the Relationship between Power Supply Line Leakage Current and Humidity - Google Patents
Evaluation of Power Supply Line Insulation Condition Based on Identification of the Relationship between Power Supply Line Leakage Current and HumidityDownload PDFInfo
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- CN112834885A CN112834885ACN202110020333.0ACN202110020333ACN112834885ACN 112834885 ACN112834885 ACN 112834885ACN 202110020333 ACN202110020333 ACN 202110020333ACN 112834885 ACN112834885 ACN 112834885A
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- leakage current
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- supply line
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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
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D21/00—Measuring or testing not otherwise provided for
- G01D21/02—Measuring two or more variables by means not covered by a single other subclass
- 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
- 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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/58—Testing of lines, cables or conductors
- 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
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
Description
Technical Field
The invention belongs to the field of leakage monitoring of electrical equipment of a power supply system, and provides power supply line insulation state assessment based on identification of a relation between leakage current and humidity of a power supply line.
Background
At present, a rural power grid adopts a three-level leakage protection mode, and the three-level leakage protection mode is respectively installed on a public transformer, an electric meter box and a client side or a two-level leakage protection mode skipping the electric meter box. At present, the wire arrangement of rural families is mostly hidden in a wall, and the line is easy to generate leakage current due to the influence of factors such as line quality, construction process and the like. In addition, the rural power grid adopts a three-phase four-wire system, and a 10kV power transmission line adopts 16mm2Or 25mm2Wire diameter and partially bare wire problems. Especially, rural power grids in mountainous areas are easily affected by natural disasters such as debris flow, tree breakage and rolling, and power transmission lines often have fault conditions such as electric leakage and short circuit.
Because rural power grid region is wide, the power consumption customer disperses, and is mostly single-phase power consumption. Therefore, when a fault occurs, the number of affected household users is usually small, and the fault is often not reported in time after the fault occurs, so that a fault line cannot be processed in time, and surrounding residents and animals are at risk of electric shock.
In conclusion, how to find the insulation fault of the power supply line of the power grid in the rural area in time becomes a problem which needs to be solved urgently by the technical personnel in the field.
Disclosure of Invention
Therefore, the invention aims to solve the problem of how to find the insulation fault of the power supply line of the power grid in rural areas in time and avoid electric shock accidents.
In order to solve the technical problems, the invention adopts the following technical scheme:
power supply line insulation state aassessment based on power supply line leakage current and humidity relation are discerned includes:
s1, acquiring an environment humidity value and a leakage current value of the target line by using the humidity sensor and the leakage current sensor;
s2, inputting the environmental humidity value of the target circuit into a correlation model between the leakage current and the humidity to obtain a leakage current model prediction value;
and S3, calculating a difference value between the predicted value of the leakage current model and the leakage current value, judging that the target line is abnormal in insulation if the difference value is larger than a preset threshold value, and judging that the target line is normal in insulation if the difference value is smaller than or equal to the preset threshold value.
Preferably, the method for establishing the correlation model between the leakage current and the humidity includes:
and acquiring a historical environment humidity value set and a historical leakage current value set, obtaining a fitting equation between leakage current and humidity by using a mean square least square target fitting method, and establishing a correlation model between the leakage current and the humidity.
Preferably, the leakage current value is set to ylEnvironment humidity value of xiRemember yl＝f(xi)；
f(xi)＝a1r1(x1)+a2r2(x2)+…+amrm(xm) (1)
r1(x1) To rm(xm) Is a set of linearly independent functions, ajThe undetermined coefficient is j is 1,2,3, …, m is less than n, n is the number of measurement times at different positions of the target line, and m is the number of elements in the linear independent group;
note the book
To select a1,a2,…,amLet J (a)1,a2,…,am) Minimum, using extreme requirements
Is obtained about a1,a2,…,amSystem of linear equations of
Namely, it is
Note the book
R represents a parameter matrix, A represents a pending coefficient matrix, and Y represents a leakage current matrix, and equation set (5) can be expressed as
RTRA＝RTY (6)
When the function r is selected1(x),r2(x),…,rm(x) When linearly independent, R is full rank, RTR is reversible, so equation set (6) has a unique solution:
A＝(RTR)-1RTY (7)
and obtaining a fitting equation between the leakage current and the humidity.
Compared with the prior art, the invention has the following advantages:
in order to solve the problems of insensitivity and unreliability of the insulation state evaluation of the power supply line of the conventional power system, the method comprises the steps of firstly utilizing a humidity sensor and a leakage current sensor to obtain environmental humidity data and leakage current data of power supply equipment, accumulating the environmental humidity data and the leakage current data in a certain time period, and then fitting to obtain a relation curve between the environmental humidity and the leakage current as the correlation characteristic between the leakage current and the environmental humidity of the power supply line. Substituting the newly acquired humidity and leakage current values into a fitting equation obtained in history for checking, and when the historical fitting characteristic is met, indicating that the insulation state of the line is intact; and when the historical fitting characteristic is not met, judging that the power supply equipment is abnormal in insulation, thereby realizing the evaluation of the insulation state of the power supply line. The invention effectively evaluates the influence degree of the environment on the leakage current generated by the power supply line insulation, provides a reference basis for judging the real state of the power supply line insulation, can find the insulation fault of the power supply line of the power grid in rural areas in time and avoids electric shock accidents.
Drawings
For purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made in detail to the present invention as illustrated in the accompanying drawings, in which:
FIG. 1 is a flow chart of power supply line insulation status evaluation based on power supply line leakage current and humidity relationship identification disclosed in the present invention;
FIG. 2 is a schematic diagram of a humidity sensor and a leakage current sensor for obtaining an ambient humidity value and a leakage current value of a target line;
fig. 3 is a schematic diagram of a fitting equation between the leakage current and the humidity obtained by a method of fitting an object using a least square mean square method.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
As shown in fig. 1, the power supply line insulation state evaluation based on the power supply line leakage current and humidity relationship identification includes:
s1, acquiring an environment humidity value and a leakage current value of the target line by using the humidity sensor and the leakage current sensor;
s2, inputting the environmental humidity value of the target circuit into a correlation model between the leakage current and the humidity to obtain a leakage current model prediction value;
and S3, calculating a difference value between the predicted value of the leakage current model and the leakage current value, judging that the target line is abnormal in insulation if the difference value is larger than a preset threshold value, and judging that the target line is normal in insulation if the difference value is smaller than or equal to the preset threshold value.
In the schematic diagram of measuring the ambient humidity and the leakage current of the three-phase power supply line shown in fig. 2, the key component is a leakage current sensor, which is a detection element composed of an iron core and a secondary coil wound on the iron core, a power phase line and a neutral line pass through an annular iron core to form a primary coil N1 of a transformer, a winding wound on the annular iron core forms a secondary coil N2 of the transformer, and under normal conditions, the sum of the phasor of the primary coil current of the leakage current sensor is zero, and the secondary side induced current is also zero; when the insulation of the electric equipment is damaged and electric leakage occurs, if a person contacts with the electrified part, the human body forms a loop through the ground, and the vector sum of the current flowing through the primary coil of the leakage current sensor is not equal to zero (unbalanced current flows through the electric loop).
In the invention, the actual environment humidity value measured by the humidity sensor is W (%), and the leakage current value measured by the leakage current sensor is i0(μA)。
At this time, the predicted value of the leakage current model corresponding to the environmental humidity W (%) is i0' (μ A) calculating a difference between the predicted value of the leakage current model and the leakage current value
The preset threshold value is
If i0(μA)＞i0' (μ A) and
the target line insulation is abnormal.
In specific implementation, the method for establishing the correlation model between the leakage current and the humidity comprises the following steps:
and acquiring a historical environment humidity value set and a historical leakage current value set, obtaining a fitting equation between leakage current and humidity by using a mean square least square target fitting method, and establishing a correlation model between the leakage current and the humidity.
As shown in FIG. 3, in the specific implementation, the leakage current value is set to ylEnvironment humidity value of xiRemember yl＝f(xi)；
f(xi)＝a1r1(x1)+a2r2(x2)+…+amrm(xm) (1)
r1(x1) To rm(xm) Is a set of linearly independent functions, ajThe undetermined coefficient is j is 1,2,3, …, m is less than n, n is the number of measurement times at different positions of the target line, and m is the number of elements in the linear independent group;
note the book
To select a1,a2,…,amLet J (a)1,a2,…,am) Minimum, using extreme requirements
Is obtained about a1,a2,…,amSystem of linear equations of
Namely, it is
Note the book
R represents a parameter matrix, A represents a pending coefficient matrix, and Y represents a leakage current matrix, and equation set (5) can be expressed as
RTRA＝RTY (6)
When the function r is selected1(x),r2(x),…,rm(x) When linearly independent, R is full rank, RTR is reversible, so equation set (6) has a unique solution:
A＝(RTR)-1RTY (7)
and obtaining a fitting equation between the leakage current and the humidity.
Finally, it is noted that the above-mentioned embodiments illustrate rather than limit the invention, and that, while the invention has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (3)
1. Power supply line insulation state aassessment based on power supply line leakage current and humidity relation are discerned, its characterized in that includes:
s1, acquiring an environment humidity value and a leakage current value of the target line by using the humidity sensor and the leakage current sensor;
s2, inputting the environmental humidity value of the target circuit into a correlation model between the leakage current and the humidity to obtain a leakage current model prediction value;
and S3, calculating a difference value between the predicted value of the leakage current model and the leakage current value, judging that the target line is abnormal in insulation if the difference value is larger than a preset threshold value, and judging that the target line is normal in insulation if the difference value is smaller than or equal to the preset threshold value.
2. The method for evaluating the insulation state of the power supply line based on the identification of the relation between leakage current and humidity of the power supply line is characterized in that the method for establishing the correlation model between the leakage current and the humidity comprises the following steps:
and acquiring a historical environment humidity value set and a historical leakage current value set, obtaining a fitting equation between leakage current and humidity by using a mean square least square target fitting method, and establishing a correlation model between the leakage current and the humidity.
3. The power supply line insulation state assessment based on power supply line leakage current and humidity relationship identification as claimed in claim 2, wherein let the leakage current value be ylEnvironment humidity value of xiRemember yl＝f(xi)；
f(xi)＝a1r1(x1)+a2r2(x2)+…+amrm(xm) (1)
r1(x1) To rm(xm) Is a set of linearly independent functions, ajThe undetermined coefficient is j is 1,2,3, …, m is less than n, n is the number of measurement times at different positions of the target line, and m is the number of elements in the linear independent group;
note the book
To select a1,a2,…,amLet J (a)1,a2,…,am) Minimum, using extreme requirements
Is obtained about a1,a2,…,amOfSystem of equations of nature
Namely, it is
Note the book
R represents a parameter matrix, A represents a pending coefficient matrix, and Y represents a leakage current matrix, and equation set (5) can be expressed as
RTRA＝RTY (6)
When the function r is selected1(x),r2(x),…,rm(x) When linearly independent, R is full rank, RTR is reversible, so equation set (6) has a unique solution:
A＝(RTR)-1RTY (7)
and obtaining a fitting equation between the leakage current and the humidity.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110020333.0ACN112834885B (en) | 2021-01-07 | 2021-01-07 | Power supply line insulation state assessment based on power supply line leakage current and humidity relation identification |
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| CN202110020333.0ACN112834885B (en) | 2021-01-07 | 2021-01-07 | Power supply line insulation state assessment based on power supply line leakage current and humidity relation identification |
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| CN112834885Atrue CN112834885A (en) | 2021-05-25 |
| CN112834885B CN112834885B (en) | 2022-08-26 |
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Citations (7)
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|---|---|---|---|---|
| CN103135033A (en)* | 2013-02-01 | 2013-06-05 | 江苏省电力公司电力科学研究院 | Insulator saturation damped maximum leakage current prediction method under non-temperature difference condition |
| CN104459489A (en)* | 2014-12-05 | 2015-03-25 | 深圳供电局有限公司 | Method for identifying contamination degree of post insulator |
| CN105137265A (en)* | 2015-08-26 | 2015-12-09 | 芜湖市凯鑫避雷器有限责任公司 | Insulator leakage current prediction method |
| WO2016057946A1 (en)* | 2014-10-10 | 2016-04-14 | Halliburton Energy Services, Inc. | Electrode -based tool measurement corrections based on leakage currents estimated using a predetermined internal impedance model table |
| CN108629520A (en)* | 2018-05-10 | 2018-10-09 | 国网辽宁省电力有限公司鞍山供电公司 | A kind of ultra-high-tension power transmission line operating status appraisal procedure under microclimate environment |
| CN108680604A (en)* | 2018-05-18 | 2018-10-19 | 云南电网有限责任公司电力科学研究院 | A kind of suspension insulator pollution degree monitoring system and method |
| CN110609220A (en)* | 2019-09-27 | 2019-12-24 | 国网江苏省电力有限公司盐城供电分公司 | A detection and evaluation system for transmission cable insulation status based on multiple signal acquisition and analysis |
- 2021
- 2021-01-07CNCN202110020333.0Apatent/CN112834885B/enactiveActive
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103135033A (en)* | 2013-02-01 | 2013-06-05 | 江苏省电力公司电力科学研究院 | Insulator saturation damped maximum leakage current prediction method under non-temperature difference condition |
| WO2016057946A1 (en)* | 2014-10-10 | 2016-04-14 | Halliburton Energy Services, Inc. | Electrode -based tool measurement corrections based on leakage currents estimated using a predetermined internal impedance model table |
| CN104459489A (en)* | 2014-12-05 | 2015-03-25 | 深圳供电局有限公司 | Method for identifying contamination degree of post insulator |
| CN105137265A (en)* | 2015-08-26 | 2015-12-09 | 芜湖市凯鑫避雷器有限责任公司 | Insulator leakage current prediction method |
| CN108629520A (en)* | 2018-05-10 | 2018-10-09 | 国网辽宁省电力有限公司鞍山供电公司 | A kind of ultra-high-tension power transmission line operating status appraisal procedure under microclimate environment |
| CN108680604A (en)* | 2018-05-18 | 2018-10-19 | 云南电网有限责任公司电力科学研究院 | A kind of suspension insulator pollution degree monitoring system and method |
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