CN114779030B - Method and system for determining insulation strength of transformer wire outlet device - Google Patents
Method and system for determining insulation strength of transformer wire outlet device Download PDFInfo
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- CN114779030B CN114779030B CN202210682944.6A CN202210682944A CN114779030B CN 114779030 B CN114779030 B CN 114779030B CN 202210682944 A CN202210682944 A CN 202210682944A CN 114779030 B CN114779030 B CN 114779030B
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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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- G06F—ELECTRIC DIGITAL DATA PROCESSING
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Abstract
The invention discloses a method and a system for determining the insulation strength of a transformer wire outlet device, wherein the method comprises the following steps: determining a transformer outlet device calculation model; calculating an electric field value based on the transformer wire outlet device calculation model to obtain electric field data of a critical path; wherein the critical path electric field data comprises: position information and electric field values corresponding to each path point in the key path; and calculating the allowable field intensity corresponding to each path point according to the position information, and determining the insulation strength of the transformer outlet device according to the allowable field intensity and the electric field value corresponding to each path point. The method of the invention constructs and calculates the equipotential surface and the ground potential surface of the pressure-equalizing ball, sets the insulating barrier and the oil gap by reasonably equating and simplifying the actual assembly structure, more accurately calculates the electric field intensity of the key structure, analyzes and calculates the allowable insulating property, judges whether the insulating strength meets the design requirement, and can quickly judge whether the insulating strength meets the requirement.
Description
Technical Field
The present invention relates to the field of high voltage and insulation technology, and more particularly, to a method and system for determining the insulation strength of a transformer outlet device.
Background
The main insulating materials of the oil immersed transformer are transformer oil and a transformer oil paperboard, and the oil paper insulation cooperation is the basic structure of transformer insulation. The solid insulating paper board is used as a framework, insulating oil can fill gaps on the surface of the solid material, materials such as the insulating paper board are protected, the insulating distance can be reduced, the insulating performance is improved, and the manufacturing cost is reduced. The insulating oil has high specific heat, low viscosity and good heat conductivity, and can be used as a transformer cooling medium. The insulating oil isolates the equipment from contacting with air, thereby preventing oxidation and moisture immersion and ensuring that the insulation is not reduced. In order to save production cost, reduce loss and reduce transportation cost, the design size is reduced as much as possible under the condition that the insulation strength meets the requirement. The thin paper tube-small oil gap structure is usually adopted, and the oil gap is divided by the insulating paper board so as to meet the requirement of insulating design and avoid insulation failure caused by high voltage in operation. The wire outlet device is the key of the transformer, is positioned at the connecting part of the winding lead and the sleeve, has the most concentrated and asymmetric electric field, narrow space and more material interface types, is an important mechanical support structure while bearing the electric field, and has complex installation process. In order to verify whether the insulation design meets the requirements, allowable calculation and judgment of the insulation strength can be carried out on the insulation design.
Disclosure of Invention
The invention provides a method and a system for determining the insulation strength of a transformer wire outlet device, which aim to solve the problem of how to quickly determine whether the transformer wire outlet device meets the allowable insulation strength.
In order to solve the above-mentioned problems, according to an aspect of the present invention, there is provided a method of determining an insulation strength of a transformer outlet device, the method including:
determining a transformer outlet device calculation model;
calculating an electric field value based on the transformer outlet device calculation model to obtain electric field data of a key path; wherein the critical path electric field data comprises: position information and electric field values corresponding to each path point in the key path;
and calculating the allowable field intensity corresponding to each path point according to the position information, and determining the insulation strength of the transformer outlet device according to the allowable field intensity and the electric field value corresponding to each path point.
Preferably, the determining a transformer outlet device calculation model includes:
the structure of the actual transformer outlet device is simplified, a cross-sectional view is introduced, the structure of an insulating material for dividing an oil gap and a metal material for shielding an electric field or serving as a conductor is arranged, the equipotential surface of a voltage-sharing ball of the outlet device is set to be a high-voltage electrode, the ground potential closest to the outlet device is set to be a ground electrode, and the potential on a sleeve on the inner side of the outlet device is set to be a linear potential.
Preferably, the determining a transformer outlet device calculation model further includes:
when the insulating material is a wet forming material, setting the ratio of the dielectric constant of the wet forming material to the dielectric constant of the insulating oil to be 1.6: 1; when the insulating material is an insulating paper tube, the ratio of the dielectric constant of the insulating paper tube to the dielectric constant of the insulating oil is set to be 2: 1.
Preferably, the calculating an electric field value based on the transformer outlet device calculation model to obtain the critical path electric field data includes:
carrying out volume subdivision and surface subdivision on the transformer outgoing line device calculation model by using a finite element method, and determining subdivision units;
based on the subdivision units, calculating an electric field by using an electrostatic field solver to obtain an electric field value of the grid vertex of each subdivision unit;
and determining the electric field data of the critical path based on the electric field value of the top point of each subdivision unit grid.
Preferably, the determining the critical path electric field data based on the electric field value of each mesh vertex of the split cells comprises:
determining a key path according to power lines which start from the surface of a voltage-sharing ball of the wire outlet device and respectively pass through different parts at chamfers of the upper edge and the lower edge of the voltage-sharing ball, and start from any position of an electrode of the wire outlet device and pass through different parts in a large oil clearance on the outermost side;
and extracting the position information of the grid vertex on the key path and the corresponding electric field value to acquire the electric field data of the key path.
Preferably, wherein the method further comprises:
and performing data expansion on the electric field data of the critical path by adopting an interpolation method.
Preferably, the calculating the allowable field strength corresponding to each path point according to the position information includes:
wherein the content of the first and second substances,
allowable field intensity corresponding to the ith path point; a is a shape coefficient;
and tau is attenuation index for the position information corresponding to the ith path point.
Preferably, the determining the insulation strength of the transformer outlet device according to the allowable field strength and the electric field value corresponding to each path point comprises:
calculating an insulation allowable value corresponding to each path point according to the allowable field intensity and the electric field value corresponding to each path point, wherein the method comprises the following steps:
determining an insulation permissivity minimum based on the minimum of the insulation permissibility values in all critical paths
；
If the minimum value of allowable insulation
Satisfy the requirement of
Determining that the insulation strength of the transformer outlet device meets an insulation allowable condition;
wherein the content of the first and second substances,
the insulation allowable value corresponding to the ith path point;
allowable field intensity corresponding to the ith path point;
an electric field value corresponding to the ith path point; and B is a process coefficient.
According to another aspect of the present invention, there is provided a system for determining an insulation strength of a transformer outlet device, the system comprising:
the calculation model determining unit is used for determining a calculation model of the transformer wire outlet device;
the critical path electric field data acquisition unit is used for calculating an electric field value based on the transformer outlet device calculation model to acquire critical path electric field data; wherein the critical path electric field data comprises: position information and electric field values corresponding to each path point in the key path;
and the allowable insulation strength determining unit is used for calculating allowable field intensity corresponding to each path point according to the position information and determining the insulation strength of the transformer wire outlet device according to the allowable field intensity and the electric field value corresponding to each path point.
Preferably, the calculation model determining unit determines a calculation model of the transformer outlet device, and includes:
the structure of the actual transformer outlet device is simplified, a cross-sectional view is introduced, the structure of an insulating material for dividing an oil gap and a metal material for shielding an electric field or serving as a conductor is arranged, the equipotential surface of a voltage-sharing ball of the outlet device is set to be a high-voltage electrode, the ground potential closest to the outlet device is set to be a ground electrode, and the potential on a sleeve on the inner side of the outlet device is set to be a linear potential.
Preferably, the calculation model determining unit determines a calculation model of the transformer outlet device, and further includes:
when the insulating material is a wet forming material, setting the ratio of the dielectric constant of the wet forming material to the dielectric constant of the insulating oil to be 1.6: 1; when the insulating material is an insulating paper cylinder, the ratio of the dielectric constant of the insulating paper cylinder to the dielectric constant of the insulating oil is set to be 2: 1.
Preferably, the obtaining unit of the electric field data of the critical path performs calculation of an electric field value based on the calculation model of the transformer outlet device, and obtains the electric field data of the critical path, including:
carrying out volume subdivision and surface subdivision on the transformer outlet device calculation model by using a finite element method, and determining subdivision units;
based on the subdivision units, calculating an electric field by using an electrostatic field solver to obtain an electric field value of the grid vertex of each subdivision unit;
and determining the electric field data of the critical path based on the electric field value of the top point of each subdivision unit grid.
Preferably, the determining the critical path electric field data based on the electric field value at the vertex of each mesh of the subdivision units by the critical path electric field data obtaining unit includes:
determining a key path according to power lines which start from the surface of a voltage-sharing ball of the wire outlet device and respectively pass through different parts at chamfers of the upper edge and the lower edge of the voltage-sharing ball, and start from any position of an electrode of the wire outlet device and pass through different parts in a large oil gap at the outermost side;
and extracting the position information of the grid vertex on the key path and the corresponding electric field value to acquire the electric field data of the key path.
Preferably, wherein the system further comprises:
and the data expansion unit is used for performing data expansion on the electric field data of the critical path by adopting an interpolation method.
Preferably, the allowable field strength corresponding to each path point is calculated by the allowable insulation strength determining unit according to the position information, and the allowable insulation strength determining unit includes:
wherein the content of the first and second substances,
allowable field intensity corresponding to the ith path point; a is a shape coefficient;
and tau is attenuation index for the position information corresponding to the ith path point.
Preferably, the allowable insulation strength determining unit determines the insulation strength of the transformer outlet device according to the allowable field strength and the electric field value corresponding to each path point, and includes:
calculating an insulation allowable value corresponding to each path point according to the allowable field intensity and the electric field value corresponding to each path point, wherein the method comprises the following steps:
determining an insulation permissivity minimum based on the minimum of the insulation permissibility values in all critical paths
；
If the minimum value of allowable insulation
Satisfy the requirement of
Determining that the insulation strength of the transformer outlet device meets an insulation allowable condition;
wherein the content of the first and second substances,
the insulation allowable value corresponding to the ith path point;
allowable field intensity corresponding to the ith path point;
an electric field value corresponding to the ith path point; and B is a process coefficient.
Based on another aspect of the invention, the invention provides a computer readable storage medium having stored thereon a computer program which, when being executed by a processor, realizes the steps of any one of the methods of determining the insulation strength of a transformer outlet device.
Based on another aspect of the present invention, the present invention provides an electronic device comprising:
the computer-readable storage medium described above; and
one or more processors to execute the program in the computer-readable storage medium.
The invention provides a method and a system for determining the insulation strength of a transformer wire outlet device, wherein the method comprises the following steps: determining a transformer outlet device calculation model; calculating an electric field value based on the transformer wire outlet device calculation model to obtain electric field data of a critical path; wherein the critical path electric field data comprises: position information and electric field values corresponding to each path point in the key path; and calculating the allowable field intensity corresponding to each path point according to the position information, and determining the insulation strength of the transformer outlet device according to the allowable field intensity and the electric field value corresponding to each path point. The method of the invention constructs and calculates the equipotential surface and the ground potential surface of the pressure-equalizing ball, sets the insulating barrier and the oil gap by reasonably equating and simplifying the actual assembly structure, more accurately calculates the electric field intensity of the key structure, analyzes and calculates the allowable insulating property, judges whether the insulating strength meets the design requirement, and can quickly judge whether the insulating strength meets the requirement.
Drawings
A more complete understanding of exemplary embodiments of the present invention may be had by reference to the following drawings in which:
fig. 1 is a flow chart of a method 100 of determining the dielectric strength of a transformer outlet device according to an embodiment of the present invention;
FIG. 2 is a flowchart of allowable calculation and determination of insulation strength of the transformer outlet device according to the embodiment of the present invention;
fig. 3 is a schematic diagram illustrating the allowable insulation strength determination of the transformer outlet device according to the embodiment of the present invention;
fig. 4 is a schematic diagram of a system 400 for determining the insulation strength of a transformer outlet device according to an embodiment of the present invention.
Detailed Description
Example embodiments of the present invention will now be described with reference to the accompanying drawings, however, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, which are provided for a complete and complete disclosure of the invention and to fully convey the scope of the invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
Fig. 1 is a flowchart of a method 100 of determining an insulation strength of a transformer outlet device according to an embodiment of the present invention. As shown in fig. 1, the method for determining the insulation strength of the transformer outlet device according to the embodiment of the present invention constructs and calculates the equipotential surface and the ground potential surface of the voltage-sharing ball, sets the insulation barrier and the oil gap by reasonably equating and simplifying the actual assembly structure, more accurately calculates the electric field strength of the key structure, analyzes and calculates the insulation allowable property, determines whether the insulation strength meets the design requirement, and can quickly determine whether the insulation strength meets the requirement. The method 100 for determining the insulation strength of the transformer outlet device provided by the embodiment of the invention starts from step 101, and determines a transformer outlet device calculation model in step 101.
Preferably, the determining of the transformer outlet device calculation model includes:
the structure of the actual transformer wire outlet device is simplified, a sectional view is introduced, the structure of an insulating material for dividing an oil gap and a metal material for shielding an electric field or serving as a conductor is arranged, the equipotential surface of a voltage-sharing ball of the wire outlet device is set to be a high-voltage electrode, the ground potential closest to the wire outlet device is set to be a ground electrode, and the potential on a sleeve pipe on the inner side of the wire outlet device is set to be a linear potential.
Preferably, the determining a transformer outlet device calculation model further includes:
when the insulating material is a wet forming material, setting the ratio of the dielectric constant of the wet forming material to the dielectric constant of the insulating oil to be 1.6: 1; when the insulating material is an insulating paper cylinder, the ratio of the dielectric constant of the insulating paper cylinder to the dielectric constant of the insulating oil is set to be 2: 1.
The method of the embodiment of the invention solves the problem of allowable verification of the insulation strength of the transformer wire outlet device. Referring to fig. 2, in the present invention, a wire outlet device calculation model is provided. The simplification is mainly based on the structure of the actual wire outlet device, and a section is firstly introduced, wherein the fixed support structures such as bolts, pins, and braces which are irrelevant to the field intensity calculation are ignored in the calculation, and only the insulating materials for dividing the oil gap, such as insulating paper boards, wet forming materials and other structures, and the metal material structures for shielding the electric field or serving as conductors are reserved. The equipotential surface of the voltage-sharing ball of the wire outlet device is set as a high-voltage electrode, the ground potential closest to the wire outlet device is set as a ground electrode, and the potential on the sleeve on the inner side of the wire outlet device is set as a linear potential. Alternatively, the ratio of the dielectric constant of the wet forming material to the dielectric oil is set to 1.6:1, and the ratio of the dielectric constant of the insulating paper tube to the dielectric oil is set to 2: 1. Among them, the dielectric constant is used for electric field calculation, and is known. And other parameters are reasonably simplified and obtained mainly according to the original drawing of the calculation model.
In step 102, calculating an electric field value based on the transformer outlet device calculation model to obtain electric field data of a critical path; wherein the critical path electric field data comprises: and position information and electric field values corresponding to each path point in the critical path.
Preferably, the calculating an electric field value based on the transformer outlet device calculation model to obtain the critical path electric field data includes:
carrying out volume subdivision and surface subdivision on the transformer outlet device calculation model by using a finite element method, and determining subdivision units;
based on the subdivision units, calculating an electric field by using an electrostatic field solver to obtain an electric field value of the grid vertex of each subdivision unit;
and determining the electric field data of the critical path based on the electric field value of the top point of each subdivision unit grid.
Preferably, the determining the critical path electric field data based on the electric field value of each mesh vertex of the split cells comprises:
determining a key path according to power lines which start from the surface of a voltage-sharing ball of the wire outlet device and respectively pass through different parts at chamfers of the upper edge and the lower edge of the voltage-sharing ball, and start from any position of an electrode of the wire outlet device and pass through different parts in a large oil gap at the outermost side;
and extracting the position information of the grid vertex on the key path and the corresponding electric field value to acquire the electric field data of the key path.
In the invention, after the outlet device calculation model is determined, the electric field data of a critical path is determined based on the outlet device calculation model, wherein the number of the critical path is at least one, and the electric field data of the critical path comprises: and position information and electric field values corresponding to each path point in each key path.
Specifically, in finite element software, a wire outlet device calculation model is subjected to unit subdivision, the surfaces of materials are subdivided, and after the subdivision units are arranged, an electrostatic field solver is adopted to calculate an electric field value. And determining a key path according to the electric field value in the obtained electric field calculation result, and obtaining the position information and the corresponding electric field value of each path point in the key path, thereby determining the electric field data of the key path. The critical paths comprise a critical path from a voltage-sharing ball and a critical path from the ground potential.
In the invention, based on the set subdivision units, an electrostatic field solver is used for calculating an electric field to obtain an electric field value of the grid top of each subdivision unit; and determining the electric field data of the critical path based on the electric field value of the top point of each subdivision unit mesh. When determining the electric field data of the critical path based on the electric field value of the top point of each mesh of the subdivision units, the critical path is selected from the power lines of the calculation result, including but not limited to the following 10 paths: starting from the surface of a voltage-sharing ball of a wire outlet device, and passing through 5 power lines at different positions at the chamfer angles of the upper edge and the lower edge of the voltage-sharing ball; starting from any position of an electrode of the wire outlet device, passing through power lines of 5 different parts in the large oil clearance on the outermost side, and then extracting position information of grid vertexes and corresponding electric field values on the critical path to obtain electric field data of the critical path.
In step 103, allowable field strength corresponding to each path point is calculated according to the position information, and the insulation strength of the transformer outlet device is determined according to the allowable field strength and the electric field value corresponding to each path point.
Preferably, wherein the method further comprises:
and performing data expansion on the electric field data of the critical path by adopting an interpolation method.
Preferably, the calculating the allowable field strength corresponding to each path point according to the position information includes:
wherein the content of the first and second substances,
allowable field intensity corresponding to the ith path point; a is a shape coefficient;
and tau is attenuation index for the position information corresponding to the ith path point.
Preferably, the determining the insulation strength of the transformer outlet device according to the allowable field strength and the electric field value corresponding to each path point includes:
determining an insulation permissivity minimum based on the minimum of the insulation permissibility values in all critical paths
；
If the minimum value of allowable insulation
Satisfy the requirement of
Determining that the insulation strength of the transformer outlet device meets an insulation allowable condition;
wherein, the first and the second end of the pipe are connected with each other,
the insulation allowable value corresponding to the ith path point;
allowable field intensity corresponding to the ith path point;
an electric field value corresponding to the ith path point; and B is a process coefficient.
With reference to fig. 2 and 3, in the present invention, after acquiring the critical path electric field data, first, the critical path electric field data corresponding to each critical path is stored in the corresponding memory matrix unit M (one critical path corresponds to one memory matrix M); then, performing data expansion on the memory matrix M by adopting an interpolation method; and finally, performing field intensity allowable calculation on each path point in the matrix M, and calculating an insulation allowable value according to the allowable field intensity and the electric field value so as to judge whether the insulation intensity of the transformer outlet device meets the insulation allowable condition or not according to the insulation allowable value.
In the invention, the memory matrix M is represented as follows:
wherein the content of the first and second substances,
as the location information of the ith path point,
an electric field value corresponding to the ith path point; n is the number of path points in the key path.
In the present invention, the critical path electric field data may also be expanded. Data expansion refers to the complementary interpolation of a continuous function on the basis of discrete data, so that the continuous curve passes through all given discrete data points, and the data expansion can adopt an interpolation method, generally an adjacent difference value or a linear interpolation method.
In the invention, the allowable field intensity calculation formula is adopted
Wherein, in the step (A),
allowable field intensity corresponding to the ith path point; a is a shape coefficient;
and tau is attenuation index for the position information corresponding to the ith path point. A is related to the calculated model shape coefficient, can be the shape coefficient of the bare metal electrode oil gap or the shape coefficient of the surface insulation covered oil gap, and is selected according to the electrode covering condition in the oil gap. τ is related to the quality of the insulating oil used in the actual model, and is determined according to the content of impurities such as granularity and moisture in the transformer oil used.
After the allowable field intensity corresponding to each path point is determined, the insulation allowable value corresponding to each path point is calculated according to the allowable field intensity and the electric field value corresponding to each path point, the minimum value of the insulation allowable values in all the key paths is extracted, and the minimum value of the insulation allowable values is determined
(ii) a If the minimum value of allowable insulation
Satisfy the requirement of
Determining that the insulation strength of the transformer outlet device meets an insulation allowable condition; wherein B is a process coefficient.
The method for calculating the insulation permissibility value corresponding to each path point by using the following formula comprises the following steps:
wherein the content of the first and second substances,
the insulation allowable value corresponding to the ith path point;
allowable field intensity corresponding to the ith path point;
the electric field value corresponding to the ith path point.
The method comprises the steps of firstly setting a calculation model, setting the equipotent surface of a voltage-sharing ball of the calculated line device, the peripheral ground potential, the linear potential of the calculated sleeve, and setting the properties of a wet-process forming material, an insulating paper tube and insulating oil, including temperature, dielectric constant and conductivity.
And then extracting a key path, dividing the volume calculation unit, dividing the surface calculation unit, calculating by adopting a finite element method, extracting a key field intensity allowable path from a pressure equalizing ball according to the calculation result, and extracting a key field intensity allowable path from the ground potential.
And finally, carrying out allowable insulation strength judgment, pouring field intensity values on key field intensity allowable paths, carrying out storage matrix unit setting on path data and electric field intensity data, carrying out storage matrix unit data expansion by adopting an interpolation method, carrying out allowable insulation calculation on each path point on the path, calculating and extracting the minimum allowable insulation value in the whole field, and carrying out allowable insulation judgment according to the minimum allowable insulation value.
The method comprises the steps of constructing and calculating an equipotential surface and a ground potential surface of a voltage-sharing ball, setting an insulating barrier and an oil gap, calculating the electric field intensity of a key structure, analyzing and calculating the allowable insulating property and judging whether the insulating strength meets the design requirement or not by reasonably equating and simplifying the actual assembly structure; when the actual assembly structure is equivalent and simplified, a method for constructing entities such as a voltage-sharing ball, a ground potential plane, a linear potential plane, wet forming, an insulating paper tube, insulating oil and the like is adopted, so that simplification is realized, and the equivalence of material properties and structural characteristics is ensured; when the extraction of the critical path is carried out, two extraction modes of starting from a voltage-sharing ball and starting from the ground potential are adopted, so that the allowable insulation conditions on different paths can be fully verified; the method provides a calculation step for judging the allowable insulation strength, and provides a method for selecting the allowable threshold of an oil gap of a bare metal electrode and an oil gap outside the electrode with insulation covering on the surface, which is used as a basis for judging the allowable insulation.
The method is used for calculating and judging the allowable electric field of the insulation structure of the transformer wire outlet device, and is mainly applied to the design of the oil paper insulation structure of the transformer wire outlet device. The existing method mainly carries out insulation design and estimation of the wire outlet device according to an empirical formula or an analytical method, along with the development of a finite element technology, the method constructs and calculates a voltage-sharing ball equipotential surface and a ground potential surface, sets an insulation barrier and an oil gap according to an electric field accurate calculation result obtained by finite element calculation through reasonable equivalence and simplification of an actual assembly structure, calculates the electric field intensity of a key structure, analyzes the insulation permissibility, and judges whether the insulation strength meets the design requirement.
Fig. 4 is a schematic diagram of a system 400 for determining the insulation strength of a transformer outlet device according to an embodiment of the present invention. As shown in fig. 4, a system 400 for determining the insulation strength of a transformer outlet device according to an embodiment of the present invention includes: a calculation model determination unit 401, a critical path electric field data acquisition unit 402, and an insulation strength permissivity determination unit 403.
Preferably, the calculation model determining unit 401 is configured to determine a transformer outlet device calculation model.
Preferably, the calculation model determining unit 401 determines a transformer outlet device calculation model, including:
the structure of the actual transformer outlet device is simplified, a cross-sectional view is introduced, the structure of an insulating material for dividing an oil gap and a metal material for shielding an electric field or serving as a conductor is arranged, the equipotential surface of a voltage-sharing ball of the outlet device is set to be a high-voltage electrode, the ground potential closest to the outlet device is set to be a ground electrode, and the potential on a sleeve on the inner side of the outlet device is set to be a linear potential.
Preferably, the calculation model determining unit 401 determines a transformer outlet device calculation model, and further includes:
when the insulating material is a wet forming material, setting the ratio of the dielectric constant of the wet forming material to the dielectric constant of the insulating oil to be 1.6: 1; when the insulating material is an insulating paper cylinder, the ratio of the dielectric constant of the insulating paper cylinder to the dielectric constant of the insulating oil is set to be 2: 1.
Preferably, the critical path electric field data obtaining unit 402 is configured to perform electric field value calculation based on the transformer outlet device calculation model, and obtain critical path electric field data; wherein the critical path electric field data comprises: and position information and electric field values corresponding to each path point in the key path.
Preferably, the critical path electric field data obtaining unit 402, which performs electric field value calculation based on the transformer outlet device calculation model to obtain the critical path electric field data, includes:
carrying out volume subdivision and surface subdivision on the transformer outlet device calculation model by using a finite element method, and determining subdivision units;
based on the subdivision units, calculating an electric field by using an electrostatic field solver to obtain an electric field value of the grid vertex of each subdivision unit;
and determining the electric field data of the critical path based on the electric field value of the top point of each subdivision unit mesh.
Preferably, the determining the critical path electric field data based on the electric field value of the vertex of each mesh of the subdivision units by the critical path electric field data obtaining unit 402 includes:
determining a key path according to power lines which start from the surface of a voltage-sharing ball of the wire outlet device and respectively pass through different parts at chamfers of the upper edge and the lower edge of the voltage-sharing ball, and start from any position of an electrode of the wire outlet device and pass through different parts in a large oil clearance on the outermost side;
and extracting the position information of the grid vertex on the key path and the corresponding electric field value to acquire the electric field data of the key path.
Preferably, the allowable insulation strength determining unit 403 is configured to calculate an allowable field strength corresponding to each path point according to the position information, and determine the insulation strength of the transformer outlet device according to the allowable field strength and the electric field value corresponding to each path point.
Preferably, wherein the system further comprises:
and the data expansion unit is used for performing data expansion on the electric field data of the critical path by adopting an interpolation method.
Preferably, the allowable insulation strength determining unit 403 calculates an allowable field strength corresponding to each path point according to the position information, including:
wherein the content of the first and second substances,
allowable field intensity corresponding to the ith path point; a is a shape coefficient;
and tau is the attenuation index of the position information corresponding to the ith path point.
Preferably, the insulation strength permissibility determining unit 403 determines the insulation strength of the transformer outlet device according to the permissible field strength and the electric field value corresponding to each path point, including:
calculating an insulation allowable value corresponding to each path point according to the allowable field intensity and the electric field value corresponding to each path point, wherein the method comprises the following steps:
determining an insulation permissivity minimum based on the minimum of the insulation permissibility values in all critical paths
；
If the minimum value of allowable insulation
Satisfy the requirement of
Determining that the insulation strength of the transformer outlet device meets an insulation allowable condition;
wherein the content of the first and second substances,
the insulation allowable value corresponding to the ith path point;
allowable field intensity corresponding to the ith path point;
an electric field value corresponding to the ith path point; and B is a process coefficient.
The system 400 for determining the insulation strength of the transformer outlet device according to the embodiment of the present invention corresponds to the method 100 for determining the insulation strength of the transformer outlet device according to another embodiment of the present invention, and is not described herein again.
Based on another aspect of the invention, the invention provides a computer readable storage medium having stored thereon a computer program which, when being executed by a processor, realizes the steps of any one of the methods of determining the insulation strength of a transformer outlet device.
Based on another aspect of the present invention, the present invention provides an electronic device comprising:
the computer-readable storage medium described above; and
one or more processors to execute the program in the computer-readable storage medium.
The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.
Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ means, component, etc ]" are to be interpreted openly as referring to at least one instance of said means, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.
Claims (8)
1. A method of determining the dielectric strength of a transformer outlet device, the method comprising:
determining a transformer outlet device calculation model;
calculating an electric field value based on the transformer wire outlet device calculation model to obtain electric field data of a critical path; wherein the critical path electric field data comprises: position information and electric field values corresponding to each path point in the key path;
calculating allowable field intensity corresponding to each path point according to the position information, and determining the insulation strength of the transformer outlet device according to the allowable field intensity and the electric field value corresponding to each path point;
the determining of the calculation model of the transformer outgoing line device comprises the following steps:
simplifying the structure of an actual transformer wire outlet device, introducing a sectional view, setting the structures of an insulating material for dividing an oil gap and a metal material for shielding an electric field or serving as a conductor, setting a voltage-equalizing ball equipotential surface of the wire outlet device as a high-voltage electrode, setting the ground potential closest to the wire outlet device as a ground electrode, and setting the potential on a sleeve pipe at the inner side of the wire outlet device as a linear potential;
the determining of the calculation model of the transformer outgoing line device further comprises:
when the insulating material is a wet forming material, setting the ratio of the dielectric constant of the wet forming material to the dielectric constant of the insulating oil to be 1.6: 1; when the insulating material is an insulating paper tube, setting the ratio of the dielectric constant of the insulating paper tube to the dielectric constant of the insulating oil to be 2: 1;
wherein, the calculating of the electric field value based on the transformer outlet device calculation model to obtain the electric field data of the critical path comprises:
carrying out volume subdivision and surface subdivision on the transformer outlet device calculation model by using a finite element method, and determining subdivision units;
based on the subdivision units, calculating an electric field by using an electrostatic field solver to obtain an electric field value of the grid vertex of each subdivision unit;
determining the electric field data of the critical path based on the electric field value of the top point of each subdivision unit mesh;
wherein, the calculating the allowable field intensity corresponding to each path point according to the position information comprises:
wherein the content of the first and second substances,
allowable field intensity corresponding to the ith path point; a is a shape coefficient;
position information corresponding to the ith path point is obtained, and tau is a decay index;
wherein, the determining the insulation strength of the transformer outlet device according to the allowable field strength and the electric field value corresponding to each path point comprises:
calculating an insulation allowable value corresponding to each path point according to the allowable field intensity and the electric field value corresponding to each path point, wherein the method comprises the following steps:
determining an insulation permissivity minimum based on the minimum of the insulation permissibility values in all critical paths
；
If the minimum value of allowable insulation
Satisfy the requirement of
Determining that the insulation strength of the transformer outlet device meets an insulation allowable condition;
wherein the content of the first and second substances,
the insulation allowable value corresponding to the ith path point;
allowable field intensity corresponding to the ith path point;
an electric field value corresponding to the ith path point; and B is a process coefficient.
2. The method of claim 1, wherein determining critical path electric field data based on the electric field values at the vertices of each of the split cell meshes comprises:
determining a key path according to power lines which start from the surface of a voltage-sharing ball of the wire outlet device and respectively pass through different parts at chamfers of the upper edge and the lower edge of the voltage-sharing ball, and start from any position of an electrode of the wire outlet device and pass through different parts in a large oil clearance on the outermost side;
and extracting the position information of the grid vertex on the key path and the corresponding electric field value to acquire the electric field data of the key path.
3. The method of claim 1, further comprising:
and performing data expansion on the electric field data of the critical path by adopting an interpolation method.
4. A system for determining the dielectric strength of a transformer outlet device, the system comprising:
the calculation model determining unit is used for determining a calculation model of the transformer wire outlet device;
the critical path electric field data acquisition unit is used for calculating an electric field value based on the transformer outlet device calculation model to acquire critical path electric field data; wherein the critical path electric field data comprises: position information and electric field values corresponding to each path point in the key path;
the allowable insulation strength determining unit is used for calculating allowable field intensity corresponding to each path point according to the position information and determining the insulation strength of the transformer wire outlet device according to the allowable field intensity and the electric field value corresponding to each path point;
the calculation model determining unit determines a calculation model of the transformer outgoing line device, and includes:
simplifying the structure of an actual transformer wire outlet device, introducing a cross-sectional view, setting the structures of an insulating material for dividing an oil gap and a metal material for shielding an electric field or serving as a conductor, setting a voltage-sharing ball equipotential surface of the wire outlet device as a high-voltage electrode, setting the ground potential closest to the wire outlet device as a ground electrode, and setting the potential on a sleeve on the inner side of the wire outlet device as a linear potential;
the calculation model determining unit determines a calculation model of the transformer outlet device, and further includes:
when the insulating material is a wet forming material, setting the ratio of the dielectric constant of the wet forming material to the dielectric constant of the insulating oil to be 1.6: 1; when the insulating material is an insulating paper tube, setting the ratio of the dielectric constant of the insulating paper tube to the dielectric constant of the insulating oil to be 2: 1;
the critical path electric field data obtaining unit calculates an electric field value based on the transformer outlet device calculation model, and obtains the critical path electric field data, including:
carrying out volume subdivision and surface subdivision on the transformer outlet device calculation model by using a finite element method, and determining subdivision units;
based on the subdivision units, calculating an electric field by using an electrostatic field solver to obtain an electric field value of the grid vertex of each subdivision unit;
determining electric field data of a key path based on the electric field value of the grid vertex of each subdivision unit;
wherein, the allowable insulation strength determining unit calculates the allowable field strength corresponding to each path point according to the position information, and includes:
wherein the content of the first and second substances,
allowable field intensity corresponding to the ith path point; a is a shape factor;
position information corresponding to the ith path point is obtained, and tau is a decay index;
the allowable insulation strength determining unit determines the insulation strength of the transformer outgoing line device according to the allowable field strength and the electric field value corresponding to each path point, and includes:
calculating an insulation allowable value corresponding to each path point according to the allowable field intensity and the electric field value corresponding to each path point, wherein the method comprises the following steps:
determining an insulation permissivity minimum based on the minimum of the insulation permissibility values in all critical paths
；
If the minimum value of allowable insulation
Satisfy the requirement of
Determining that the insulation strength of the transformer outlet device meets an insulation allowable condition;
wherein the content of the first and second substances,
the insulation allowable value corresponding to the ith path point;
allowable field intensity corresponding to the ith path point;
an electric field value corresponding to the ith path point; and B is a process coefficient.
5. The system of claim 4, wherein the critical path electric field data obtaining unit determines the critical path electric field data based on the electric field values at the vertices of each of the meshes of the subdivision unit, and comprises:
determining a key path according to power lines which start from the surface of a voltage-sharing ball of the wire outlet device and respectively pass through different parts at chamfers of the upper edge and the lower edge of the voltage-sharing ball, and start from any position of an electrode of the wire outlet device and pass through different parts in a large oil clearance on the outermost side;
and extracting the position information of the grid vertex on the key path and the corresponding electric field value to acquire the electric field data of the key path.
6. The system of claim 4, further comprising:
and the data expansion unit is used for performing data expansion on the electric field data of the critical path by adopting an interpolation method.
7. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 3.
8. An electronic device, comprising:
the computer-readable storage medium recited in claim 7; and
one or more processors to execute the program in the computer-readable storage medium.
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| CN114034988A (en) * | 2021-08-31 | 2022-02-11 | 四川大学 | Method for realizing insulation degradation characterization through partial discharge characteristic experiment platform |
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| US20100274529A1 (en) * | 2009-04-24 | 2010-10-28 | Josef Altmann | On-line diagnostic and prediction of dielectric behavior of power transformers |
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| CN104199717A (en) * | 2014-08-04 | 2014-12-10 | 西安交通大学 | Numerical simulation method for three-dimensional dynamic evolution process of streamer discharge of insulating oil |
| CN109101716A (en) * | 2018-08-06 | 2018-12-28 | 南方电网科学研究院有限责任公司 | A kind of the influence emulation mode and device of bushing shell for transformer external insulation electric field |
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