CN113806974B - Stability evaluation method, device and system for electric connection of transformer bushing - Google Patents
Stability evaluation method, device and system for electric connection of transformer bushing Download PDFInfo
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Abstract
The invention discloses a method, a device and a system for evaluating the stability of electric connection of transformer bushings, comprising the following steps: obtaining mechanical vibration data by vibration monitoring of the lifting seat; calculating first mechanical vibration load data of the sleeve mounting flange according to the mechanical vibration data based on a first finite element model of the transformer; calculating second mechanical vibration load data of a bushing electric connection area of the transformer according to the first mechanical vibration load data based on a second finite element model of the lifting seat area; and evaluating the stability of the sleeve electric connection area according to the mechanical characteristics of the components in the sleeve electric connection area and the second mechanical vibration load data. By adopting the embodiment of the invention, the mechanical vibration load of the transformer under various working conditions can be equivalent to the electric connection area of the transformer bushing, so that the electric connection stability of the transformer bushing can be accurately evaluated.
Description
Technical Field
The invention relates to the field of power grid stability analysis, in particular to a stability evaluation method, device and system for electric connection of transformer bushings.
Background
The stability of the electrical connection of the transformer bushing is closely related to whether the transformer can normally operate, and in recent years, serious accidents (local overheating, ignition of the transformer and explosion of the transformer) caused by the connection failure of the conductors of the internal main current-carrying loop of the multi-pole extra-high voltage converter transformer generated by a power grid reflect the current scientific understanding, engineering experience and research depth of the connection characteristics and failure modes of the internal main current-carrying loop of the super-large capacity transformer. Therefore, ten parts are necessary to research the failure mechanism of the internal conductor connecting system of the ultra-large capacity transformer and the measures for improving the reliability under the combined actions of long-term mechanical vibration, electrodynamic force, harmonic characteristic, material cold and hot effect, conductor stress relaxation effect and other working conditions so as to ensure the long-term operation reliability of equipment and avoid similar accidents.
However, the current research on electrical connection is mainly focused on gas medium (SF 6, air and vacuum), the research on electrical connection characteristics of conductors in oil is less, the research on failure process and failure mode of the electrical connection of the transformer bushing current-carrying loop is still in the primary stage, and the stability of the electrical connection of the transformer bushing cannot be accurately evaluated according to mechanical vibration generated during the operation of the transformer.
Disclosure of Invention
In view of the above problems, an object of the embodiments of the present invention is to provide a method, an apparatus, and a system for evaluating stability of electrical connection of transformer bushings, which can obtain a mechanical vibration load of an electrical connection area of a transformer bushing according to a mechanical vibration load of a transformer under various working conditions, so as to accurately evaluate the stability of electrical connection of the transformer bushing according to the mechanical vibration load of the electrical connection area of the transformer bushing.
To achieve the above object, a first aspect of the present invention provides a method for evaluating stability of electrical connection of transformer bushings, including: the method comprises the steps of obtaining mechanical vibration data of a lifting seat of a transformer by carrying out vibration monitoring on the lifting seat; calculating first mechanical vibration load data of the sleeve mounting flange according to the mechanical vibration data based on a first finite element model of the transformer; calculating second mechanical vibration load data of a bushing electric connection area of the transformer according to the first mechanical vibration load data based on a second finite element model of a lifting seat area, wherein components in the lifting seat area comprise a transformer bushing, the lifting seat and a bushing mounting flange, and the bushing electric connection area is a preset area for connecting the transformer bushing with a lead-out wire of a transformer winding; obtaining relative displacement data of the components in the sleeve electric connection area according to the mechanical characteristics of the components in the sleeve electric connection area and the second mechanical vibration load data; and evaluating the stability of the sleeve electric connection area according to the relative displacement data.
Further, the vibration monitoring of the lifting seat of the transformer, and the obtaining of the mechanical vibration data of the lifting seat specifically includes: the vibration data of each operation condition of the transformer is tested through a vibration monitoring device arranged on the lifting seat, and the mechanical vibration data are obtained; the vibration monitoring device comprises a vibration sensor, a vibration monitoring host and a background data acquisition and analysis device; the mechanical vibration data includes a direction and an amplitude of the mechanical vibration.
Further, the method for evaluating the stability of the electrical connection of the transformer bushing acquires a first finite element model of the transformer by: and constructing a first finite element model of the transformer by adopting finite element analysis software at least according to the structure and the size of the transformer bushing, the structure and the size of the lifting seat and the structure and the size of the bushing mounting flange.
Further, the method for evaluating the stability of the electrical connection of the transformer bushing obtains a second finite element model of the elevated seat area by: and constructing a second finite element model of the lifting seat area by adopting finite element analysis software according to the structure and the size of the transformer bushing, the structure and the size of the lifting seat, the structure and the size of the bushing mounting flange and the type and the structure of bushing electric connection.
Further, the calculating the first mechanical vibration load data of the mounting flange according to the mechanical vibration data specifically includes: loading the mechanical vibration data to the first finite element model; performing segmentation processing and interpolation calculation on the first finite element model by adopting a finite element method to obtain first mechanical vibration load data of the sleeve mounting flange; wherein the first mechanical vibration load data includes first displacement data, first stress data, and first stress data.
Further, the calculating the second mechanical vibration load data of the bushing electric connection area of the transformer according to the first mechanical vibration load data specifically includes: loading the first mechanical vibration load data to the sleeve mounting flange as a load of the second finite element model; performing segmentation processing and interpolation calculation on the second finite element model by adopting a finite element method to obtain second mechanical vibration load data of the sleeve electric connection area; wherein the second mechanical vibration load data includes second displacement data, second stress data, and second strain data.
A second aspect of the present invention provides a stability assessment device for electrical connection of transformer bushings, comprising: the first load data acquisition module is used for calculating first mechanical vibration load data of the mounting flange according to mechanical vibration data obtained by vibration monitoring of the lifting seat of the transformer based on a first finite element model of the transformer; the second load data acquisition module is used for calculating second mechanical vibration load data of a sleeve electric connection area of the transformer according to the first mechanical vibration load data based on a second finite element model of a lifting seat area, wherein the lifting seat area comprises a transformer sleeve, a lifting seat and a sleeve mounting flange, and the sleeve electric connection area is a preset area for connecting the transformer sleeve with a lead-out wire of a transformer winding; and the stability evaluation module is used for obtaining relative displacement data of the components in the sleeve electric connection area according to the mechanical characteristics of the components in the sleeve electric connection area and the second mechanical vibration load data, and evaluating the stability of the sleeve electric connection area according to the relative displacement data.
Further, the stability evaluation device of the transformer bushing electrical connection further comprises a first finite element model acquisition module for: and constructing a first finite element model of the transformer by adopting finite element analysis software at least according to the structure and the size of the transformer bushing, the structure and the size of the lifting seat and the structure and the size of the bushing mounting flange.
Further, the stability evaluation device of the transformer bushing electrical connection further comprises a second finite element model acquisition module for: and constructing a second finite element model of the lifting seat area by adopting finite element analysis software according to the structure and the size of the transformer bushing, the structure and the size of the lifting seat, the structure and the size of the bushing mounting flange and the type and the structure of bushing electric connection.
A third aspect of the embodiment of the present invention provides a system for evaluating the stability of electrical connection of transformer bushings, including a vibration monitoring device and a device for evaluating the stability of electrical connection of transformer bushings according to any one of the second aspects; the vibration monitoring device is used for monitoring vibration of the lifting seat of the transformer and obtaining mechanical vibration data of the lifting seat; the stability assessment device of the transformer bushing electrical connection is used for performing the stability assessment method of the transformer bushing electrical connection according to any of the first aspects.
Compared with the prior art, the embodiment of the invention has the beneficial effects that: according to the method, the device and the system for evaluating the stability of the electrical connection of the transformer bushing, provided by the embodiment of the invention, the mechanical vibration load of the transformer under various working conditions can be equivalent to the electrical connection area of the transformer bushing by a method combining actual measurement and simulation, the problem that the electrical connection load of the transformer bushing and the mechanical vibration generated when the transformer works cannot be correlated and mapped is solved, and the electrical connection stability of the transformer bushing can be accurately evaluated according to the mechanical vibration load equivalent to the electrical connection area of the transformer bushing.
Drawings
FIG. 1 is a flow chart of a preferred embodiment of a method for evaluating the stability of an electrical connection of transformer bushings provided by the present invention;
FIG. 2 is a schematic diagram of a first finite element model of a method for evaluating stability of an electrical connection of transformer bushings according to the present invention;
FIG. 3 is a schematic diagram of a cylindrical coordinate system of a ring unit of a preferred embodiment of finite element calculation in a method for evaluating stability of electrical connection of transformer bushings according to the present invention;
FIG. 4 is a schematic cross-sectional view of a ring unit of another preferred embodiment of finite element computation in a method for evaluating stability of an electrical connection of transformer bushings provided by the present invention;
FIG. 5 is a schematic diagram of a second finite element model of a method for evaluating stability of an electrical connection of transformer bushings according to the present invention;
FIG. 6 is a schematic diagram of a preferred embodiment of a stability assessment apparatus for electrical connection of transformer bushings provided by the present invention;
fig. 7 is a schematic structural diagram of a preferred embodiment of a stability evaluation system for electrical connection of transformer bushings provided by the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, a flow chart of a preferred embodiment of a method for evaluating the stability of an electrical connection of a transformer bushing according to the present invention is shown.
The first aspect of the embodiment of the invention provides a method for evaluating the stability of electrical connection of transformer bushings, which comprises the following steps of S1 to S5:
step S1: and obtaining mechanical vibration data of the lifting seat by vibration monitoring of the lifting seat of the transformer.
It should be noted that, when vibration monitoring is performed on the lifting seat of the transformer, a single displacement and acceleration sensor can be used for performing on-site monitoring and recording, and automatic monitoring and data processing of vibration data of the transformer can be realized through an integrated intelligent on-line vibration monitoring device.
Preferably, the vibration monitoring device adopted in the embodiment of the invention is an intelligent online vibration monitoring device, and the intelligent online vibration monitoring device is generally composed of three parts, namely a vibration sensor (a sensing layer), a vibration monitoring host (a sensing layer) and a background data acquisition and analysis device (a software layer). The sensing layer acquires multidimensional information such as mechanical vibration signals, running voltage and current of the transformer through sensors such as a vibration sensor and an electric quantity sensor; the sensing layer adopts a vibration monitoring IED host to collect multi-state quantity information of the transformer; the software layer comprises functions of data acquisition, feature quantity extraction, comprehensive research and judgment and the like, and can automatically give out fault diagnosis reports. The vibration monitoring host is provided with a network communication interface, the data report can be stored in the host, and can be sent to a station control layer background CAC or an auxiliary monitoring platform AMC of a transformer substation through a network cable or an optical fiber according to IEC61850 or 104 protocol, so that remote online monitoring and fault diagnosis are realized.
Preferably, vibration monitoring of the lifting seat of the transformer requires a station arrangement on the lifting seat, the choice of station arrangement being dependent on the structure and height of the lifting seat and on the engineering experience of the technician. In the embodiment of the invention, two layers of measuring points are arranged in the axial direction of the lifting seat, and one measuring point is arranged every 90 degrees in the radial direction, so that eight measuring points are arranged in total on one lifting seat.
After the measuring point arrangement of the lifting seat is completed, the mechanical vibration characteristics of the transformer under different working conditions can be monitored on line, and monitoring data are recorded in the background. Typical transformer operating conditions include test conditions and normal operating conditions, and the test conditions include a transformer charging test, an idle load pressurization test and the like. The on-line monitoring of the resulting mechanical vibration data includes the direction of the mechanical vibration and the magnitude of the mechanical vibration over time in each direction.
Step S2: and calculating first mechanical vibration load data of the sleeve mounting flange according to the mechanical vibration data based on the first finite element model of the transformer.
Referring to fig. 2, a schematic structural diagram of a first finite element model of a method for evaluating stability of an electrical connection of transformer bushings is provided.
In another preferred embodiment, the acquiring the first finite element model of the transformer in the step S2 specifically includes: and constructing a first finite element model of the transformer by adopting finite element analysis software at least according to the structure and the size of the transformer bushing, the structure and the size of the lifting seat and the structure and the size of the bushing mounting flange.
Preferably, the three-dimensional finite element simulation model of the transformer is built using industry-wide finite element commercial software such as ANSYS, ABAQUS, HYPERMESH, etc.
Preferably, since the three-dimensional structure of the transformer is very complex, simplification can be suitably performed for the region far from the elevating seat at the time of modeling, the actual structure and model are replaced by a counterweight, and the time-varying field is selected as the simulation environment at the time of loading and solving.
In another preferred embodiment, the calculating the first mechanical vibration load data of the sleeve mounting flange according to the mechanical vibration data in the step S2 specifically includes steps S21 to S22, as follows:
step S21: the mechanical vibration data is loaded to the first finite element model.
And loading the mechanical vibration data of the lifting seat obtained by monitoring in the step S1 to the position of the lifting seat in the first finite element model.
Step S22: performing segmentation processing and interpolation calculation on the first finite element model by adopting a finite element method to obtain first mechanical vibration load data of the sleeve mounting flange; wherein the first mechanical vibration load data includes first displacement data, first stress data, and first stress data.
The key point of the part is that the measured data of vibration monitoring is equivalent to the sleeve mounting flange of the transformer, and the lifting seat is a cylindrical elastic continuous body and is in an axisymmetric three-dimensional shape. And performing finite element calculation on the first finite element model, firstly performing sectioning, separation and dispersion on a continuum, taking a discrete unit as a circular ring shape, taking a section unit as a triangle of two-dimensional three-node, then performing finite element interpolation calculation, establishing a rigidity matrix, and solving and calculating to obtain the mechanical vibration load of the sleeve mounting flange position of the transformer under the actual operation working condition, wherein the mechanical vibration load comprises movement displacement, effective stress, strain and the like.
Step S3: and calculating second mechanical vibration load data of a bushing electric connection area of the transformer according to the first mechanical vibration load data based on a second finite element model of the lifting seat area, wherein components in the lifting seat area comprise a transformer bushing, the lifting seat and a bushing mounting flange, and the bushing electric connection area is a preset area for connecting the transformer bushing with an outgoing line of a transformer winding.
Referring to fig. 3, a schematic structural diagram of a second finite element model of a method for evaluating stability of electrical connection of transformer bushings is provided.
In another preferred embodiment, the acquiring the second finite element model of the elevated seat area in the step S3 specifically includes: and constructing a second finite element model of the lifting seat area by adopting finite element analysis software according to the structure and the size of the transformer bushing, the structure and the size of the lifting seat, the structure and the size of the bushing mounting flange and the type and the structure of bushing electric connection.
It should be noted that the finite element simulation model of the elevated seat area must truly reflect the structure and stress transfer characteristics between the transformer bushing, the elevated seat and the bushing mounting flange, and the modeling of the bushing electrical connection portion must conform to the type and structure of the actual bushing electrical connection, so that structural constraints and boundaries of the bushing electrical connection area must be guaranteed to conform to the actual situation. Typical bushing electrical connection types are of face-to-face compression, threaded, watchband plug-in and bolted types, and there are large differences in the structural constraints of the different connection types, so modeling should be performed according to the actual connection type.
Specifically, the sleeve electric connection area is a preset area where the transformer sleeve is connected with the outgoing line of the transformer winding, and is an area where the transformer sleeve is electrically connected with the outgoing line of the transformer winding in a surface-to-surface compression joint mode, a threaded connection mode, a watchband plug-in mode, a bolt connection mode and other connection modes.
In another preferred embodiment, the calculating the second mechanical vibration load data of the bushing electric connection area of the transformer according to the first mechanical vibration load data in the step S3 specifically includes steps S31 to S32, as follows:
step S31: and loading the first mechanical vibration load data to the sleeve mounting flange as a load of the second finite element model.
Step S32: performing segmentation processing and interpolation calculation on the second finite element model by adopting a finite element method to obtain second mechanical vibration load data of the sleeve electric connection area; wherein the second mechanical vibration load data includes second displacement data, second stress data, and second strain data.
The key of the part is that the first mechanical vibration load data of the sleeve mounting flange obtained in the step S2 is equivalent to the sleeve electric connection area, and the sleeve mounting flange is a cylindrical elastic continuous body and is in an axisymmetric three-dimensional shape. And performing finite element calculation on the second finite element model, firstly performing subdivision discretization on a continuum, taking discrete units as circular rings, taking cross section units as triangles of two-dimensional three-node, then performing finite element interpolation calculation, establishing a stiffness matrix, and solving and calculating to obtain the mechanical vibration load of the sleeve electric connection area of the transformer under the actual operation working condition, wherein the mechanical vibration load comprises motion displacement, effective stress, strain and the like.
In a preferred embodiment, the specific calculation process of the step S22 and the step S32 is as follows:
as shown in fig. 4, the cell nodes are circumferential hinges, each cell forms a grid in the rz plane, and only one section needs to be taken out for grid division and analysis during calculation.
As shown in fig. 5, a section of the annular unit is taken, and the unit node displacement is:
a linear displacement mode is selected and the displacement is controlled,wherein: />φ=[1 r z],β=[β 1 β 2 β 3 ...β 6 ] T 。
Wherein a is i 、a j And a m For displacement of three nodes of the ring unit, u i 、u j And u m For u coordinate, w of each node i 、w j And w m Is the w coordinate of each node.
Displacement mode:
similar to the plane problem, the node displacement is expressed by 6 generalized coordinates
u=N i u i +N j u j +N m u m (2)
w=N i w i +N j w j +N m w m
Interpolation function N i Expressed as:
wherein a is i =r j z m -r m z j ,b i =z j -z m ,c i =-(r j -r m ), r i 、r j And r m R coordinate, z for each node i 、z j And z m For each node, A is the cross-sectional area of the triangular ring-shaped unit.
Cell strain:
wherein,,
it can be seen that the strain component ε r ,ε z ,γ rz Are all constant but have a circumferential strain epsilon θ Not constant, f k In relation to the position (r, z) of each point, and when the structure comprises an axis of symmetry (r=0),f k is singular.
Cell stress:
wherein,,d represents modulus, v is Poisson's ratio, and B is strain matrix.
Shear stress τ rz Is constant, sigma r 、σ z Sum sigma θ Is positive stress in different directions and sigma r 、σ z Sum sigma θ Neither is a constant.
Furthermore, cell stiffness matrix K e The calculation method of (2) is as follows:
in order to simplify the calculation and eliminate the singular induced when the structure contains an axis of symmetry, the calculation f is calculated k When using the coordinates at the centroid of the cell, the r and z of the cell, which change with point, are usedTo approximate, then:
the strain matrix B and the strain matrix S are then both converted into constant matrices.
A in the formula (9) is the cross-sectional area of the triangular ring unit. Wherein,,
wherein:
K 1 =b r b s +f r f s +A 1 (b r f s +f r b s )+A 2 c r c s
K 2 =A 1 c r (b s +f s )+A 2 b r c S
K 3 =A 1 c S (b r +f r )+A 2 c r b s
K 4 =c r c S +A 2 b r b s
the higher precision can be ensured by closely dividing the grid near the symmetry axis.
Force concentration:
volumetric force on cellCan be expressed by the following formula (11), internal initial stress +.>Can be expressed by the following formula (12), concentrating force P F Can be expressed by the following formula (13).
P F =2πF (13)
Wherein,, and->The boundary distribution force and the initial strain acting on the cell are respectively represented by T, which represents the boundary distribution force matrix of the cell.
Force of concentration P F Should be the sum of the concentrated forces acting on a circle of nodes, r i Is the r coordinate of node i, F ir 、F iz Is the component in the r and z directions of the concentrated load acting on the circumference of the node i per unit length.
Step S4: and obtaining relative displacement data of the components in the sleeve electric connection area according to the mechanical characteristics of the components in the sleeve electric connection area and the second mechanical vibration load data.
Step S5: and evaluating the stability of the sleeve electric connection area according to the relative displacement data.
Since the bushing electrical connection is made by contacting the plurality of components to conduct current, the operational reliability is directly reflected by the reliability of the contact between the components. The mechanical vibration load of the sleeve electric connection area is obtained through finite element calculation in the step S3, namely the mechanical vibration load of each component in the sleeve electric connection area, the deformation condition of each component can be obtained by combining the mechanical characteristics of the materials of each component, such as elastoplasticity, and the like, so that the relative displacement between each component can be deduced, whether the components are actually contacted or not can be judged according to the relative displacement of each component, if the relative displacement is larger than 0, the contact failure is considered, and the stability of the sleeve electric connection area can be evaluated through counting the area of the contact failure area.
According to the method for evaluating the stability of the electrical connection of the transformer bushing, provided by the embodiment of the invention, the mechanical vibration load of the transformer under various working conditions can be equivalent to the electrical connection area of the transformer bushing by a method combining actual measurement and simulation, the problem that the electrical connection load of the transformer bushing and the mechanical vibration generated when the transformer works cannot be correlated and mapped is solved, and the electrical connection stability of the transformer bushing can be accurately evaluated according to the mechanical vibration load equivalent to the electrical connection area of the transformer bushing.
Referring to fig. 6, a schematic structural diagram of a preferred embodiment of a device for evaluating the stability of electrical connection of transformer bushings is provided.
A second aspect of an embodiment of the present invention provides a device for evaluating stability of electrical connection of transformer bushings, including: the first load data obtaining module 401 is configured to calculate, based on a first finite element model of the transformer, first mechanical vibration load data of the mounting flange according to mechanical vibration data obtained by vibration monitoring of a lifting seat of the transformer.
And a second load data acquisition module 402, configured to calculate, based on a second finite element model of a lifting seat area, second mechanical vibration load data of a bushing electrical connection area of the transformer according to the first mechanical vibration load data, where the lifting seat area includes a transformer bushing, the lifting seat, and the bushing mounting flange, and the bushing electrical connection area is a preset area where the transformer bushing is connected with an outgoing line of a transformer winding.
And the stability evaluation module 403 is configured to obtain relative displacement data of the component in the electrical connection region of the sleeve according to the mechanical characteristics of the component in the electrical connection region of the sleeve and the second mechanical vibration load data, and evaluate the stability of the electrical connection region of the sleeve according to the relative displacement data.
Further, the device for evaluating the stability of the electrical connection of the transformer bushing further comprises a first finite element model obtaining module 404, configured to: and constructing a first finite element model of the transformer by adopting finite element analysis software at least according to the structure and the size of the transformer bushing, the structure and the size of the lifting seat and the structure and the size of the bushing mounting flange.
Further, the device for evaluating the stability of the electrical connection of the transformer bushing further comprises a second finite element model obtaining module 405, configured to: and constructing a second finite element model of the raised seat area by adopting finite element analysis software according to the structure and the size of the transformer bushing, the structure and the size of the raised seat, the structure and the size of the bushing mounting flange and the type and the structure of bushing electric connection.
Further, the first load data obtaining module 401 is further configured to: loading the mechanical vibration data to the first finite element model; performing subdivision processing and interpolation calculation on the first finite element model by adopting a finite element method to obtain first mechanical vibration load data of the sleeve mounting flange; wherein the first mechanical vibration load data includes first displacement data, first stress data, and first strain data.
Further, the second load data obtaining module 402 is further configured to: loading the first mechanical vibration load data to the sleeve mounting flange as a load of the second finite element model; performing segmentation processing and interpolation calculation on the second finite element model by adopting a finite element method to obtain second mechanical vibration load data of the sleeve electric connection area; wherein the second mechanical vibration load data includes second displacement data, second stress data, and second strain data.
It should be noted that, the stability evaluation device for electrical connection of transformer bushings provided by the embodiment of the present invention can implement all the processes of the stability evaluation method for electrical connection of transformer bushings described in any embodiment, and the functions and the implemented technical effects of each module in the device are respectively the same as those of the stability evaluation method for electrical connection of transformer bushings described in the embodiment, and are not repeated herein.
Referring to fig. 7, a schematic structural diagram of a preferred embodiment of a system for evaluating the stability of an electrical connection of transformer bushings is provided.
A third aspect of the embodiment of the present invention provides a system for evaluating the stability of an electrical connection of a transformer bushing, which includes a vibration monitoring device 501 and a device 502 for evaluating the stability of an electrical connection of a transformer bushing according to any embodiment of the second aspect.
The vibration monitoring device 501 is used for vibration monitoring of the lifting seat of the transformer, and mechanical vibration data of the lifting seat are obtained.
The stability assessment device 502 is configured to perform a method for assessing stability of an electrical connection of a transformer bushing according to any of the embodiments of the first aspect.
It should be noted that, the stability evaluation system for electrical connection of transformer bushings provided by the embodiment of the present invention can implement all the processes of the stability evaluation method for electrical connection of transformer bushings described in any embodiment, and the functions and the implemented technical effects of each device in the system are respectively the same as those of the stability evaluation method for electrical connection of transformer bushings described in the embodiment, and are not described herein again.
While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles of the invention, such changes and modifications are also intended to be within the scope of the invention.
Claims (10)
1. A method for evaluating the stability of an electrical connection of transformer bushings, comprising:
the method comprises the steps of obtaining mechanical vibration data of a lifting seat of a transformer by carrying out vibration monitoring on the lifting seat;
calculating first mechanical vibration load data of the sleeve mounting flange according to the mechanical vibration data based on a first finite element model of the transformer;
calculating second mechanical vibration load data of a bushing electric connection area of the transformer according to the first mechanical vibration load data based on a second finite element model of a lifting seat area, wherein components in the lifting seat area comprise a transformer bushing, the lifting seat and a bushing mounting flange, and the bushing electric connection area is a preset area for connecting the transformer bushing with a lead-out wire of a transformer winding;
obtaining relative displacement data of the components in the sleeve electric connection area according to the mechanical characteristics of the components in the sleeve electric connection area and the second mechanical vibration load data;
and evaluating the stability of the sleeve electric connection area according to the relative displacement data.
2. The method for evaluating the stability of an electrical connection of transformer bushings according to claim 1, wherein said vibration monitoring of a lifting seat of a transformer, obtaining mechanical vibration data of said lifting seat, comprises:
the vibration data of each operation condition of the transformer is tested through a vibration monitoring device arranged on the lifting seat, and the mechanical vibration data are obtained;
the vibration monitoring device comprises a vibration sensor, a vibration monitoring host and a background data acquisition and analysis device;
the mechanical vibration data includes a direction and an amplitude of the mechanical vibration.
3. The method of evaluating the stability of a transformer bushing electrical connection of claim 1, wherein the method obtains the first finite element model of the transformer by:
and constructing a first finite element model of the transformer by adopting finite element analysis software at least according to the structure and the size of the transformer bushing, the structure and the size of the lifting seat and the structure and the size of the bushing mounting flange.
4. The method of evaluating the stability of a transformer bushing electrical connection of claim 1, wherein the method obtains the second finite element model of the elevated seat region by:
and constructing a second finite element model of the raised seat area by adopting finite element analysis software according to the structure and the size of the transformer bushing, the structure and the size of the raised seat, the structure and the size of the bushing mounting flange and the type and the structure of bushing electric connection.
5. A method of evaluating the stability of an electrical connection of a transformer bushing according to claim 3, wherein calculating first mechanical vibration load data of the bushing mounting flange based on the mechanical vibration data comprises:
loading the mechanical vibration data to the first finite element model;
performing subdivision processing and interpolation calculation on the first finite element model by adopting a finite element method to obtain first mechanical vibration load data of the sleeve mounting flange;
wherein the first mechanical vibration load data includes first displacement data, first stress data, and first strain data.
6. The method of claim 4, wherein calculating second mechanical vibration load data of the bushing electrical connection region of the transformer from the first mechanical vibration load data comprises:
loading the first mechanical vibration load data to the sleeve mounting flange as a load of the second finite element model;
performing subdivision processing and interpolation calculation on the second finite element model by adopting a finite element method to obtain second mechanical vibration load data of the sleeve electric connection area;
wherein the second mechanical vibration load data includes second displacement data, second stress data, and second strain data.
7. A stability assessment device for electrical connection of transformer bushings, comprising:
the first load data acquisition module is used for calculating first mechanical vibration load data of the sleeve mounting flange according to mechanical vibration data obtained by vibration monitoring of the lifting seat of the transformer based on a first finite element model of the transformer;
the second load data acquisition module is used for calculating second mechanical vibration load data of a bushing electric connection area of the transformer according to the first mechanical vibration load data based on a second finite element model of a lifting seat area, wherein the lifting seat area comprises a transformer bushing, a lifting seat and a bushing mounting flange, and the bushing electric connection area is a preset area for connecting the transformer bushing with a lead-out wire of a transformer winding;
and the stability evaluation module is used for obtaining relative displacement data of the components in the sleeve electric connection area according to the mechanical characteristics of the components in the sleeve electric connection area and the second mechanical vibration load data, and evaluating the stability of the sleeve electric connection area according to the relative displacement data.
8. The stability assessment apparatus of a transformer bushing electrical connection of claim 7, further comprising a first finite element model acquisition module to:
and constructing a first finite element model of the transformer by adopting finite element analysis software at least according to the structure and the size of the transformer bushing, the structure and the size of the lifting seat and the structure and the size of the bushing mounting flange.
9. The stability assessment apparatus of a transformer bushing electrical connection of claim 8, further comprising a second finite element model acquisition module to:
and constructing a second finite element model of the raised seat area by adopting finite element analysis software according to the structure and the size of the transformer bushing, the structure and the size of the raised seat, the structure and the size of the bushing mounting flange and the type and the structure of bushing electric connection.
10. A stability assessment system of an electrical connection of transformer bushings, characterized by comprising vibration monitoring means and a stability assessment device of an electrical connection of transformer bushings according to any of claims 7 to 9;
the vibration monitoring device is used for monitoring vibration of the lifting seat of the transformer and obtaining mechanical vibration data of the lifting seat;
the stability assessment apparatus is for performing the stability assessment method of the transformer bushing electrical connection according to any of claims 1 to 6.
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