CN113806974A - Stability evaluation method, device and system for transformer bushing electric connection - Google Patents
Stability evaluation method, device and system for transformer bushing electric connection 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, wherein the method comprises the following steps: the method comprises the steps that mechanical vibration data are obtained by monitoring vibration of a lifting seat; calculating to obtain 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 electrical connection area of the transformer according to the first mechanical vibration load data based on a second finite element model of the elevated seat area; evaluating the stability of the electrical connection region of the bushing based on the mechanical properties of the components in the electrical connection region of the bushing and the second mechanical vibration loading 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 transformer bushing electrical connection.
Background
The stability of the transformer bushing electric connection is closely related to whether the transformer can normally operate, in recent years, serious accidents (local overheating, transformer ignition and transformer explosion) caused by connection failure of an internal main current-carrying loop conductor of a plurality of extra-high voltage converter transformers in a power grid reflect that the current characteristics of the connection of the internal main current-carrying loop conductor of the ultra-large-capacity transformer and the scientific knowledge, engineering experience and research depth of a failure mode are far from sufficient. Therefore, it is necessary to research the failure mechanism and reliability improvement measure of the conductor connection system in the ultra-large capacity transformer under the combined action of long-term mechanical vibration, electrodynamic force, harmonic characteristics, material cold and hot effects, stress relaxation effects of the conductor and other working conditions, so as to ensure the long-term operation reliability of the equipment and avoid similar accidents.
However, the research on the electrical connection is mainly focused on the gas medium (SF6, air and vacuum), the research on the electrical connection characteristics of the conductor in oil is less, the research on the failure process and the failure mode of the transformer bushing current-carrying loop electrical connection is still in the primary stage, and the stability of the transformer bushing electrical connection cannot be accurately evaluated according to the mechanical vibration generated during the operation of the transformer.
Disclosure of Invention
In view of the foregoing problems, an object of the embodiments of the present invention is to provide a method, an apparatus, and a system for evaluating electrical connection stability of transformer bushings, which can obtain mechanical vibration loads of electrical connection regions of transformer bushings according to mechanical vibration loads of transformers under various working conditions, so as to accurately evaluate electrical connection stability of transformer bushings according to the mechanical vibration loads of the electrical connection regions of transformer bushings.
In order to achieve the above object, a first aspect of an embodiment of the present invention provides a method for evaluating stability of a transformer bushing electrical connection, including: the method comprises the steps that vibration monitoring is carried out on a lifting seat of a transformer, and mechanical vibration data of the lifting seat are obtained; calculating to obtain 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; 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 raised seat area, wherein components in the raised seat area comprise a transformer bushing, the raised seat and a bushing mounting flange, and the bushing electric connection area is a preset area in which the transformer bushing is connected with an outgoing line of a transformer winding; obtaining relative displacement data of the components in the sleeve electrical connection area according to the mechanical characteristics of the components in the sleeve electrical connection area and the second mechanical vibration load data; and evaluating the stability of the sleeve electric connection region according to the relative displacement data.
Further, the monitoring vibration of the lifting seat of the transformer, and the obtaining of the mechanical vibration data of the lifting seat specifically includes: testing vibration data of each operation condition of the transformer by a vibration monitoring device arranged on the lifting seat to obtain the mechanical vibration data; 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 a magnitude of the mechanical vibration.
Further, the stability evaluation method for the transformer bushing electrical connection obtains a first finite element model of the transformer by the following steps: and constructing a first finite element model of the transformer by adopting finite element analysis software according to at least 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 method of the transformer bushing electrical connection obtains a second finite element model of the elevated seat region by: and constructing a second finite element model of the region of the elevated seat by using finite element analysis software according to the structure and the size of the transformer bushing, the structure and the size of the elevated seat, the structure and the size of the bushing mounting flange and the type and the structure of the bushing electric connection.
Further, the step of calculating the first mechanical vibration load data of the mounting flange according to the mechanical vibration data specifically includes: loading the mechanical vibration data into the first finite element model; performing dissection 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 calculating and obtaining second mechanical vibration load data of the bushing electrical connection region of the transformer according to the first mechanical vibration load data specifically includes: loading the first mechanical vibration load data to the casing mounting flange as a load for 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 vibratory load data comprises second displacement data, second stress data, and second strain data.
The second aspect of the present invention provides a stability evaluation device for electrical connection of a transformer bushing, comprising: the first load data acquisition module is used for calculating and obtaining first mechanical vibration load data of the mounting flange according to mechanical vibration data obtained by carrying out vibration monitoring on a 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 raised seat area, the raised seat area comprises a transformer bushing, the raised seat and a bushing mounting flange, and the bushing electric connection area is a preset area for connecting the transformer bushing and an outgoing line 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 for the electrical connection of the transformer bushing further comprises a first finite element model obtaining module, configured to: and constructing a first finite element model of the transformer by using finite element analysis software according to at least 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 for the electrical connection of the transformer bushing further comprises a second finite element model obtaining module, configured to: and constructing a second finite element model of the region of the elevated seat by using finite element analysis software according to the structure and the size of the transformer bushing, the structure and the size of the elevated seat, the structure and the size of the bushing mounting flange and the type and the structure of the bushing electric connection.
A third aspect of the embodiments of the present invention provides a stability evaluation system for electrical connection of a transformer bushing, including a vibration monitoring device and the stability evaluation device for electrical connection of a transformer bushing according to any one of the second aspect; the vibration monitoring device is used for carrying out vibration monitoring on a lifting seat of the transformer to obtain mechanical vibration data of the lifting seat; the stability evaluation device for the transformer bushing electrical connection is used for executing the stability evaluation method for the transformer bushing electrical connection according to any one of the first aspect.
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 electric 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 electric connection area of the transformer bushing by a method of combining actual measurement and simulation, the problem that the load of the electric connection of the transformer bushing and the mechanical vibration generated when the transformer works can not be associated and mapped is solved, and the electric connection stability of the transformer bushing can be accurately evaluated according to the mechanical vibration load equivalent to the electric connection area of the transformer bushing.
Drawings
FIG. 1 is a schematic flow chart diagram illustrating a method for evaluating the stability of a transformer bushing electrical connection according to a preferred embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a first finite element model of a stability evaluation method for a transformer bushing electrical connection according to a preferred embodiment of the present invention;
FIG. 3 is a schematic diagram of a cylindrical coordinate system of a ring-shaped element of a preferred embodiment of finite element calculation in a stability evaluation method for electrical connection of a transformer bushing according to the present invention;
FIG. 4 is a schematic cross-sectional view of an annular element of another preferred embodiment of finite element calculation in a method for evaluating the stability of a transformer bushing electrical connection provided by the present invention;
FIG. 5 is a schematic structural diagram of a second finite element model of a stability evaluation method for transformer bushing electrical connection according to a preferred embodiment of the present invention;
FIG. 6 is a schematic structural diagram of a preferred embodiment of an apparatus for evaluating the stability of a transformer bushing electrical connection provided by the present invention;
fig. 7 is a schematic structural diagram of a stability evaluation system for transformer bushing electrical connection according to a preferred embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without any inventive step, are within the scope of the present invention.
Referring to fig. 1, a schematic flow chart of a method for evaluating the stability of a transformer bushing electrical connection according to a preferred embodiment of the present invention is shown.
The first aspect of the embodiment of the present invention provides a method for evaluating stability of electrical connection of a transformer bushing, including steps S1 to S5, specifically as follows:
step S1: the mechanical vibration data of the lifting seat is obtained by monitoring the vibration 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 on-site monitoring and recording, and automatic monitoring and data processing of transformer vibration data can also be realized through an integrated intelligent online vibration monitoring device.
Preferably, the vibration monitoring device adopted in the embodiment of the present invention is an intelligent online vibration monitoring device, and the intelligent online vibration monitoring device generally comprises three parts, namely, a vibration sensor (sensing layer), a vibration monitoring host (sensing layer), and a background data acquisition and analysis device (software layer). The sensing layer acquires multi-dimensional information such as mechanical vibration signals, operating 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 machine to acquire multi-state quantity information of the transformer; the software layer comprises functions of data acquisition, characteristic quantity extraction, comprehensive study and judgment and the like, and can automatically give a fault diagnosis report. The vibration monitoring host computer is provided with a network communication interface, and the data report can be stored in the vibration monitoring host computer and also can be sent to a substation control layer background CAC or an auxiliary monitoring platform AMC of a transformer substation through a network cable or an optical fiber according to an IEC61850 or 104 protocol, so that remote online monitoring and fault diagnosis are realized.
Preferably, vibration monitoring of the elevated base of the transformer requires a measuring point arrangement on the elevated base, the choice of which is related to the structure and height of the elevated base and the engineering experience of the skilled person. 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 at every 90 degrees in the radial direction, so that eight measuring points are arranged on one lifting seat.
After the measuring points of the lifting seats are arranged, 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 further include a transformer charging test, a no-load pressurization test and the like. The mechanical vibration data obtained by online monitoring includes the direction of the mechanical vibration and the amplitude of the mechanical vibration in each direction as a function of time.
Step S2: and calculating to obtain 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 stability evaluation method for a transformer bushing electrical connection according to a preferred embodiment of the present invention is shown.
In another preferred embodiment, the obtaining of the first finite element model of the transformer in step S2 specifically includes: constructing a first finite element model of the transformer using finite element analysis software based at least on the structure and dimensions of the transformer bushing, the structure and dimensions of the riser, and the structure and dimensions of the bushing mounting flange.
Preferably, the three-dimensional finite element simulation model of the transformer is established by using industry-common finite element commercial software such as ANSYS, ABAQUS, HYPERMESH and the like.
Preferably, since the three-dimensional structure of the transformer is very complex, the three-dimensional structure can be simplified properly for the region far away from the lifting seat when modeling, the actual structure and the model are replaced by a counterweight mode, and the time-varying field is selected as a simulation environment when loading and solving.
In another preferred embodiment, the step S2 of calculating the first mechanical vibration load data of the bushing mounting flange according to the mechanical vibration data specifically includes the following steps S21 to S22:
step S21: loading the mechanical vibration data 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 dissection 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.
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 carrying out finite element calculation on the first finite element model, firstly, carrying out splitting and scattering on the continuum, taking the scattered units as circular rings, taking the cross-section units as two-dimensional triangular shapes with three nodes, then, carrying out 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 the motion displacement, the effective stress, the 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 elevated seat area, wherein components in the elevated seat area comprise a transformer bushing, the elevated seat and a bushing mounting flange, and the bushing electric connection area is a preset area for connecting the transformer bushing and a lead-out wire of a transformer winding.
Referring to fig. 3, a structural diagram of a second finite element model of a stability evaluation method for transformer bushing electrical connection according to a preferred embodiment of the present invention is shown.
In another preferred embodiment, the step S3 of obtaining the second finite element model of the elevated seat region specifically includes: and constructing a second finite element model of the region of the elevated seat by using finite element analysis software according to the structure and the size of the transformer bushing, the structure and the size of the elevated seat, the structure and the size of the bushing mounting flange and the type and the structure of the bushing electrical connection.
It should be noted that the finite element simulation model of the elevated seat region must actually reflect the structure and stress transmission characteristics among the transformer bushing, the elevated seat, and the bushing mounting flange, and the modeling of the bushing electrical connection portion must be consistent with the type and structure of the actual bushing electrical connection, and it is necessary to ensure that the structural constraints and boundaries of the bushing electrical connection region are consistent with the actual situation. Typical sleeve electric connection types include a surface pressing connection type, a thread connection type, a watchband inserting connection type and a bolt connection type, and structural constraints of different connection types are greatly different, so that modeling is carried out according to actual connection types during modeling.
Specifically, the bushing electrical connection area is a preset area where the transformer bushing is connected with the outgoing line of the transformer winding, and the preset area is an area where the transformer bushing is electrically connected with the outgoing line of the transformer winding in a surface-to-surface press-fit type, a threaded connection type, a watchband plug-in type, a bolt connection type and other connection modes.
In another preferred embodiment, the step S3 of calculating the second mechanical vibration load data of the bushing electrical connection region of the transformer according to the first mechanical vibration load data specifically includes the following steps S31 to S32:
step S31: loading the first mechanical vibration load data to the bushing mounting flange as a load for the second finite element model.
Step S32: performing dissection 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 comprises second displacement data, second stress data, and second strain data.
The key of this part is to equate the first mechanical vibration load data of the sleeve mounting flange obtained in step S2 to the sleeve electrical connection area, and the sleeve mounting flange is a cylindrical elastic continuous body and is an axisymmetric three-dimensional shape. And carrying out finite element calculation on the second finite element model, firstly carrying out subdivision discretization on the continuum, taking the discrete units as circular rings and taking the cross-section units as triangles with three two-dimensional nodes, then carrying out finite element interpolation calculation, establishing a rigidity matrix, and solving and calculating to obtain mechanical vibration loads including motion displacement, effective stress, strain and the like of the sleeve electric connection area of the transformer under the actual operation condition.
In a preferred embodiment, the specific calculation processes of the above steps S22 and S32 are:
as shown in fig. 4, the unit nodes are circumferential hinges, each unit forms a grid in the rz plane, and only one cross section needs to be taken out for grid division and analysis during calculation.
Taking a section of the ring-shaped unit as shown in fig. 5, the unit node displacement is:
the linear displacement mode is selected and the linear displacement mode,
wherein:
φ＝[1 r z]，β＝[β1β2β3...β6]T。
wherein, ai、ajAnd amIs the displacement of three nodes of a ring-shaped unit, ui、ujAnd umIs the u coordinate, w, of each nodei、wjAnd wmIs the w coordinate of each node.
Displacement mode:
similar to the planar problem, the node displacement is expressed by 6 generalized coordinates
u＝Niui+Njuj+Nmum (2)
w＝Niwi+Njwj+Nmwm
Interpolation function NiExpressed as:
wherein, ai＝rjzm-rmzj，bi＝zj-zm，ci＝-(rj-rm)，
ri、rjAnd rmIs the r coordinate, z, of each nodei、zjAnd zmA is the cross-sectional area of the triangular ring-shaped element, which is the z-coordinate of each node.
Unit strain:
wherein,
it follows that the strain component εr，εz，γrzAre all constant, but the hoop strain εθNot a constant value, fkIn relation to each point position (r, z), and when the structure includes an axis of symmetry (r is 0), fkIs singular.
Unit stress:
wherein,
d represents modulus, v is Poisson's ratio, and B is a strain matrix.
Shear stress taurzIs a constant value, σr、σzAnd σθIs a positive stress in different directions, and σr、σzAnd σθAre not constant.
Furthermore, a cell stiffness matrix KeThe calculation method of (2) is as follows:
to simplify the calculation and to eliminate singularities arising when the structure contains an axis of symmetry, f is calculatedkWhile, the r and z in the cell, which vary from point to point, are represented by the coordinates at the centroid of the cell
To approximate, then:
thus, the strain matrix B and the strain matrix S are converted into constant matrixes.
A in the formula (9) is the cross-sectional area of the triangular cyclic unit. Wherein,
wherein:
K1＝brbs+frfs+A1(brfs+frbs)+A2crcs
K2＝A1cr(bs+fs)+A2brcS
K3＝A1cS(br+fr)+A2crbs
K4＝crcS+A2brbs
the grid near the symmetry axis is divided densely, so that higher precision can be ensured.
Concentration force:
volumetric force on the cell
Can be expressed by the following formula (11), internal initial stress
Can be expressed by the following formula (12), concentration force PFCan be expressed by the following formula (13).
PF＝2πF (13)
Wherein,
and
the boundary distribution force and the initial strain acting on the cell, respectively, and T represents the boundary distribution force matrix of the cell.
Concentration force PFIt is the sum of the concentrated forces acting on a ring of nodes, riIs the r coordinate of node i, Fir、FizAre the components in the r and z directions of the concentrated load acting on node i circumference per unit length.
Step S4: and obtaining relative displacement data of the components in the casing electric connection region according to the mechanical characteristics of the components in the casing electric connection region and the second mechanical vibration load data.
Step S5: and evaluating the stability of the sleeve electric connection region according to the relative displacement data.
Because the sleeve electric connection part is contacted by a plurality of parts to conduct current, the working reliability of the sleeve electric connection part is directly reflected by the contact reliability among the parts. The mechanical vibration load of the sleeve electrical connection area is obtained through finite element calculation in step S3, that is, the mechanical vibration load of each component in the sleeve electrical connection area, and the deformation condition of each component can be obtained by combining the mechanical properties of each component material, such as elastoplasticity, etc., so that the relative displacement between each component can be inferred, whether each component is actually contacted can be judged according to the relative displacement of each component, if the relative displacement is greater than 0, the contact failure is considered, and the stability of the sleeve electrical connection area can be evaluated by counting the area of the contact failure area.
According to the stability evaluation method for the transformer bushing electrical connection provided by the embodiment of the invention, the mechanical vibration load of the transformer under various working conditions can be equivalent to the transformer bushing electrical connection area through a method of combining actual measurement and simulation, the problem that the mechanical vibration generated when the transformer works and the load electrically connected with the transformer bushing can not be associated and mapped is solved, and the stability of the transformer bushing electrical connection can be accurately evaluated according to the mechanical vibration load equivalent to the transformer bushing electrical connection area.
Fig. 6 is a schematic structural diagram of a preferred embodiment of the apparatus for evaluating the stability of the transformer bushing electrical connection according to the present invention.
A second aspect of an embodiment of the present invention provides a stability evaluation apparatus for electrical connection of a transformer bushing, including: the first load data obtaining module 401 is configured to calculate, based on the first finite element model of the transformer, first mechanical vibration load data of the mounting flange according to mechanical vibration data obtained by performing vibration monitoring on the lifting seat of the transformer.
A second load data obtaining module 402, configured to calculate, based on a second finite element model of a raised seat region, second mechanical vibration load data of a bushing electrical connection region of the transformer according to the first mechanical vibration load data, where the raised seat region includes a transformer bushing, the raised seat, and the bushing mounting flange, and the bushing electrical connection region is a preset region where the transformer bushing is connected to an outgoing line of a transformer winding.
A stability evaluation module 403, configured to obtain relative displacement data of the component in the casing electrical connection region according to the mechanical characteristic of the component in the casing electrical connection region and the second mechanical vibration load data, and evaluate the stability of the casing electrical connection region according to the relative displacement data.
Further, the apparatus for evaluating the stability of the transformer bushing electrical connection further comprises a first finite element model obtaining module 404 for: and constructing a first finite element model of the transformer by using finite element analysis software according to at least 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 apparatus for evaluating the stability of the transformer bushing electrical connection further comprises a second finite element model obtaining module 405 for: 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 payload data acquiring module 401 is further configured to: loading the mechanical vibration data into the first finite element model; carrying out 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 comprises first displacement data, first stress data, and first strain data.
Further, the second payload data acquiring module 402 is further configured to: loading the first mechanical vibration load data to the casing mounting flange as a load of the second finite element model; performing dissection 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 comprises second displacement data, second stress data, and second strain data.
It should be noted that, the stability evaluation apparatus for electrical connection of a transformer bushing according to an embodiment of the present invention can implement all the processes of the stability evaluation method for electrical connection of a transformer bushing according to any one of the above embodiments, and the functions and implemented technical effects of each module in the apparatus are respectively the same as those of the stability evaluation method for electrical connection of a transformer bushing according to the above embodiments, and are not described herein again.
Fig. 7 is a schematic structural diagram of a preferred embodiment of the system for evaluating the stability of the transformer bushing electrical connection provided by the present invention.
In a third aspect of the embodiments of the present invention, a stability evaluation system for transformer bushing electrical connection is provided, which includes a vibration monitoring device 501 and a transformer bushing electrical connection stability evaluation device 502 according to any one of the embodiments of the second aspect.
The vibration monitoring device 501 is configured to monitor vibration of a lifting seat of a transformer, and obtain mechanical vibration data of the lifting seat.
The stability evaluation device 502 is configured to perform a stability evaluation method for a transformer bushing electrical connection 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 in the embodiments of the present invention can implement all the processes of the stability evaluation method for electrical connection of transformer bushings described in any one of the embodiments, and the functions and 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 embodiments described above, and are not described herein again.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.
Claims (10)
1. A stability assessment method for transformer bushing electrical connection is characterized by comprising the following steps:
the method comprises the steps that vibration monitoring is carried out on a lifting seat of a transformer, and mechanical vibration data of the lifting seat are obtained;
calculating to obtain 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;
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 raised seat area, wherein components in the raised seat area comprise a transformer bushing, the raised seat and a bushing mounting flange, and the bushing electric connection area is a preset area in which the transformer bushing is connected with an outgoing line of a transformer winding;
obtaining relative displacement data of the components in the casing electric connection area according to the mechanical characteristics of the components in the casing electric connection area and the second mechanical vibration load data;
and evaluating the stability of the sleeve electric connection region according to the relative displacement data.
2. The method for evaluating the stability of the electrical connection of the transformer bushing according to claim 1, wherein the step of monitoring the vibration of the elevated base of the transformer to obtain the mechanical vibration data of the elevated base comprises:
testing vibration data of each operation condition of the transformer by a vibration monitoring device arranged on the lifting seat to obtain the mechanical vibration data;
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 a magnitude of the mechanical vibration.
3. The method for assessing 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 using finite element analysis software according to at least 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 for assessing 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 region of the elevated seat by using finite element analysis software according to the structure and the size of the transformer bushing, the structure and the size of the elevated seat, the structure and the size of the bushing mounting flange and the type and the structure of the bushing electric connection.
5. The method for evaluating the stability of the electrical connection of the transformer bushing of claim 3, wherein the calculating the first mechanical vibration load data of the bushing mounting flange according to the mechanical vibration data specifically comprises:
loading the mechanical vibration data into the first finite element model;
carrying out 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 comprises first displacement data, first stress data, and first strain data.
6. The method for evaluating the stability of the bushing electrical connection of the transformer according to claim 4, wherein the calculating the second mechanical vibration load data of the bushing electrical connection region of the transformer according to the first mechanical vibration load data specifically comprises:
loading the first mechanical vibration load data to the casing mounting flange as a load of the second finite element model;
carrying out 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 vibratory load data comprises second displacement data, second stress data, and second strain data.
7. A stability assessment device for a transformer bushing electrical connection, comprising:
the first load data acquisition module is used for calculating and obtaining first mechanical vibration load data of the sleeve mounting flange according to mechanical vibration data obtained by carrying out vibration monitoring on a 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 raised seat area, wherein the raised seat area comprises a transformer bushing, the raised seat and a bushing mounting flange, and the bushing electric connection area is a preset area for connecting the transformer bushing and an outgoing line 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 evaluation 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 using finite element analysis software according to at least 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 evaluation 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 region of the elevated seat by using finite element analysis software according to the structure and the size of the transformer bushing, the structure and the size of the elevated seat, the structure and the size of the bushing mounting flange and the type and the structure of the bushing electric connection.
10. A stability evaluation system of a transformer bushing electrical connection, comprising a vibration monitoring device and a transformer bushing electrical connection stability evaluation device according to any one of claims 7 to 9;
the vibration monitoring device is used for carrying out vibration monitoring on a lifting seat of the transformer to obtain mechanical vibration data of the lifting seat;
the stability evaluation device is used for executing the stability evaluation method of the transformer bushing electrical connection according to any one of claims 1 to 6.
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