Design method for bushing insulation on converter transformer valve side under DC voltage superposition of multi-frequency harmonics

Abstract

The invention discloses a method for designing insulation of a converter transformer valve side bushing under direct current voltage superimposed with multi-frequency harmonics, comprising: under preset simulation conditions, performing thermal field analysis of a converter transformer valve side bushing with initial structural parameters under direct current voltage superimposed with multi-frequency harmonics, establishing a thermal field-current field finite element simulation model and a thermal field-electrostatic field finite element simulation model of the converter transformer valve side bushing, performing electric field analysis on the converter transformer valve side bushing, and obtaining total field strength values ​​of key parts of the converter transformer valve side bushing; when the total field strength values ​​of key parts are greater than preset reference values, performing internal and external coordinated optimization of the initial structural parameters to obtain optimized structural parameters; and repeatedly performing thermal field and electric field analysis on the converter transformer valve side bushing based on the optimized structural parameters until the total field strength values ​​of key parts of the converter transformer valve side bushing are less than or equal to the preset reference values, and determining the optimal structural parameters of the converter transformer valve side bushing.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current power transmission and transformation equipment, and more specifically, to a method for designing insulation of a bushing on a converter transformer valve side under direct current voltage superimposed with multi-frequency harmonics. Background Art

[0002] When conducting laboratory tests on the insulation structure design of the bushing on the converter transformer side, only pure DC test voltage and pure industrial frequency AC test voltage can be used to solve the technical problems that the current laboratory insulation test of bushings before leaving the factory, the traditional mathematical analytical calculation method of the existing bushing electric field, and the multi-optimal design method assisted by computers cannot solve the insulation structure reliability of the bushing under long-term special waveform voltage conditions. Specifically: ① The current international and domestic standards do not stipulate the direct use of DC superimposed multi-frequency harmonic voltage waveform to verify the insulation performance of the bushing; ② The design of the main insulating capacitor core for the current high-voltage bushing ③ The traditional mathematical analytical analysis method of the capacitor model is used, which cannot calculate and evaluate the electric field distribution of the converter transformer valve side bushing whose capacitor core is a resistor-capacitor equivalent model under DC superimposed multi-frequency harmonic voltage; ③ The current multi-objective optimization design method is suitable for gas-insulated bushings without capacitor cores. There is a capacitor core inside the converter transformer valve side bushing. The change of the plate distance inside the capacitor core has a relatively small effect on other electric fields. The multi-objective optimization algorithm is difficult to converge the optimization function. The constraints of the multi-objective optimization design of gas-insulated bushings under AC voltage are not suitable for converter transformer valve side bushings with DC superimposed multi-frequency harmonics. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a method for designing bushing insulation on the valve side of a converter transformer under a DC voltage superimposed with multi-frequency harmonics.

[0004] According to one aspect of the present invention, a method for designing insulation of a converter transformer valve-side bushing under a DC voltage superimposed with multi-frequency harmonics is provided, comprising:

[0005] Under the premise of ensuring that the bushing on the converter transformer valve side does not experience discharge breakdown, flashover discharge and partial discharge under the specified power frequency, lightning, impulse and DC test voltage, determine the initial structural parameters of the bushing internal insulation capacitor core and the bushing external insulation hollow insulator of the bushing on the converter transformer valve side;

[0006] Under the preset simulation conditions, the thermal field analysis of DC voltage superimposed multi-frequency harmonics is carried out on the converter transformer valve side bushing with initial structural parameters, and the thermal field-current field finite element simulation model and thermal field-electrostatic field finite element simulation model of the converter transformer valve side bushing are established;

[0007] Based on the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model, the electric field analysis of the converter transformer valve side bushing is carried out to obtain the total field strength value of each key part of the converter transformer valve side bushing;

[0008] The total field strength value of each key part is compared with the preset reference value of each key part, and when the total field strength value of each key part is greater than the preset reference value, the initial parameters of the structure are optimized in a coordinated manner inside and outside the casing to obtain the optimized structural parameters;

[0009] Based on the optimized structural parameters, the thermal field and electric field analysis of the converter transformer valve side bushing is repeatedly performed until the total field strength value of each key part of the converter transformer valve side bushing is less than or equal to the preset reference value, so as to determine the optimal structural parameters of the converter transformer valve side bushing.

[0010] Optionally, under preset simulation conditions, a thermal field analysis of a converter transformer valve side bushing with DC voltage superimposed on multi-frequency harmonics is performed on the initial structural parameters, and a thermal field-current field finite element simulation model and a thermal field-electrostatic field finite element simulation model of the converter transformer valve side bushing are established, including:

[0011] Under the preset simulation conditions, the converter transformer valve side bushing with the initial structural parameters is simulated and analyzed to obtain the thermal equilibrium temperature when the internal and external insulation of the converter transformer valve side bushing reaches thermal equilibrium;

[0012] The bushing on the valve side of the converter transformer is sampled and monitored through the capacitive voltage divider of the bushing on the valve side of the converter transformer in the converter station to obtain voltage waveform data of the bushing on the valve side of the converter transformer;

[0013] According to the voltage waveform data, the DC voltage components borne by the bushings at different installation positions on the converter transformer valve side and the peak values ​​of the multi-frequency superimposed voltage waveforms are obtained;

[0014] According to the thermal equilibrium temperature, the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model of the converter transformer valve side bushing are established respectively, and the material resistance curve, DC voltage component and multi-frequency superimposed voltage waveform peak value involved in the insulation structure of the converter transformer valve side bushing are loaded.

[0015] Optionally, under preset simulation conditions, simulation analysis is performed on the converter transformer valve side bushing with initial structural parameters to obtain a thermal equilibrium temperature when the internal and external insulation of the converter transformer valve side bushing reaches thermal equilibrium, including:

[0016] Under the preset simulation conditions, the bushing on the converter transformer valve side with the initial structural parameters is simulated and analyzed, and a finite element electric field-temperature field calculation model of the bushing is established;

[0017] The thermal equilibrium temperature when the internal and external insulation of the bushing on the converter transformer valve side reaches thermal equilibrium is calculated based on the bushing finite element electric field-temperature field calculation model.

[0018] Optionally, the DC voltage components and multi-frequency superimposed voltage waveform peak values ​​borne by the bushings at different installation positions on the converter transformer valve side are obtained according to the voltage waveform data, including:

[0019] Performing Fourier transform spectrum analysis on the voltage waveform data to obtain spectrum data corresponding to the voltage waveform data;

[0020] The DC voltage components borne by the bushings at different installation positions on the converter transformer valve side and the peak values ​​of the multi-frequency superimposed voltage waveforms are obtained from the spectrum data.

[0021] Optionally, the preset simulation conditions include: rated current, 90° C. converter transformer oil temperature, and 50° C. valve hall temperature.

[0022] Optionally, an electric field analysis is performed on the bushing on the valve side of the converter transformer based on the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model to obtain the total field strength values ​​of key parts of the bushing on the valve side of the converter transformer, including:

[0023] The DC electric field distribution of the bushing on the converter transformer valve side and the peak field intensity distribution under the multi-frequency harmonic superposition voltage waveform are calculated based on the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model considering the influence of temperature on resistivity;

[0024] Extract the first field strength value of the DC electric field at the key position in the peak field strength distribution under the multi-frequency harmonic superposition voltage waveform and the second field strength value under the multi-harmonic superposition voltage waveform;

[0025] The first field strength value and the second field strength value are added together to obtain the total field strength value of each key part of the bushing on the converter transformer valve side under the superposition of DC voltage and multi-frequency harmonic voltage.

[0026] Optionally, comparing the total field strength value of each key part with a preset reference value of each key part includes:

[0027] When the total field strength value of each key part is less than the preset reference value of each key part, it is determined that the current structural parameters meet the preset margin requirements, and the current result parameters are used as the optimal structural parameters of the converter transformer valve side bushing.

[0028] Optionally, the key parts include: key parts of the bushing hollow insulator and key parts of the bushing capacitor core, wherein

[0029] The key parts of the hollow core insulator of the bushing include: the surface field strength of the inner wall of the hollow core of the bushing air composite insulator, the surface field strength of the silicone rubber shed of the bushing air composite insulator, and the surface field strength of the grading ring at the high voltage end of the bushing;

[0030] The key parts of the bushing capacitor core include: the radial field strength of the bushing core, the axial field strength inside the bushing oil middle end capacitor core, the axial field strength on the oil middle side of the bushing air end capacitor core, and the surface field strength along the interface between the bushing air end capacitor core and the insulating medium.

[0031] According to another aspect of the present invention, a device for designing bushing insulation on the valve side of a converter transformer under a DC voltage superimposed with multi-frequency harmonics is provided, comprising:

[0032] The first determination module is used to determine the initial structural parameters of the insulating capacitor core inside the bushing and the insulating hollow insulator outside the bushing of the converter transformer valve side bushing, under the premise of ensuring that the converter transformer valve side bushing does not cause discharge breakdown, flashover discharge and partial discharge under the specified power frequency, lightning, impulse and DC test voltage;

[0033] Thermal field analysis module, used to perform thermal field analysis of DC voltage superimposed multi-frequency harmonics on the converter transformer valve side bushing with initial structural parameters under preset simulation conditions, and establish a thermal field-current field finite element simulation model and a thermal field-electrostatic field finite element simulation model of the converter transformer valve side bushing;

[0034] The electric field analysis module is used to perform electric field analysis on the bushing on the valve side of the converter transformer based on the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model to obtain the total field strength value of each key part of the bushing on the valve side of the converter transformer;

[0035] An optimization module is used to compare the total field strength value of each key part with the preset reference value of each key part, and when the total field strength value of each key part is greater than the preset reference value, the initial parameters of the structure are optimized in a coordinated manner inside and outside the casing to obtain the optimized structural parameters;

[0036] The second determination module is used to repeatedly perform thermal field and electric field analysis on the converter transformer valve side bushing based on the optimized structural parameters until the total field strength value of each key part of the converter transformer valve side bushing is less than or equal to a preset reference value, so as to determine the optimal structural parameters of the converter transformer valve side bushing.

[0037] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the storage medium stores a computer program, and the computer program is used to execute the method described in any one of the above aspects of the present invention.

[0038] According to another aspect of the present invention, an electronic device is provided, comprising: a processor; a memory for storing instructions executable by the processor; the processor is configured to read the executable instructions from the memory and execute the instructions to implement the method described in any one of the above aspects of the present invention.

[0039] Therefore, the method for calculating the insulation structure design and verification of the converter transformer valve side bushing by using the actual operating DC voltage superimposed on the multi-frequency harmonic voltage peak value proposed in the present invention can assist in analyzing and judging the matching and rationality of the insulation structure design and the operating condition voltage, and focus on verifying the radial field strength of the capacitor, the gas-solid interface field strength, the inner wall of the hollow composite insulator glass tube and the surface field strength of the silicone rubber shed, so as to avoid the typical core radial breakdown discharge, core and insulation filling gas gas-solid interface discharge, and hollow composite insulator glass fiber reinforced plastic tube discharge of the converter transformer valve side bushing that occurred in early projects, thereby improving the long-term operating reliability of the converter transformer valve side bushing, and solving the problem that the long-term insulation performance of the bushing under special operating voltage cannot be directly verified by DC superimposed on multi-frequency harmonic voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0041] Figure 1 It is a flow chart of a method for designing bushing insulation on the valve side of a converter transformer under DC voltage superimposed with multi-frequency harmonics provided by an exemplary embodiment of the present invention;

[0042] Figure 2 is a schematic diagram of a bushing insulation structure provided by an exemplary embodiment of the present invention;

[0043] Figure 3 is a schematic diagram of key external dimension parameters of a casing provided by an exemplary embodiment of the present invention;

[0044] Figure 4 is a schematic diagram of key dimension parameters of a casing core provided by an exemplary embodiment of the present invention;

[0045] Figure 5 It is a schematic diagram of field intensity control of key parts of a casing provided by an exemplary embodiment of the present invention;

[0046] Figure 6 It is another flow chart of a method for designing bushing insulation on the valve side of a converter transformer under DC voltage superimposed with multi-frequency harmonics provided by an exemplary embodiment of the present invention;

[0047] Figure 7 It is a schematic diagram of the voltage waveform of the bushing on the valve side of a ±800kV converter transformer provided by an exemplary embodiment of the present invention;

[0048] Figure 8 It is a schematic diagram of the bushing voltage spectrum at the valve side of a ±800kV converter transformer provided by an exemplary embodiment of the present invention;

[0049] Fig. 9 It is a flow chart of a method for coordinated control of internal and external insulation of a high-voltage bushing provided by an exemplary embodiment of the present invention;

[0050] Fig.10 It is a structural schematic diagram of a converter transformer valve-side bushing insulation design device under DC voltage superimposed multi-frequency harmonics provided by an exemplary embodiment of the present invention;

[0051] Fig.11 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0052] Below, the exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention, and it should be understood that the present invention is not limited to the exemplary embodiments described here.

[0053] It should be noted that the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

[0054] Those skilled in the art can understand that the terms "first" and "second" in the embodiments of the present invention are only used to distinguish different steps, devices or modules, etc., and neither represent any specific technical meaning nor indicate the necessary logical order between them.

[0055] It should also be understood that, in the embodiments of the present invention, “plurality” may refer to two or more than two, and “at least one” may refer to one, two or more than two.

[0056] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more, unless explicitly limited or otherwise indicated in the context.

[0057] In addition, the term "and / or" in the present invention is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects before and after are in an "or" relationship.

[0058] It should also be understood that the description of the various embodiments of the present invention focuses on the differences between the various embodiments, and the same or similar aspects thereof can be referenced to each other, and for the sake of brevity, they will not be described one by one.

[0059] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0060] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0061] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0062] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0063] Embodiments of the present invention can be applied to electronic devices such as terminal devices, computer systems, servers, etc., which can operate with many other general or special computing system environments or configurations. Examples of well-known terminal devices, computing systems, environments and / or configurations suitable for use with electronic devices such as terminal devices, computer systems, servers, etc. include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network personal computers, small computer systems, large computer systems, and distributed cloud computing technology environments including any of the above systems, etc.

[0064] Electronic devices such as terminal devices, computer systems, servers, etc. can be described in the general context of computer system executable instructions (such as program modules) executed by computer systems. Generally, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in a distributed cloud computing environment, where tasks are performed by remote processing devices linked through a communication network. In a distributed cloud computing environment, program modules can be located on local or remote computing system storage media including storage devices.

[0065] Exemplary Methods

[0066] Figure 1 1 is a flow chart of a method for designing bushing insulation on the valve side of a converter transformer under DC voltage superimposed with multi-frequency harmonics provided by an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as Figure 1 As shown, the method 100 for designing the insulation of the bushing on the valve side of the converter transformer under the condition of DC voltage superimposed with multi-frequency harmonics includes the following steps:

[0067] Step 101, determining the initial structural parameters of the insulating capacitor core inside the bushing and the insulating hollow insulator outside the bushing of the converter transformer valve side bushing, under the premise of ensuring that the bushing on the converter transformer valve side does not cause discharge breakdown, flashover discharge and partial discharge under the specified power frequency, lightning, impulse and DC test voltage;

[0068] Step 102, under preset simulation conditions, a thermal field analysis of a converter transformer valve-side bushing with DC voltage superimposed on multi-frequency harmonics of the initial structural parameters is performed to establish a thermal field-current field finite element simulation model and a thermal field-electrostatic field finite element simulation model of the converter transformer valve-side bushing;

[0069] Step 103, performing electric field analysis on the bushing on the converter transformer valve side based on the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model to obtain the total field strength value of each key part of the bushing on the converter transformer valve side;

[0070] Step 104, comparing the total field strength value of each key part with the preset reference value of each key part, and when the total field strength value of each key part is greater than the preset reference value, performing casing internal and external collaborative optimization on the initial structural parameters to obtain optimized structural parameters;

[0071] Step 105, repeatedly performing thermal and electric field analysis on the converter transformer valve side bushing based on the optimized structural parameters until the total field strength value of each key part of the converter transformer valve side bushing is less than or equal to a preset reference value, thereby determining the optimal structural parameters of the converter transformer valve side bushing.

[0072] Specifically, the present invention proposes a method for verifying the insulation design of the bushing on the valve side of the converter transformer under the condition of DC voltage superimposed with multi-frequency harmonics, verifies the design values ​​of the key dimension parameters of the insulation structure of the bushing on the valve side of the converter transformer, and verifies the design values ​​of the field strength of the key parts of the insulation structure of the bushing on the valve side of the converter transformer, thereby optimizing the key dimension parameters of the insulation structure and the field strength of the key parts, so that the insulation structure of the bushing on the valve side of the converter transformer is safe and reliable for a long time under the DC voltage superimposed with multi-frequency harmonics in operation. Figure 2-Figure 5 The insulation structure of the bushing on the converter transformer valve side is designed and verified under DC voltage superimposed with multi-frequency harmonics.

[0073] Figure 2 Schematic diagram of the bushing insulation structure on the converter transformer valve side: 1 is the bushing high-voltage conductive tube, 1-1 is the high-voltage terminal on the air side of the bushing high-voltage conductive tube, 1-2 is the terminal on the oil side of the bushing high-voltage conductive tube, 1-3 is the external grading ring on the high-voltage side of the bushing, 2 is the bushing capacitor core, 2-1 is the aluminum foil plate inside the bushing capacitor core, 2-2 is the edge of the aluminum foil plate on the gas side of the bushing capacitor core, 2-3 is the edge of the aluminum foil plate on the oil side of the bushing capacitor core, 3 is the insulating filling medium, 4 is the middle grounding connection sleeve of the bushing, 5 is the hollow composite insulator, 5-1 is the inner wall of the hollow composite insulator, 5-2 is the surface of the silicone rubber umbrella skirt of the hollow composite insulator, and 0 is the mounting flange of the bushing and the converter transformer (above 0 is the air side of the bushing, and below 0 is the oil side of the bushing).

[0074] Figure 3The main external dimensional parameters designed for the bushing insulation structure on the converter transformer valve side are: 6 is the axial length of the innermost high-voltage plate to the grounding plate in the capacitor core on the oil side of the bushing, 7 is the axial length of the innermost high-voltage plate to the grounding plate in the capacitor core on the air side of the bushing, 8 is the axial length of the high-voltage conductor on the air side of the bushing to the grounding plate of the capacitor core, 9 is the axial length from the high-voltage end cover of the bushing to the innermost plate of the capacitor core, 10 is the inner diameter of the hollow composite insulator, and 11 is the arc distance of the outer insulation on the air side of the bushing.

[0075] Figure 4 The internal dimension parameters of the capacitor core designed for the bushing insulation structure on the converter transformer valve side are as follows: 12 is the radius of the bushing high-voltage current-carrying conductive tube, 13-1 is the radius of the first innermost plate of the bushing capacitor core, 13-2 is the length of the first innermost plate of the bushing capacitor core, 14-1 is the radius of the i-th plate of the middle layer of the bushing capacitor core, 14-2 is the length of the i-th plate of the middle layer of the bushing capacitor core, 15-1 is the radius of the outermost grounding plate of the bushing capacitor core, and 15-2 is the length of the outermost grounding plate of the bushing capacitor core.

[0076] Figure 5 The field strengths at key parts inside the capacitor core designed for the bushing insulation structure on the converter transformer valve side are as follows: 16 is the radial field strength of the bushing core, 17 is the axial field strength inside the capacitor core at the oil middle end of the bushing, 18 is the axial field strength inside the capacitor core at the oil middle end of the bushing air end, 19 is the surface field strength along the interface between the capacitor core surface at the air end of the bushing and the insulating medium, 20 is the surface field strength of the inner wall of the empty bushing of the bushing air composite insulator, 21 is the surface field strength of the silicone rubber shed of the bushing air composite insulator, and 22 is the surface field strength of the grading ring at the high-voltage end of the bushing.

[0077] Furthermore, the insulation structure design verification process of the rheological valve side bushing under the DC voltage superimposed with multi-frequency harmonics is as follows: Figure 6 As shown, the following steps are included:

[0078] Step 1: Initial insulation structure and parameters of bushing are determined:

[0079] According to the insulation level of the converter transformer valve side bushing given by the project, determine the lightning impulse withstand voltage value, operating impulse withstand voltage value, power frequency withstand voltage value, DC withstand voltage value, bushing current capacity (valve side winding rated operating current value, bushing temperature rise test current value), installation conditions (the size of the valve hall wall through which the grounding part of the bushing passes, the connection method between the bushing oil side and the converter transformer valve side winding), and ensure that the bushing does not have discharge breakdown, flashover discharge and partial discharge under the specified power frequency, lightning, impulse and DC test voltage. Figure 3 and Figure 4 The main external dimension parameters (6, 7, 8, 9, 10, 11) and Figure 4The internal dimension parameters (12, 13-1, 13-2, 14-1, 14-2, 15-1, 15-2) of the capacitor core are designed for the bushing insulation structure on the transformer valve side.

[0080] Step 2: Calculation of steady-state temperature distribution inside and outside the casing:

[0081] The bushing is simulated and analyzed under rated current, simulated oil temperature of 90℃ for converter transformer and maximum temperature of 50℃ for valve hall. A finite element electric field-temperature field calculation model of bushing on valve side of converter transformer is established. The temperature when the insulation inside and outside the bushing reaches thermal equilibrium is calculated based on the finite element electric field-temperature field calculation model of bushing on valve side of converter transformer.

[0082] Step 3: Determination of DC voltage and multi-frequency harmonic components:

[0083] The bushing is sampled and monitored through the capacitive voltage divider on the bushing on the converter transformer valve side of the converter station to obtain the voltage waveform data of the bushing. Then, the voltage waveform data is subjected to Fourier transform spectrum analysis to obtain the spectrum of the voltage waveform data. The DC voltage components borne by the bushing at different installation positions on the converter transformer valve side and the peak value of the multi-frequency superimposed voltage waveform in the spectrum are obtained.

[0084] Among them, for example Figure 7 The DC bias voltage of the bushing on the valve side of the ±800kV converter transformer is 700kV. The voltage waveform is decomposed by Fourier transform to obtain the AC voltage spectrum amplitude of the main insulation of the bushing on the valve side of the converter transformer. Figure 8 As shown in Table 1. The main insulation of the bushing on the valve side of the ±800kV converter transformer is subjected to DC voltage superimposed with multi-frequency harmonic voltage, of which the DC voltage bias component is 700kV, and the AC voltage includes higher harmonic voltage components such as 150, 250, 350, 450, 550, and 600Hz in addition to the highest content of the 50Hz power frequency AC voltage.

[0085] Table 1 ±800kV converter transformer valve side bushing voltage waveform characteristic spectrum voltage (unit: kV)

[0086]

[0087] Step 4: Resistivity curve and multi-frequency voltage value loading:

[0088] According to the thermal equilibrium temperature in step 2, the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model of the converter transformer valve side bushing are established respectively, and the material resistance curve involved in the bushing insulation structure and the DC voltage component in step 6 and the peak value of the multi-frequency superimposed voltage waveform are loaded.

[0089] Step 5: Calculation of DC electric field and multi-frequency harmonic electric field:

[0090] The thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model of step 5 are used to calculate the DC electric field distribution of the casing considering the influence of temperature on resistivity and the peak field intensity distribution under the multi-frequency harmonic superposition voltage waveform.

[0091] Step 6: DC superimposed multi-frequency harmonic electric field calculation:

[0092] The DC electric field distribution of the bushing in step 6 and the peak field strength distribution under the multi-frequency harmonic superposition voltage waveform are post-processed, and the field strength values ​​under the DC electric field of key parts and the field strength values ​​under the multi-harmonic superposition voltage waveform are extracted and added to obtain the total field strength values ​​of key parts of the bushing under the superposition of DC voltage and multi-frequency harmonic voltage.

[0093] Among them, the calculation method of the DC voltage superimposed multi-frequency harmonic electric field on the converter transformer valve side bushing is:

[0094] Since the bushing on the converter transformer valve side carries DC voltage and multi-frequency harmonic voltage at the same time during operation, the basic principles and principles of electric field calculation under operating voltage are: first, the DC electric field is calculated under the DC voltage bias component; second, the AC electric field is calculated under the peak voltage of the multi-frequency harmonic voltage; third, based on the resistor-capacitor series-parallel model, the DC electric field and the multi-frequency harmonic peak electric field are superimposed to obtain the field strength at a certain location.

[0095] Step 7: Electric field margin analysis of key parts:

[0096] The field strength values ​​of the key parts of the bushings on the valve side of the converter transformer that have been in operation for more than 10 years without any discharge failure in the project are used as the benchmark, and the key parts are compared and analyzed to determine the Figure 5 (16, 17, 18, 19, 20, 21) The rationality of the field strength control value.

[0097] The field strength value of the key part is less than the benchmark or the margin meets the benchmark requirements, the result is confirmed, and step 9 is entered;

[0098] If the field strength value at the key position is greater than the benchmark or the margin does not meet the benchmark requirements, the coordinated optimization design of internal and external insulation is started and the process goes to step 8.

[0099] Step 8: Adjustment and optimization of internal and external insulation parameters:

[0100] Analyze and judge the field strength control of key parts of bushing hollow insulators ( Figure 5 If the parameters of the bushing hollow insulator are unreasonable, adjust the parameters of the bushing hollow insulator and repeat steps 2 to 7 until the field strength control requirements are met; at the same time, analyze and determine the field strength control of the key parts of the bushing capacitor core ( Figure 5 If 16, 17, 18, 19) are unreasonable, adjust the bushing capacitor core parameters and repeat steps 2 to 7 until the field strength control requirements are met.

[0101] Step 9: Determine the DC superimposed multi-frequency harmonic insulation design results:

[0102] When the dimensional parameters and field strength values ​​of key parts of the bushing are analyzed and judged to meet the design requirements, the insulation structure design of the bushing on the converter transformer valve side is determined to meet the long-term operation of DC superimposed multi-frequency harmonics, the insulation structure design verification is completed, and a design verification report is issued.

[0103] Furthermore, the detailed implementation process and specific practices of step 8 "Internal and external insulation parameter adjustment and optimization" are as follows: Fig. 9 As shown:

[0104] When the insulation key part inside the bushing ( Figure 5 16, 17, 18, 19) or insulation key parts key parts field strength control ( Figure 5 When the field strength value margin is unreasonable (19, 20, 21), return to optimize the parameters of the hollow insulator for the outer insulation of the bushing (inner diameter of the hollow insulator, parameters of the silicone rubber shed of the hollow insulator, and surface shape of the equalizing ring at the high-voltage end of the bushing) and the parameters of the punch body at the inner insulation point, and recalculate the electric field and margin analysis of the key parts of the inner and outer insulation until the inner and outer insulation meet the field strength control requirements.

[0105] Therefore, the actual operation DC voltage superimposed multi-frequency harmonic voltage peak value calculation converter transformer valve side bushing insulation structure design verification method proposed in the present invention can assist in analyzing and judging the matching and rationality of the insulation structure design and the operating condition voltage, and focus on verifying the capacitor radial field strength, gas-solid interface field strength, hollow composite insulator glass tube inner wall and silicone rubber shed surface field strength, which can avoid the typical core radial breakdown discharge, core and insulation filling gas gas-solid interface discharge, and hollow composite insulator glass fiber reinforced plastic tube discharge of the converter transformer valve side bushing in early projects, improve the long-term operation reliability of the converter transformer valve side bushing, and solve the current problem that the long-term insulation performance of the bushing under special operating voltage cannot be directly verified by DC superimposed multi-frequency harmonic voltage test. The actual operation DC voltage superimposed multi-frequency harmonic voltage peak value calculation converter transformer valve side bushing insulation structure design verification method proposed in the present invention solves the problems of multi-objective optimization method for converter transformer valve side bushing, optimization function convergence difficulty, complex design process, and design circumference.

[0106] Exemplary Devices

[0107] Fig.10 1 is a schematic diagram of a structure of a bushing insulation design device for a converter transformer valve side under a DC voltage superimposed with multi-frequency harmonics provided by an exemplary embodiment of the present invention. Fig.10 As shown, the device 1000 includes:

[0108] The first determination module 1010 is used to determine the initial structural parameters of the insulating capacitor core inside the bushing and the insulating hollow insulator outside the bushing of the converter transformer valve side bushing, under the premise of ensuring that the converter transformer valve side bushing does not cause discharge breakdown, flashover discharge and partial discharge under the specified power frequency, lightning, impulse and DC test voltage;

[0109] The thermal field analysis module 1020 is used to perform a thermal field analysis of the converter transformer valve side bushing with DC voltage superimposed with multi-frequency harmonics under preset simulation conditions, and establish a thermal field-current field finite element simulation model and a thermal field-electrostatic field finite element simulation model of the converter transformer valve side bushing;

[0110] The electric field analysis module 1030 is used to perform electric field analysis on the bushing on the converter transformer valve side based on the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model to obtain the total field strength value of each key part of the bushing on the converter transformer valve side;

[0111] The optimization module 1040 is used to compare the total field strength value of each key part with the preset reference value of each key part, and when the total field strength value of each key part is greater than the preset reference value, the initial parameters of the structure are optimized in a coordinated manner inside and outside the casing to obtain the optimized structural parameters;

[0112] The second determination module 1050 is used to repeatedly perform thermal field and electric field analysis on the converter transformer valve side bushing based on the optimized structural parameters until the total field strength value of each key part of the converter transformer valve side bushing is less than or equal to a preset reference value, so as to determine the optimal structural parameters of the converter transformer valve side bushing.

[0113] Optionally, the thermal field analysis module 1020 includes:

[0114] The simulation analysis submodule is used to perform simulation analysis on the converter transformer valve side bushing with initial structural parameters under preset simulation conditions to obtain the thermal equilibrium temperature when the internal and external insulation of the converter transformer valve side bushing reaches thermal equilibrium;

[0115] The sampling submodule is used to sample and monitor the bushing on the converter transformer valve side through the bushing capacitive voltage divider of the converter transformer valve side of the converter station to obtain voltage waveform data of the bushing on the converter transformer valve side;

[0116] An acquisition submodule is used to acquire the DC voltage components borne by the bushings at different installation positions on the converter transformer valve side and the peak values ​​of the multi-frequency superimposed voltage waveforms according to the voltage waveform data;

[0117] A submodule is established to establish the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model of the converter transformer valve side bushing according to the thermal equilibrium temperature, and to load the material resistance curve, DC voltage component and multi-frequency superimposed voltage waveform peak involved in the insulation structure of the converter transformer valve side bushing.

[0118] Optionally, the simulation analysis submodule includes:

[0119] A simulation analysis unit is used to simulate and analyze the bushing on the converter transformer valve side with the initial structural parameters under preset simulation conditions, and establish a finite element electric field-temperature field calculation model of the bushing;

[0120] The calculation unit is used to calculate the thermal equilibrium temperature when the internal and external insulation of the bushing on the converter transformer valve side reaches thermal equilibrium according to the bushing finite element electric field-temperature field calculation model.

[0121] Optionally, get submodules, including:

[0122] A spectrum analysis unit, used for performing Fourier transform spectrum analysis on the voltage waveform data to obtain spectrum data corresponding to the voltage waveform data;

[0123] The acquisition unit is used to obtain the DC voltage components borne by the bushings at different installation positions on the converter transformer valve side in the spectrum data and the peak values ​​of the multi-frequency superimposed voltage waveforms.

[0124] Optionally, the preset simulation conditions include: rated current, 90° C. converter transformer oil temperature, and 50° C. valve hall temperature.

[0125] Optionally, the electric field analysis module 1030 includes:

[0126] A calculation submodule is used to calculate the DC electric field distribution of the bushing on the converter transformer valve side considering the influence of temperature on resistivity and the peak field intensity distribution under the multi-frequency harmonic superposition voltage waveform according to the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model;

[0127] An extraction submodule is used to extract the first field strength value of the DC electric field at a key position in the peak field strength distribution under the multi-frequency harmonic superposition voltage waveform and the second field strength value under the multi-harmonic superposition voltage waveform;

[0128] The adding submodule is used to add the first field strength value and the second field strength value to obtain the total field strength value of each key part of the bushing on the converter transformer valve side under the superposition of DC voltage and multi-frequency harmonic voltage.

[0129] Optionally, the optimization module 1040 compares the total field strength value of each key part with a preset reference value of each key part, including:

[0130] The determination submodule is used to determine whether the current structural parameters meet the preset margin requirements when the total field strength value of each key part is less than the preset reference value of each key part, and use the current result parameters as the optimal structural parameters of the converter transformer valve side bushing.

[0131] Optionally, the key parts include: key parts of the bushing hollow insulator and key parts of the bushing capacitor core, wherein

[0132] The key parts of the hollow core insulator of the bushing include: the surface field strength of the inner wall of the hollow core of the bushing air composite insulator, the surface field strength of the silicone rubber shed of the bushing air composite insulator, and the surface field strength of the grading ring at the high voltage end of the bushing;

[0133] The key parts of the bushing capacitor core include: the radial field strength of the bushing core, the axial field strength inside the bushing oil middle end capacitor core, the axial field strength on the oil middle side of the bushing air end capacitor core, and the surface field strength along the interface between the bushing air end capacitor core and the insulating medium.

[0134] Exemplary Electronic Devices

[0135] Fig.11 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. Fig.11 As shown, the electronic device 110 includes one or more processors 111 and a memory 112 .

[0136] The processor 111 may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0137] The memory 112 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 111 may run the program instructions to implement the methods of the software programs of the various embodiments of the present invention described above and / or other desired functions. In one example, the electronic device may also include: an input device 113 and an output device 114, which are interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0138] In addition, the input device 113 may also include, for example, a keyboard, a mouse, etc.

[0139] The output device 114 can output various information to the outside, and can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto.

[0140] Of course, to simplify, Fig.11Only some of the components related to the present invention in the electronic device are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, the electronic device may further include any other appropriate components according to specific application conditions.

[0141] Exemplary computer program products and computer-readable storage media

[0142] In addition to the above-mentioned methods and devices, an embodiment of the present invention may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of the method according to various embodiments of the present invention described in the above-mentioned "Exemplary Method" section of this specification.

[0143] The computer program product may be written in any combination of one or more programming languages ​​to write program code for performing the operations of the embodiments of the present invention, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0144] In addition, an embodiment of the present invention may also be a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, enable the processor to execute the steps of the method according to various embodiments of the present invention described in the above “Exemplary Method” section of this specification.

[0145] The computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, system or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0146] The basic principle of the present invention is described above in conjunction with specific embodiments. However, it should be pointed out that the advantages, strengths, effects, etc. mentioned in the present invention are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. must be possessed by each embodiment of the present invention. In addition, the specific details disclosed above are only for the purpose of illustration and facilitation of understanding, rather than limitation, and the above details do not limit the present invention to being implemented by adopting the above specific details.

[0147] Each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0148] The block diagrams of the devices, systems, equipment, and systems involved in the present invention are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, systems, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to", and can be used interchangeably with it.

[0149] The method and system of the present invention may be implemented in many ways. For example, the method and system of the present invention may be implemented by software, hardware, firmware or any combination of software, hardware, firmware. The above order of steps for the method is only for illustration, and the steps of the method of the present invention are not limited to the order specifically described above, unless otherwise specifically stated. In addition, in some embodiments, the present invention may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present invention. Thus, the present invention also covers a recording medium storing a program for executing the method according to the present invention.

[0150] It should also be noted that in the system, device and method of the present invention, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present invention. The above description of the disclosed aspects is provided to enable any technician in the field to make or use the present invention. Various modifications to these aspects are very obvious to those skilled in the art, and the general principles defined here can be applied to other aspects without departing from the scope of the present invention. Therefore, the present invention is not intended to be limited to the aspects shown here, but in accordance with the widest range consistent with the principles and novel features disclosed here.

[0151] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present invention to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A method for designing bushing insulation on the converter transformer valve side under DC voltage superimposed with multi-frequency harmonics, characterized in that: include: Under the premise of ensuring that the bushing on the converter transformer valve side does not cause discharge breakdown, flashover discharge and partial discharge under the specified power frequency, lightning, impulse and DC test voltage, determine the initial structural parameters of the bushing internal insulation capacitor core and the bushing external insulation hollow insulator of the bushing on the converter transformer valve side; Under preset simulation conditions, a thermal field analysis of DC voltage superimposed multi-frequency harmonics is performed on the converter transformer valve side bushing with the initial structural parameters, and a thermal field-current field finite element simulation model and a thermal field-electrostatic field finite element simulation model of the converter transformer valve side bushing are established; Based on the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model, an electric field analysis is performed on the converter transformer valve side bushing to obtain the total field strength value of each key part of the converter transformer valve side bushing; Comparing the total field strength value of each key part with the preset reference value of each key part, and when the total field strength value of each key part is greater than the preset reference value, performing casing internal and external coordinated optimization on the initial parameters of the structure to obtain optimized structural parameters; Repeating thermal and electric field analysis on the converter transformer valve side bushing based on the optimized structural parameters until the total field strength value of each key part of the converter transformer valve side bushing is less than or equal to the preset reference value, and determining the optimal structural parameters of the converter transformer valve side bushing; Under preset simulation conditions, a thermal field analysis of the converter transformer valve side bushing with the initial structural parameters is performed with DC voltage superimposed on multi-frequency harmonics, and a thermal field-current field finite element simulation model and a thermal field-electrostatic field finite element simulation model of the converter transformer valve side bushing are established, including: Under the preset simulation conditions, a simulation analysis is performed on the converter transformer valve side bushing with the initial structural parameters to obtain a thermal equilibrium temperature when the internal and external insulation of the converter transformer valve side bushing reaches thermal equilibrium; Sampling and monitoring the bushing on the converter transformer valve side through a capacitive voltage divider on the bushing on the converter transformer valve side of the converter station to obtain voltage waveform data of the bushing on the converter transformer valve side; According to the voltage waveform data, the DC voltage components borne by the bushings at different installation positions on the converter transformer valve side and the peak values ​​of the multi-frequency superimposed voltage waveforms are obtained; According to the thermal equilibrium temperature, a thermal field-current field finite element simulation model and a thermal field-electrostatic field finite element simulation model of the converter transformer valve side bushing are respectively established, and the material resistance curve involved in the insulation structure of the converter transformer valve side bushing, the DC voltage component and the peak value of the multi-frequency superimposed voltage waveform are loaded.

2. The method according to claim 1, characterized in that Under the preset simulation conditions, a simulation analysis is performed on the converter transformer valve side bushing with the initial structural parameters to obtain a thermal equilibrium temperature when the internal and external insulation of the converter transformer valve side bushing reaches thermal equilibrium, including: Under the preset simulation conditions, simulation analysis is performed on the converter transformer valve-side bushing with the initial structural parameters, and a bushing finite element electric field-temperature field calculation model is established; The thermal equilibrium temperature when the internal and external insulation of the converter transformer valve side bushing reaches thermal equilibrium is calculated according to the bushing finite element electric field-temperature field calculation model.

3. The method according to claim 1, characterized in that The DC voltage components and multi-frequency superimposed voltage waveform peak values ​​borne by the bushings at different installation positions on the converter transformer valve side are obtained according to the voltage waveform data, including: Performing Fourier transform spectrum analysis on the voltage waveform data to obtain spectrum data corresponding to the voltage waveform data; The DC voltage components borne by the converter transformer valve-side bushings at different installation positions and the peak values ​​of the multi-frequency superimposed voltage waveforms in the frequency spectrum data are obtained.

4. The method according to claim 1, characterized in that: The preset simulation conditions include: rated current, 90° C. converter oil temperature, and 50° C. valve hall temperature.

5. The method according to claim 1, characterized in that Based on the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model, an electric field analysis is performed on the converter transformer valve side bushing to obtain the total field strength value of each key part of the converter transformer valve side bushing, including: Calculate the DC electric field distribution of the converter transformer valve-side bushing considering the effect of temperature on resistivity and the peak field intensity distribution under the multi-frequency harmonic superposition voltage waveform according to the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model; Extracting the first field strength value of the direct current electric field at a key position in the direct current electric field distribution and the peak field strength distribution under the multi-frequency harmonic superposition voltage waveform and the second field strength value under the multi-harmonic superposition voltage waveform; The first field strength value and the second field strength value are added together to obtain the total field strength value of each key part of the converter transformer valve side bushing under the superposition of the DC voltage and the multi-frequency harmonic voltage.

6. The method according to claim 1, characterized in that Comparing the total field strength value of each key part with the preset reference value of each key part, including: When the total field strength value of each key part is less than the preset reference value of each key part, it is determined that the current structural parameters meet the preset margin requirements, and the current result parameters are used as the optimal structural parameters of the converter transformer valve side bushing.

7. The method according to claim 1, characterized in that The key parts include: key parts of the bushing hollow insulator and key parts of the bushing capacitor core, wherein The key parts of the bushing hollow insulator include: the field strength on the inner wall surface of the bushing air composite insulator, the field strength on the silicone rubber shed surface of the bushing air composite insulator, and the field strength on the surface of the grading ring at the high-voltage end of the bushing; The key parts of the bushing capacitor core include: the radial field strength of the bushing core, the axial field strength inside the bushing oil middle end capacitor core, the axial field strength on the oil middle side inside the bushing air end capacitor core, and the surface field strength along the interface between the bushing air end capacitor core surface and the insulating medium.

8. A device for designing bushing insulation on the converter transformer valve side under DC voltage superimposed with multi-frequency harmonics, characterized in that: include: The first determination module is used to determine the initial structural parameters of the insulating capacitor core inside the bushing and the insulating hollow insulator outside the bushing of the converter transformer valve side bushing, under the premise of ensuring that the converter transformer valve side bushing does not cause discharge breakdown, flashover discharge and partial discharge under the specified power frequency, lightning, impulse and DC test voltage; A thermal field analysis module, used for performing a thermal field analysis of the converter transformer valve side bushing with the initial structural parameters by superimposing a DC voltage with multiple frequency harmonics under preset simulation conditions, and establishing a thermal field-current field finite element simulation model and a thermal field-electrostatic field finite element simulation model of the converter transformer valve side bushing; An electric field analysis module, used to perform electric field analysis on the converter transformer valve side bushing based on the thermal field-current field finite element simulation model and the thermal field-electrostatic field finite element simulation model to obtain the total field strength value of each key part of the converter transformer valve side bushing; An optimization module, used to compare the total field strength value of each key part with the preset reference value of each key part, and when the total field strength value of each key part is greater than the preset reference value, perform casing internal and external collaborative optimization on the initial structural parameters to obtain optimized structural parameters; A second determination module is used to repeatedly perform thermal field and electric field analysis on the converter transformer valve side bushing based on the optimized structural parameters until the total field strength value of each key part of the converter transformer valve side bushing is less than or equal to the preset reference value, so as to determine the optimal structural parameters of the converter transformer valve side bushing; Thermal field analysis module, including: Under the preset simulation conditions, a simulation analysis is performed on the converter transformer valve side bushing with the initial structural parameters to obtain a thermal equilibrium temperature when the internal and external insulation of the converter transformer valve side bushing reaches thermal equilibrium; Sampling and monitoring the bushing on the converter transformer valve side through a capacitive voltage divider on the bushing on the converter transformer valve side of the converter station to obtain voltage waveform data of the bushing on the converter transformer valve side; According to the voltage waveform data, the DC voltage components borne by the bushings at different installation positions on the converter transformer valve side and the peak values ​​of the multi-frequency superimposed voltage waveforms are obtained; According to the thermal equilibrium temperature, a thermal field-current field finite element simulation model and a thermal field-electrostatic field finite element simulation model of the converter transformer valve side bushing are respectively established, and the material resistance curve involved in the insulation structure of the converter transformer valve side bushing, the DC voltage component and the peak value of the multi-frequency superimposed voltage waveform are loaded.

9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and the computer program is used to execute the method according to any one of claims 1 to 7.

10. An electronic device, characterized in that: The electronic device comprises: processor; a memory for storing instructions executable by the processor; The processor is used to read the executable instructions from the memory and execute the instructions to implement the method described in any one of claims 1 to 7.

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