Electrothermal mechanical vibration combined aging test platform and method for epoxy resin

Abstract

In the platform, an adjustable power supply is used for generating voltage to simulate an electric field in turn-to-turn epoxy resin insulation; the heat insulation cavity is installed on the insulation support, the two sides of the heat insulation cavity are each provided with an open hole, the two open holes are coaxial, the high-voltage sleeve is installed in one open hole, and one end of the high-voltage sleeve is connected with the voltage output end of the adjustable power source; the turn-to-turn epoxy resin insulation sample is arranged in the heat insulation cavity, the blast heater is installed on the heat insulation cavity to provide temperature in the aging process of the turn-to-turn epoxy resin insulation sample, the vibration exciter generates periodic mechanical vibration, one end of the vibration excitation connecting rod is connected with the vibration exciter, and the other end of the vibration excitation connecting rod is connected with the turn-to-turn epoxy resin insulation sample to transmit the periodic mechanical vibration.

Description

Technical Field

[0001] The invention relates to the technical field of transformer inter-turn epoxy resin aging, in particular to an epoxy resin electrothermal mechanical vibration combined aging test platform and method. Background Art

[0002] Dry-type transformers are core components in the power grid, and their reliability directly affects the stability of the entire power grid. Inside the transformer, electrical epoxy resin, as an insulating medium, undertakes the dual tasks of protection and insulation. During the operation of the transformer, this material will inevitably be subjected to the combined effects of electric fields, heat and mechanical vibrations. Under the combined effects of these factors, the insulation performance of epoxy resin will gradually degrade, which may cause transformer failure and pose a threat to the safety of the power grid.

[0003] Although existing studies have focused on the aging behavior of epoxy resins under single stress conditions, such as only considering the effects of temperature or electric fields, these studies often cannot fully reflect the complex environment faced by epoxy resins in actual operation. In practical applications, epoxy resins are simultaneously affected by electrical, thermal, and mechanical vibrations. The effects of this composite stress are far more complex than those of single stress, and its aging process and mechanism are also more complex. Studies have shown that the combined effects of electrical, thermal, and mechanical vibrations on epoxy resins are far greater than the effects of a single factor. Electrical, thermal, and mechanical vibrations interact with each other, exacerbating aging, that is, the combined effects of electrical-thermal-mechanical vibrations accelerate the aging process of epoxy resins.

[0004] It can be seen that the traditional aging test method cannot simulate the stress state of epoxy resin under actual working conditions, resulting in limitations in the evaluation results. Therefore, it is necessary to develop an aging test platform and method that can comprehensively consider multiple stress factors such as electrical, thermal and mechanical vibration, so as to more accurately simulate and study the aging behavior of transformer epoxy resin inter-turn insulation under actual working conditions, and provide a more scientific and reasonable test method for the performance evaluation of epoxy resin inter-turn insulation and the design and manufacture of transformers, in order to improve the operating reliability and safety of transformers.

[0005] The information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0006] In view of the shortcomings or defects of the above-mentioned prior art, a test platform and method for epoxy resin electric, thermal and mechanical vibration combined aging are provided, which have good equivalence to actual working conditions and can study the breakdown characteristics of various epoxy resin materials under combined aging of electrical, thermal and mechanical vibration stresses.

[0007] The purpose of the present invention is achieved through the following technical solutions.

[0008] An epoxy resin electrothermal mechanical vibration combined aging test platform includes:

[0009] Vibration isolation base,

[0010] an adjustable power supply for generating a voltage to simulate the electric field within the inter-turn epoxy insulation;

[0011] an insulating bracket, which is supported on the vibration isolation base,

[0012] The heat-insulating cavity is mounted on the insulating bracket, and each side of the heat-insulating cavity has an opening and the two openings are coaxial.

[0013] A high-voltage bushing is installed in an opening, and one end of the high-voltage bushing is connected to a voltage output end of an adjustable power supply;

[0014] The inter-turn epoxy resin insulation sample is arranged in the thermal insulation cavity, and the inter-turn epoxy resin insulation sample includes:

[0015] Epoxy resin samples,

[0016] The turn-to-turn winding model is sealed in an epoxy resin sample. The turn-to-turn winding model includes a pair of turn-to-turn winding segments.

[0017] A pair of lead wires, each of which is connected to a pair of inter-turn winding sections, wherein one of the lead wires is connected to the other end of the high-voltage bushing;

[0018] The blast heater is installed in the insulation cavity and provides the temperature of the inter-turn epoxy resin insulation sample during the aging process.

[0019] a temperature controller connected to the blast heater to adjust the temperature provided by the blast heater;

[0020] A mechanical vibration excitation module, which is used to generate controllable periodic mechanical vibration, includes:

[0021] An exciter, which generates periodic mechanical vibrations,

[0022] A vibration controller, which is connected to the exciter to control the periodic mechanical vibration,

[0023] An exciting connecting rod has one end connected to the exciter and the other end connected to the inter-turn epoxy resin insulation sample to transmit periodic mechanical vibration.

[0024] In the epoxy resin electrothermal mechanical vibration combined aging test platform, both ends of the inter-turn winding segment are bent into an arc shape.

[0025] In the epoxy resin electrothermal mechanical vibration combined aging test platform, another lead wire of the epoxy resin sample is connected to the ground potential.

[0026] In the epoxy resin electrothermal mechanical vibration combined aging test platform, the excitation connecting rod is an insulating rod, one end of which is connected to the exciter, and the other end is connected to an inter-turn winding section of the inter-turn epoxy resin insulation sample.

[0027] In the epoxy resin electrothermal mechanical vibration combined aging test platform, an acceleration sensor for measuring the vibration signal applied to the inter-turn epoxy resin insulation sample is installed on the exciting connecting rod.

[0028] In the epoxy resin electrothermal mechanical vibration combined aging test platform, the insulating bracket is an L-shaped structure, which includes a horizontal section installed on a vibration isolation base and a vertical section extending vertically from the horizontal section, and the thermal insulation cavity is installed on the vertical section.

[0029] The test method of the epoxy resin electrothermal mechanical vibration combined aging test platform includes the following steps:

[0030] An inter-turn epoxy resin insulation test specimen is prepared, and the epoxy resin sample is cast, the inter-turn winding model is sealed in the epoxy resin sample, and a pair of lead wires are respectively connected to a pair of inter-turn winding segments;

[0031] Set test parameters, adjust the amplitude and frequency of mechanical vibration, control the temperature of epoxy resin samples and applied voltage, and carry out electrical-thermal-mechanical vibration combined aging;

[0032] After aging for a certain period of time, the inter-turn epoxy resin insulation sample is taken out, and the partial discharge inception voltage and breakdown voltage of the inter-turn epoxy resin insulation sample after aging are tested in transformer oil. The aging parameters are adjusted, and the insulation properties of the inter-turn epoxy resin insulation sample under different working conditions are obtained through multiple measurements.

[0033] In the test method, a sample preparation device is used to prepare an inter-turn epoxy resin insulation sample. The sample preparation device includes an electrode fixture, a sample preparation mold, a differential head and a device bracket. The electrode fixture and the differential head are installed on the device bracket. The sample preparation mold is a metal box with an open upper end and an opening on the opposite side for the end lead wires of the inter-turn winding segment of the inter-turn epoxy resin insulation sample to pass through. The center of the opening is on the axis of the differential head.

[0034] In the test method, when preparing the sample, the terminal lead wire of the inter-turn winding section is fixed on the electrode fixture, and the inter-turn distance is controlled by the differential head.

[0035] In the test method, after the device is fully preheated to 80° C., a differential head is used to control the turn-to-turn distance, and the configured epoxy reactant is injected into the sample preparation mold. After curing and demoulding, an inter-turn epoxy resin insulation sample is obtained.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention can simulate the complex stress environment faced by electrical epoxy resin in power transformers under actual working conditions. This integrated test method not only improves the accuracy and practicality of the test results, but also reduces the cost and complexity of operation. By adjusting parameters such as voltage, temperature, and mechanical vibration, the present invention enhances the flexibility of the test, allowing researchers to more deeply explore the effects of different stress conditions on the aging characteristics of epoxy resin. This test platform that comprehensively simulates multiple stresses not only fills the gap in the field, but also provides a new perspective and method for the aging research of power transformer insulation materials, which helps to improve the operational reliability and safety of power transformers. The electric-thermal-mechanical vibration combined aging test platform provided by the present invention has the advantages of simple structure, easy use, and good equivalence with actual working conditions. It can study the breakdown characteristics of various epoxy resin materials under the combined aging of electrical, thermal, and mechanical vibration stresses.

[0038] The above description is only an overview of the technical solution of the present invention. In order to make the technical means of the present invention clearer and to achieve the extent that those skilled in the art can implement it according to the contents of the specification, and in order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are exemplified below. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0040] In the attached picture:

[0041] Figure 1 It is a structural schematic diagram of an epoxy resin electric-thermal-mechanical vibration combined aging test platform according to an embodiment of the invention;

[0042] Figure 2 is a schematic structural diagram of an epoxy resin sample according to an embodiment of the invention;

[0043] Figure 3 The present invention is a schematic structural diagram of an epoxy resin sample preparation device according to an embodiment of the present invention.

[0044] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0045] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0046] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.

[0047] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.

[0048] For a better understanding, Figures 1 to 3 As shown, an epoxy resin electrothermal mechanical vibration combined aging test platform includes:

[0049] Vibration isolation base 1,

[0050] An adjustable power supply 2, which is used to generate a voltage to simulate the electric field in the inter-turn epoxy insulation;

[0051] The insulating bracket 3 is supported on the vibration isolation base 1.

[0052] The heat-insulating cavity 4 is mounted on the insulating bracket 3. The heat-insulating cavity 4 has an opening on each side and the two openings are coaxial.

[0053] A high-voltage bushing 5 is installed in an opening, and one end of the high-voltage bushing 5 is connected to the voltage output end of the adjustable power supply 2;

[0054] The inter-turn epoxy resin insulation sample is arranged in the thermal insulation cavity 4, and the inter-turn epoxy resin insulation sample includes:

[0055] Epoxy resin sample 6,

[0056] The inter-turn winding model 7 is sealed in the epoxy resin sample 6, and the inter-turn winding model 7 includes a pair of inter-turn winding sections.

[0057] a pair of lead wires 8, which are respectively connected to a pair of inter-turn winding sections, wherein one of the lead wires 8 is connected to the other end of the high-voltage bushing 5;

[0058] The blast heater 9 is installed in the heat insulation cavity 4 and provides the temperature of the inter-turn epoxy resin insulation sample during the aging process.

[0059] a temperature controller 10 connected to the blast heater 9 to adjust the temperature provided by the blast heater 9;

[0060] A mechanical vibration excitation module, which is used to generate controllable periodic mechanical vibration, includes:

[0061] an exciter 11, which generates periodic mechanical vibrations,

[0062] A vibration controller 12, which is connected to the vibration exciter 11 to control the periodic mechanical vibration,

[0063] An excitation connecting rod 13 has one end connected to the exciter 11 and the other end connected to the inter-turn epoxy resin insulation sample to transmit periodic mechanical vibration.

[0064] In a preferred embodiment of the epoxy resin electrothermal mechanical vibration combined aging test platform, both ends of the inter-turn winding segment are bent into an arc shape.

[0065] In a preferred embodiment of the epoxy resin electrothermal mechanical vibration combined aging test platform, another lead wire 8 of the epoxy resin sample is connected to the ground potential.

[0066] In a preferred embodiment of the epoxy resin electrothermal mechanical vibration combined aging test platform, the excitation connecting rod 13 is an insulating rod, one end of which is connected to the exciter 11, and the other end is connected to an inter-turn winding segment of the inter-turn epoxy resin insulation sample.

[0067] In a preferred embodiment of the epoxy resin electrothermal mechanical vibration combined aging test platform, an acceleration sensor for measuring the vibration signal applied to the inter-turn epoxy resin insulation sample is installed on the excitation connecting rod 13.

[0068] In a preferred embodiment of the epoxy resin electrothermal mechanical vibration combined aging test platform, the insulating bracket 3 is an L-shaped structure, which includes a horizontal section installed on the vibration isolation base 1 and a vertical section extending vertically from the horizontal section, and the thermal insulation cavity 4 is installed on the vertical section.

[0069] The test method of the epoxy resin electrothermal mechanical vibration combined aging test platform includes the following steps:

[0070] An inter-turn epoxy resin insulation sample is prepared, and an epoxy resin sample 6 is cast, an inter-turn winding model 7 is sealed in the epoxy resin sample 6, and a pair of lead wires 8 are respectively connected to a pair of inter-turn winding segments;

[0071] Set the test parameters, adjust the amplitude and frequency of mechanical vibration, control the temperature and applied voltage of epoxy resin sample 6, and carry out electric-thermal-mechanical vibration combined aging;

[0072] After aging for a certain period of time, the inter-turn epoxy resin insulation sample is taken out, and the partial discharge inception voltage and breakdown voltage of the inter-turn epoxy resin insulation sample after aging are tested in transformer oil. The aging parameters are adjusted, and the insulation properties of the inter-turn epoxy resin insulation sample under different working conditions are obtained through multiple measurements.

[0073] Advantages of the test method In a specific implementation, a sample preparation device is used to prepare an inter-turn epoxy resin insulation sample, and the sample preparation device includes an electrode fixture 17, a sample preparation mold 15, a differential head 16 and a device bracket 14. One of the two electrode fixtures is fixed on the device bracket, and the other is connected to the differential head, which can move with the differential head to control the inter-turn distance. The sample preparation mold 15 is a metal box with an open upper end, and an opening on the opposite side for the end lead wire of the inter-turn winding segment of the inter-turn epoxy resin insulation sample to pass through, and the center of the opening is on the axis of the differential head 16.

[0074] Advantages of the test method In a specific implementation, when preparing a sample, the terminal lead wire of the inter-turn winding segment is fixed on the electrode fixture 17, and the inter-turn distance is controlled by the differential head 16. The electrode fixtures on both sides respectively fix two electrodes. One of the electrode fixtures is fixed on the device bracket. The other fixture is connected to the differential head and can move with the differential head.

[0075] Advantages of the test method In a specific implementation, after the device is fully preheated to 80° C., the inter-turn distance is controlled using a differential head 16, and the configured epoxy reactant is injected into the sample preparation mold 15. After curing and demoulding, an inter-turn epoxy resin insulation sample is obtained.

[0076] In one embodiment, the temperature controller further connects a temperature sensor to the inter-turn epoxy insulation sample to measure its temperature.

[0077] In one embodiment, the epoxy resin electrothermal mechanical vibration combined aging test platform includes:

[0078] An adjustable high-voltage power module, which is used to generate voltage to simulate the electric field within the inter-turn epoxy insulation;

[0079] The sample temperature control module is used to accurately control the temperature conditions during the aging process;

[0080] A mechanical vibration excitation module, which is used to generate controllable periodic mechanical vibration;

[0081] A precision vibration isolation platform is used to isolate external vibrations, provide good mechanical support for the sample temperature control module and the mechanical vibration excitation module, and ensure the accuracy of the test. The inter-turn epoxy resin insulation sample is a block epoxy resin sample 6 with an inter-turn winding model 7 sealed inside. The inter-turn winding model 7 is a pair of inter-turn winding segments, and the two ends of the inter-turn winding segment are bent into an arc to make the edge electric field more uniform. A lead wire 8 is welded on the inter-turn winding segment for applying voltage. The lead wire 8 of the inter-turn winding segment is respectively connected to the voltage output terminal of the adjustable high-voltage power supply module and the ground potential, and an approximately uniform electric field can be generated in the inter-turn epoxy resin. The sample temperature control module includes a blast heater 9, an insulation cavity 4, a temperature controller 10, etc. There is an opening on each of the left and right sides of the insulation cavity 4, and the two openings are coaxial. The left opening is installed with a high-voltage bushing 5, one end of which is connected to the voltage output end of the adjustable high-voltage power supply module, and the other end is connected to the lead-out wire 8 of an inter-turn winding section of the inter-turn epoxy resin insulation sample. The mechanical vibration excitation module includes an exciter 11, a vibration controller 12, an excitation connecting rod 13, etc. The excitation connecting rod 13 is an insulating rod, one end of which is connected to the exciter 11, and the other end is connected to another inter-turn winding section of the inter-turn epoxy resin insulation sample. An acceleration sensor is installed on the excitation connecting rod 13 to measure the vibration signal applied to the inter-turn epoxy resin insulation sample. The precision vibration isolation platform includes a vibration isolation base 1 and an insulating bracket 3. The adjustable high-voltage power supply module, the sample temperature control module and the mechanical vibration excitation module are installed on the vibration isolation base 1 in sequence.

[0082] An epoxy resin electric-thermal-mechanical vibration combined aging test method comprises the following steps:

[0083] 1) Preparation of inter-turn epoxy resin insulation specimens: The inter-turn epoxy resin insulation specimens are cast using a special sample preparation device.

[0084] 2) Set the test parameters, adjust the amplitude and frequency of mechanical vibration, control the sample temperature and applied voltage, and carry out electrical-thermal-mechanical vibration combined aging.

[0085] 3) After aging for a certain period of time, the inter-turn epoxy resin insulation sample is taken out, and the partial discharge inception voltage and breakdown voltage of the inter-turn epoxy resin insulation sample after aging are tested in transformer oil. The aging parameters are adjusted, and the insulation properties of the inter-turn epoxy resin insulation sample under different working conditions are obtained by multiple measurements.

[0086] The main structure of the sample preparation device includes an electrode fixture 17 , a sample preparation mold 15 , a differential head 16 , a device support 14 , etc. The electrode fixture 17 and the differential head 16 are installed on the device support 14 .

[0087] The sample preparation mold 15 is a metal box with an open top, and has an opening on the opposite side for the end lead wire 8 of the inter-turn winding section of the inter-turn epoxy resin insulation sample to pass through. The center of the opening is on the axis of the differential head 16.

[0088] When preparing the sample, the terminal lead wire of the inter-turn winding section is fixed on the electrode fixture 17. The inter-turn distance can be controlled by the differential head 16.

[0089] The preparation process of the inter-turn epoxy resin insulation sample is as follows: after fully preheating the device to 80° C., using the differential head 16 to control the inter-turn distance, injecting the configured epoxy reactant into the sample preparation mold 15, and obtaining the inter-turn epoxy resin insulation sample after curing and demoulding.

[0090] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0091] 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 application to the forms disclosed herein. Although multiple 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. An epoxy resin electrothermal mechanical vibration combined aging test platform, characterized in that: These include, Vibration isolation base, an adjustable power supply for generating a voltage to simulate the electric field within the inter-turn epoxy insulation; an insulating bracket, which is supported on the vibration isolation base, The heat-insulating cavity is mounted on the insulating bracket, and each side of the heat-insulating cavity has an opening and the two openings are coaxial. A high-voltage bushing is installed in an opening, and one end of the high-voltage bushing is connected to a voltage output end of an adjustable power supply; The inter-turn epoxy resin insulation sample is arranged in the thermal insulation cavity, and the inter-turn epoxy resin insulation sample includes: Epoxy resin samples, The turn-to-turn winding model is sealed in an epoxy resin sample. The turn-to-turn winding model includes a pair of turn-to-turn winding segments. A pair of lead wires, each of which is connected to a pair of inter-turn winding sections, wherein one of the lead wires is connected to the other end of the high-voltage bushing; The blast heater is installed in the insulation cavity and provides the temperature of the inter-turn epoxy resin insulation sample during the aging process. a temperature controller connected to the blast heater to adjust the temperature provided by the blast heater; A mechanical vibration excitation module, which is used to generate controllable periodic mechanical vibration, includes: An exciter, which generates periodic mechanical vibrations, A vibration controller, which is connected to the exciter to control the periodic mechanical vibration, An exciting connecting rod has one end connected to the exciter and the other end connected to the inter-turn epoxy resin insulation sample to transmit periodic mechanical vibration.

2. The epoxy resin electrothermal mechanical vibration combined aging test platform as claimed in claim 1, characterized in that: Preferably, two ends of the inter-turn winding segment are bent into arc shapes.

3. The epoxy resin electrothermal mechanical vibration combined aging test platform as claimed in claim 1, characterized in that: Another lead wire of the epoxy resin sample is connected to the ground potential.

4. The epoxy resin electrothermal mechanical vibration combined aging test platform as claimed in claim 1, characterized in that: The exciting connecting rod is an insulating rod, one end of which is connected to the exciter, and the other end of which is connected to an inter-turn winding section of the inter-turn epoxy resin insulation sample.

5. The epoxy resin electrothermal mechanical vibration combined aging test platform as claimed in claim 1, characterized in that: An acceleration sensor for measuring the vibration signal applied to the inter-turn epoxy resin insulation sample is installed on the exciting connecting rod.

6. The epoxy resin electrothermal mechanical vibration combined aging test platform as claimed in claim 1, characterized in that: The insulating bracket is an L-shaped structure, which includes a horizontal section installed on the vibration isolation base and a vertical section vertically extending from the horizontal section, and the heat insulation cavity is installed on the vertical section.

7. The test method of the epoxy resin electrothermal mechanical vibration combined aging test platform as described in any one of claims 1 to 6.

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