Epoxy resin electrothermal mechanical vibration combined aging test platform and method

Abstract

Disclosed are an epoxy resin electrothermal mechanical vibration combined aging test platform and method. In the platform, an adjustable power supply is used to generate voltage to simulate the electric field in the inter-turn epoxy resin insulation. A thermal insulation cavity is installed on an insulating bracket, with an opening on each side of the thermal insulation cavity and the two openings being coaxial. A high-voltage bushing is installed in one opening, and one end of the high-voltage bushing is connected to the voltage output end of the adjustable power supply. The inter-turn epoxy resin insulation sample is arranged in the thermal insulation cavity, and a blast heater is installed on the thermal insulation cavity to provide the temperature of the inter-turn epoxy resin insulation sample during the aging process. An exciter generates periodic mechanical vibrations. One end of an excitation connecting rod is connected to the exciter, and the other end is connected to the inter-turn epoxy resin insulation sample to transmit the periodic mechanical vibrations.

Description

Technical Field

[0001] The present 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 power grids, and their reliability directly impacts the stability of the entire grid. Within the transformer, electrical epoxy resin serves as the insulating medium, fulfilling the dual roles of protection and insulation. During transformer operation, this material is inevitably subjected to the combined effects of electric fields, heat, and mechanical vibration. These combined forces can gradually degrade the epoxy resin's insulation properties, potentially leading to transformer failure and posing a threat to grid security.

[0003] While previous studies have focused on the aging behavior of epoxy resins under single stress conditions, such as considering only the effects of temperature or electric fields, these studies often fail to fully reflect the complex environments epoxy resins face during actual operation. In practical applications, epoxy resins are simultaneously affected by electrical, thermal, and mechanical vibrations. The effects of this combined stress are far more complex than those of a single stress, and the 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 those of any single factor alone. The three factors interact, exacerbating aging. In other words, the combined effects of electrical, thermal, and mechanical vibrations accelerate the aging process of epoxy resins.

[0004] Therefore, traditional aging test methods are unable to simulate the stress state of epoxy resin under actual operating conditions, resulting in limitations in 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. This can more accurately simulate and study the aging behavior of transformer epoxy resin interturn insulation under actual operating conditions. This will provide a more scientific and reasonable test method for epoxy resin interturn insulation performance evaluation and transformer design and manufacturing, thereby improving the operational 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 response to the shortcomings or defects of the existing technology, a platform and method for epoxy resin electric, thermal and mechanical vibration combined aging test is provided, which has 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 stress.

[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 interturn epoxy insulation;

[0011] an insulating bracket 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 the voltage output end of the 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 inter-turn winding model is sealed in the epoxy resin sample. The inter-turn winding model includes a pair of inter-turn winding segments.

[0017] a pair of lead wires, each connected to a pair of inter-turn winding segments, 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] The mechanical vibration excitation module is used to generate controllable periodic mechanical vibration. The mechanical vibration excitation module 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 excitation 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 segment 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 excitation 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 the vibration isolation base and a vertical section extending vertically from the horizontal section, and the thermal insulation cavity is installed in 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 sample is prepared and cast into an epoxy resin sample, an 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 the test parameters, adjust the amplitude and frequency of mechanical vibration, control the temperature of the epoxy resin sample and the applied voltage, and carry out electric-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 top 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. 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 segment 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, the inter-turn distance is controlled using a micrometer head, and the configured epoxy reactant is injected into the sample preparation mold. After curing and demolding, the 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 resins 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 the 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 impact of different stress conditions on the aging characteristics of epoxy resins. 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 electric, 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 easier to understand, so that those skilled in the art can implement it according to the contents of the description, 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 embodiments of the present invention are illustrated below. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are intended only to illustrate preferred embodiments and are not to be construed as limiting the present invention. It should be understood that the drawings described below are merely examples of the present invention, and that those skilled in the art will be able to derive other drawings from these drawings without inventive effort. Throughout the drawings, identical reference numerals are used to denote identical components.

[0040] In the attached figure:

[0041] Figure 1 This is a schematic structural diagram of an epoxy resin electric-thermal-mechanical vibration combined aging test platform according to one 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 figure is a schematic structural diagram of an epoxy resin sample preparation device according to one embodiment of the invention.

[0044] The present invention will be further explained below with reference to the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0045] Specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although 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. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention 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 invention. The scope of protection of the present invention shall be as defined in 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. However, the accompanying drawings do not limit the embodiments of the present invention.

[0048] For 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 for generating a voltage to simulate an 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. There is an opening on each side of the heat-insulating cavity 4 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. The inter-turn winding model 7 includes a pair of inter-turn winding segments.

[0057] a pair of lead wires 8, each connected to a pair of inter-turn winding segments, 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] The mechanical vibration excitation module is used to generate controllable periodic mechanical vibration. The mechanical vibration excitation module includes:

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

[0062] A vibration controller 12 connected to the 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 in 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 cast into an epoxy resin sample 6. An inter-turn winding model 7 is sealed in the epoxy resin sample 6. 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 embodiment, a sample preparation device is used to prepare an inter-turn epoxy resin insulation sample. 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 and can move with the differential head to control the inter-turn distance. The sample preparation mold 15 is a metal box with an open top 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. The center of the opening is on the axis of the differential head 16.

[0074] In a specific embodiment of the advantageous test method, during sample preparation, the terminal lead wires of the interturn winding segments are fixed to the electrode fixture 17, and the interturn distance is controlled by the differential head 16. The electrode fixtures on either side each hold two electrodes. One of the electrode fixtures is fixed to the device bracket. The other fixture is connected to the differential head and can move with it.

[0075] Advantages of the test method In a specific embodiment, after the device is fully preheated to 80° C., the inter-turn distance is controlled using a micrometer 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] Sample temperature control module, which 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 shape 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, which can generate an approximately uniform electric field 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 equipped 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 link 13, etc. The excitation link 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 link 13 for measuring 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 electric-thermal-mechanical vibration combined aging.

[0085] 3) After aging for a certain period of time, the inter-turn epoxy resin insulation sample is removed, 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 micrometer head 16 , a device support 14 , etc. The electrode fixture 17 and the micrometer head 16 are installed on the device support 14 .

[0087] The sample preparation mold 15 is a metal box with an open top and an opening on the opposite side for the terminal 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 micrometer head 16.

[0088] During sample preparation, the terminal lead wires of the inter-turn winding segments are fixed on the electrode fixture 17. The inter-turn distance can be controlled by the differential head 16.

[0089] The inter-turn epoxy resin insulation sample preparation process 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 have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in this application are merely illustrative and not restrictive, and it should not be assumed that these advantages, strengths, and effects are required of each embodiment of this application. In addition, the specific details disclosed above are merely illustrative and facilitating understanding, and are not restrictive. The above details do not limit this application to necessarily being implemented using the above specific details.

[0091] The above description has been provided 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 a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. An epoxy resin electrothermal mechanical vibration combined aging test platform, characterized in that: It includes, Vibration isolation base, an adjustable power supply for generating a voltage to simulate the electric field within the interturn epoxy insulation; an insulating bracket 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 the voltage output end of the 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: An epoxy resin sample, wherein an inter-turn epoxy resin insulation sample is prepared by casting the epoxy resin sample, wherein an inter-turn winding model is sealed within the epoxy resin sample, and a pair of lead wires are respectively connected to a pair of inter-turn winding segments; the inter-turn epoxy resin insulation sample is prepared using a sample preparation device, the sample preparation device comprising an electrode fixture, a sample preparation mold, a differential head, and a device support, wherein one of the two electrode fixtures is fixed to the device support, and the other is connected to the differential head and can move with the differential head to control the inter-turn distance; the sample preparation mold is a metal box with an open top end and an opening on the opposite side for the terminal lead wires 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; The inter-turn winding model is sealed in the epoxy resin sample. The inter-turn winding model includes a pair of inter-turn winding segments. a pair of lead wires, each connected to a pair of inter-turn winding segments, 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; The mechanical vibration excitation module is used to generate controllable periodic mechanical vibration. The mechanical vibration excitation module includes: an exciter, which generates periodic mechanical vibrations, A vibration controller, which is connected to the exciter to control the periodic mechanical vibration, an excitation connecting rod, one end of which is connected to the exciter and the other end is connected to the inter-turn epoxy resin insulation sample to transmit periodic mechanical vibration; 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 segment of the inter-turn epoxy resin insulation sample; Both ends of the inter-turn winding segment are bent into arc shapes; 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 thermal insulation cavity is installed in the vertical section.

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

3. The epoxy resin electrothermal mechanical vibration combined aging test platform according to 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 excitation connecting rod.

4. The test method of the epoxy resin electrothermal mechanical vibration combined aging test platform according to any one of claims 1 to 3, comprising the following steps: 1) Preparation of inter-turn epoxy resin insulation specimens, which are cast using a special sample preparation device; 2) Set test parameters, adjust the amplitude and frequency of mechanical vibration, control sample temperature and applied voltage, and conduct electric-thermal-mechanical vibration combined aging; 3) After aging for a certain period of time, the inter-turn epoxy resin insulation sample is removed, 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.

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