Method and device for determining wave height of wave fin of totally-enclosed transformer

Abstract

The invention provides a method and device for determining the wave height of a wave wing of a totally-enclosed transformer, and the method comprises the steps: determining a wave height range according to historical data, and selecting oil tanks with different wave heights; strain gauges are attached to multiple positions of wave fins of an oil tank to monitor stress, oil is injected, and the relation between oil increase and pressure and expansion coefficients is recorded. And a wave height formula is derived, and a wave height coefficient K is introduced to be taken into consideration of multiple factors. The K value is adjusted, so that the calculation result is closer to reality, the design accuracy and reliability are improved, and the wave wing wave height is accurately determined.

Description

Technical Field

[0001] The present application belongs to the field of transformer wave fin determination, and in particular, relates to a method and device for determining the wave height of a fully enclosed transformer wave fin. Background Art

[0002] Fully sealed transformers have broad application prospects due to their advantages such as no need for core inspection, less maintenance, time saving, convenience for users, and suitability for installation in harsh environments. In order to further improve the performance and reliability of fully sealed transformers, corrugated oil tanks are widely used in fully sealed transformers due to their unique structural advantages. The characteristics of the corrugated oil tank are that its wall is thin (usually 1-1.5mm thin steel plate), and the corrugated fins can flexibly accommodate the increase or decrease of oil volume, thereby effectively protecting the oil tank from damage.

[0003] In the design of corrugated oil tanks, the corrugation height (i.e., the depth of the corrugated fins) is a crucial parameter. The determination of the corrugation height not only needs to consider the requirements of the heat dissipation surface, but also needs to meet the requirements of oil volume expansion. Especially in fully sealed transformers, the expansion of the oil volume is mainly borne by the expansion of the corrugated fins to ensure the integrity and safety of the oil tank.

[0004] However, traditional methods for determining wave height often rely on historical data formulas or simple thermal calculations, lacking systematic experimental verification and accurate calculation models, resulting in the designed wave height possibly not being able to fully meet actual needs and posing safety risks. Summary of the invention

[0005] The purpose of the present application is to overcome the defects in the above-mentioned prior art and to provide a method and device for determining the wave height of the wave wing of a fully enclosed transformer.

[0006] The present application provides a method for determining the wave height of a fully enclosed transformer wave wing, comprising:

[0007] Determining a wave height range of a wave fin of a fully enclosed transformer based on historical data, wherein the wave fin is located on an oil tank;

[0008] According to the wave height range of the wave wing, a plurality of the oil tanks having different wave heights are selected;

[0009] Strain gauges are respectively arranged at multiple positions of the wave fins on multiple oil tanks to perform stress monitoring, including: injecting a preset amount of oil into the oil tank; recording the correlation between the volume increase of the oil and the oil tank pressure and expansion coefficient;

[0010] Based on the correlation, a wave height calculation formula for the wave wing of a fully enclosed transformer is derived;

[0011] Introducing a wave height coefficient into the wave height calculation formula so that the calculation result of the wave height calculation formula is within the wave height range;

[0012] The wave height is corrected according to the wave height coefficient to obtain the wave height size. Optionally, the wave height calculation formula is expressed as follows:

[0013]

[0014] Among them, h is the wave height, B is the width of the inner frame of the tank, and L is the length of the inner frame of the tank.

[0015] Optionally, a wave height coefficient K is introduced into the wave height calculation formula so that the calculation result of the wave height calculation formula is within the wave height range. The expression is as follows:

[0016]

[0017] Among them, K is the wave height coefficient, h is the wave height, B is the width of the inner frame of the fuel tank, and L is the length of the inner frame of the fuel tank.

[0018] Optionally, among the multiple oil tanks with different wave heights, the wave heights include: 80mm, 120mm, 160mm, 200mm, 240mm, 280mm and 320mm.

[0019] Optionally, the fuel tank pressure and expansion coefficient include:

[0020] The oil tank pressure and expansion coefficient of the oil tank at the deformation limit point.

[0021] The present application provides a device for determining the wave height of a fully enclosed transformer wave wing, comprising:

[0022] A determination module, which determines a wave height range of a wave fin of a fully enclosed transformer based on historical data, wherein the wave fin is located on an oil tank;

[0023] A selection module, selecting a plurality of said oil tanks with different wave fin heights according to said wave height range;

[0024] The test module is configured to set strain gauges at multiple positions of the wave wings of multiple oil tanks to perform stress monitoring, including: injecting a preset amount of oil into the oil tank; recording the correlation between the increase in the volume of the oil and the oil tank pressure and expansion coefficient;

[0025] A formula module, based on the association relationship, derives a wave height calculation formula for the wave wing of the oil tank in the fully enclosed transformer;

[0026] A range module, which introduces a wave height coefficient K into the wave height calculation formula so that the calculation result of the wave height calculation formula is within the wave height range;

[0027] The size module corrects the wave height according to the wave height coefficient to obtain the wave height size.

[0028] Optionally, the wave height calculation formula is expressed as follows:

[0029]

[0030] Among them, h is the wave height, B is the width of the inner frame of the tank, and L is the length of the inner frame of the tank.

[0031] Optionally, the range module introduces a wave height coefficient K into the wave height calculation formula so that the calculation result of the wave height calculation formula is within the wave height range. The expression is as follows:

[0032]

[0033] Among them, K is the wave height coefficient, h is the wave height, B is the width of the inner frame of the fuel tank, and L is the length of the inner frame of the fuel tank.

[0034] Optionally, among the multiple oil tanks with different wave heights, the wave heights include: 80mm, 120mm, 160mm, 200mm, 240mm, 280mm and 320mm.

[0035] Optionally, the fuel tank pressure and expansion coefficient include:

[0036] The oil tank pressure and expansion coefficient of the oil tank at the deformation limit point.

[0037] The beneficial effects of this application are:

[0038] The present application provides a method for determining the wave height of the wave wing of a fully enclosed transformer, including: determining the wave height range of the wave wing of the fully enclosed transformer based on historical data, wherein the wave wing is located on the oil tank; selecting multiple oil tanks with different wave heights according to the wave height range of the wave wing; setting strain gauges at multiple positions of the wave wing on multiple oil tanks to perform stress monitoring, including: injecting a preset amount of oil into the oil tank; recording the correlation between the volume increase of the oil and the oil tank pressure and expansion coefficient; deriving the wave height calculation formula of the wave wing of the fully enclosed transformer according to the correlation; introducing the wave height coefficient into the wave height calculation formula so that the calculation result of the wave height calculation formula is within the wave height range; correcting the wave height according to the wave height coefficient to obtain the wave height size. The present application introduces the wave height coefficient K into the wave height calculation formula to comprehensively consider multiple factors affecting the wave height. By adjusting the K value, the calculation result of the wave height calculation formula can be closer to the actual value, thereby improving the accuracy and reliability of the design. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of the process for determining the wave height of the wave wing of the fully enclosed transformer in this application;

[0040] Figure 2 This is a schematic diagram of the relationship between wave height and tank pressure limit in this application;

[0041] Figure 3 It is a schematic diagram of the relationship between wave height and swelling coefficient in this application;

[0042] Figure 4 It is a schematic diagram of a device for determining the wave height of a fully enclosed transformer wave wing in this application. DETAILED DESCRIPTION

[0043] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that various forms of implementing the present disclosure should not be limited by the embodiments set forth herein. On the contrary, the embodiments are provided to more thoroughly understand the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0044] Please refer to Figure 1 As shown, a method for determining the wave height of a fully enclosed transformer wave wing comprises the following steps:

[0045] S101. Determine a wave height range of a wave fin of a fully enclosed transformer based on historical data, wherein the wave fin is located on an oil tank.

[0046] In order to accurately determine the wave height of the oil tank wing in the fully enclosed transformer, a representative transformer capacity of 315kVA was selected, and a series of corrugated oil tanks with different wave heights were designed for testing. These oil tanks are all rectangular structures with a unified inner frame size of 400x1040x1080 mm to ensure the consistency and comparability of the test.

[0047] S102, selecting a plurality of oil tanks with different wave heights according to the wave height range of the wave fin.

[0048] Seven corrugated tanks with wave heights of 80, 120, 160, 200, 240, 280, and 320 mm were selected to cover a wide range of wave heights and thus comprehensively evaluate the effects of different wave heights on the tank performance.

[0049] S103, respectively setting strain gauges at multiple positions of the wave fins on multiple oil tanks to perform stress monitoring, including: injecting a preset amount of oil into the oil tank; and recording the correlation between the volume increase of the oil and the oil tank pressure and expansion coefficient.

[0050] According to the design requirements, seven corrugated tanks with different wave heights were selected.

[0051] The fuel tank is made of thin steel plates with a thickness of 1 to 1.5 mm. The pitch and width of the wave fins are determined according to the design requirements to ensure the structural integrity and performance stability of the fuel tank.

[0052] Strain gauges are attached to the wave fins of each oil tank at multiple locations to monitor the stress changes on the tank wall in real time during the test. The strain gauges must be arranged evenly and accurately to ensure the reliability and accuracy of the measurement data.

[0053] Seven oil tanks were fully sealed and subjected to mechanical strength tests. During the test, a certain amount of oil was injected into the oil tank to simulate the expansion process of the oil volume. As the oil volume increases, the pressure in the oil tank gradually increases, and the stress on the oil tank wall also changes.

[0054] like Figure 2 and Figure 3 As shown, during the test, the correlation between the increase in oil volume of each tank and the tank pressure and expansion coefficient was recorded in detail.

[0055] Specifically, the data changes of the strain gauges are monitored in real time by the resistance strain method to obtain the stress change curve of the oil tank wall during the oil volume expansion process. At the same time, the whole process of the oil tank from elastic deformation to plastic deformation (material yield point) to destruction is observed and recorded.

[0056] Strain gauges are attached to multiple locations of the oil tank's wave fins, and the resistance strain method is used to monitor the stress changes on the tank wall in real time. As the pressure in the tank increases, the stress on the tank wall also increases accordingly.

[0057] During the test, the relationship between the increase in oil volume and the tank pressure and stress of each tank was recorded in detail. These data are the basis for subsequent analysis.

[0058] As the volume of oil increases, the tank wall first deforms elastically. During this phase, the tank is able to return to its original shape with no permanent structural damage. The recorded pressure-stress relationship is used to plot Figure 1 The curve shows the relationship between the wave height h and the pressure at the elastic deformation limit point. This curve shows that below the curve, the oil tank is within the elastic range and can compliantly accommodate the expansion of the oil volume.

[0059] When the pressure in the tank continues to increase and exceeds the elastic limit of the material, the tank wall begins to deform plastically. At this point, the tank cannot return to its original shape and permanent structural damage occurs. Continue to increase the amount of oil until the tank is destroyed, and record the relationship between the oil volume increase and the pressure increase during the entire process.

[0060] Combining the test data of seven tanks with different wave heights, we can draw Figure 2 and Figure 3 Two curves. Figure 2 The relationship between the wave height h and the pressure of the tank at the limit of elastic deformation is intuitively shown. Below the curve, the tank can safely withstand the expansion of the oil volume without plastic deformation. Figure 3 The relationship between the wave height h and the wave fin expansion coefficient β% is revealed. Below the curve, the wave fin can effectively absorb the expansion of the oil volume and meet the requirements of the fully sealed transformer for the wave height h.

[0061] Figure 2 Analysis: Make sure that the wave height h of the oil tank is below the curve to ensure that the tank can maintain an elastic deformation state when the oil volume expands to avoid plastic deformation or damage.

[0062] Figure 3 Analysis: By adjusting the wave height h, the expansion coefficient β% of the wave fin can be kept within a reasonable range, thereby ensuring that the oil tank can effectively absorb the expansion of the oil volume. The wave height h selected below the curve will meet the requirements of the fully sealed transformer for the oil tank performance.

[0063] S104. According to the association relationship, a wave height calculation formula of the wave wing of the fully enclosed transformer tank is derived.

[0064] The corrugated oil tank of the fully sealed transformer must meet the following requirements:

[0065] (V+V.)[1+0.0007(t 2 -t 1 )]<V+(1+β)V.

[0066] According to the above formula, we can get:

[0067] 0.0007(V+V)(t 2 -t 1 )<βV.

[0068] Among them, V. is the volume of the corrugated fin oil gap under normal pressure, V is the oil volume of the inner frame of the oil tank (excluding the corrugated fin oil gap), and the volume occupied by the core, winding, etc. should be deducted. 2 is the average temperature rise in the oil tank when the oil top surface temperature reaches the highest (considering the worst conditions, take = 60K), t 1 is the oil temperature when the oil is injected (taken as = 20°C),

[0069] 0.0007 is the average expansion coefficient of the oil volume when the unit volume of oil temperature increases by one degree, and β is the volume expansion coefficient of the corrugated fin.

[0070] The validity of the above formula should be understood as that the increase in oil volume due to the increase in oil temperature in the tank is completely borne by the expansion of the wave fins, so that the tank is not damaged.

[0071] When deriving, it is assumed that the core, windings and other components take up one third of the oil tank volume, so the oil volume in the tank is:

[0072]

[0073] Among them, B is the width of the rectangular fuel tank inner frame, L is the length of the rectangular fuel tank inner frame, and H is the height of the rectangular fuel tank inner frame.

[0074] When the wave fin oil gap is 6mp, the oil volume of the wave fin oil gap is:

[0075] V. =6Nbh

[0076] Where N is the number of fins, N≈2(B / τ+L / τ), τ is the pitch of the fins, τ=40-50mm, b is the width of the corrugated board,

[0077] The formula that the corrugated oil tank of the fully sealed transformer must satisfy is sorted out:

[0078] 0.0007V(t 1 -t 2 )<[β-0.0007(t 2 -t 1 )

[0079] Will BLH, ​​V. = 6Nbh, N≈2 is substituted into the previous formula to obtain:

[0080]

[0081] Arranging the previous formula yields:

[0082]

[0083] Because 0.0007(t 1 -t 2 ) value is much smaller than β value and can be ignored, so the above formula can be rearranged as follows:

[0084]

[0085] like Figure 2 As shown, when h = 160 ~ 240mm, it can be considered that B = 0.0020h, substituting into the above formula:

[0086]

[0087] Further sorting:

[0088]

[0089] Under the worst conditions, the ambient temperature is 40°C, and we get:

[0090] t 2 -t 1 =60+40-20=80℃

[0091] And take the wave wing pitch τ = 45, we get:

[0092]

[0093] S105, introducing a wave height coefficient into the wave height calculation formula so that a calculation result of the wave height calculation formula is within the wave height range.

[0094] The coefficient K is called the wave height coefficient, which combines various factors that affect the wave height. Adding the coefficient K gives:

[0095]

[0096] Appropriately correct the K value to make h closer to the actual value. This requires more experiments and data obtained from long-term operation to improve the K value.

[0097] S106. Correct the wave height according to the wave height coefficient to obtain the wave height size.

[0098] According to the calculated wave height coefficient K, the initially determined wave height h is corrected.

[0099] Specifically, based on the comprehensive consideration of various factors affecting wave height by the wave height coefficient K, it can more accurately reflect the actual requirements for wave height.

[0100] Finally, the value of the wave height h obtained after correction is the wave height size that should be used when designing the fully sealed transformer corrugated oil tank. This value not only meets the requirements of oil volume expansion, but also ensures the structural integrity and safety of the oil tank when the oil volume changes.

[0101] The present application also provides a device for determining the wave height of a fully enclosed transformer wave wing, comprising:

[0102] A determination module, which determines a wave height range of a wave fin of a fully enclosed transformer based on historical data, wherein the wave fin is located on an oil tank;

[0103] A selection module, selecting a plurality of said oil tanks with different wave fin heights according to said wave height range;

[0104] The test module is configured to set strain gauges at multiple positions of the wave wings of multiple oil tanks to perform stress monitoring, including: injecting a preset amount of oil into the oil tank; recording the correlation between the increase in the volume of the oil and the oil tank pressure and expansion coefficient;

[0105] A formula module, based on the association relationship, derives a wave height calculation formula for the wave wing of the oil tank in the fully enclosed transformer;

[0106] A range module, which introduces a wave height coefficient K into the wave height calculation formula so that the calculation result of the wave height calculation formula is within the wave height range;

[0107] The size module corrects the wave height according to the wave height coefficient to obtain the wave height size.

[0108] Furthermore, the wave height calculation formula is expressed as follows:

[0109]

[0110] Among them, h is the wave height, B is the width of the inner frame of the tank, and L is the length of the inner frame of the tank.

[0111] Furthermore, the range module introduces a wave height coefficient K into the wave height calculation formula so that the calculation result of the wave height calculation formula is within the wave height range. The expression is as follows:

[0112]

[0113] Among them, K is the wave height coefficient, h is the wave height, B is the width of the inner frame of the fuel tank, and L is the length of the inner frame of the fuel tank.

[0114] Furthermore, the different wave heights include: 80mm, 120mm, 160mm, 200mm, 240mm, 280mm and 320mm.

[0115] Furthermore, the oil tank pressure and expansion coefficient include:

[0116] The oil tank pressure and expansion coefficient of the oil tank at the deformation limit point.

Claims

1. A method for determining the wave height of a fully enclosed transformer wave wing, characterized in that: include: Determining a wave height range of an oil tank wave fin of a fully enclosed transformer based on historical data, wherein the wave fin is located on the oil tank; According to the wave height range of the wave wing, a plurality of the oil tanks having different wave heights are selected; Strain gauges are respectively arranged at multiple positions of the wave fins on multiple oil tanks to perform stress monitoring, including: injecting a preset amount of oil into the oil tank; recording the correlation between the volume increase of the oil and the oil tank pressure and expansion coefficient; Based on the correlation, a wave height calculation formula for the oil tank wave wing of a fully enclosed transformer is derived; Introducing a wave height coefficient into the wave height calculation formula so that the calculation result of the wave height calculation formula is within the wave height range; The wave height is corrected according to the wave height coefficient to obtain the wave height size.

2. According to claim 1, a method for determining the wave height of a fully enclosed transformer wave wing, characterized in that: The wave height calculation formula is expressed as follows: Among them, h is the wave height, B is the width of the inner frame of the tank, and L is the length of the inner frame of the tank.

3. According to claim 2, a method for determining the wave height of a fully enclosed transformer wave wing is characterized in that: The wave height coefficient K is introduced into the wave height calculation formula so that the calculation result of the wave height calculation formula is within the wave height range. The expression is as follows: Among them, K is the wave height coefficient, h is the wave height, B is the width of the inner frame of the fuel tank, and L is the length of the inner frame of the fuel tank.

4. According to claim 1, a method for determining the wave height of a fully enclosed transformer wave wing, characterized in that: The different wave heights include: 80mm, 120mm, 160mm, 200mm, 240mm, 280mm and 320mm.

5. A method for determining the wave height of a fully enclosed transformer wave wing according to claim 4, characterized in that: The oil tank pressure and expansion coefficient are: The oil tank pressure and expansion coefficient of the oil tank at the deformation limit point.

6. A device for determining the wave height of a fully enclosed transformer wave wing, characterized in that: include: A determination module, which determines a wave height range of a wave fin of a fully enclosed transformer tank based on historical data, wherein the wave fin is located on the tank; A selection module, selecting a plurality of said oil tanks with different wave fin heights according to said wave height range; The test module is configured to set strain gauges at multiple positions of the wave wings of multiple oil tanks to perform stress monitoring, including: injecting a preset amount of oil into the oil tank; recording the correlation between the increase in the volume of the oil and the oil tank pressure and expansion coefficient; A formula module, based on the association relationship, derives a wave height calculation formula for the wave wing of the oil tank in the fully enclosed transformer; A range module, which introduces a wave height coefficient K into the wave height calculation formula so that the calculation result of the wave height calculation formula is within the wave height range; The size module corrects the wave height according to the wave height coefficient to obtain the wave height size.

7. A device for determining the wave height of a fully enclosed transformer wave fin according to claim 6, characterized in that: The wave height calculation formula is expressed as follows: Among them, h is the wave height, B is the width of the inner frame of the tank, and L is the length of the inner frame of the tank.

8. A device for determining the wave height of a fully enclosed transformer wave fin according to claim 7, characterized in that: The range module introduces a wave height coefficient K into the wave height calculation formula so that the calculation result of the wave height calculation formula is within the wave height range. The expression is as follows: Among them, K is the wave height coefficient, h is the wave height, B is the width of the inner frame of the fuel tank, and L is the length of the inner frame of the fuel tank.

9. A device for determining the wave height of a fully enclosed transformer wave fin according to claim 6, characterized in that: The different wave heights include: 80mm, 120mm, 160mm, 200mm, 240mm, 280mm and 320mm.

10. A device for determining the wave height of a fully enclosed transformer wave fin according to claim 9, characterized in that: The oil tank pressure and expansion coefficient are: The oil tank pressure and expansion coefficient of the oil tank at the deformation limit point.

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