Interlayer insulation and distribution transformer, winding method and equipment

Abstract

The invention discloses a distribution transformer interlayer insulator with a nonlinear structure, which is arranged between two adjacent wire layers in a coil of a distribution transformer, and takes the direction in which the voltage difference between the two wire layers is gradually increased as the winding direction. And the thickness and voltage difference of the interlayer insulation at each turn of lead are related to the rule that the average electric strength changes along with the thickness, so that the thickness of the interlayer insulation in the winding direction is gradually increased in a nonlinear amplitude. The thickness of the interlayer insulation of the distribution transformer with the nonlinear structure adopts nonlinear distribution, so that the design redundancy of the insulation layer can be effectively reduced, the utilization rate of the interlayer insulation is further improved, and the overall volume of the transformer is reduced. The invention further provides the distribution transformer, and an interlayer insulation winding method and equipment for the distribution transformer with the nonlinear structure.

Description

Technical Field

[0001] The invention belongs to the technical field of transformer manufacturing, and in particular relates to interlayer insulation of a distribution transformer with a nonlinear structure, a distribution transformer, and a winding method and equipment for interlayer insulation. Background Art

[0002] At present, the high-voltage coil of the distribution transformer generally adopts the layer winding form. The multiple turns of wires that make up the coil are wound in layers and connected in sequence. In order to ensure the insulation strength between adjacent layers of wires and avoid breakdown discharge of adjacent layers of wires, interlayer insulation paper is usually placed between adjacent layers of wires. In the insulation structure of traditional transformers, a whole piece of insulation paper or half a piece of insulation paper is used as interlayer insulation.

[0003] But in actual transformers, the voltage difference between two adjacent layers of conductors increases linearly. For example, if the voltage difference between two adjacent turns of conductors is u and the number of turns per layer is n, then the voltage difference between the two layers of conductors at the minimum voltage difference is u, and the voltage difference at the maximum voltage difference is u*n. However, the traditional insulation paper has the same insulation thickness between the layers, that is, the same insulation thickness is used at the voltage difference u and u*n, resulting in a waste of insulation at the low voltage between the layers. Summary of the invention

[0004] For the above-mentioned deficiencies in the prior art, there is currently a technical solution that adopts an insulation layer thickness solution that changes with the increase of voltage difference, that is, the interlayer insulation thickness is linearly related to the voltage difference. Compared with the full-width or half-width insulation paper solution, it can improve the utilization rate of the insulation layer and reduce the overall volume of the transformer.

[0005] However, the inventors of the present invention discovered that the electrical strength of the insulating layer has a volume effect, that is, as the thickness of the insulating layer increases, the average electrical strength per unit thickness will decrease accordingly, and the average electrical strength and the thickness of the insulating layer are distributed in a power function. Therefore, in this case, the current technical solution of the insulating layer thickness that changes linearly with the voltage difference still has a waste of the insulating layer, resulting in the overall volume of the transformer being still large.

[0006] Accordingly, the present invention provides a nonlinear structure of interlayer insulation for a distribution transformer, wherein the thickness of the interlayer insulation is nonlinearly distributed, which can effectively reduce the design redundancy of the insulation layer, further improve the utilization rate of the interlayer insulation, and reduce the overall volume of the transformer. The present invention also provides a distribution transformer, and a method and device for winding interlayer insulation of a distribution transformer with a nonlinear structure.

[0007] The present invention provides an interlayer insulation of a distribution transformer with a nonlinear structure. The interlayer insulation is arranged between two adjacent wire layers in the coil of the distribution transformer. The winding direction is the direction in which the voltage difference between the two wire layers gradually increases. The thickness of the interlayer insulation at each turn of the wire is related to the voltage difference, and the average dielectric strength varies with the thickness, so that the thickness of the interlayer insulation along the winding direction gradually increases with a nonlinear amplitude.

[0008] Furthermore, assuming that the voltage difference between two adjacent turns of the conductor is u, the thickness D of the interlayer insulation at the nth turn of the conductor is determined by the following formula:

[0009] U / D=a*D b

[0010] Among them, U=u*n is the voltage difference at the nth turn of the conductor, and a and b are the relationship coefficients of the average dielectric strength changing with thickness.

[0011] Furthermore, the interlayer insulation is obtained by winding an insulating paper tape in a spiral line around the coil along the winding direction, and the number of windings of the insulating paper tape at each turn of the conductor gradually increases with a nonlinear amplitude along the winding direction, so that the thickness of the interlayer insulation along the winding direction gradually increases with a nonlinear amplitude.

[0012] Furthermore, the number of turns N of the insulating paper tape at the nth turn of the conductor is determined by the following formula:

[0013] N=D / d

[0014] Where d is the thickness of a single turn of insulating paper tape, and D is the thickness of the interlayer insulation at the nth turn of the conductor.

[0015] Furthermore, the spiral wire surrounding the coil is a variable pitch spiral wire, and the winding pitch of the insulating paper tape at each turn of the conductor gradually decreases with a nonlinear amplitude along the winding direction, so that the number of windings of the insulating paper tape at each turn of the conductor gradually increases with a nonlinear amplitude along the winding direction.

[0016] Furthermore, the winding pitch W of the insulating paper tape at the nth turn of the conductor is determined by the following formula:

[0017] W=w / N

[0018] Wherein, w is the width of the insulating paper tape, and N is the number of turns of the insulating paper tape at the nth turn of the conductor.

[0019] The present invention also provides a distribution transformer, including a coil, wherein the coil includes a conductor layer and the above-mentioned distribution transformer interlayer insulation of the nonlinear structure, wherein the conductor layer has multiple layers from the inside to the outside, and the interlayer insulation is arranged between two adjacent conductor layers.

[0020] The present invention also provides a method for interlayer insulation winding of a distribution transformer with a nonlinear structure, comprising the following steps:

[0021] Determine winding parameters based on voltage difference and average electrical strength variation with thickness;

[0022] The winding direction is the direction in which the voltage difference between the two conductor layers gradually increases, and the conductor is wound along the winding direction according to the winding parameters to form an interlayer insulation whose thickness gradually increases with a nonlinear amplitude along the winding direction.

[0023] Furthermore, the winding parameters are determined according to the voltage difference and the average electrical strength varying with the thickness, specifically including:

[0024] According to the voltage difference between two conductor layers and the variation law of average dielectric strength with thickness, the thickness of interlayer insulation at each turn of conductor is obtained;

[0025] According to the thickness of the interlayer insulation at each turn of the conductor, the number of turns of the insulating paper tape at each turn of the conductor is obtained;

[0026] According to the number of turns of the insulating paper tape at each turn of the conductor, the winding pitch of the insulating paper tape at each turn of the conductor is obtained;

[0027] The method of taking the direction in which the voltage difference between the two conductor layers gradually increases as the winding direction and winding along the winding direction according to the winding parameters to form interlayer insulation with a thickness gradually increasing with a nonlinear amplitude along the winding direction specifically includes:

[0028] The winding direction is the direction in which the voltage difference between the two layers of conductors gradually increases. According to the winding pitch of the insulating paper tape at each turn of the conductor, the insulating paper tape is wound on the coil along the winding direction to form interlayer insulation whose thickness gradually increases with a nonlinear amplitude along the winding direction.

[0029] Further, the thickness of the interlayer insulation at each turn of the conductor is obtained according to the voltage difference between the two conductor layers and the law of variation of the average dielectric strength with thickness, specifically including determining the thickness D of the interlayer insulation at the nth turn of the conductor by the following formula:

[0030] U / D=a*D b

[0031] Among them, U = u*n, is the voltage difference at the nth turn of the conductor, a and b are the coefficients of the relationship between the average dielectric strength and the thickness;

[0032] The step of obtaining the number of turns of the insulating paper tape at each turn of the conductor according to the thickness of the interlayer insulation at each turn of the conductor specifically includes determining the number of turns N at the nth turn of the conductor by the following formula:

[0033] N=D / d

[0034] Where, d is the thickness of a single-turn insulating paper tape;

[0035] The step of obtaining the winding pitch of the insulating paper tape at each turn of the conductor according to the number of turns of the insulating paper tape at each turn of the conductor specifically includes determining the winding pitch W at the nth turn of the conductor by the following formula:

[0036] W=w / N

[0037] Where w is the width of the insulating paper tape.

[0038] The present invention also provides a nonlinear structure distribution transformer interlayer insulation winding device, comprising:

[0039] The winding device is used to install the coil and wind the insulating paper tape around the coil by rotating and winding.

[0040] The unwinding device is used to unwind the insulating paper tape to the rewinding device by rotating the unwinding device and moving axially relative to the rewinding device.

[0041] The control unit is electrically connected to the winding device and the unwinding device, and is used to determine the winding parameters according to the voltage difference and the law of the average dielectric strength varying with the thickness, and to control the rotation of the unwinding device and the winding device, and take the direction in which the voltage difference between the two conductor layers gradually increases as the winding direction, control the relative moving speed of the unwinding device and the winding device according to the winding parameters, and perform winding of the insulating paper tape along the winding direction to form interlayer insulation whose thickness gradually increases with a nonlinear amplitude along the winding direction.

[0042] Compared with the currently widely used solution in which the thickness of interlayer insulation is linearly related to the voltage difference, the thickness of the interlayer insulation of the distribution transformer of the nonlinear structure of the present invention is no longer simply set based on the voltage difference. Instead, while being based on the voltage difference, the law of variation of the average dielectric strength of the interlayer insulation with the thickness is also introduced. Therefore, when setting the thickness of the interlayer insulation, the volume effect of the dielectric strength of the insulation layer is taken into account, and the thickness of the interlayer insulation finally obtained is gradually thickened with a nonlinear amplitude.

[0043] Compared with the conventional linear layout scheme, this structural setting can eliminate unnecessary insulation thickness in the linear layout scheme, reduce the design redundancy of the insulation layer, reduce production costs, greatly improve the effective utilization rate of interlayer insulation, and effectively reduce the overall volume of the transformer while ensuring the electrical strength of the insulation layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a schematic structural diagram of interlayer insulation of a distribution transformer with a nonlinear structure in Embodiment 1 of the present invention;

[0045] Figure 2It is a schematic diagram of the distribution of voltage, thickness, and number of turns along the number of turns in the interlayer insulation of the distribution transformer with a nonlinear structure in Example 1 of the present invention;

[0046] Figure 3 It is a schematic diagram of the winding of interlayer insulation of a distribution transformer with a nonlinear structure in Example 1 of the present invention.

[0047] In the figure: 1, conductor layer; 11, first conductor layer; 12, second conductor layer; 2, interlayer insulation; 21, insulating paper tape. DETAILED DESCRIPTION

[0048] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0049] In the description of the present invention, it should be noted that the terms "upper", "lower" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience and simplification of the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present invention.

[0050] In the description of the present invention, the terms “first”, “second” and “third” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0051] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connect", "set", "install", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0052] Example 1

[0053] like Figure 1 As shown, the interlayer insulation of the distribution transformer with a nonlinear structure in this embodiment, the interlayer insulation 2 is arranged between two adjacent wire layers 1 in the coil of the distribution transformer, and the winding direction is the direction in which the voltage difference between the two wire layers 1 gradually increases. The thickness of the interlayer insulation 2 at each turn of the wire is related to the voltage difference, and the average dielectric strength varies with the thickness, so that the thickness of the interlayer insulation 2 along the winding direction gradually increases with a nonlinear amplitude.

[0054] Compared with the currently widely used solution in which the thickness of interlayer insulation is linearly related to the voltage difference, the thickness of the interlayer insulation of the distribution transformer with nonlinear structure in this embodiment is no longer simply set based on the voltage difference. Instead, while being based on the voltage difference, the variation law of the average dielectric strength of the interlayer insulation 2 with the thickness is also introduced. Therefore, when setting the thickness of the interlayer insulation 2, the volume effect of the dielectric strength of the insulation layer is taken into account, and the thickness of the interlayer insulation 2 is finally obtained to gradually increase with a nonlinear amplitude.

[0055] Compared with the conventional linear layout scheme, this structural setting can eliminate unnecessary insulation thickness in the linear layout scheme, reduce the design redundancy of the insulation layer, reduce production costs, greatly improve the effective utilization rate of the interlayer insulation 2, and effectively reduce the overall volume of the transformer while ensuring the electrical strength of the insulation layer.

[0056] In this embodiment, assuming that the voltage difference between two adjacent turns of the conductor is u, the thickness D of the interlayer insulation 2 at the nth turn of the conductor is determined by the following formula:

[0057] U / D=a*D b (1)

[0058] Among them, U=u*n is the voltage difference at the nth turn of the conductor, and a and b are the relationship coefficients of the average dielectric strength changing with thickness.

[0059] Specifically, due to the difference in the thickness of the interlayer insulation, the breakdown field strength is different. The breakdown field strength varies with the thickness in a power function distribution, and the specific form is E = a*D b , where E is the breakdown field strength; and the electric field strength at the voltage difference U and the spacing distance D is U / D, then the breakdown field strength and the electric field strength are combined, that is, when U / D=E=a*D b When equation (1) is obtained, the minimum interlayer insulation size without breakdown can be obtained. It can be seen that the interlayer insulation thickness setting scheme in this embodiment can eliminate redundant usage while meeting the insulation function, thereby achieving the effect of improving effective utilization.

[0060] In this embodiment, the relationship coefficients a and b of the average dielectric strength variation with thickness can be calculated by experimental testing, simulation, etc. according to the specific size, material and operating parameters of the insulating paper tape 21 used in the interlayer insulation 2, and will not be described in detail here.

[0061] In this embodiment, the interlayer insulation 2 is obtained by winding an insulating paper tape 21 in a spiral line around the coil along the winding direction. The number of windings of the insulating paper tape 21 at each turn of the conductor gradually increases with a nonlinear amplitude along the winding direction, so that the thickness of the interlayer insulation 2 along the winding direction gradually increases with a nonlinear amplitude.

[0062] In this embodiment, the number of turns N of the insulating paper tape 21 at the nth turn of the conductor is determined by the following formula:

[0063] N=D / d

[0064] Wherein, d is the thickness of a single-turn insulating paper tape 21, and D is the thickness D of the interlayer insulation 2 at the n-th turn of the conductor.

[0065] In this embodiment, the spiral wire surrounding the coil is a variable pitch spiral wire, and the winding pitch of the insulating paper tape 21 at each turn of the conductor gradually decreases at a nonlinear amplitude along the winding direction, so that the number of windings of the insulating paper tape 21 at each turn of the conductor gradually increases at a nonlinear amplitude along the winding direction.

[0066] In this embodiment, the winding pitch W of the insulating paper tape 21 at the nth turn of the conductor is determined by the following formula:

[0067] W=w / N

[0068] Wherein, w is the width of the insulating paper tape 21, and N is the number of turns of the insulating paper tape 21 at the nth turn of the conductor. In this embodiment, when selecting the specifications of the insulating paper tape 21, the thickness of the insulating paper tape 21 is 0.05mm-0.2mm. This selection range can avoid the thickness being too thin, which may cause friction damage during the winding of the paper tape, and can also avoid the thickness being too thick, which may cause increased insulation redundancy. The width of the insulating paper tape 21 is 10mm-40mm, which can avoid the width being too narrow, which may cause surface discharge along the gap of the paper tape, and can also avoid insulation redundancy caused by being too wide. That is, the paper tape selection specification range of this embodiment minimizes insulation redundancy while ensuring the integrity and functionality of the insulating paper tape 21.

[0069] In general, the purpose of this embodiment is to provide a nonlinear interlayer insulation structure that can improve the utilization rate of the insulation layer and reduce the overall volume of the transformer. It is assumed that two adjacent wire layers 1 include a first wire layer 11 and a second wire layer 12, and the interlayer insulation 2 (i.e., the insulation layer) is wound on the outside of the first wire layer 11, and the second wire layer 12 is wound on the outside of the interlayer insulation 2. Among them, the interlayer insulation 2 is formed by spirally winding an insulating paper tape 21 of the same width, and the winding pitch of the insulating paper tape 21 decreases nonlinearly along the winding direction, so that the number of winding turns of the insulating paper tape 21 increases nonlinearly along the winding direction, which is used to form an interlayer insulation 2 with a nonlinearly increasing thickness along the winding direction. Among them, the number of winding turns of the insulating paper tape 21 increases with a power function amplitude along the winding direction, and the insulating paper tape 21 can be a dotted paper, a heat-resistant paper, or other cellulose insulating paper tapes, and the winding direction is the direction in which the voltage between the first wire layer 11 and the second wire layer 12 increases. Insulating paper tapes 21 with different numbers of turns form interlayer insulation 2. The thickness of the interlayer insulation 2 changes as the number of turns of the insulating paper tape 21 increases. The thickness of the interlayer insulation 2 increases with a power function amplitude along the winding direction.

[0070] The transformer interlayer insulation structure proposed in this embodiment starts from the actual electric field distribution faced by the insulation layer and takes into account the volume effect of the insulation layer's electrical strength, so that the insulation layer thickness is nonlinearly distributed. This improves the insulation layer utilization rate and reduces the overall volume of the transformer while maintaining the insulation layer's electrical strength. A method for calculating the pitch of the insulating paper tape 21 is provided, and the winding of the nonlinear interlayer insulation structure is achieved by adjusting the pitch.

[0071] The following are specific examples:

[0072] Assume that there are 40 turns of wire in each layer of the coil, and the voltage between two adjacent turns is 140V. Figure 1 The transformer interlayer insulation 2 structure shows the distribution of voltage difference between the insulation layers from left to right. Figure 2 As shown by the dashed line (dashed line), that is, between the first conductor layer 11 and the second conductor layer 12, the voltage difference at 0 turns is 0.14 kV, and the voltage difference increases to 5.6 kV at 40 turns.

[0073] According to the above voltage difference distribution, the thickness distribution of the insulating layer is calculated. The breakdown field strength of insulating layers of different thicknesses is different, and the breakdown field strength varies with thickness in a power function distribution, specifically in the form of E = a*D b , where E is the breakdown field strength, D is the thickness of the interlayer insulation 2, in this embodiment, E = 4.9 * D -0.34 , the electric field strength is U / D, so the calculation method for the thickness of the interlayer insulation 2 is U / D=4.9*D -0.34 Based on this, the insulation thickness at 0 turns is 0.0015mm, and the insulation thickness at 40 turns is 0.4146mm.

[0074] According to the above thickness distribution, the number of turns of the insulating paper tape 21 is calculated, and the number of turns should be N = D / d. Since the number of turns of the insulating paper tape 21 (that is, the number of layers of interlayer insulation 2 formed after stacking must be an integer), in order to ensure the insulation performance, the number of turns obtained after taking the value according to N = D / d is rounded up. In this embodiment, the thickness of each layer of insulating paper tape 21 is 0.08mm, and the number of turns is distributed as follows: Figure 2 As shown by the solid line, the number of turns of the paper tape at 0 turns is 1, and the number of turns of the paper tape at 40 turns is 6, and the winding is carried out in sequence.

[0075] According to the above winding number, the winding pitch of the insulating paper tape 21 is calculated, and the winding pitch should be W = w / N. In this embodiment, the paper tape width is 25mm, and the paper tape winding pitch at 0 turns is 25mm, and the paper tape winding pitch at 40 turns is 4.2mm.

[0076] The interlayer insulation 2 structure finally formed is as follows Figure 3 shown.

[0077] Example 2

[0078] The distribution transformer of this embodiment includes a coil, which includes a conductor layer 1 and interlayer insulation of the distribution transformer with a nonlinear structure in Embodiment 1. The conductor layer 1 has multiple layers from the inside to the outside, and the interlayer insulation 2 is arranged between two adjacent conductor layers 1.

[0079] Specifically, the coil includes a first conductor layer 11, an interlayer insulation 2, and a second conductor layer 12 from the inside to the outside. The interlayer insulation 2 is spirally wound on the outside of the first conductor layer 11, and the second conductor layer 12 is spirally wound on the outside of the interlayer insulation 2. The interlayer insulation 2 is spirally wound by an insulating paper tape 21 of the same width. The paper tape is successively wound along different pitches to form an interlayer insulation 2 containing different numbers of paper tape turns. The thickness distribution of the interlayer insulation 2 can be controlled by adjusting the pitch of the paper tape winding. During the winding, the winding pitch of the insulating paper tape 21 decreases nonlinearly along the winding direction, so that the number of winding turns of the insulating paper tape 21 increases nonlinearly along the winding direction, so as to form an interlayer insulation 2 whose thickness increases nonlinearly along the winding direction.

[0080] Since the interlayer insulation of the distribution transformer with a nonlinear structure is adopted, the volume of the coil of the distribution transformer in this embodiment is effectively reduced, and the effective utilization rate of the interlayer insulation 2 is improved.

[0081] Example 3

[0082] The interlayer insulation winding method of the distribution transformer with a nonlinear structure of this embodiment comprises the following steps:

[0083] Determine winding parameters based on voltage difference and average electrical strength variation with thickness;

[0084] The winding direction is the direction in which the voltage difference between the two conductor layers 1 gradually increases, and the conductor is wound along the winding direction according to the winding parameters to form an interlayer insulation 2 whose thickness gradually increases with a nonlinear amplitude along the winding direction.

[0085] Specifically, the winding parameters are determined according to the voltage difference and the variation law of the average electrical strength with thickness, including:

[0086] According to the voltage difference between the two conductor layers 1 and the variation law of the average dielectric strength with thickness, the thickness of the interlayer insulation 2 at each turn of the conductor is obtained;

[0087] According to the thickness of the interlayer insulation 2 at each turn of the conductor, the number of windings of the insulating paper tape 21 at each turn of the conductor is obtained;

[0088] According to the number of turns of the insulating paper tape 21 at each turn of the conductor, the winding pitch of the insulating paper tape 21 at each turn of the conductor is obtained;

[0089] The winding direction is a direction in which the voltage difference between the two conductor layers 1 gradually increases, and the winding is performed along the winding direction according to the winding parameters to form an interlayer insulation 2 whose thickness gradually increases along the winding direction with a nonlinear amplitude, specifically including:

[0090] The winding direction is the direction in which the voltage difference between the two conductor layers 1 gradually increases. According to the winding pitch of the insulating paper tape 21 at each turn of the conductor, the insulating paper tape 21 is wound on the coil along the winding direction to form an interlayer insulation 2 whose thickness gradually increases with a nonlinear amplitude along the winding direction.

[0091] In this embodiment, according to the voltage difference between the two conductor layers 1 and the law of variation of the average dielectric strength with thickness, the thickness of the interlayer insulation 2 at each turn of the conductor is obtained, specifically including determining the thickness D of the interlayer insulation 2 at the nth turn of the conductor by the following formula:

[0092] U / D=a*D b

[0093] Among them, U = u*n, is the voltage difference at the nth turn of the conductor, a and b are the coefficients of the relationship between the average dielectric strength and the thickness;

[0094] According to the thickness of the interlayer insulation 2 at each turn of the conductor, the number of turns of the insulating paper tape 21 at each turn of the conductor is obtained, specifically including determining the number of turns N at the nth turn of the conductor by the following formula:

[0095] N=D / d

[0096] Wherein, d is the thickness of a single-turn insulating paper tape 21;

[0097] According to the number of turns of the insulating paper tape 21 at each turn of the conductor, the winding pitch of the insulating paper tape 21 at each turn of the conductor is obtained, specifically including determining the winding pitch W at the nth turn of the conductor by the following formula:

[0098] W=w / N

[0099] Wherein, w is the width of the insulating paper tape 21 .

[0100] The winding steps of this embodiment start from the actual electric field distribution faced by the insulation layer, and consider the volume effect of the insulation layer's dielectric strength, so that the insulation layer thickness is nonlinearly distributed, thereby improving the insulation layer utilization rate and reducing the overall volume of the transformer while maintaining the dielectric strength of the insulation layer. The insulation winding method uses an insulating paper tape to realize the winding of the insulation layer, and proposes a method for calculating the pitch of the insulating paper tape, and realizes the winding of the nonlinear interlayer insulation structure by adjusting the pitch. The method can be simply divided into the following steps:

[0101] Step 1: Calculate the voltage difference distribution between the first conductor layer 11 and the second conductor layer 12; the voltage difference distribution U is calculated as follows: U=u*n, where u is the voltage difference between two adjacent turns of conductors, and n is the number of turns of conductors;

[0102] Step 2: Calculate the thickness distribution of the interlayer insulation 2 according to the voltage difference distribution; the thickness of the interlayer insulation 2 increases with the amplitude of the power function along the winding direction; the calculation method of the thickness distribution D of the interlayer insulation 2 is, U / D=a*D b , a and b are the coefficients of the relationship between the average dielectric strength tested and the thickness, which can also be called the coefficient of the relationship between the thickness of the interlayer insulation 2 tested and the breakdown field strength;

[0103] Step 3: Calculate the number of turns of the insulating paper tape 21 according to the thickness distribution of the interlayer insulation 2; the number of turns of the insulating paper tape 21 increases with the amplitude of a power function along the winding direction; the calculation method of the number of turns N of the insulating paper tape 21 is, N=D / d, where d is the thickness of a single layer of insulating paper tape;

[0104] Step 4: Calculate the winding pitch of the insulating paper tape 21 according to the number of winding turns of the insulating paper tape 21; the winding pitch W is calculated as follows: W=w / N, where W is the width of the paper tape;

[0105] Step five: Wind the insulating paper tape 21 according to the winding pitch to form the interlayer insulation 2.

[0106] Combined with the specific situation of the example provided in Embodiment 1, the interlayer insulation winding method of the distribution transformer with a nonlinear structure in this embodiment can further specify the above steps as follows:

[0107] Step 1: Calculate the voltage difference distribution between the first conductor layer 11 and the second conductor layer 12. Each conductor layer has 40 turns, and the voltage between two adjacent turns is 140V. Figure 1 The interlayer insulation structure of the transformer shows the distribution of the voltage difference between the layers from left to right. Figure 2 As shown by the dashed line (dashed line), the voltage difference at 0 turns is 0.14 kV, and increases to 5.6 kV at 40 turns.

[0108] Step 2: Calculate the thickness distribution of interlayer insulation 2 (i.e., insulation layer) based on the voltage difference distribution in step 1. Insulation layers of different thicknesses have different breakdown field strengths, and the breakdown field strength varies with thickness in a power function distribution, specifically in the form of E=a*D b , where E is the breakdown field strength, D is the thickness of the interlayer insulation 2, in this embodiment, E = 4.9 * D -0.34 , the electric field strength is U / D, so the calculation method for the thickness of the interlayer insulation 2 is U / D=4.9*D -0.34 According to this calculation method, the thickness distribution of the insulation layer is as follows Figure 2As shown by the dotted lines, the insulation thickness at 0 turns is 0.0015 mm, and the insulation thickness at 40 turns is 0.4146 mm.

[0109] Step 3: Calculate the number of turns of the insulating paper tape 21 according to the insulation layer thickness distribution calculated in step 2. The number of turns should be N = D / d. The number of turns of the paper tape must be an integer. To ensure the insulation performance, the number of turns is rounded up. In this embodiment, the thickness of each layer of paper tape is 0.08 mm, and the number of turns is distributed as follows: Figure 2 As shown by the solid line, the number of turns of the paper tape at 0 turns is 1, and the number of turns of the paper tape at 40 turns is 6, and the winding is carried out in sequence.

[0110] Step 4: Calculate the winding pitch of the insulating paper tape (21) according to the number of turns of the insulating paper tape (21) calculated in step 3, and the winding pitch should be W=w / N. In this embodiment, the width of the paper tape is 25 mm, the winding pitch of the paper tape at 0 turns is 25 mm, and the winding pitch of the paper tape at 40 turns is 4.2 mm.

[0111] The interlayer insulation 2 structure finally formed is as follows Figure 3 shown.

[0112] Example 4

[0113] The interlayer insulation winding device of the distribution transformer with a nonlinear structure of this embodiment can be used to implement the method in Example 3, and the device includes: a winding device, which is used to install the coil and wind the insulating paper tape 21 around the coil by rotating and winding, a unwinding device, which is used to unwind the insulating paper tape 21 to the winding device by rotating and unwinding and axially moving relative to the winding device, and a control unit, which is electrically connected to the winding device and the unwinding device, and is used to determine the winding parameters according to the voltage difference and the law of the average dielectric strength changing with the thickness, and to control the unwinding device and the winding device to rotate, and take the direction in which the voltage difference between the two layers of conductor layers 1 gradually increases as the winding direction, control the relative movement speed of the unwinding device and the winding device according to the winding parameters, and perform winding of the insulating paper tape 21 along the winding direction to form an interlayer insulation 2 whose thickness gradually increases with a nonlinear amplitude along the winding direction.

[0114] Specifically, the control unit is used to obtain the thickness of the interlayer insulation 2 at each turn of the wire according to the voltage difference between the two layers of wire layers 1 and the law of change of the average dielectric strength with thickness, and, according to the thickness of the interlayer insulation 2 at each turn of the wire, obtain the number of windings of the insulating paper tape 21 at each turn of the wire, and, according to the number of windings of the insulating paper tape 21 at each turn of the wire, obtain the winding pitch of the insulating paper tape 21 at each turn of the wire, and control the rotation of the unwinding device and the winding device, and take the direction in which the voltage difference between the two layers of wire layers 1 gradually increases as the winding direction, control the relative movement speed of the unwinding device and the winding device according to the winding pitch of the insulating paper tape 21 at each turn of the wire, and perform the winding of the insulating paper tape 21 along the winding direction to form an interlayer insulation 2 whose thickness gradually increases with a nonlinear amplitude along the winding direction.

[0115] The above-mentioned embodiment only expresses one implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A distribution transformer interlayer insulation with a nonlinear structure, characterized in that: The interlayer insulation (2) is arranged between two adjacent conductor layers (1) in the coil of the distribution transformer. The winding direction is the direction in which the voltage difference between the two conductor layers (1) gradually increases. The thickness of the interlayer insulation (2) at each turn of the conductor is related to the voltage difference, and the average dielectric strength varies with the thickness. So that the thickness of the interlayer insulation (2) along the winding direction gradually increases with a nonlinear amplitude.

2. The interlayer insulation of the distribution transformer with nonlinear structure according to claim 1, characterized in that: Assuming that the voltage difference between two adjacent turns of the conductor is u, the thickness D of the interlayer insulation (2) at the nth turn of the conductor is determined by the following formula: U / D=a*D b Among them, U=u*n is the voltage difference at the nth turn of the conductor, and a and b are the relationship coefficients of the average dielectric strength changing with thickness.

3. The interlayer insulation of the distribution transformer with nonlinear structure according to claim 1, characterized in that: The interlayer insulation (2) is obtained by winding an insulating paper tape (21) along a winding direction with a spiral wire surrounding the coil. The number of turns of the insulating paper tape (21) at each turn of the conductor gradually increases in a nonlinear amplitude along the winding direction. So that the thickness of the interlayer insulation (2) along the winding direction gradually increases with a nonlinear amplitude.

4. The interlayer insulation of the distribution transformer with nonlinear structure according to claim 3 is characterized in that: The number of turns N of the insulating paper tape (21) at the nth turn of the conductor is determined by the following formula: N=D / d Wherein, d is the thickness of a single-turn insulating paper tape (21), and D is the thickness D of the interlayer insulation (2) at the n-th turn of the conductor.

5. The interlayer insulation of the distribution transformer with nonlinear structure according to claim 3 is characterized in that: The helical wire surrounding the coil is a variable pitch helical wire, The winding pitch of the insulating paper tape (21) at each turn of the conductor gradually decreases in a nonlinear amplitude along the winding direction. The number of windings of the insulating paper tape (21) at each turn of the conductor is gradually increased in a nonlinear amplitude along the winding direction.

6. The interlayer insulation of the distribution transformer with nonlinear structure according to claim 5, characterized in that: The winding pitch W of the insulating paper tape (21) at the nth turn of the conductor is determined by the following formula: W=w / N Wherein, w is the width of the insulating paper tape (21), and N is the number of turns of the insulating paper tape (21) at the nth turn of the conductor.

7. A distribution transformer, characterized in that: A distribution transformer comprising a coil, the coil comprising a conductor layer (1) and an interlayer insulation of a nonlinear structure according to any one of claims 1 to 6, The conductor layer (1) has multiple layers from the inside to the outside. The interlayer insulation (2) is arranged between two adjacent conductor layers (1).

8. A method for interlayer insulation winding of a distribution transformer with a nonlinear structure, characterized in that: The following steps are involved: Determine winding parameters based on voltage difference and average electrical strength variation with thickness; The winding direction is the direction in which the voltage difference between the two conductor layers (1) gradually increases, and the conductor is wound along the winding direction according to the winding parameters to form an interlayer insulation (2) whose thickness gradually increases along the winding direction with a nonlinear amplitude.

9. The interlayer insulation winding method of a distribution transformer with a nonlinear structure according to claim 8 is characterized in that: The winding parameters are determined according to the voltage difference and the law of average electrical strength varying with thickness, specifically including: Obtaining the thickness of the interlayer insulation (2) at each turn of the conductor according to the voltage difference between the two conductor layers (1) and the law of variation of the average dielectric strength with thickness; According to the thickness of the interlayer insulation (2) at each turn of the conductor, the number of turns of the insulating paper tape (21) at each turn of the conductor is obtained; Obtaining the winding pitch of the insulating paper tape (21) at each turn of the conductor according to the number of turns of the insulating paper tape (21) at each turn of the conductor; The method of taking the direction in which the voltage difference between the two conductor layers (1) gradually increases as the winding direction and winding along the winding direction according to the winding parameters to form an interlayer insulation (2) whose thickness gradually increases with a nonlinear amplitude along the winding direction specifically comprises: The direction in which the voltage difference between the two conductor layers (1) gradually increases is taken as the winding direction, and the insulating paper tape (21) is wound on the coil along the winding direction according to the winding pitch of the insulating paper tape (21) at each turn of the conductor, so as to form an interlayer insulation (2) whose thickness gradually increases with a nonlinear amplitude along the winding direction.

10. The interlayer insulation winding method of a distribution transformer with a nonlinear structure according to claim 9, characterized in that: The method of obtaining the thickness of the interlayer insulation (2) at each turn of the conductor according to the voltage difference between the two conductor layers (1) and the law of variation of the average dielectric strength with thickness specifically includes determining the thickness D of the interlayer insulation (2) at the nth turn of the conductor according to the following formula: U / D=a*D b Among them, U = u*n, is the voltage difference at the nth turn of the conductor, a and b are the coefficients of the relationship between the average dielectric strength and the thickness; The method of obtaining the number of windings of the insulating paper tape (21) at each turn of the conductor according to the thickness of the interlayer insulation (2) at each turn of the conductor specifically includes determining the number of windings N at the nth turn of the conductor by the following formula: N=D / d Wherein, d is the thickness of a single-turn insulating paper tape (21); The step of obtaining the winding pitch of the insulating paper tape (21) at each turn of the conductor according to the number of turns of the insulating paper tape (21) at each turn of the conductor specifically includes determining the winding pitch W at the nth turn of the conductor by the following formula: W=w / N Wherein, w is the width of the insulating paper tape (21).

11. A nonlinear structure distribution transformer interlayer insulation winding equipment, characterized in that: include: The winding device is used to install the coil and wind the insulating paper tape (21) around the coil by rotating and winding. The unwinding device is used to unwind the insulating paper tape (21) to the rewinding device by rotating the unwinding device and moving axially relative to the rewinding device. A control unit is electrically connected to the winding device and the unwinding device, and is used to determine the winding parameters according to the voltage difference and the law of average dielectric strength changing with thickness, and, The unwinding device and the rewinding device are controlled to rotate, and the direction in which the voltage difference between the two conductor layers (1) gradually increases is used as the winding direction. The relative moving speed of the unwinding device and the rewinding device is controlled according to the winding parameters, and the insulating paper tape (21) is wound along the winding direction to form an interlayer insulation (2) whose thickness gradually increases with a nonlinear amplitude along the winding direction.

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