Voltage transformer with staged winding high-voltage winding

Abstract

The utility model relates to the technical field of transformers, in particular to a voltage transformer with a hierarchical winding high-voltage winding, which comprises a magnetic core and a primary winding wound on the magnetic core, the two ends of a coil wire of the primary winding are connected with two wiring terminals connected with a high-voltage circuit. Two ends of the primary winding are respectively provided with two side parts connected with a wiring terminal, and the two side parts are called high-voltage sections; the middle part of the primary winding is also provided with a middle part which is far away from the wiring terminals at two sides and is called a low-voltage section; an insulating layer is arranged between every two adjacent coil layers of the high-voltage section, and is called as a high-voltage insulating layer; an insulating layer is arranged between every two adjacent coil layers of the low-voltage section, and is called as a low-voltage insulating layer; the thickness of the high-voltage insulating layer is more than twice that of the low-voltage insulating layer; shielding paper is arranged between the high-voltage section and the low-voltage section and is called a shielding layer; the concentrated distribution of an electric field in the coil is avoided, the possibility of partial discharge is reduced, the capability of the insulating layer for bearing high voltage is improved, and the risk of partial discharge is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of transformers, and in particular to a voltage transformer. Background Art

[0002] A voltage transformer is a high-voltage device that converts high voltage in the power grid into low voltage for easy monitoring and measurement. It is usually composed of a high-voltage primary winding and a low-voltage primary winding. It converts the voltage signal on the high-voltage side into a signal output on the low-voltage side through the principle of electromagnetic induction for use in measurement, protection and control systems.

[0003] However, the primary winding of the voltage transformer is subjected to the high voltage in the power grid, which will cause the insulation of the primary winding to be subjected to a large electric field strength, easily leading to local breakdown of the insulating medium and local discharge. Local discharge has always been the main problem affecting the performance of the voltage transformer. The traditional winding method is full-layer winding, which will cause the local electric field of the primary winding to concentrate, resulting in a very high voltage on the outermost side of the coil, causing local discharge. Utility Model Content

[0004] The purpose of this section is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract of the specification and the name of the utility model of this application to avoid blurring the purpose of this section, the abstract of the specification and the name of the utility model, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0005] In view of the problems existing in the above-mentioned prior art, the present utility model is proposed.

[0006] In order to solve the above technical problems, the utility model provides the following technical solutions:

[0007] A voltage transformer with a graded wound high voltage winding, comprising a magnetic core and a primary winding wound on the magnetic core;

[0008] Two terminals for connecting to a high-voltage circuit are provided at both ends of the coil wire of the primary winding;

[0009] The coil of the primary winding is arranged in a segmented winding structure;

[0010] The two ends of the primary winding have two side parts close to and connected to the terminal, which are called high-voltage sections;

[0011] The primary winding also has a middle section away from the terminals on both sides, which is called the low-voltage section;

[0012] An insulating layer is provided between each adjacent coil layer of the high voltage section, which is called the high voltage insulating layer;

[0013] An insulating layer is provided between each adjacent coil layer of the low voltage section, which is called the low voltage insulating layer;

[0014] The thickness of the high-voltage insulation layer is more than twice that of the low-voltage insulation layer;

[0015] A shielding paper is provided between the high-voltage section and the low-voltage section, which is called a shielding layer;

[0016] The shielding layer includes capacitor paper and semiconductor corrugated paper stacked on the capacitor paper, wherein the corrugated surface of the semiconductor corrugated paper faces the low voltage section.

[0017] The above design, firstly, divides the coil into multiple levels by setting a segmented winding structure, so as to avoid the concentrated distribution of the electric field inside the coil and reduce the possibility of local discharge. Secondly, the thickness of the high-voltage insulation layer is more than twice that of the low-voltage insulation layer, so that the large diameter at both ends of the coil can improve the insulation strength, increase the ability of the insulation layer to withstand high voltage, and reduce the risk of local discharge. Finally, by setting a capacitor paper and semiconductor corrugated paper stacked shielding layer between the high-voltage section and the low-voltage section, the concentrated distribution of the electric field inside the coil is avoided, the voltage breakdown between the high-voltage section and the low-voltage section is avoided, and local discharge is avoided.

[0018] Preferably, the insulating layer is made of polyvinyl chloride material; the polyethylene insulating layer has good insulating properties and is heat-resistant, corrosion-resistant and pressure-resistant, thereby preventing the insulating layer from being punctured and causing local discharge.

[0019] Preferably, the thickness of the high-voltage insulation layer is 4-8 mm; the thickness of the low-voltage insulation layer is 1-3 mm; a thicker high-voltage insulation layer is provided to prevent the high-voltage section from being broken down by high-voltage electricity, and a thinner insulation layer is provided to save materials.

[0020] Preferably, the surface of the coil wire of the primary winding is sprayed with insulating paint, and the coil sprayed with insulating paint is wound with mica tape; the spacing between the high-voltage section coils is 12-25mm; the spacing between the low-voltage section coils is 4-10mm; by spraying insulating paint on the surface of the coil wire and winding it with mica tape, and setting the coil of the high-voltage section larger, local discharge caused by breakdown between the coil wires is prevented, thereby improving the performance of the voltage transformer.

[0021] Preferably, the coil diameter of the high-voltage section is larger than the coil diameter of the low-voltage section; the coil structure with a small diameter in the middle coil section and large coil sections at both ends can make the electric field distribution more uniform, reduce the possibility of electric field concentration, and reduce the probability of local discharge.

[0022] Preferably, the magnetic core is provided with an insulating sleeve made of polypropylene, and the primary winding is wound on the insulating sleeve; by providing the insulating sleeve on the magnetic core, high voltage electricity in the coil is prevented from breaking through the coil and the conductor, local discharge is avoided, and the performance of the voltage transformer is improved.

[0023] Preferably, it also includes a shell made of stainless steel metal material, and the magnetic core and the primary winding are arranged in the inner cavity of the shell; the inner cavity of the shell is poured and filled with epoxy resin, which is called the epoxy resin layer; the epoxy resin layer wraps the magnetic core and the primary winding; by setting a shell made of stainless steel metal material and filling the inner cavity with epoxy resin, the stability of the voltage transformer is improved.

[0024] Optimization, the shell is connected with a block of phenolic resin material, called a connecting block, and the wiring terminals are connected and arranged on the connecting block; the wiring terminals are connected and arranged on the phenolic resin connecting block to avoid high-voltage circuit breakdown of the connecting block and the shell to cause local discharge or leakage, thereby improving the stability of the voltage transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0026] Figure 1 A schematic diagram of the connection structure between the winding and the magnetic core in a voltage transformer with a graded high-voltage winding according to an embodiment of the utility model;

[0027] Figure 2 A schematic diagram of the structure of a single-layer insulation layer of a primary winding in a voltage transformer with a graded-wound high-voltage winding according to an embodiment of the utility model;

[0028] Figure 3 In a voltage transformer with a graded winding high voltage winding according to an embodiment of the utility model Figure 2 Schematic diagram of the cross-section structure. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purposes, features and advantages of the present invention more understandable, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0030] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0031] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general proportion, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0032] Secondly, the "one embodiment" or "embodiment" referred to herein refers to a specific feature, structure or characteristic that can be included in at least one implementation of the utility model. The "in one embodiment" that appears in different places in this specification does not refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0033] Example 1

[0034] Reference Figure 1 to Figure 3 This embodiment provides a voltage transformer with a graded wound high-voltage winding, including a magnetic core 1 and a primary winding wound on the magnetic core 1 .

[0035] Two terminals 2 for connecting to the high-voltage circuit are connected at both ends of the coil conductor 3 of the primary winding; the coil of the primary winding is arranged as a segmented winding structure; the two ends of the primary winding respectively have two side parts close to and connected to the terminal 2, which are called high-voltage sections 4; the middle of the primary winding also has an intermediate part away from the terminal 2 on both sides, which is called low-voltage section 5; an insulating layer is arranged between each adjacent coil layer of the high-voltage section 4, which is called high-voltage insulating layer 7; an insulating layer is arranged between each adjacent coil layer of the low-voltage section 5, which is called low-voltage insulating layer 8; the thickness of the high-voltage insulating layer 7 is more than twice that of the low-voltage insulating layer 8; shielding paper is arranged between the high-voltage section 4 and the low-voltage section 5, which is called shielding layer 6; the shielding layer 6 includes Capacitor paper and semiconductor corrugated paper stacked on the capacitor paper, the corrugated surface of the semiconductor corrugated paper faces the low-voltage section 5; firstly, by setting a segmented winding structure, the coil is divided into multiple levels to avoid the concentrated distribution of the electric field inside the coil and reduce the possibility of local discharge; secondly, the thickness of the high-voltage insulation layer 7 is more than twice that of the low-voltage insulation layer 8, so that the large diameter at both ends of the coil can improve the insulation strength, increase the ability of the insulation layer to withstand high voltage, and reduce the risk of local discharge; finally, by setting a capacitor paper and semiconductor corrugated paper stacked shielding layer 6 between the high-voltage section 4 and the low-voltage section 5, the concentrated distribution of the electric field inside the coil is avoided, and the voltage breakdown between the high-voltage section 4 and the low-voltage section 5 is avoided.

[0036] The insulating layer is made of polyvinyl chloride material; the polyethylene insulating layer has good insulating properties and is also heat-resistant, corrosion-resistant and pressure-resistant, thereby preventing the insulating layer from being punctured and causing local discharge.

[0037] The thickness of the high-voltage insulation layer 7 is 4-8 mm; the thickness of the low-voltage insulation layer 8 is 1-3 mm; a thicker high-voltage insulation layer 7 is provided to prevent the high-voltage section 4 from being broken down by high-voltage electricity, and a thinner insulation layer is provided to save materials.

[0038] The surface of the coil conductor 3 of the primary winding is sprayed with insulating paint, and the coil sprayed with insulating paint is wound with mica tape; the spacing between the coils of the high-voltage section 4 is 12-25mm; the spacing between the coils of the low-voltage section 5 is 4-10mm; by spraying insulating paint on the surface of the coil conductor 3 and winding it with mica tape, and setting the coil of the high-voltage section 4 larger, the coil conductors 3 are prevented from being punctured and causing local discharge, thereby improving the performance of the voltage transformer.

[0039] The coil diameter of the high-voltage section 4 is larger than that of the low-voltage section 5; the coil structure with a small diameter in the middle coil section and large coil sections at both ends can make the electric field distribution more uniform, reduce the possibility of electric field concentration, and reduce the probability of local discharge.

[0040] When in use, when the primary winding is wound on the magnetic core 1, an insulating layer is first placed on the magnetic core 1, and the thickness of each high-voltage insulating layer 7 of the high-voltage section 4 on both sides close to and connected to the terminal 2 is greater than the thickness of each low-voltage insulating layer 8 in the middle, and then the coil wire 3 sprayed with insulating paint and wrapped with mica tape is wound on the insulating layer, and the spacing between the coils wound by the coil wire 3 of the high-voltage coil section is greater than the spacing of the coils of the low-voltage section 5, and finally a shielding layer 6 made of capacitor paper and semiconductor corrugated paper is placed between the low-voltage section 5 and the high-voltage section 4 to shield The wrinkled surface of the semiconductor corrugated paper in layer 6 faces the low-voltage section 5, and the coil diameter of the high-voltage section 4 is larger than the coil diameter of the low-voltage section 5; the coil structure with a small diameter in the middle coil section and large coil sections at both ends can make the electric field distribution more uniform, reduce the possibility of electric field concentration, and reduce the probability of local discharge. An insulating pad is placed on each layer of the coil, and the thickness of the high-voltage insulating pad is greater than that of the low-voltage insulating pad. A capacitor paper and semiconductor corrugated paper stacked shielding layer 6 is arranged between the high-voltage section 4 and the low-voltage section 5 to prevent the coil from being broken down by high voltage at various locations and avoid local discharge.

[0041] Example 2

[0042] Reference Figure 1 , which is the second embodiment of the utility model, and this embodiment is based on the previous embodiment.

[0043] An insulating sleeve 9 made of polypropylene is sleeved on the magnetic core 1, and the primary winding is wound on the insulating sleeve 9; by sleeved on the magnetic core 1, the high voltage in the coil is prevented from breaking through the coil and the conductor, and local discharge is avoided to improve the performance of the voltage transformer.

[0044] It also includes a stainless steel metal shell, in which the magnetic core 1 and the primary winding are arranged; the inner cavity of the shell is poured and filled with epoxy resin, which is called the epoxy resin layer; the epoxy resin layer wraps the magnetic core 1 and the primary winding; by setting a stainless steel metal shell and filling the inner cavity with epoxy resin, the stability of the voltage transformer is improved.

[0045] The primary winding is wrapped in oil paper to improve the insulation between the primary winding and the casing.

[0046] A block of phenolic resin material is connected to the shell, called a connection block, and terminal 2 is connected to the connection block; connecting terminal 2 to the phenolic resin connection block can avoid high-voltage circuit breakdown of the connection block and the shell to cause local discharge or leakage, thereby improving the performance of the voltage transformer.

[0047] When in use, before the primary winding is wound on the magnetic core 1, an insulating sleeve 9 is first sleeved on the magnetic core 1, and then the primary winding is wound on the insulating sleeve 9, the wound voltage transformer is installed in the inner cavity of the stainless steel metal shell, the terminal 2 is connected and set on the connection block, and then phenolic resin mixed with an oxidant is poured into the shell, the air in the phenolic resin is removed, and the phenolic resin is waited to solidify, and the metal shell is encapsulated. The voltage transformer of the graded winding high-voltage winding is installed, which prevents the high voltage electricity in the coil from breaking through the coil and the conductor, and improves the stability of the voltage transformer.

[0048] Importantly, it should be noted that the construction and arrangement of the present application shown in a number of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible, for example, the size, scale, structure, shape and proportion of various elements, and parameter values ​​such as temperature, pressure, etc., mounting arrangements, use of materials, color, directional changes, etc., without substantially departing from the novel angles and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present utility model. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure of the execution function described herein, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present utility model, other substitutions, modifications, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to several modifications still falling within the scope of the appended claims.

[0049] Additionally, in order to provide a concise description of the exemplary embodiments, all features of the actual embodiments may not be described, ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those features that are not relevant to implementing the invention.

[0050] It should be understood that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but for those of ordinary skill having the benefit of this disclosure, the development effort will be a routine task of design, fabrication, and production without undue experimentation.

[0051] It should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A voltage transformer with a graded wound high voltage winding, comprising a magnetic core and a primary winding wound on the magnetic core, characterized in that: Two terminals for connecting to a high-voltage circuit are provided at both ends of the coil wire of the primary winding; The coil of the primary winding is arranged in a segmented winding structure; The two ends of the primary winding have two side parts close to and connected to the terminal, which are called high-voltage sections; The primary winding also has a middle section away from the terminals on both sides, which is called the low-voltage section; An insulating layer is provided between each adjacent coil layer of the high voltage section, which is called the high voltage insulating layer; An insulating layer is provided between each adjacent coil layer of the low voltage section, which is called the low voltage insulating layer; The thickness of the high-voltage insulation layer is more than twice that of the low-voltage insulation layer; A shielding paper is provided between the high-voltage section and the low-voltage section, which is called a shielding layer; The shielding layer includes capacitor paper and semiconductor corrugated paper stacked on the capacitor paper, wherein the corrugated surface of the semiconductor corrugated paper faces the low voltage section.

2. The voltage transformer with a graded winding high voltage winding according to claim 1, characterized in that: The insulating layer is made of polyvinyl chloride material.

3. The voltage transformer with graded winding high voltage winding according to claim 2, characterized in that: The thickness of the high voltage insulation layer is 4-10 mm; The thickness of the low voltage insulation layer is 1-3 mm.

4. The voltage transformer with a graded winding high voltage winding according to claim 3, characterized in that: The surface of the coil wire of the primary winding is sprayed with insulating paint, and the coil sprayed with insulating paint is wrapped with mica tape; The spacing between each layer of coils in the high-voltage section is 12-25 mm; The spacing between each layer of coils in the low-voltage section is 4-10 mm.

5. The voltage transformer with graded winding high voltage winding according to claim 4, characterized in that: The coil diameter of the high voltage section is greater than the coil diameter of the low voltage section.

6. The voltage transformer with graded winding high voltage winding according to claim 5, characterized in that: The magnetic core is covered with an insulating sleeve made of polypropylene material, and the primary winding is wound on the insulating sleeve.

7. The voltage transformer with graded winding high voltage winding according to claim 6, characterized in that: It also includes a stainless steel metal shell, and the magnetic core and the primary winding are arranged in the inner cavity of the shell; The inner cavity of the shell is filled with epoxy resin, which is called epoxy resin layer; The epoxy resin layer wraps the magnetic core and the primary winding.

8. The voltage transformer with graded winding high voltage winding according to claim 7, characterized in that: The housing is connected with a block made of phenolic resin, called a connection block, and the connection terminal is connected with the connection block.

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