Voltage transformer and gas insulated switchgear comprising same

Abstract

The invention relates to a voltage transformer and a switchgear comprising the same, the voltage transformer comprising a primary voltage conductor (4) for electrically connecting the voltage transformer to a primary voltage source, a voltage conversion assembly (5) for converting a primary voltage into a secondary voltage, a fuse (1) and a cylindrical first shield (3), wherein the main body part (2) of the voltage transformer is molded by casting, and a cavity (21) for receiving the fuse (1) is formed in the main body part (2); a first shield (3) is embedded in the main body portion (2) and surrounds the fuse (1) over the entire length of the fuse (1). The single first shielding piece is adopted to shield the whole fuse (1), so that better shielding and discharge prevention effects are achieved, the number of parts is reduced, the manufacturing cost is reduced, and the manufacturing process is simplified.

Description

Technical Field

[0001] This invention relates to the technical field of switchgear (also known as switch cabinets), and more particularly to a voltage transformer with fuse protection for gas-insulated switchgear. Background Technology

[0002] Voltage transformers are used to transform high voltage into low voltage for measuring instruments and / or relay protection devices to measure the voltage, power and energy of a line, or to protect valuable equipment in a line in the event of a fault.

[0003] In recent years, GIS gas-insulated switchgear has been widely used due to its high operational safety, small size, and strong environmental adaptability. As a result, the performance requirements for voltage transformers matched with gas-insulated switchgear are also increasing.

[0004] Existing voltage transformers, such as in Figure 16A The voltage transformer shown includes a voltage conversion component 103. As those skilled in the art will know, the voltage conversion component 103 may include a primary winding, a secondary winding, and an iron core, such as... Figure 16A The voltage transformer shown also includes a terminal 1031 leading from the secondary winding. The main body 106 of the voltage transformer can be cast from an insulating material such as epoxy resin, and a chamber for accommodating a fuse 1011 is formed on its upper part. The outer layer of the voltage transformer can be a metallic conductive layer 102. The existing voltage transformer includes two separate conductive shields 1010 and 1012 for shielding the fuse 1011. One end of the shield 1010 is connected to a conductive rod 1014 to be electrically connected to a high-voltage source (also called a primary voltage source) via the conductive rod 1014, the primary voltage conductor, and a spring 108 (e.g., connected to the high-voltage section inside the gas chamber of a gas-insulated switchgear). One end of the conductive shield 1012 (left end in the figure) is connected to a metallic conductive element 1015. One end of the fuse 1011 ( Figure 16A The left end of the middle section is connected to the metal conductive component 1015, and the other end is as follows: Figure 16A The circuit is electrically connected to the conductive rod 1014 via a spring. A conductive wire 1016 connected to the voltage conversion assembly 103 is provided on the conductive shield 1012. When the fuse 1011 blows, the electrical connection path between the primary voltage source and the voltage conversion assembly 103 is broken.

[0005] However, this voltage transformer uses two separate shielding components (i.e., shielding component 1010 and shielding component 1012), with a gap between their ends. To prevent electrical connection between the two shielding components even after the fuse has blown, this gap cannot be too small, for example, it needs to be greater than 20 mm. At this gap, the fuse is not effectively shielded. Moreover, this structure uses more components, making manufacturing and assembly complex, especially in some prior art where the metal conductive component 1015 is manufactured as multiple components.

[0006] Furthermore, when the fuse blows, since one end of the shield 1010 remains electrically connected to the high-voltage source via the conductive rod 1014, even when the fuse 1011 blows, the shield 1010 remains connected to the high-voltage source and is at a high potential. Meanwhile, the shield 1012, the connecting line 1016, and the voltage conversion assembly 103 are at a low potential due to the breakage of the fuse 1011. At this time, the shield 1010, which is at a high potential, will have a large voltage difference to other components, and the insulating material will be at great risk of electrical breakdown.

[0007] Furthermore, the voltage transformer also includes another shield 109 disposed adjacent to the right end face of the main body 106 and surrounding the conductive rod 1014. For example... Figure 16B As shown, the shielding component 109 includes a metal ring 1091 and three fixing members 1092 welded to the metal ring. The shielding component 109 is connected to the housing of the voltage transformer via the fixing members to achieve grounding. The disadvantages of this shielding component structure are that the shielding area of ​​the metal ring is small, the three-point installation of the three fixing members 1092 requires high positional accuracy of the three fixing members, and the metal ring 1091, as a rigid ring, is difficult to deform. Therefore, the manufacturing precision requirements for the shielding component 109 are high, and even slight manufacturing errors make it difficult to achieve correct installation of the three fixing members.

[0008] like Figure 16A As shown, the voltage transformer also includes an insulating plug 1013 to seal the chamber of the fuse 1011. An air gap still exists at the adjacent portion of the insulating plug 1013 and the metal conductive element 1015, making it prone to air discharge. Typically, a shielding element 1017 electrically connected to the metal conductive element 1015 is also provided at the inner end of the insulating plug 1013 to suppress partial discharge at that location, which further increases the number of components. Summary of the Invention

[0009] The purpose of this invention is to solve at least one of the above-mentioned problems and / or other problems existing in the prior art.

[0010] To achieve the above objectives, according to one aspect of the present invention, a voltage transformer for a gas-insulated switchgear is provided, wherein the main body of the voltage transformer is cast and formed therein with a cavity, and the voltage transformer includes a primary voltage conductor, a voltage transformation assembly, a fuse adapted to be received in the cavity, and a cylindrical first shield, wherein the primary voltage conductor is used to electrically connect the voltage transformer to a primary voltage source; the voltage transformation assembly is configured to convert the primary voltage into a secondary voltage; wherein a first end of the fuse is electrically connected to the primary voltage conductor, and a second end opposite to the first end is electrically connected to the voltage transformation assembly; the first shield is embedded as an insert in the main body during the casting process of the voltage transformer and surrounds the fuse along its entire length.

[0011] In this design, the first shielding element surrounds the fuse along its entire length, thus avoiding the situation in the prior art where multiple separate shielding elements cannot provide shielding protection for the fuse at the gaps between them. Furthermore, by using only a single shielding element, the number of components is reduced, and manufacturing costs and process complexity are lowered.

[0012] The voltage transformer of this invention is used in gas-insulated switchgear (also known as gas-insulated switch cabinets). Unlike conventional air-insulated switchgear that is open to the atmosphere, the gas-insulated switchgear used in this invention employs pressurized gases such as SF6, new environmentally friendly gases such as nitrogen, or dry air as the insulating medium. The structures of air-insulated switchgear and gas-insulated switchgear differ significantly, and the performance and structural requirements for their components, such as voltage transformers, also differ. The voltage transformer of this invention is structurally suitable for gas-insulated switchgear, meeting its safety requirements for preventing discharge and ensuring insulation.

[0013] In this article, "electrical connection" can refer to direct contact and electrical connection, or it can refer to electrical connection via one or more intermediate conductive components. During normal operation, the fuse conducts voltage from a primary voltage source (typically a high-voltage component) to a voltage conversion assembly, such as the primary winding, where the primary voltage is converted to a secondary voltage, such as the voltage suitable for measuring instruments. When the fuse blows due to excessive current, for example, due to a circuit malfunction, it disconnects the primary voltage source from the voltage conversion assembly.

[0014] According to one embodiment of the invention, the electrical connection between the first shield and the fuse is achieved solely through a conductive component disposed between the end of the first shield furthest from the primary voltage conductor and the end of the fuse furthest from the primary voltage conductor.

[0015] According to one embodiment of the present invention, the first shielding member includes a first end near the primary voltage conductor and a second end opposite to the first end. No conductive component is provided between the first end of the first shielding member and the first end of the fuse to electrically connect the two. A conductive component is provided between the second end of the first shielding member and the second end of the fuse to electrically connect the two. This means that there is no direct conductor connecting the first end of the first shielding member and the first end of the fuse. A conductive component connecting the first shielding member to the fuse is only provided at the second end of the first shielding member. Thus, after the fuse blows, the second end of the fuse is disconnected from the primary voltage conductor, thereby disconnecting the first shielding member, which is electrically connected to the second end of the fuse, from the primary voltage conductor and is no longer at a high potential. Therefore, there is no longer a large voltage difference and the risk of electrical breakdown of the insulating material between the first shielding member and other components, such as voltage conversion components, as in the prior art solutions.

[0016] According to one embodiment of the invention, the conductive component includes a first conductive element embedded within the first shield and a second conductive element adjustablely connected to the first conductive element, wherein a second end of the fuse is supported within the second conductive element.

[0017] In this example, the position of the second conductive element is adjustable, so the position of the fuse in the chamber can be fine-tuned as needed.

[0018] According to one embodiment of the present invention, the first conductive element has an internal thread, and the second conductive element has an external thread that mates with the internal thread, so as to be adjustablely connected in the first conductive element.

[0019] According to one embodiment of the invention, the voltage transformer further includes a plug that can be inserted into the chamber to close its end, wherein the first shield extends beyond the inner end of the plug.

[0020] In this example, the first shielding element also extends to the inner end of the plug. The same shielding element not only provides shielding for the fuse, but also provides shielding at the junction of the plug and the conductive component. This saves on shielding for the plug, further reduces the number of parts, saves manufacturing costs, and simplifies the manufacturing process.

[0021] According to one embodiment of the invention, the voltage transformer further includes a conductor configured to receive a first end of the fuse, the conductor extending out of the body portion and connected to the primary voltage conductor, and the voltage transformer further includes a second shield disposed adjacent to an end face of the body portion and surrounding the conductor, wherein the second shield includes a cylindrical mesh.

[0022] The second shielding component of this structure has a larger shielding area and better shielding effect due to the inclusion of cylindrical mesh components. Furthermore, the cylindrical mesh components have a large flexibility, meaning they have a large deformable space, making installation easier and requiring lower manufacturing precision from the second shielding component.

[0023] According to one embodiment of the present invention, the second shielding member further includes two legs extending from the cylindrical mesh member for securing the second shielding member. Compared to rigid metal rings and shielding members with three or more fixed points in the prior art, the two-leg design is easier to install and has lower requirements for the positional accuracy of the legs than the installation method with three or more fixed members; furthermore, in this embodiment of the present invention, the cylindrical mesh member is joined with the two fixed legs, and the deformability of the cylindrical mesh member makes the installation of the two fixed legs on it easier and lowers the requirements for the manufacturing precision of the second shielding member.

[0024] According to another aspect of the invention, a bulk-insulated switchgear is also provided, which includes a voltage transformer as described in any of the foregoing embodiments. Attached Figure Description

[0025] The features and advantages of the present invention will become clear from the following detailed description provided with reference to the accompanying drawings. It should be understood that the following drawings are merely schematic and not necessarily drawn to scale, and therefore should not be considered as limitations on the invention, wherein:

[0026] Figure 1 A perspective view of an exemplary voltage transformer according to the present invention is shown.

[0027] Figure 2 Show Figure 1 A three-dimensional schematic diagram of the voltage transformer from another angle.

[0028] Figure 3 Show Figure 1 The diagram shows a cross-sectional view of the voltage transformer along line AA.

[0029] Figure 4 A three-dimensional schematic diagram of the first shielding component is shown.

[0030] Figure 5 A three-dimensional schematic diagram of the first conductive element is shown.

[0031] Figure 6 Show Figure 5 The diagram shows a cross-sectional view of the first conductive element.

[0032] Figure 7 A three-dimensional schematic diagram of the second conductive element is shown.

[0033] Figure 8 Show Figure 7A three-dimensional schematic diagram of the second conductive element from another angle.

[0034] Figure 9A A perspective view of the second shielding component of the present invention is shown.

[0035] Figure 9B A color three-dimensional schematic diagram of the second shielding component of the present invention is shown.

[0036] Figure 10 Show Figure 9A The diagram shows a cross-sectional view of the second shielding component.

[0037] Figure 11 A three-dimensional schematic diagram of a fuse is shown.

[0038] Figure 12 A three-dimensional schematic diagram of a conductor is shown.

[0039] Figure 13 Show Figure 12 A cross-sectional schematic diagram of the conductor shown.

[0040] Figure 14 A three-dimensional schematic diagram of the plug is shown.

[0041] Figure 15 The internal structure of a voltage transformer is schematically shown in color.

[0042] Figure 16A A cross-sectional schematic diagram of a voltage transformer in the prior art is shown.

[0043] Figure 16B Show Figure 16A A color 3D schematic diagram of the shielding component 109. Detailed Implementation

[0044] Specific embodiments of the present invention are described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth to enable those skilled in the art to more fully understand and implement the present invention. However, it will be apparent to those skilled in the art that implementations of the present invention may not include some of these specific details. Furthermore, it should be understood that the present invention is not limited to the specific embodiments described. Rather, the present invention can be conceived to be practiced with any combination of the features and elements described below, regardless of whether they relate to different embodiments.

[0045] Figure 1 and Figure 2 A perspective view of the voltage transformer 100 of this specific embodiment is shown. Figure 3 It shows along Figure 1 A cross-sectional view along line AA in the diagram. Figure 15The internal structure of the voltage transformer is also schematically shown in color. As these figures show, the voltage transformer includes a voltage transformation component 5, which specifically includes a primary winding, a secondary winding, and an iron core, for converting a primary voltage (e.g., a high voltage of 40.5 kV) into a secondary voltage (e.g., a voltage suitable for measuring instruments). The voltage transformation component 5, being prior art, will not be described in detail herein. The voltage transformer includes a connection terminal 10 adapted for electrical connection to a high-voltage component, which, for example, is inserted into the gas chamber of a gas-insulated switchgear to allow passage through the primary voltage conductor 4 therein and a compressible spring (see [reference]). Figure 3 The spring on the right side is electrically connected to the high-voltage component (also known as the primary voltage source) in the gas chamber. The voltage transformer also includes a fuse 1 for fusible protection. The first end 11 of the fuse 1 is electrically connected to the primary voltage conductor 4 via a conductor 8, and the second end 12 of the fuse 1, opposite to the first end 11, is electrically connected to the voltage conversion assembly 5 (the specific electrical connection path will be described below).

[0046] The main body 2 of the voltage transformer can be cast from an insulating material such as epoxy resin, and a fuse 1 (also called a fuse wire, such as...) is formed therein. Figure 11 The chamber 21 (shown) is into which the fuse 1 is inserted during assembly and sealed by an end plug 7. The end plug 7 is removable, allowing the fuse 1 to be removed and replaced, for example, after it has blown. Figure 3 The components of the voltage transformer shown, including the voltage conversion assembly 5, the conductor 8, and the first shield 3, second shield 9, first conductor 61, and third conductor 63 (described below), are all positioned and cast as inserts into the integrally formed main body 2 during the casting process. Unlike voltage transformers in conventional air-cooled cabinets, the outer layer of the main body 2 of the voltage transformer of this invention may have a metal layer or a metal shell to achieve grounding. This metal layer can be formed, for example, by spraying.

[0047] In this embodiment, a cylindrical first shielding member 3 (e.g., cast into the main body 2) is provided. Figure 4 As shown), it is electrically connected to fuse 1 via conductive component 6. Figure 3 and Figure 15As shown, the first shielding member 3 extends radially outward from the wall of the chamber 21 and surrounds the fuse 1 along its entire length to reduce or avoid discharge at the air gap between the high-voltage fuse 1 and the wall of the chamber 21. Since the first shielding member 3 is electrically connected to the fuse 1, they have the same potential, and no discharge occurs at the air gap between them. In this embodiment, because the first shielding member 3 extends to surround the fuse 1 along its entire length, it effectively shields the entire fuse 1, providing better shielding and discharge prevention, especially compared to the two separate shielding members described in the background art.

[0048] Moreover, since a single shielding component, namely the first shielding component 3, is used, compared with the existing technology which uses two separate shielding components (i.e. shielding component 1010 and shielding component 1012) and each shielding component is connected to the conductive rod 1014 and the conductive component 1015 respectively, the number of components is reduced, the manufacturing cost is reduced, and the manufacturing process is simplified.

[0049] like Figure 3 As shown, the first shield 3 includes a first end 31 closer to the primary voltage conductor 4 and a second end 32 opposite to the first end. Correspondingly, the fuse 1 has a first end 11 closer to the primary voltage conductor 4 and a second end 12 opposite to it. No conductive component is provided between the first end 31 and the first end 11 of the fuse 1 to electrically connect the two, while a conductive component 6 is provided between the second end 32 and the second end 12 of the fuse 1 to electrically connect the two. The absence of a conductive component between the first end 31 and the first end 11 of the fuse 1 means that there is no direct conductor connecting the two between the first end 31 of the first shield 3 and the first end 11 of the fuse 1. Figure 3 As shown, apart from the end of the conductor 8, only cast insulating material exists between the first end 31 of the first shield 3 and the first end 11 of the fuse 1. In this embodiment, only at one end of the first shield 3 (the second end 32, the end furthest from the primary voltage conductor 4), Figure 3The first shield 3 is electrically connected to the fuse 1 via a conductive component 6 at its left end. No conductive component is provided between the first end 31 of the first shield 3 near the primary voltage conductor 4 (high-voltage conductor) and the first end 11 of the fuse 1. In other words, from the perspective of the arrangement structure, disregarding the casting material of the main body 2, the first shield 3 is cantilevered to the second end 12 of the fuse 1 via its second end 32 and the conductive component 6. A third conductive component 63 (in this specific embodiment, a spring) is also provided between the conductive component 6 and the voltage conversion assembly 5 to electrically connect the two. When the voltage transformer is operating, the primary voltage conductor 4 conducts high voltage to the conductor 8, then through the conductive spring 14 between the conductor 8 and the fuse 1, to the fuse 1, then to the conductive component 6, the third conductive component 63, and finally to the voltage conversion assembly 5. After the fuse 1 blows, the first shield 3 is disconnected from the primary voltage conductor 4 and no longer connected to the high voltage. Therefore, the large voltage difference between the first shield 3 and other components, such as the voltage conversion assembly 5, and the risk of electrical breakdown of the insulating material, which still exists between the shield 1010 and other components after the fuse blows, as in the prior art solution, no longer exist.

[0050] As a specific example, in this embodiment, such as Figure 3 As shown, the conductive component 6 includes a first conductive component 61 embedded within the first shielding component 3 (e.g., ...). Figure 5 , Figure 6 (as shown) and a second conductive element 62 adjustablely connected to the first conductive element 61 (as shown) Figure 7 , Figure 8 As shown, the second end 12 of the fuse 1 is supported within the second conductive member 62. The first conductive member 61 and, for example, a mesh-like first shielding member 3 can be fixed through fastener holes 611 and are molded together in the main body 2. As an example of a connection method, the first conductive member 61 may have an internal thread 612, and the second conductive member 62 may have an external thread 621, so that the second conductive member 62 can be threadedly connected to the first conductive member 61. Furthermore, the position of the second conductive member 62 relative to the first conductive member 61 can be adjusted by twisting it, thereby adjusting the insertion position of the fuse 1. Figure 3 As shown, a spring 14 is provided between the fuse 1 and the cavity of the conductor 8.

[0051] Preferably, such as Figure 3 and Figure 14As shown, the voltage transformer also includes an insulating plug 7 for removably sealing the chamber 21, with a first shield 3 extending to surround the inner end of the plug 7. This method uses the same first shield 3 to achieve shielding for both the fuse 1 and the junction between the plug 7 and the conductive component 6, achieving reduced partial discharge with as few components as possible (e.g., eliminating the need for the shield 1017 in prior art solutions), saving manufacturing costs and simplifying the manufacturing process.

[0052] like Figure 3 and Figure 12 , 13 As shown, the voltage transformer also includes a conductor 8 configured to receive the first end 11 of the fuse 1, the conductor 8 extending out of the body 2 to connect with the primary voltage conductor 4. Figure 3 , 12 As shown in Figures 1 and 13, the conductor 8 is exemplary constructed as a rod-shaped member, one end of which ( Figure 3 The cavity at the left end of the fuse 1 is used to receive the first end 11 of the fuse 1, and the other end ( Figure 3 The right end of the primary voltage conductor 4 is exemplarily provided with a threaded inner hole, and the primary voltage conductor 4 is configured as a screw that can be screwed into the threaded inner hole. To shield the high-voltage conductor 8 passing through the end face of the main body 2 (near the end face of the primary voltage conductor 4) and to uniformly distribute the electric field there, embodiments of the present invention also provide a second shield 9 surrounding the conductor 8 near the end face of the main body 2. Figure 3 , Figure 9A , Figure 9B and Figure 10 As shown, the second shielding member 9 is arranged near the right end face of the main body 2, including a cylindrical mesh member 91 (e.g., made of stainless steel) and two fixing legs 92 extending from the cylindrical mesh member 91. The two fixing legs 92 are used to fix the second shielding member 9 to the end plate 13, and the two fixing legs 92 are in contact with the outer metal layer of the main body 2 for electrical connection. Figure 9B As shown, a rolled edge 93 is also provided at the end of the cylindrical mesh 91, providing better structural stability and higher strength for the entire cylindrical mesh 91. However, it should be understood that this rolled edge 93 and Figure 16B The metal ring 1091 in the middle is completely different, and the rolled edge 93 does not affect the flexibility and variable space of the cylindrical mesh 91.

[0053] The second shielding element 9 of this structure, due to its inclusion of a cylindrical mesh element 91, has a larger shielding area and better shielding effect. Furthermore, the cylindrical mesh element 91 has a large flexibility, meaning it has a deformable space, which makes the fixed legs 92 easier to install even with certain manufacturing errors. Moreover, the use of two fixed legs 92 connected to the cylindrical mesh element in this design is more convenient to install and requires less manufacturing precision compared to installation methods with three or more fixed elements. Especially compared to… Figure 16B The advantages of the second shielding element of the present invention are more obvious compared to the existing technology.

[0054] The present invention also provides a switching device including the voltage transformer, particularly a gas-insulated switching device. The connection terminal 10 of the voltage transformer can be inserted into the gas chamber of the gas-insulated switching device and electrically connected to the high-voltage components therein.

[0055] Various modifications and variations can be made to the embodiments disclosed above without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art based on the practice of the invention disclosed in this specification. This specification and the examples disclosed herein should be considered illustrative only, and the true scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A voltage transformer for gas-insulated switchgear, characterized in that, The main body (2) of the voltage transformer (100) is cast and molded, and a chamber (21) is formed therein. The voltage transformer includes: Primary voltage conductor (4), which is used to electrically connect the voltage transformer to the primary voltage source; Voltage conversion component (5) is configured to convert primary voltage into secondary voltage; A fuse (1), adapted to be received in the chamber (21), wherein a first end (11) of the fuse (1) is electrically connected to the primary voltage conductor (4), and a second end (12) opposite to the first end (11) is electrically connected to the voltage conversion assembly (5); and A cylindrical first shield (3), wherein the first shield (3) is embedded in the main body (2) and surrounds the fuse (1) over its entire length.

2. The voltage transformer according to claim 1, characterized in that, The electrical connection between the first shield (3) and the fuse (1) is achieved only through a conductive component (6) disposed between the end of the first shield (3) and the fuse (1) away from the primary voltage conductor (4).

3. The voltage transformer according to claim 2, characterized in that, The first shield (3) includes a first end (31) near the primary voltage conductor (4) and a second end (32) opposite to the first end, wherein a conductive member (6) is provided between the second end (32) of the first shield (3) and the second end (12) of the fuse (1) to electrically connect the two, and no conductive member is provided between the first end (31) of the first shield (3) and the first end (11) of the fuse (1) to electrically connect the two.

4. The voltage transformer according to claim 3, characterized in that, The conductive component (6) includes a first conductive component (61) embedded in the first shield (3) and a second conductive component (62) adjustablely connected to the first conductive component (61), wherein the second end (12) of the fuse (1) is supported in the second conductive component (62).

5. The voltage transformer according to claim 4, characterized in that, The first conductive element (61) has an internal thread, and the second conductive element (62) has an external thread that mates with the internal thread, so as to be adjustablely connected to the first conductive element (61).

6. The voltage transformer according to any one of claims 1-5, characterized in that, The voltage transformer also includes a plug (7) that can be inserted into the chamber (21) to close its end, wherein the first shield (3) extends beyond the inner end of the plug (7).

7. The voltage transformer according to any one of claims 1-5, characterized in that, The voltage transformer also includes: A conductor (8) configured to receive the first end (11) of a fuse (1), the conductor (8) extending out of the main body (2) and connected to a primary voltage conductor (4); and A second shield (9) is provided on the end face adjacent to the main body (2) and surrounds the conductor (8), wherein the second shield (9) includes a cylindrical mesh (91).

8. The voltage transformer according to claim 7, characterized in that, The second shielding member (9) also includes two legs (92) extending from the cylindrical mesh member (91) for securing the second shielding member (9).

9. The voltage transformer according to any one of claims 1-5 and 8, characterized in that, The exterior of the main body (2) has a metal layer.

10. A gas-insulated switchgear, characterized in that, Includes the voltage transformer according to any one of claims 1-9.

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