Gas-insulated surge arrester

Abstract

Disclosed is a gas-insulated surge arrester. The gas-insulated surge arrester includes: a tank having a longitudinal direction and including an end cover adapted to be grounded; and a core assembly arranged inside the tank and extending along the longitudinal direction. The core assembly includes a first end fitting and a second end fitting at opposite ends thereof and a plurality of blocks arranged along the longitudinal direction and held between the first end fitting and the second end fitting. The plurality of blocks at least include a plurality of varistor blocks. The second end fitting is closer to the end cover than the first end fitting, and the second end fitting is connected to the end cover. The core assembly further includes an insulating member, and the insulating member is arranged between one of the plurality of varistor blocks closest to the second end fitting and the second end fitting in the longitudinal direction. The gas-insulated surge arrester has a simplified manufacturing process, reduced manufacturing cost, and reduced longitudinal dimension.

Description

GAS-INSULATED SURGE ARRESTERRELATED FIELD

[0001] The present disclosure generally relates to the technical field of gas-insulated surge arresters.BACKGROUND

[0002] At present, different types of surge arresters are used in switchgears, such as gas insulated switchgears, to protect power grid equipment against overvoltage. The surge arrester can be connected between a phase line and the ground. The surge arrester typically includes multiple varistor blocks made of metal oxides. The resistance of the varistor block is higher at low voltage and lower at high voltage. When the voltage level in the phase line exceeds a critical value, the surge arrester would allow current to be conducted to the ground through the varistor blocks, thereby reducing overvoltage.

[0003] A gas-insulated surge arrester typically includes a tank filled with insulating gas and a core assembly arranged inside the tank. An end cover of the tank is made of metal and is adapted to be grounded. The core assembly may include a stack of varistor blocks and two end fittings arranged at two ends of the stack of varistor blocks and clamping the stack of varistor blocks therebetween. One of the two end fittings of the core assembly closer to the end cover is connected to the end cover.

[0004] Referring to FIG. 1, in some gas-insulated surge arresters, an insulating plate 1 is arranged between the end fitting that is closer to the end cover and the end cover to isolate the core assembly from the end cover and avoid the grounding of the core assembly, so that other components configured for monitoring and diagnosing the status of the surge arrester can be arranged between the core assembly and the ground. The insulating plate 1 is respectively connected to the end fitting and the end cover through threaded fasteners such as bolts and studs, so that the core assembly is connected to the end cover through the insulating plate 1. However, as shown in FIG. 1, such configuration requires a lot of fastening holes 2 on the insulating plate 1, which reduce the mechanical strength of the insulating plate and may even cause cracking of the insulating plate during use, thereby adversely affecting the insulation performance of theinsulating plate and reducing the strength of the connection between the core assembly and the end cover. In addition, in order to minimize possible damage to the insulating plate 1, the insulating plate is generally designed to have a relatively large thickness, which increases the cost of the surge arrester.SUMMARY

[0005] It is an object of the present disclosure to solve the above issues in the prior art, and to provide an improved gas-insulated surge arrester.

[0006] For this object, the present disclosure provides a gas-insulated surge arrester, which includes: a tank having a longitudinal direction and including an end cover at one end of the tank in the longitudinal direction, the end cover being adapted to be grounded; and a core assembly arranged inside the tank and extending along the longitudinal direction, the core assembly including a first end fitting and a second end fitting at opposite ends thereof and a plurality of blocks arranged along the longitudinal direction and held between the first end fitting and the second end fitting, the plurality of blocks at least including a plurality of varistor blocks, the second end fitting being closer to the end cover than the first end fitting and the second end fitting being connected to the end cover; wherein the core assembly further includes an insulating member, and the insulating member is arranged between one of the plurality of varistor blocks closest to the second end fitting and the second end fitting in the longitudinal direction.

[0007] According to the above technical concept, the present disclosure may further include one or more of the following optional embodiments.

[0008] In some optional embodiments, the insulating member is arranged between one of the plurality of blocks closest to the second end fitting and the second end fitting in the longitudinal direction.

[0009] In some optional embodiments, the plurality of blocks further include at least one spacer block, wherein the one of the plurality of blocks closest to the second end fitting is a varistor block or a spacer block.

[0010] In some optional embodiments, the insulating member and the second end fitting aremade separately, or the insulating member and the second end fitting are made in one piece.

[0011] In some optional embodiments, the insulating member and the second end fitting are made of insulating material and made in one piece.

[0012] In some optional embodiments, the insulating member is configured to satisfy at least one of the following: a) the insulating member is in the shape of a circular plate, a ring or a cylinder; b) the insulating member has a cross-sectional shape substantially the same as that of the block; and c) the insulating member has a cross-sectional area substantially the same as that of the block.

[0013] In some optional embodiments, the second end fitting includes a central portion and a flange surrounding the central portion, wherein the flange includes a plurality of fastening holes through which fasteners pass through for connecting the second end fitting to the end cover.

[0014] In some optional embodiments, the second end fitting includes a limiting recess on a side thereof adjacent to the insulating member, and the limiting recess is configured to receive at least part of the insulating member to limit movement of the insulating member relative to the second end fitting in a direction substantially perpendicular to the longitudinal direction.

[0015] In some optional embodiments, the gas-insulated surge arrester further includes a bushing and a conductive component; wherein the conductive component is configured to guide a current flowing through the core assembly to the bushing; wherein the bushing extends through the end cover and is insulated relative to the end cover, and the bushing provides a current path from an inside of the tank to an outside of the tank.

[0016] In some optional embodiments, the conductive component includes a first conductive portion and a second conductive portion, wherein the first conductive portion is arranged between the one of the plurality of varistor blocks closest to the second end fitting and the insulating member in the longitudinal direction to be electrically connected to the core assembly, wherein the second conductive portion is electrically connected to the bushing.

[0017] In some optional embodiments, the bushing includes a conductive rod and an insulating sleeve wrapping the conductive rod.

[0018] In some optional embodiments, the second end fitting is made of metal.

[0019] In some optional embodiments, the core assembly includes one core unit or a pluralityof core units arranged along the longitudinal direction; wherein each core unit includes a pair of end fittings, some / multiple blocks among the plurality of blocks and a coupling assembly; wherein the some / multiple blocks are stacked in the longitudinal direction, and the pair of end fittings are coupled by the coupling assembly and hold the some / multiple blocks therebetween; wherein the two end fittings located at opposite ends of the core assembly are the first end fitting and the second end fitting.

[0020] The insulating member of the gas-insulated surge arrester according to the present disclosure can achieve insulation between the one of the plurality of varistor blocks closest to the second end fitting (i.e., the varistor block with the lowest potential in the core assembly) and the second end fitting in the core assembly. In the case where the second end fitting is made of conductive material, such as metal, such configuration can prevent the current flowing through the plurality of varistor blocks from being guided to ground via the second end fitting and the end cover connected to the second end fitting. Moreover, for the gas-insulated surge arrester according to the present disclosure, the insulating member is arranged inside the core assembly, which can simplify the assembly of the gas-insulated surge arrester. For example, in the case where the insulating member and the second end fitting are made separately, the insulating member can be held in the core assembly in a similar manner to the blocks; as an example, the insulating member and the blocks can be stacked together and clamped between the end fittings. For another example, in the case where the insulating member and the second end fitting are made in one piece, the insulating member itself is fixed to the second end fitting, so that there is no need for additional fixing structures. Furthermore, there is no need to open fastening holes on the insulating member, which can simplify the manufacturing process of the insulating member, allow the insulating member to have a smaller thickness but good mechanical properties, thereby reducing the dimension of the gas-insulated surge arrester in the aforementioned longitudinal direction and reducing the cost of the gas-insulated surge arrester. In addition, the aforementioned configuration of the gas-insulated surge arrester allows the second end fitting of the core assembly to be made of high-strength material and directly connected to the end cover, thereby connecting the core assembly to the end cover. Compared to the configuration described in the background in which the core assembly is connected to the end cover through an insulating plate, this can enhance the strength of the connection between the core assembly and the end cover.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other features and advantages of the present disclosure will be readily understood through the following optional embodiments described in detail with reference to the accompanying drawings, in which the same reference numerals indicate the same or similar components.

[0022] FIG. 1 is a schematic diagram of an insulating plate of a gas-insulated surge arrester described in the background;

[0023] FIG. 2 is a schematic diagram of a gas-insulated surge arrester according to an exemplary embodiment of the present disclosure;

[0024] FIG. 3 is a partial schematic diagram of the gas-insulated surge arrester according to the exemplary embodiment of the present disclosure; and

[0025] FIG. 4A to FIG. 4C are respectively schematic diagrams of a conductive component, an insulating member, and an end fitting of the gas-insulated surge arrester according to the exemplary embodiment of the present disclosure.DETAILED DESCRIPTION

[0026] The implementation and usage of the embodiments are discussed in detail below. However, it is conceivable that the specific embodiments discussed herein are merely intended to illustrate specific ways of implementing and using the present disclosure, and are not intended to limit the scope of the present disclosure. When describing structures and positions of components, the orientation-related expressions herein, such as "upper", "lower", "top", and "bottom", are not absolute, but relative. When the components are arranged as shown in the drawings, these orientation-related expressions are appropriate, but when the positions of these components in the drawings are altered, these orientation-related expressions should be altered accordingly.

[0027] In the present disclosure, the axial direction of a tubular or annular component refers to the direction along the central axis of the component, the circumferential direction of the tubular or annular component refers to the direction along the circumference of the component,and the radial direction of the tubular or annular component refers to the direction passing through the central axis of the component and perpendicular to the axial direction of the component.

[0028] The terms, such as "first" and "second", are only used for description, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features referred to. In the present disclosure, unless otherwise specified, the terms, such as "mount", "join", "connect", and "fix", should be understood in a broad sense. For example, "connection" may be a fixed connection, a detachable connection, or an integral connection, and may be a direct connection or an indirect connection via an intermediary. For those skilled in the art, specific meanings of the above terms in the present disclosure should be understood according to specific circumstances.

[0029] FIG. 2 to FIG. 4C illustrate a gas-insulated surge arrester 10 and its components according to an exemplary embodiment of the present disclosure.

[0030] Referring to FIG. 2 and FIG. 3, the gas-insulated surge arrester 10 includes a tank 100 and a core assembly 200. The tank 100 has a longitudinal direction L and includes an end cover 102 at one end of the tank 100 in the longitudinal direction L. The end cover 102 is adapted to be grounded. The core assembly 200 is arranged inside the tank 100 and extends along the longitudinal direction L. The core assembly 200 includes a first end fitting 202A and a second end fitting 202F at opposite ends thereof and a plurality of blocks 206 arranged along the longitudinal direction L and held between the first end fitting 202A and the second end fitting 202F. The plurality of blocks 206 at least include a plurality of varistor blocks 206A. The second end fitting 202F is closer to the end cover 102 than the first end fitting 202A and the second end fitting 202F is connected to the end cover 102. The core assembly 200 further includes an insulating member 208, and the insulating member 208 is arranged between one of the plurality of varistor blocks 206A closest to the second end fitting 202F (in other words, the varistor block closest to the second end fitting 202F among the plurality of varistor blocks 206A) and the second end fitting 202F in the longitudinal direction L.

[0031] Herein, the statement “component A is arranged between component B and component C” may indicate that: only component A is provided between component B and component C, or component A and other component(s) are provided between component B and component C.

[0032] The insulating member 208 of the gas-insulated surge arrester 10 can achieve insulation between the one of the plurality of varistor blocks closest to the second end fitting 202F (i.e., the varistor block at the lowest potential in the core assembly 200) and the second end fitting 202F in the core assembly 200. In the case where the second end fitting 202F is made of conductive material, such as metal, such configuration can prevent the current flowing through the plurality of varistor blocks 206A from being guided to the ground via the second end fitting 202F and the end cover 102 connected to the second end fitting 202F. Moreover, for the gas-insulated surge arrester 10, the insulating member 208 is arranged inside the core assembly 200, which can simplify the assembly of the gas-insulated surge arrester 10. For example, in the case where the insulating member 208 and the second end fitting 202F are made separately, the insulating member 208 can be held in the core assembly 200 in a similar manner to the blocks 206; as an example, the insulating member 208 and the blocks 206 can be stacked together and clamped between the end fittings. For another example, in the case where the insulating member 208 and the second end fitting 202F are made in one piece, the insulating member 208 itself is fixed to the second end fitting 202F, so that there is no need for additional fixing structures. Furthermore, there is no need to open fastening holes on the insulating member 208, which allows the insulating member 208 to have a smaller thickness but good mechanical properties, thereby reducing the dimension of the gas-insulated surge arrester 10 in the longitudinal direction and reducing the cost of the gas-insulated surge arrester 10. In addition, the aforementioned configuration of the gas-insulated surge arrester 10 allows the second end fitting 202F of the core assembly 200 to be made of high-strength material and directly connected to the end cover 102, thereby connecting the core assembly 200 to the end cover 102. Compared to the configuration described in the background in which the core assembly is connected to the end cover through an insulating plate, this can enhance the strength of the connection between the core assembly and the end cover.

[0033] Referring to FIG. 2, in the illustrated embodiment, the tank 100 includes a tubular body 104 with two open ends, an insulator 106 and an end cover 102. The insulator 106 and the end cover 102 are respectively arranged at two opposite ends of the tubular body 104. The longitudinal direction L of tank 100 is the axial direction of tubular body 104. The tubular body 104, the insulator 106, and the end cover 102 jointly define an internal space S for accommodating insulating gas. In some embodiments, the insulating gas may be SFe. In someother embodiments, the insulating gas may include an organic fluorine compound and at least one air component used as a carrier gas or background gas. Alternatively, the organic fluorine compound is selected from the group consisting of: fluoroether, especially hydrofluoromonoether, fluoroketone, especially perfluoroketone, fluoroalkene, especially hydrofluoroalkene, fluoronitrile, especially perfluoronitrile, and a mixture thereof. Alternatively, the at least one air component may be selected from the group consisting of oxygen (O2), nitrogen (N2), carbon dioxide (CO2), and a mixture thereof.

[0034] In the illustrated embodiment, the tubular body 104 includes a first section 108 and a second section 110 which are made separately and connected to each other. It is conceivable that in other embodiments not shown, the tubular body may also be made in one piece. The tubular body 104 may include conductive material, and, for example, be made of metal (including but not limited to aluminum or aluminum alloy), conductive plastic (including but not limited to polyethylene filled with conductive carbon black), or insulating material (coated with conductive material, such as metal or conductive plastic).

[0035] The insulator 106 is arranged to cover an end of the first section 108 of the tubular body 104 that is away from the second section 110. The insulator 106 may be a basin-type insulator and may include an insulator body 112 and a metal insert 114 embedded in the middle of the insulator body 112. The insulator body 112 may be made of insulating material (including but not limited to filler-reinforced insulating material, such as filler-reinforced epoxy resin). The metal insert 114 may be electrically connected to a phase line (not shown).

[0036] The end cover 102 is arranged to cover an end of the second section 110 of the tubular body 104 that is away from the first section 108, and is adapted to be grounded. The end cover 102 may include conductive material, and, for example, be made of metal (including but not limited to aluminum or aluminum alloy), conductive plastic (including but not limited to polyethylene filled with conductive carbon black), or insulating material (coated with conductive material, such as metal or conductive plastic).

[0037] Referring to FIG. 2 and FIG. 3, the core assembly 200 is arranged in the internal space S of the tank 100. An end of the core assembly 200 closer to the insulator 106 is high-voltage end. The high-voltage end of the core assembly 200 may be electrically connected to the metal insert 114 of the insulator 106 through a conductor 300 provided in the internal space S, andthen be electrically connected to the phase line. An end of the core assembly 200 closer to the end cover 102 is low-voltage end. The low-voltage end of the core assembly 200 may be grounded. The means of the grounding of the low-voltage end of the core assembly 200 will be described in detail in the following.

[0038] The first end fitting 202A and the second end fitting 202F of the core assembly 200 are located at the high-voltage end and the low-voltage end of the core assembly 200, respectively. The plurality of blocks 206 of the core assembly 200 may include multiple varistor blocks 206 A and one or more spacer blocks 206B.

[0039] In the illustrated embodiment, the core assembly 200 includes multiple core units 212 arranged in sequence along the longitudinal direction L. Each core unit 212 includes a pair of end fittings 202, some / multiple blocks among the plurality of blocks 206 and a coupling assembly 214. The some / multiple blocks 206 are stacked on top of each other in the longitudinal direction L of the tank 100. The pair of end fittings 202 are spaced apart in the longitudinal direction L and coupled by the coupling assembly 214, and hold the some / multiple blocks 206 therebetween.

[0040] The multiple blocks 206 of each core unit 212 may include multiple varistor blocks 206A and at least one spacer block 206B. The multiple varistor blocks 206A and the at least one spacer block 206B may be arranged coaxially and stacked on top of each other along the longitudinal direction L of the tank 100. It is conceivable that each core unit may include any suitable number of varistor blocks and spacer blocks. In the illustrated embodiment, each varistor block 206A may be substantially in the shape of a cylinder or a circular plate. Each varistor block 206Amay be made of a metal-oxide based material, such as a ZnO based material. Each spacer block 206B may be substantially in the shape of a cylinder or a circular plate. Each spacer block 206B includes a conductive material, and, for example, is made of a conductive material (such as aluminum, aluminum alloy, or any other suitable metal). The spacer block 206B can compensate the gap between the varistor blocks 206A, provide cushioning between the varistor blocks 206A, and mechanically strengthen the core unit 212. As shown in FIG. 3, in the illustrated embodiment, the spacer block 206B may be provided at an end of the core unit 212 and between the varistor block 206A and the second end fitting 202F. It is conceivable that in other embodiments not shown, the spacer block(s) may also be arranged between the varistor blocks of the core unit.

[0041] In the illustrated embodiment, the multiple blocks 206 of each core unit 212 may have substantially the same outer diameter / cross-sectional area. In other words, the outer diameter / cross-sectional area of each varistor block 206A may be substantially equal to the outer diameter / cross-sectional area of each spacer block 206B. It is conceivable that in other embodiments not shown, the varistor block and the spacer block may also have other suitable dimension relation.

[0042] The coupling assembly 214 of each core unit 212 may include multiple coupling elements 218 arranged at intervals along the circumferential direction of the end fittings 202. Each coupling element 218 is made of insulating material and may be in the form of a pull rod or pull ring. Two ends of each coupling element 218 are coupled to the pair of end fittings 202 respectively, to apply prestress to the pair of end fittings 202 and press the pair of end fittings 202 toward each other. This can maintain sufficient contact pressure and desirable electrical contact between the end fittings 202 and the blocks 206, as well as between the blocks 206, allowing high current to be carried through the core unit 212 and providing good mechanical stability for the core unit 212.

[0043] Referring to FIG. 2, in the illustrated embodiment, the core assembly 200 includes three core units 212 arranged in sequence along the longitudinal direction L, namely, a first core unit 212A, a second core unit 212B, and a third core unit 212C. The first core unit 212A is located at the high-voltage end of the core assembly 200, and the third core unit 212C is located at the low-voltage end of the core assembly 200. Correspondingly, the core assembly 200 includes three pairs of end fittings 202, namely, a pair of end fittings 202A and 202B of the first core unit 212 A, a pair of end fittings 202C and 202D of the second core unit 212B, and a pair of end fittings 202E and 202F of the third core unit 212C. In the illustrated embodiment, the end fitting 202A of the first core unit 212A closer to the insulator 106 is formed as the first end fitting, and the end fitting 202F of the third core unit 212C closer to the end cover 102 is formed as the second end fitting. In other words, the two end fittings located at two opposite ends of the core assembly 200 are respectively formed as the first end fitting 202A and the second end fitting 202F. It is conceivable that in other embodiments not shown, the core assembly may also include other suitable numbers of core units, such as one core unit, two core units, or more than three core units.

[0044] Referring further to FIG. 2 and FIG. 3, in the illustrated embodiment, the first endfitting 202 A of the first core unit 212A of the core assembly 200 may be electrically connected to the metal insert 114 of the insulator 106 through components such as the conductor 300 in the internal space S, thereby electrically connecting the high-voltage end of the core assembly 200 to the phase line electrically connected to the metal insert 114. In the illustrated embodiment, the insulating member 208 and the second end fitting 202F are made separately. The insulating member 208 is provided in the third core unit 212C and is arranged between the block 206 of the third core unit 212C closest to the second end fitting 202F (i.e., one of the plurality of blocks 206 of the core assembly 200 closest to the second end fitting 202F, in other words, the block closest to the second end fitting 202F among the plurality of blocks 206 of the core assembly 200) and the second end fitting 202F in the longitudinal direction L, so as to cut off the conductive path between the block 206 of the third core unit 212C closest to the second end fitting 202F and the second end fitting 202F. Therefore, the low-voltage end of the core assembly 200 is prevented from being grounded through the second end fitting 202F and the end cover 102 connected to the second end fitting 202F. The insulating member 208 may be substantially in the shape of a circular plate, a cylinder, a ring, a polygon, or any other suitable shape. In the illustrated embodiment, both the blocks 206 and the insulating member 208 have a circular cross-section. The outer diameter / cross-sectional area of the insulating member 208 may be substantially equal to the outer diameter / cross-sectional area of the spacer block 206B, and substantially equal to the outer diameter / cross-sectional area of the varistor block 206A. It can be understood that in other embodiments not shown, the blocks and the insulating member may also have other suitable cross-sectional shapes.

[0045] Since the insulating member 208 is arranged between the block 206B of the third core unit 212C and the second end fitting 202F, the insulating member 208 can be held in the third core unit 212C by the contact pressure inside the third core unit 212C, so that there is no need for additional fixing structures, and more specifically, no need for fastening holes on the insulating member 208. Furthermore, in the assembly process of the gas-insulated surge arrester 10, there is no need to connect the insulating member 208 respectively to the second end fitting 202F and the end cover 102 through bolts or studs. Instead, when assembling the third core unit 212C, the insulating member 208 is placed between the block 206B of the third core unit 212C closest to the second end fitting 202F and the second end fitting 202F, and after the third core unit 212C is assembled, the second end fitting 202F is connected to the end cover 102, therebysimplifying the assembly of the gas-insulated surge arrester 10. As shown in FIG. 4B, in the illustrated embodiment, no holes are provided in the insulating member 208, which can simplify the manufacturing process of the insulating member 208, allow a reduction in the thickness of the insulating member 208 while ensuring its mechanical properties, thereby reducing the dimension of the gas-insulated surge arrester 10 in the longitudinal direction L, and lowering the manufacturing cost of the gas-insulated surge arrester 10. It is conceivable that in other embodiments not shown, the insulating member may also have a hole. For example, in the case where the insulating member is in a circular shape, a hole may be provided at its center.

[0046] In the illustrated embodiment, the one of the plurality of blocks 206 of the core assembly 200 closest to the second end fitting 202F is the spacer block 206B. It is conceivable that in other embodiments not shown, the spacer block may be not adjacent to the second end fitting, or no spacer block is included in the plurality of blocks. In these cases, the one of the plurality of blocks of the core assembly closest to the second end fitting may be a varistor block.

[0047] In the illustrated embodiment, the insulating member 208 is sandwiched / clamped between the block 206 of the third core unit 212C closest to the second end fitting 202F and the second end fitting 202F. It is conceivable that the insulating member 208 may also be placed in other suitable positions. For example, with reference to FIG. 3, in the case where a spacer block 206B is provided between one of the plurality of varistor blocks 206A of the core assembly 200 closest to the second end fitting 202F and the second end fitting 202F, the insulating member may also be sandwiched / clamped between the varistor block 206A closest to the second end fitting 202F and the aforementioned spacer block 206B.

[0048] Referring to FIG. 3 to FIG. 4C, the second end fitting 202F of the third core unit 212C of the core assembly 200 includes a central portion 220 and a flange 222 surrounding the central portion 220. The thickness of the flange 222 may be smaller than the thickness of the central portion 220. The central portion 220 faces the insulating member 208. In the illustrated embodiment, multiple notches 224 are provided on the flange 222, and accordingly, multiple grooves 226 are provided on a side surface of the central portion 220. Each notch 224 on the flange 222 is adapted to guide a corresponding coupling element 218 in the form of a pull ring into a corresponding groove 226, in other words, to guide the corresponding coupling element 218 to be fitted onto the second end fitting 202F. It is conceivable that in other embodiments not shown, the thickness of the flange may be equal to the thickness of the central portion. It isconceivable that in other embodiments not shown, the second end fitting may have other configurations, for example, may be configured to be adapted to a coupling element in the form of a pull rod.

[0049] In the illustrated embodiment, the flange 222 includes a plurality of fastening holes 210 through which fasteners 228 pass through for connecting the second end fitting 202F to the end cove 102. In the illustrated embodiment, the flange 222 includes eight fastening holes 210 allowing bolts to pass through. It is conceivable that in other embodiments not shown, the flange 222 may also include other suitable numbers of fastening holes. In the illustrated embodiment, the flange 222 extends around the entire circumference of the central portion 220, forming a circular shape. It is conceivable that in other embodiments not shown, a plurality of flanges spaced apart along the circumferential direction of the central portion may be provided for providing fastening holes.

[0050] In the illustrated embodiment, the central portion 220 includes a limiting recess 230 on the side thereof facing / adjacent to the insulating member 208. The limiting recess 230 is configured to receive at least part of the insulating member 208 to limit the movement of the insulating member 208 relative to the second end fitting 202F in a direction substantially perpendicular to the longitudinal direction L, thereby avoiding displacement of the insulating member 208 and the resulting insulation failure. In the illustrated embodiment, the limiting recess 230 has substantially a circular cross-section. The inner diameter of the limiting recess 230 is substantially equal to or slightly larger than the outer diameter of the insulating member 208.

[0051] In the illustrated embodiment, the gas-insulated surge arrester 10 further includes a bushing 400 and a conductive component 500. The conductive component 500 is configured to guide the current flowing through the core assembly 200 to the bushing 400. The bushing 400 extends through the end cover 102 and is insulated relative to the end cover 102, and the bushing 400 provides a current path from an inside of the tank 100 to an outside of the tank 100.

[0052] In the illustrated embodiment, the conductive component 500 includes a first conductive portion 502 and a second conductive portion 504. The first conductive portion 502 is arranged between the one of the plurality of varistor blocks 206A closest to the second end fitting 202F and the insulating member 208 in the longitudinal direction L, to be electricallyconnected to the core assembly 200. The second conductive portion 504 is electrically connected to the bushing 400. As shown in FIG. 4A, in the illustrated embodiment, the first conductive portion 502 is in the form of a conductive ring, and the second conductive portion 504 is in the form of a conductive strip. The conductive strip 504 extends from the conductive ring 502. The conductive ring 502 is sandwiched / clamped between the block 206 of the third core unit 212C closest to the second end fitting 202F and the insulating member 208, to be electrically connected to the core assembly 200. An end of the conductive strip 504 is electrically connected to the bushing 400. The outer diameter of the conductive ring 502 may be substantially equal to or smaller than the outer diameter of the insulating member 208. It is conceivable that in other embodiments not shown, the first conductive portion may be in the form of a circular or other suitable shaped conductive sheet.

[0053] In the illustrated embodiment, the block 206, closest to the second end fitting 202F, of the third core unit 212C of the core assembly 200 and the insulating member 208 clamp the conductive ring 502 of the conductive component 500 therebetween, so that the low-voltage end of the core assembly 200 is electrically connected to the conductive component 500 and then to the bushing 400. In some embodiments, the bushing 400 may be electrically connected to a monitoring device (including but not limited to an ammeter, such as a microampere meter) located outside the tank 100 to monitor the status of the gas-insulated surge arrester 10, and the monitoring device is further grounded. Therefore, the low-voltage end of the core assembly 200 can be grounded through the conductive component 500 and the bushing 400. In other words, the current flowing through the core assembly 200 is guided to the outside of the tank 100 and ultimately to the ground via the conductive component 500 and the bushing 400, and the current would not flow through the second end fitting 202F.

[0054] For the illustrated embodiment, the end fittings among the three pairs of end fittings 202, except for the second end fitting 202F, include conductive material to allow current to flow from the high-voltage end of the core assembly 200 to the low-voltage end of the core assembly 200. In some embodiments, the end fittings mentioned above may be made of metal (including but not limited to aluminum or aluminum alloy) to provide desirable mechanical properties while providing a conductive path. As the second end fitting 202F is not required to be conductive, the material of the second end fitting 202F is mainly selected based on the required mechanical properties. In some embodiments, the second end fitting 202F is made of metal(including but not limited to aluminum or aluminum alloy) or high-strength plastic (including but not limited to fiber-reinforced plastic, polyphenylene ether, polyphenylene sulfide, polysulfone, reinforced epoxy resin).

[0055] In the illustrated embodiment, the insulating member 208 and the second end fitting 202F are made separately, that is, the insulating member 208 and the second end fitting 202F are made as two pieces. It is conceivable that in some other embodiments not shown, the insulating member and the second end fitting may be made in one piece. In this case, the one piece including the insulating member and the second end fitting is connected to the end cover, and the insulating member is the part of the one piece adjacent to the plurality of blocks. This one piece can prevent the current flowing through the plurality of varistor blocks from being guided to the ground by the end cover, and can allow the assembly of the core assembly through the combination of the second end fitting and the coupling elements. In other words, this one piece integrates the functions of insulation and assembly, which can further reduce the number of components required for gas-insulated surge arrester and simplify its assembly process. For example, in some embodiments, the insulating member is made of insulating material, the second end fitting is made of metal or high-strength plastic, and the insulating member and the second end fitting may be made in one piece by insert molding, double-shot molding, and overmolding. For another example, in some other embodiments, both the insulating member and the second end fitting are made of insulating material and made in one piece.

[0056] In the illustrated embodiment, the bushing 400 includes a conductive rod 402 and an insulating sleeve 404 wrapping the conductive rod 402. The conductive rod 402 may include conductive material, and optionally, may be made of metal. The insulating sleeve 404 is made of insulating material (including but not limited to fiber-reinforced insulating material, such as fiber-reinforced epoxy resin). The conductive rod 402 includes two ends extending from the insulating sleeve 404, one of which is electrically connected to the conductive strip 502 of the conductive component 500, and the other is electrically connected to a component outside the tank 100. The insulating sleeve 404 extends through a through hole 116 in the end cover 102 in a sealed manner to prevent insulating gas from escaping from the internal space S of the gas- insulated surge arrester 10.

[0057] It should also be understood that the various components and features described herein can be made of a variety of materials, including but not limited to polymer, rubber, metal andother suitable materials familiar to those skilled in the art or combinations thereof. The embodiments shown in FIGS. 2 to 4C only illustrate the shape, amount, size and arrangement of each optional component of the gas-insulated surge arrester according to the exemplary embodiments of the present disclosure. However, these embodiments are merely intended to illustrate, rather than to limit. Other shapes, sizes and arrangements may be adopted without departing from the idea and scope of the present disclosure.

[0058] The technical contents and technical features of the present disclosure have been disclosed as above. However, it can be understood that under the creative concept of the present disclosure, those skilled in the art can easily make modifications, variants and equivalents of these embodiments according to the disclosure. For example, feature(s) shown or described as part of one embodiment may be combined with another embodiment to form yet another embodiment. The present disclosure is intended to cover these modifications, variants and equivalents. The description of the foregoing embodiments is illustrative rather than restrictive, and the scope of protection of the present disclosure is determined by the appended claims.

Claims

CLAIMS1. A gas-insulated surge arrester (10) comprising: a tank (100) having a longitudinal direction (L) and comprising an end cover (102) at one end of the tank (100) in the longitudinal direction (L), the end cover (102) being adapted to be grounded; and a core assembly (200) arranged inside the tank (100) and extending along the longitudinal direction (L), the core assembly (200) comprising a first end fitting (202A) and a second end fitting (202F) at opposite ends thereof and a plurality of blocks (206) arranged along the longitudinal direction (L) and held between the first end fitting (202A) and the second end fitting (202F), the plurality of blocks (206) at least comprising a plurality of varistor blocks (206 A), the second end fitting (202F) being closer to the end cover (102) than the first end fitting (202A) and the second end fitting (202F) being connected to the end cover (102); wherein the core assembly (200) further comprises an insulating member (208), and the insulating member (208) is arranged between one of the plurality of varistor blocks (206A) closest to the second end fitting (202F) and the second end fitting (202F) in the longitudinal direction (L).

2. The gas-insulated surge arrester according to claim 1, wherein the insulating member (208) is arranged between one of the plurality of blocks (206) closest to the second end fitting (202F) and the second end fitting (202F) in the longitudinal direction (L).

3. The gas-insulated surge arrester according to claim 2, wherein the plurality of blocks (206) further comprise at least one spacer block (206B), wherein the one of the plurality of blocks (206) closest to the second end fitting (202F) is a varistor block (206A) or a spacer block (206B).

4. The gas-insulated surge arrester according to claim 1, wherein the insulating member (208) and the second end fitting (202F) are made separately, or the insulating member (208)and the second end fitting (202F) are made in one piece.

5. The gas-insulated surge arrester according to claim 1, wherein the insulating member(208) and the second end fitting (202F) are made of insulating material and made in one piece.

6. The gas-insulated surge arrester according to any one of claims 1 to 5, wherein the insulating member (208) is configured to satisfy at least one of the following: a) the insulating member (208) is in the shape of a circular plate, a ring or a cylinder; b) the insulating member (208) has a cross-sectional shape substantially the same as that of the block (206); and c) the insulating member (208) has a cross-sectional area substantially the same as that of the block (206).

7. The gas-insulated surge arrester according to any one of claims 1 to 5, wherein the second end fitting (202F) comprises a central portion (220) and a flange (222) surrounding the central portion (220), wherein the flange (222) comprises a plurality of fastening holes (210) through which fasteners (228) pass through for connecting the second end fitting (202F) to the end cover (102).

8. The gas-insulated surge arrester according to any one of claims 1 to 4, wherein the second end fitting (202F) comprises a limiting recess (230) on a side thereof adjacent to the insulating member (208), and the limiting recess (230) is configured to receive at least part of the insulating member (208) to limit movement of the insulating member (208) relative to the second end fitting (202F) in a direction substantially perpendicular to the longitudinal direction (L).

9. The gas-insulated surge arrester according to any one of claims 1 to 5, wherein the gas- insulated surge arrester (10) further comprises a bushing (400) and a conductive component (500); wherein the conductive component (500) is configured to guide a current flowing through the core assembly (200) to the bushing (400); wherein the bushing (400) extendsthrough the end cover (102) and is insulated relative to the end cover (102), and the bushing (400) provides a current path from an inside of the tank (100) to an outside of the tank (100).

10. The gas-insulated surge arrester according to claim 9, wherein the conductive component (500) comprises a first conductive portion (502) and a second conductive portion (504), wherein the first conductive portion (502) is arranged between the one of the plurality of varistor blocks (206A) closest to the second end fitting (202F) and the insulating member (208) in the longitudinal direction (L) to be electrically connected to the core assembly (200), wherein the second conductive portion (504) is electrically connected to the bushing (400).

11. The gas-insulated surge arrester according to claim 9, wherein the bushing (400) comprises a conductive rod (402) and an insulating sleeve (404) wrapping the conductive rod (402).

12. The gas-insulated surge arrester according to any one of claims 1 to 4, wherein the second end fitting (202F) is made of metal.

13. The gas-insulated surge arrester according to any one of claims 1 to 5, wherein the core assembly (200) comprises one core unit (212) or a plurality of core units (212) arranged along the longitudinal direction (L); wherein each core unit (212) comprises a pair of end fittings (202), multiple blocks among the plurality of blocks (206) and a coupling assembly (214); wherein the multiple blocks are stacked in the longitudinal direction (L), and the pair of end fittings (202) are coupled by the coupling assembly (214) and hold the multiple blocks therebetween; wherein the two end fittings (202) located at opposite ends of the core assembly (200) are the first end fitting (202A) and the second end fitting (202F).

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