Core of surge arrester, surge arrester comprising the same, and method for assembling the same

Abstract

A core (C) of a surge arrester (SA), having an axial direction (L) and a radial direction (R) perpendicular to the axial direction (L), wherein the core (C) comprises: a first electrode block (100) and a second electrode block (200) located at two opposite ends of the core (C) along the axial direction (L), wherein the first electrode block (100) is provided with a plurality of first grooves (101) opening outwards along the radial direction (R), and the second electrode block (200) is provided with a plurality of second grooves (201) opening outwards along the radial direction (R); - a plurality of varistor blocks (301) sequentially arranged along the axial direction (L) and forming a varistor-block stack (300) pressed between the first electrode block (100) and the second electrode block (200); and - a plurality of insulating support members (400) sequentially arranged around the varistor-block stack (300), wherein a first end portion (401) of each of the insulating support members (400) is radially retained in the corresponding first groove (101) by a first blocking structure integrally formed on the first electrode block (100), and / or, a second end portion (402) of each of the insulating support members (400) is radially retained in the corresponding second groove (201) by a second blocking structure integrally formed on the second electrode block (200). Further, in the core (C) each of the insulating support members (400) has an annular configuration, such that the first end portion (401) and the second end portion (402) have a U shape, trapezoidal shape or triangular shape, and each of the first grooves (101) and each of the second grooves (201) have a corresponding U shape, trapezoidal shape or triangular shape.

Description

P240091W001CORE OF SURGE ARRESTER, SURGE ARRESTER COMPRISING THE SAME,AND METHOD FOR ASSEMBLING THE SAMETECHNICAL FIELD

[0001] The present disclosure relates to the technical field of surge arresters. More specifically, the present disclosure relates to a core of a surge arrester, a surge arrester comprising the same, and a method for assembling the same.BACKGROUND

[0002] At present, different types of surge arresters are used in switchgear, such as gas insulated switchgear (GIS), to protect power grid equipment from overvoltage. A surge arrester can be connected between a phase line and the ground. The surge arrester typically comprises a plurality of varistor blocks made of metal oxides (MOV). The resistance of a 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 allows current to be conducted to the ground through the varistor block, thereby reducing overvoltage.

[0003] The surge arrester generally comprises a housing filled with insulating gas and a core (also referred to as an "active part") arranged inside the housing. The core generally comprises a varistor-block stack and two metal electrode blocks arranged at two ends of the varistor-block stack. In addition, the core may also comprise a plurality of insulating support members (such as fiberglass reinforced plastic (FPR) rings) surrounding the varistor-block stack arranged in the middle. Two opposite ends of each insulating support member are supported in grooves of the two metal electrode blocks, respectively, such that under thrust generated by a screw passing through one of the metal electrode blocks, the varistor-block stack is compressed while the surrounding insulating support members are stretched.

[0004] In general, regardless of how the surge arrester is placed, the friction generated between the insulating support members and the electrode blocks due to the pretension force of the fixation screw can retain the insulating support members in the grooves of the electrode blocks. But in the case of severe vibration, such as earthquakes with an intensity greater than or equal to VH and transportation with an acceleration greater than 15g, the insulating support1 T24CH04976P240091W001 members may slip out of the grooves of the electrode blocks, thereby loosening the core. Once the insulating support members slip out of the grooves of the electrode blocks, the pretension force on the varistor-block stack will become imbalanced, and then the entire core will collapse, which also causes loss of main function of the surge arrester.

[0005] For the above issues, there are some solutions in the prior art that can retain the insulating support members in the grooves of the electrode blocks. For example, additional plastic rings may be installed on the outer side of the electrode blocks to prevent the insulating support members from slipping out of the grooves of the electrode blocks, and additional screws may also be needed to prevent these plastic rings from being loosened or moving. For another example, the core may be tightly wrapped with filament, but the filament winding process is complex, and it will take a long time to complete the replacement once one of the varistor blocks in the stack needs to be replaced.SUMMARY

[0006] In view of the above, it is an object of the present disclosure to provide an improved core of a surge arrester that can retain the insulating support members in the grooves of the two end electrode blocks in a simple, efficient, and cost-effective way, thereby avoiding the collapse of the core due to the slippage of the insulating support members.

[0007] For this object, a first aspect of the present disclosure provides a core of a surge arrester. The core has an axial direction and a radial direction perpendicular to the axial direction, and comprises: a first electrode block and a second electrode block located at two opposite ends of the core along the axial direction, wherein the first electrode block is provided with a plurality of first grooves opening outwards along the radial direction, and the second electrode block is provided with a plurality of second grooves opening outwards along the radial direction; a plurality of varistor blocks sequentially arranged along the axial direction and forming a varistor-block stack pressed between the first electrode block and the second electrode block; and a plurality of insulating support members sequentially arranged around the varistor-block stack, wherein a first end portion of each of the insulating support members is radially retained in the corresponding first groove by a first blocking structure integrally formed on the first electrode block, and / or, a second end portion of each of the insulating support members is2 T24CH04976P240091W001 radially retained in the corresponding second groove by a second blocking structure integrally formed on the second electrode block.

[0008] According to the above technical concept, the present disclosure may further include one or more of the following alternative embodiments.

[0009] In some alternative embodiments, each of the insulating support members has an annular configuration, such that the first end portion and the second end portion have a U shape, trapezoidal shape or triangular shape, and each of the first grooves and each of the second grooves have a corresponding U shape, trapezoidal shape or triangular shape.

[0010] In some alternative embodiments, the first blocking structure is configured as a first protrusion protruding within the first groove, the first protrusion being arranged, along the radial direction, at an outer side of a first support surface of the first groove for supporting the first end portion in order to block radial and outward movement of the first end portion, and / or, the second blocking structure is configured as a second protrusion protruding within the second groove, the second protrusion being arranged, along the radial direction, at an outer side of a second support surface of the second groove for supporting the second end portion in order to block radial and outward movement of the second end portion.

[0011] In some alternative embodiments, the first support surface of the first groove for supporting the first end portion has a planar or curved shape that fits against the first end portion, and / or, the second support surface of the second groove for supporting the second end portion has a planar or curved shape that fits against the second end portion.

[0012] In some alternative embodiments, the first blocking structure is formed by a first support surface of the first groove for supporting the first end portion, the first support surface being configured to be inclined relative to the radial direction in order to block radial and outward movement of the first end portion, and / or, the second blocking structure is formed by a second support surface of the second groove for supporting the second end portion, the second support surface being configured to be inclined relative to the radial direction in order to block radial and outward movement the second end portion.

[0013] In some alternative embodiments, the first blocking structure is formed by a first support surface of the first groove for supporting the first end portion, the first support surface being roughened such that friction between the first support surface and the first end portion3 T24CH04976P240091W001 blocks radial and outward movement of the first end portion, and / or, the second blocking structure is formed by a second support surface of the second groove for supporting the second end portion, the second support surface being roughened such that friction between the second support surface and the second end portion blocks radial and outward movement of the second end portion.

[0014] In some alternative embodiments, the first blocking structure is formed by a first support surface of the first groove for supporting the first end portion, the first support surface being coated with a first adhesive layer such that adhesive force between the first support surface and the first end portion blocks radial and outward movement of the first end portion, and / or, the second blocking structure is formed by a second support surface of the second groove for supporting the second end portion, the second support surface being coated with a second adhesive layer such that adhesive force between the second support surface and the second end portion blocks radial and outward movement of the second end portion.

[0015] In some alternative embodiments, the first electrode block is further provided with a threaded hole extending along the axial direction to allow the varistor-block stack to be pressed between the first electrode block and the second electrode block by means of a screw passing through the threaded hole and abutting against the varistor-block stack.

[0016] In some alternative embodiments, the varistor-block stack comprises an end spacer facing the first electrode block and abutting against the screw.

[0017] A second aspect of the present disclosure provides a surge arrester comprising the core according to the first aspect of the present disclosure.

[0018] A third aspect of the present disclosure provides a method for assembling the core according to the first aspect of the present disclosure. The method comprises the following steps: positioning the varistor-block stack on the second electrode block and mounting the second end portion of each of the insulating support members into the corresponding second groove; positioning the first electrode block on the varistor-block stack and mounting the first end portion of each of the insulating support members into the corresponding first groove; and pressing the varistor-block stack between the first electrode block and the second electrode block by means of a fastener, and stretching each of the insulating support members by bidirectional supports provided by the corresponding first and second grooves.4 T24CH04976P240091W001

[0019] The core of the surge arrester according to the present disclosure has a plurality of beneficial technical effects, especially: the core does not require to introduce new components, but only requires to integrally arrange a blocking structure in the grooves of at least one electrode block to significantly increase the resistance for preventing the insulating support members from slipping out of the grooves. It can be understood that the core of the surge arrester according to the present disclosure only requires an additional machining process for the electrode block, thus its manufacturing process is simple, efficient, and cost-effective, and does not bring any change to its assembling process.

[0020] Generally, all terms used in the claims shall be interpreted in accordance with their general sense in this technical field, unless otherwise explicitly defined herein. The terms "element", "device", "member", "component", and "step" are interpreted here in an open-ended way as at least one element, device, member, component, and step, unless otherwise explicitly stated.BRIEF DESCRIPTION OF THE DRAWINGS

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

[0022] FIG. l is a view of the internal structure of a surge arrester comprising a core according to an embodiment of the present disclosure;

[0023] FIG. 2 is a side view of a first embodiment of the core according to the present disclosure;

[0024] FIG. 3 is a cross-sectional view of the core shown in FIG. 1;

[0025] FIG. 4 is an enlarged view of the region A shown in FIG. 2;

[0026] FIG. 5 is an enlarged view of the region B shown in FIG. 3;

[0027] FIG. 6 is a partial cross-sectional view of a second embodiment of the core according to the present disclosure;

[0028] FIG. 7 is a partial cross-sectional view of a third embodiment of the core according to5 T24CH04976P240091W001 the present disclosure; and

[0029] FIG. 8 is a partial cross-sectional view of a comparative core.

[0030] The components in the accompanying drawings are shown for simplicity and clarity, and may not be shown in the exact scale. It should be understood that these drawings not only can be used for explanation and illustration of the present disclosure, but also can help to limit the present disclosure when necessary.DETAILED DESCRIPTION

[0031] The implementation and usage of the embodiments are discussed in detail below. However, it should be understood 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.

[0032] In this specification and the accompanying drawings, the axial direction of a tubular component refers to the direction along the central axis of the component, the circumferential direction of the tubular component refers to the direction along the circumference of the component, and the radial direction of the tubular component refers to the direction passing through the central axis of the component and being perpendicular to the axial direction of the component. For example, the direction L shown in the figures is the axial direction of the surge arrester and its core, and the direction R shown in the figures is the radial direction of the surge arrester and its core.

[0033] In this specification, the terms "first", "second", etc., are only used for description, and should not be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. In addition, unless otherwise specified, the terms "mounting", "connection", etc., 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.

[0034] FIG. 1 is a view of the internal structure of a surge arrester SA according to an6 T24CH04976P240091W001 embodiment of the present disclosure.

[0035] As shown in FIG. 1, the surge arrester SA comprises a housing 600, an insulator 800 and an end cover 900 respectively arranged at two ends of the housing 600 along the axial direction L, and three cores C arranged inside the housing 600. These three cores C extend along the axial direction L and are connected in sequence, for example, by bolts or other fasteners. A core C located at one end (i.e., the lower core C shown in FIG. 1) is connected to a metal insert 801 of the insulator 800 through a conductor 700, and then connected to a phase line. Another core C located at the other end (i.e., the upper core C shown in FIG. 1) is connected to the end cover 900. The end cover 900 is adapted to be connected to the ground. It is conceivable that the number of cores C in the surge arrester SA is not limitative but can be determined according to actual needs.

[0036] FIG. 2 to FIG. 5 show a first embodiment of the core C according to the present disclosure.

[0037] As shown in FIG. 2 to FIG. 5, the core C according to the present disclosure mainly comprises a first electrode block 100, a second electrode block 200, a varistor-block stack 300, and a plurality of insulating support members 400.

[0038] The first electrode block 100 and the second electrode block 200 are made of, for example, metal material, and located at two opposite ends of the core C along the axial direction L. The first electrode block 100 is provided with a plurality of first grooves 101 opening outwards along the radial direction R, and the second electrode block 200 is correspondingly provided with a plurality of second grooves 201 opening outwards along the radial direction R. The plurality of first grooves 101 and the corresponding plurality of second grooves 201 are, for example, uniformly distributed along the circumferential direction of the core C.

[0039] The varistor-block stack 300 is composed of a plurality of varistor blocks 301 stacked in sequence along the axial direction L, and is pressed between the first electrode block 100 and the second electrode block 200 by means of a fastener. A partition spacer 303 may be provided between adjacent varistor blocks 301. It is conceivable that the varistor-block stack 300 may comprise any suitable number of varistor blocks 301 and partition spacers 303. In the illustrated embodiment, each varistor block 301 may be substantially in the shape of a cylinder or a circular plate, and be made of metal-oxide-based material, such as ZnO-based material. Each partition7 T24CH04976P240091W001 spacer 303 may also be substantially in the shape of a cylinder or a circular plate, and be made of conductive material (such as aluminum, aluminum alloy, or any other suitable metal). The thickness of each partition spacer 303 is not limitative. These partition spacers 303 can be used to compensate the gaps between adjacent varistor blocks 301, thereby providing buffer and mechanically reinforcing the core C.

[0040] In addition, the varistor-block stack 300 further comprises an end spacer 302 facing the first electrode block 100 and configured to abut against the fastener such as a screw. More specifically, in the illustrated embodiment, the center of the first electrode block 100 is further provided with a threaded hole 104 extending along the axial direction L, so as to allow the varistor-block stack 300 to be pressed between the first electrode block 100 and the second electrode block 200 by means of a screw 500 passing through the threaded hole 104 and abutting against the end spacer 302 of the varistor-block stack 300.

[0041] The plurality of insulating support members 400 are sequentially arranged around the varistor-block stack 300. Each insulating support member 400 has, for example, an annular configuration as shown, and a first end portion 401 and a second end portion 402 of each insulating support member 400 along the axial direction L are respectively supported on the first electrode block 100 and on the second electrode block 200. More specifically, the first end portion 401 of each insulating support member 400 is accommodated in the corresponding first groove 101 of the first electrode block 100 and is supported along the axial direction L on a first support surface 102 of the first groove 101, and the second end portion 402 of each insulating support member 400 is accommodated in the corresponding second groove 201 of the second electrode block 200 and is supported along the axial direction L on a second support surface of the second groove 201.

[0042] In the illustrated embodiment, the core C comprises four insulating support members 400 uniformly arranged along its circumferential direction. It is conceivable that the number of the insulating support members 400 of the core C is not limitative, and two, three, or even more insulating support members 400 may be provided according to actual needs. In the illustrated embodiment, the first end portion 401 and the second end portion 402 of each insulating support member 400 have a U shape, and each first groove 101 and each second groove 201 have a corresponding U shape. It is conceivable that the first end portion 401 and the second end portion 402 of each insulating support member 400 may also be designed to have other shapes8 T24CH04976P240091W001 such as a trapezoidal shape or a triangular shape, etc., and each first groove 101 and each second groove 201 have corresponding shapes such as a trapezoidal shape or a triangular shape, etc. In addition, the enlarged views in FIG. 4 and FIG. 5 provide a detailed illustration of the mating structure between the insulating support members 400 and the first electrode block 100. The mating structure between the insulating support members 400 and the second electrode block 200 may be similar, so it is not shown in detail through enlarged views.

[0043] In the core C of the surge arrester according to the present disclosure, in order to increase the resistance for preventing the insulating support members 400 from slipping radially and outwards, a first blocking structure is integrally formed in each first groove 101 of the first electrode block 100 so as to radially retain the first end portion 401 of each insulating support member 400 in the corresponding first groove 101, and / or a second blocking structure is integrally formed in each second groove 201 of the second electrode block 200 so as to radially retain the second end portion 402 of each insulating support member 400 in the corresponding second groove 201.

[0044] In the first embodiment, particularly as shown in FIG. 4 and FIG. 5, the first blocking structure is configured as a first protrusion 103 protruding within the first groove 101 of the first electrode block 100. The first protrusion 103 is arranged, along the radial direction R, at an outer side of the first support surface 102 of the first groove 101 for supporting the first end portion 401 of the insulating support member 400 in order to block radial and outward movement of the first end portion 401, wherein the first support surface 102 has a planar shape that fits against the first end portion 401 and is parallel to the radial direction R. And / or, the second blocking structure is similarly configured as a second protrusion protruding within the second groove 201 of the second electrode block 200. The second protrusion is arranged, along the radial direction R, at an outer side of the second support surface of the second groove 201 for supporting the second end portion 402 of the insulating support member 400 in order to block radial and outward movement of the second end portion 402, wherein the second support surface has a planar shape that fits against the second end portion 402 and is parallel to the radial direction R.

[0045] Therefore, the design of the present disclosure does not require to introduce new components but only requires slight modifications on the electrode blocks 100 and 200. The protrusions (shoulders) 103 formed by machining within the grooves 101 and 201 can9 T24CH04976P240091W001 effectively prevent the end portions 401 and 402 of the insulating support member 400 from slipping radially and out of the corresponding grooves 101 and 201. Only when the protrusions 103 are broken, the end portions 401 and 402 of the insulating support member 400 can slip out of the corresponding grooves 101 and 201. However, this situation is quite rare. It is conceivable that only one additional cutting process is required to be performed on the original grooves 101 and 201 of the electrode blocks 100 and 200 to form the protrusions 103, which brings no other impact on the overall structure. Therefore, the manufacturing process is simple, efficient, and cost-effective, and does not bring any change to the assembling process of the core C.

[0046] FIG. 6 shows a second embodiment of the core C according to the present disclosure.

[0047] As shown in FIG. 6, the core C of the second embodiment differs from the first embodiment in that, the first blocking structure is formed by the first support surface 102 of the first groove 101 of the first electrode block 100 for supporting the first end portion 401 of the insulating support member 400, wherein the first support surface 102 is configured to be inclined relative to the radial direction R, such that it can exert a radial and inward force component on the first end portion 401 when supporting the first end portion 401, thereby blocking radial and outward movement of the first end portion 401. The first support surface 102 has a planar shape that fits against the first end portion 401, and the mating surface of the first end portion 401 has an adaptive inclined planar shape. And / or, the second blocking structure is similarly formed by the second support surface of the second groove 201 of the second electrode block 200 for supporting the second end portion 402 of the insulating support member 400, wherein the second support surface is configured to be inclined relative to the radial direction R, such that it can exert a radial and inward force component on the second end portion 402 when supporting the second end portion 402, thereby blocking radial and outward movement of the second end portion 402. The second support surface has a planar shape that fits against the second end portion 402, and the mating surface of the second end portion 402 has an adaptive inclined planar shape.

[0048] FIG. 7 shows a third embodiment of the core C according to the present disclosure.

[0049] As shown in FIG. 7, the core C of the third embodiment differs from the first embodiment in that, the first blocking structure is configured as a first protrusion 103 protruding within the first groove 101 of the first electrode block 100, and the first protrusion 103 is10 T24CH04976P240091W001 arranged, along the radial direction R, at an outer side of the first support surface 102 of the first groove 101 for supporting the first end portion 401 of the insulating support member 400 in order to block radial and outward movement of the first end portion 401. The first support surface 102 has a curved shape that fits against the first end portion 401, such as the arcuate concave shape as shown, and the mating surface of the first end portion 401 has an adaptive arcuate convex shape, thereby further enhancing the effect of blocking the radial and outward movement of the first end portion 401. And / or, the second blocking structure is similarly configured as a second protrusion protruding within the second groove 201 of the second electrode block 200, and the second protrusion is arranged, along the radial direction R, at an outer side of the second support surface of the second groove 201 for supporting the second end portion 402 of the insulating support member 400 in order to block radially and outward movement of the second end portion 402. The second support surface has a curved shape that fits against the second end portion 402, such as the arcuate concave shape as shown, and the mating surface of the second end portion 402 has an adaptive arcuate convex shape, thereby further enhancing the effect of blocking the radial and outward movement of the second end portion 402.

[0050] FIG. 8 shows a comparative core C.

[0051] As shown in FIG. 8, in the core C, the first support surface 102 of the first groove 101 of the first electrode block 100 for supporting the first end portion 401 of the insulating support member 400 is a plane parallel to the radial direction R, and no protrusion is provided at the outer side of the first support surface 102. Therefore, in the case of severe vibration, the first end portion 401 of the insulating support member 400 may slip out of the first groove 101, thereby loosening the core C. The second electrode block 200 of the core C has a similar structure. Therefore, in order to increase the resistance for preventing the insulating support member 400 from slipping radially and outwards, it is necessary to further provide the first and / or second blocking structures based on this structure.

[0052] According to another variant, based on the structure shown in FIG. 8, the first blocking structure is formed by the first support surface 102 of the first groove 101 of the first electrode block 100 for supporting the first end portion 401 of the insulating support member 400, wherein the first support surface 102 is roughened such that friction between the first support surface 102 and the first end portion 401 is capable of blocking radial and outward movement11 T24CH04976P240091W001 of the first end portion 401. And / or, the second blocking structure is similarly formed by the second support surface of the second groove 201 of the second electrode block 200 for supporting the second end portion 402 of the insulating support member 400, wherein the second support surface is roughened such that friction between the second support surface and the second end portion 402 is capable of blocking radial and outward movement of the second end portion 402.

[0053] According to another variant, based on the structure shown in FIG. 8, the first blocking structure is formed by the first support surface 102 of the first groove 101 of the first electrode block 100 for supporting the first end portion 401 of the insulating support member 400, wherein the first support surface 102 is coated with a first adhesive layer such that adhesive force between the first support surface 102 and the first end portion 401 is capable of blocking radial and outward movement of the first end portion 401, wherein the first adhesive layer is, for example, a tape or strong glue. And / or, the second blocking structure is similarly formed by the second support surface of the second groove 201 of the second electrode block 200 for supporting the second end portion 402 of the insulating support member 400, wherein the second support surface is coated with a second adhesive layer such that adhesive force between the second support surface and the second end portion 402 is capable of blocking radial and outward movement of the second end portion 402, wherein the second adhesive layer is, for example, a tape or strong glue.

[0054] Below is a brief description of a method for assembling the core C of the surge arrester according to the present disclosure.

[0055] Firstly, the assembled varistor-block stack 300 is positioned on the second electrode block 200 by means of, for example, a positioning pin or other positioning member, and the second end portion 402 of each insulating support member 400 is mounted inwards along the radial direction R into the corresponding second groove 201 having the above-mentioned second blocking structure. Then, the first electrode block 100 is positioned on the end spacer 302 of the varistor-block stack 300 by means of, for example, a positioning pin or other positioning member, and the first end portion 401 of each insulating support member 400 is mounted inwards along the radial direction R into the corresponding first groove 101 having the above-mentioned first blocking structure. It can be understood that regardless of what kind of blocking structure is chosen, the axial gap G between the first electrode block 100 and the12 T24CH04976P240091W001 varistor-block stack 300 can provide some freedom for axial movement, such that the first end portion 401 of each insulating support member 400 can surmount the first blocking structure and enter into the corresponding first groove 101 to be supported on the first support surface 102 of the first groove 101. Finally, the screw 500 is threaded through the threaded hole 104 of the first electrode block 100 to tightly abut against the end spacer 302 of the varistor-block stack 300, such that the varistor-block stack 300 is pressed between the first electrode block 100 and the second electrode block 200, and each insulating support member 400 is stretched by the bidirectional (opposite) supports provided by the respective support surfaces of the corresponding first and second grooves 101 and 201. Hereto, the assembly of the core C is finished.

[0056] The technical contents and technical features of the present disclosure have been disclosed above. However, it can be understood that, those skilled in the art can make various changes and improvements to the above-disclosed concept under the creative idea of the present disclosure, and all these various changes and improvements fall within the scope of protection of the present disclosure. The description of the foregoing embodiments is exemplary rather than limitative, and the scope of protection of the present disclosure is defined by the appended claims.13 T24CH04976

Claims

P240091W001CLAIMS1. A core (C) of a surge arrester (SA), having an axial direction (L) and a radial direction (R) perpendicular to the axial direction (L), wherein the core (C) comprises: a first electrode block (100) and a second electrode block (200) located at two opposite ends of the core (C) along the axial direction (L), wherein the first electrode block (100) is provided with a plurality of first grooves (101) opening outwards along the radial direction (R), and the second electrode block (200) is provided with a plurality of second grooves (201) opening outwards along the radial direction (R); a plurality of varistor blocks (301) sequentially arranged along the axial direction (L) and forming a varistor-block stack (300) pressed between the first electrode block (100) and the second electrode block (200); and a plurality of insulating support members (400) sequentially arranged around the varistorblock stack (300), wherein a first end portion (401) of each of the insulating support members (400) is radially retained in the corresponding first groove (101) by a first blocking structure integrally formed on the first electrode block (100), and / or, a second end portion (402) of each of the insulating support members (400) is radially retained in the corresponding second groove (201) by a second blocking structure integrally formed on the second electrode block (200).

2. The core (C) according to claim 1, wherein each of the insulating support members (400) has an annular configuration, such that the first end portion (401) and the second end portion (402) have a U shape, trapezoidal shape or triangular shape, and each of the first grooves (101) and each of the second grooves (201) have a corresponding U shape, trapezoidal shape or triangular shape.

3. The core (C) according to claim 1 or 2, wherein the first blocking structure is configured as a first protrusion (103) protruding within the first groove (101), the first protrusion (103) being arranged, along the radial direction (R), at an outer side of a first support surface (102) of the first groove (101) for supporting the first end portion (401) in order to block radial and14 T24CH04976P240091W001 outward movement of the first end portion (401), and / or, the second blocking structure is configured as a second protrusion protruding within the second groove (201), the second protrusion being arranged, along the radial direction (R), at an outer side of a second support surface of the second groove (201) for supporting the second end portion (402) in order to block radial and outward movement of the second end portion (402).

4. The core (C) according to claim 3, wherein the first support surface (102) of the first groove (101) for supporting the first end portion (401) has a planar or curved shape that fits against the first end portion (401), and / or, the second support surface of the second groove (201) for supporting the second end portion (402) has a planar or curved shape that fits against the second end portion (402).

5. The core (C) according to claim 1 or 2, wherein the first blocking structure is formed by a first support surface (102) of the first groove (101) for supporting the first end portion (401), the first support surface (102) being configured to be inclined relative to the radial direction (R) in order to block radial and outward movement of the first end portion (401), and / or, the second blocking structure is formed by a second support surface of the second groove (201) for supporting the second end portion (402), the second support surface being configured to be inclined relative to the radial direction (R) in order to block radial and outward movement the second end portion (402).

6. The core (C) according to claim 1 or 2, wherein the first blocking structure is formed by a first support surface (102) of the first groove (101) for supporting the first end portion (401), the first support surface (102) being roughened such that friction between the first support surface (102) and the first end portion (401) blocks radial and outward movement of the first end portion (401), and / or, the second blocking structure is formed by a second support surface of the second groove (201) for supporting the second end portion (402), the second support surface being roughened such that friction between the second support surface and the second end portion (402) blocks radial and outward movement of the second end portion (402).15 T24CH04976P240091W0017. The core (C) according to claim 1 or 2, wherein the first blocking structure is formed by a first support surface (102) of the first groove (101) for supporting the first end portion (401), the first support surface (102) being coated with a first adhesive layer such that adhesive force between the first support surface (102) and the first end portion (401) blocks radial and outward movement of the first end portion (401), and / or, the second blocking structure is formed by a second support surface of the second groove (201) for supporting the second end portion (402), the second support surface being coated with a second adhesive layer such that adhesive force between the second support surface and the second end portion (402) blocks radial and outward movement of the second end portion (402).

8. The core (C) according to claim 1, wherein the first electrode block (100) is further provided with a threaded hole (104) extending along the axial direction (L) to allow the varistorblock stack (300) to be pressed between the first electrode block (100) and the second electrode block (200) by means of a screw (500) passing through the threaded hole (104) and abutting against the varistor-block stack (300).

9. The core (C) according to claim 8, wherein the varistor-block stack (300) comprises an end spacer (302) facing the first electrode block (100) and abutting against the screw (500).

10. A surge arrester (SA), comprising at least one core (C) according to any one of claims 1 to 9.

11. A method for assembling the core (C) of a surge arrester (SA) according to any one of claims 1 to 9, comprising following steps: positioning the varistor-block stack (300) on the second electrode block (200) and mounting the second end portion (402) of each of the insulating support members (400) into the corresponding second groove (201);16 T24CH04976P240091W001 positioning the first electrode block (100) on the varistor-block stack (300) and mounting the first end portion (401) of each of the insulating support members (400) into the corresponding first groove (101); and pressing the varistor-block stack (300) between the first electrode block (100) and the second electrode block (200) by means of a fastener, and stretching each of the insulating support members (400) by bi-directional supports provided by the corresponding first and second grooves (101, 201).17 T24CH04976

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