Surge arrester module and surge arrester

Abstract

The present disclosure provides a surge arrester module and a surge arrester. The surge arrester module comprises a varistor stack, a pair of electrodes and a coupling assembly for coupling the pair of electrodes. The varistor stack comprises a plurality of varistor blocks stacked along a longitudinal direction of the surge arrester module and is sandwiched between the pair of electrodes. The coupling assembly comprises at least one rod. Each rod comprises a longitudinally extending rod body and at least one sleeve sheathed outside the rod body for attaching the rod to the electrode. The rod body is made of an insulating material and comprises a first interlocking portion in the form of a circumferential groove lying in a plane having a normal vector parallel to the longitudinal direction. The sleeve is made of metal and comprises a second interlocking portion in the form of a circumferential protrusion and cooperates with the first interlocking portion to prevent the rod body and the sleeve from moving relative to the longitudinal direction. The coupling assembly comprises at least one nut to which the sleeve is threadedly connected. The above-mentioned surge arrester module can provide the advantages of low partial discharge risk, good functional reliability, high productivity and low cost.

Description

Technical Field

[0001] This disclosure relates to surge arrester modules and surge arresters including at least one surge arrester module. Background Technology

[0002] Currently, different types of surge arresters are used in switchgear, such as gas-insulated switchgear, to protect power grid equipment from overvoltages. Surge arresters can be connected between a phase line and ground and can comprise a stack of metal oxide (e.g., zinc oxide) varistor blocks arranged between two electrodes. In the metal oxide varistor block, the resistance is higher at low voltages and lower at high voltages. When the voltage level in the phase line exceeds a critical value, the surge arrester allows current to be conducted to ground through the varistor block, thereby reducing the overvoltage.

[0003] To carry large currents through the stacking of varistor blocks and provide good stability for the surge arrester module, sufficient contact pressure must be maintained between the varistor blocks. The required contact pressure between the varistor blocks can be achieved using elongated clamping members of electrically insulating material. These clamping members are connected to the electrodes and prestressed to press the electrodes against each other axially within the surge arrester module, thus achieving the contact pressure between the varistor blocks. The clamping members can be, for example, in the form of rings, as shown in US5517382A and US20170084368A1, or in the form of rods / bars, as shown in EP0280189A1.

[0004] Insulating rings are typically formed using a wet winding process, which may result in significant internal defects such as delamination, bubbles, and voids. These internal defects can further contribute to partial discharge (PD) in surge arresters. Insulating rods, on the other hand, are generally formed using a pultrusion process. Compared to wet winding, pultrusion allows for better quality control, resulting in insulating rods typically having fewer internal defects than insulating rings, thus reducing the likelihood of PD.

[0005] As shown in EP0280189A1, insulating rods are typically machined with external threads and connected to the electrodes via nuts. However, the strength of the external threads on insulating rods is relatively low. Tensile tests on such insulating rods show that the teeth of the external threads are more prone to fracture than the rod body, making the external thread teeth the weakest area of ​​the insulating rod. Once the teeth of the insulating rod fracture, prestress is lost, leading to unacceptable contact pressure loss between the varistor blocks, which in turn causes arrester malfunction. Furthermore, even if the plastic teeth of the insulating rod do not fracture, the nut may loosen due to factors such as tooth creep, which can also cause arrester malfunction. Moreover, if glue is applied between the nut and the plastic teeth, the plastic teeth are likely to fracture when the entire assembly needs to be disassembled for maintenance.

[0006] Document EP2382640B1 relates to an impedance assembly having a first armature body and a second armature body. The impedance body is disposed between the two armature bodies. The impedance body is supported between the armature bodies by a holding element. The holding element has a radially extended portion. The radially extended portion is limited by an extension limiting element.

[0007] Document JP3365088B2 aims to improve a device for securing support shafts to support plates used to collect component assemblies within a surge arrester bushing. This document describes inserting support plates at both ends of multiple support shafts arranged circumferentially along the stacked components. Furthermore, stops are provided on the upper and lower sides of the support plates. The stops are approximately cylindrical and have joints in a circumferential direction. The stops are used by inserting them onto the support shafts and then applying radial force using a crimping clamp with protrusions to crimp them.

[0008] Document JP2002260905A describes a surge arrester that exhibits minimal deformation and high stiffness under torsional forces. Specifically, this surge arrester is characterized by an FRP rod that is fixed to the terminal electrode while simultaneously compressing and pulling the FRP rod.

[0009] Document DE102015007933B4 provides a surge arrester comprising: at least one varistor block; and a spring element stacked together with the at least one varistor block; wherein the spring element comprises: a spring; and a locking device that holds the spring in a compressed position in a first state and releases the spring in a second state; and wherein the surge arrester comprises: a housing that houses the at least one varistor block and the spring element; and two end fittings that are attached to opposite ends of the housing and securely connected to the housing, and wherein at least one of the two end fittings has an outlet element. Summary of the Invention

[0010] In view of the above, the purpose of this disclosure is to provide a surge arrester module that overcomes at least one of the above-mentioned defects and a surge arrester including at least one surge arrester module.

[0011] To this end, a first aspect of this disclosure provides a surge arrester module comprising: a varistor stack including a plurality of varistor blocks stacked along a longitudinal direction of the surge arrester module; a pair of electrodes configured to sandwich the varistor stack therebetween in the longitudinal direction, each electrode including at least one receiving hole; and a coupling assembly configured to couple the pair of electrodes and hold the pair of electrodes and the varistor stack together, the coupling assembly including at least one rod. Each rod includes: a rod body extending along the longitudinal direction and extending into the receiving hole of the pair of electrodes, the rod body being made of an insulating material and including a first interlocking portion; and at least one sleeve sleeved outside the rod body for attaching the rod to the electrode, the sleeve being made of metal and including a second interlocking portion adapted to engage with the first interlocking portion to prevent relative movement of the rod body and the sleeve in the longitudinal direction.

[0012] Preferably, the present invention provides a surge arrester module, comprising: a varistor stack including a plurality of varistor blocks stacked along the longitudinal direction of the surge arrester module; a pair of electrodes configured to sandwich the varistor stack therebetween in the longitudinal direction, each electrode including at least one receiving hole; and a coupling assembly configured to connect the pair of electrodes and hold the pair of electrodes and the varistor stack together, the coupling assembly including at least one rod, each rod including: a rod body extending along the longitudinal direction and extending into the receiving hole of the pair of electrodes. In the connection, the rod body is made of an insulating material and includes a first interlocking portion in the form of a circumferential groove, wherein the groove lies in a plane having a normal vector parallel to the longitudinal direction; at least one sleeve is fitted over the rod body for attaching the rod to the electrode, the sleeve being made of metal and including a second interlocking portion in the form of a circumferential protrusion adapted to engage with the first interlocking portion to prevent relative movement between the rod body and the sleeve in the longitudinal direction, and wherein the connection assembly further includes at least one nut, and wherein the sleeve is threadedly connected to the nut.

[0013] For the aforementioned surge arrester module, at least one rod is used to hold the electrodes and varistor stacked together. Compared to insulating rings, insulating rods have higher production efficiency, lower cost, and fewer internal defects (which can further reduce partial discharge of the surge arrester module). Furthermore, according to this application, at least one rod is attached to the electrode via a sleeve made of metal and mating with the rod body, which improves the connection strength between the rod and the electrode compared to conventional rods, ensuring the electrical contact pressure between the varistor blocks and thus guaranteeing good functional reliability.

[0014] According to a preferred embodiment of this disclosure, the sleeve is circumferentially pressed against the rod body, and the circumferential portion of the sleeve is deformed due to the pressing to form the second interlocking portion.

[0015] According to a preferred embodiment of this disclosure, the first interlocking part is in the form of a circumferential groove, and the second interlocking part is in the form of a circumferential protrusion.

[0016] According to a preferred embodiment of the present disclosure, the sleeve includes at least one groove configured to allow at least a portion of the sleeve, including the second interlocking portion, to elastically deform in order to engage with the first interlocking portion.

[0017] According to an alternative embodiment of this disclosure, the sleeve includes a shoulder, and the receiving hole of the electrode includes an abutment surface configured to abut the shoulder to prevent the sleeve and the electrode from moving relative to each other in the longitudinal direction.

[0018] According to another alternative embodiment of this disclosure, the receiving hole is radially outwardly open.

[0019] According to yet another alternative embodiment of this disclosure, the receiving hole of the electrode further includes a limiting surface configured to abut against the shoulder to prevent the sleeve from sliding away from the electrode in the radial direction of the surge arrester module.

[0020] According to a preferred embodiment of this disclosure, the coupling assembly includes at least one nut, and the sleeve is threadedly connected to the nut.

[0021] According to a preferred embodiment of this disclosure, the surge arrester module further includes an electrical contact element for maintaining the contact pressure between the varistor blocks.

[0022] According to a preferred embodiment of this disclosure, the electrical contact element is in the form of an elastic element, and the electrical contact element is disposed between the electrode and the varistor stack.

[0023] According to a preferred embodiment of this disclosure, the electrical contact element is in the form of a screw, and the electrical contact element is threaded into a threaded hole in the electrode, wherein one end of the electrical contact element abuts against the varistor stack.

[0024] According to a preferred embodiment of this disclosure, the connection assembly includes a plurality of rods arranged in a stack around the varistor.

[0025] A second aspect of this disclosure provides a surge arrester comprising at least one surge arrester module according to a first aspect of this disclosure and a housing housing the at least one surge arrester module.

[0026] The surge arrester module and surge arrester disclosed herein offer advantages such as low partial discharge risk, high functional reliability, high productivity, and low cost. Furthermore, the surge arrester module and surge arrester disclosed herein can be easily obtained by modifying conventional surge arrester modules and surge arresters. Attached Figure Description

[0027] Other features and advantages of this disclosure will be better understood through the following detailed description of preferred embodiments in conjunction with the accompanying drawings, in which the same reference numerals denote the same or similar parts.

[0028] Figure 1 This is a perspective view of a surge arrester module according to a first embodiment of the present disclosure;

[0029] Figure 2A This is a cross-sectional view of a surge arrester module according to a first embodiment of the present disclosure;

[0030] Figure 2B This is an exploded view of the rod of the surge arrester module according to the first embodiment of the present disclosure;

[0031] Figure 3A This is a cross-sectional view of a surge arrester module according to a second embodiment of the present disclosure;

[0032] Figure 3B This is a cross-sectional view of the rod of a surge arrester module according to a second embodiment of the present disclosure;

[0033] Figure 4A and Figure 4B These are different schematic diagrams illustrating the process of pressing the sleeve of the surge arrester module onto the rod body according to the second embodiment of this disclosure;

[0034] Figure 5 This is a perspective view of a surge arrester module according to a third embodiment of the present disclosure;

[0035] Figure 6A This is a cross-sectional view of a surge arrester module according to a third embodiment of the present disclosure;

[0036] Figure 6B This is a cross-sectional view of the rod of a surge arrester module according to a third embodiment of the present disclosure;

[0037] Figure 7 This is a perspective view of the electrodes of a surge arrester module according to a third embodiment of the present disclosure; and

[0038] Figure 8 This is a schematic diagram of a surge arrester including a surge arrester module according to the present disclosure in the third embodiment. Detailed Implementation

[0039] The implementation and use of the embodiments are discussed in detail below. However, it should be understood that the specific embodiments discussed are merely for illustrating specific ways of implementing and using this disclosure and are not intended to limit the scope of protection of this disclosure.

[0040] Figures 1 to 2B A surge arrester module 10 and its components according to a first embodiment of the present disclosure are shown.

[0041] like Figure 1 and Figure 2A As shown, the surge arrester module 10 includes a varistor stack 100, a pair of electrodes 200, and a coupling assembly 300. The varistor stack 100 includes a plurality of varistor blocks 102 stacked along the longitudinal direction of the surge arrester module 10. The pair of electrodes 200 is configured to sandwich the varistor stack 100 therebetween in the longitudinal direction of the surge arrester module 10. Each electrode 200 includes at least one receiving hole 202. The coupling assembly 300 is configured to connect the pair of electrodes 200 and hold the pair of electrodes 200 and the varistor stack 100 together. The coupling assembly 300 includes at least one rod 302. Each rod 302 includes a rod body 304 and at least one sleeve 306. The rod body 304 extends along the longitudinal direction of the surge arrester module 10 and extends into the receiving hole 202 of the electrode 200. The rod body 304 is made of insulating material and includes a first interlocking portion 308. At least one sleeve 306 is fitted over the outside of the rod body 304 for attaching the rod 302 to the electrode 200. The sleeve 306 is made of metal and includes a second interlocking portion 310. The second interlocking portion 310 is adapted to cooperate with a first interlocking portion 308 to prevent relative movement between the rod body 304 and the sleeve 306 in the longitudinal direction of the surge arrester module 10.

[0042] For the surge arrester module 10 described above, at least one rod 302 is used to hold the electrode 200 and the varistor stack 100 together. Compared to insulating rings, insulating rods are more efficient to manufacture, less expensive, and have fewer internal defects (which can further reduce or avoid partial discharge in the surge arrester module). Furthermore, at least one rod 302 is attached to the electrode 200 via a sleeve 306 made of metal and mating with the rod body 304. This improves the connection strength between the rod 302 and the electrode 200 and ensures the electrical contact pressure between the varistor blocks, thereby ensuring good functional reliability. This will be explained further below.

[0043] like Figure 1 and Figure 2A As shown, the varistor stack 100 may include a plurality of generally cylindrical varistor blocks 102. The varistor blocks 102 may be made of a metal oxide-based material, such as a ZnO-based material. The varistor blocks 102 may be arranged coaxially and stacked on top of each other along the longitudinal direction of the surge arrester module 10. In the illustrated embodiment, the varistor stack 100 includes twenty-one varistor blocks 102. It should be understood that the varistor stack 100 may include any other suitable number of varistor blocks 102.

[0044] The varistor stack 100 may also include one or more circular metal plates 104 made of a conductive material (e.g., aluminum or any other suitable metal) to compensate for gaps between varistor blocks 102, provide buffering between varistor blocks 102, and mechanically reinforce the surge arrester module 10. Figure 2A As shown, two metal plates 104 are respectively disposed at opposite ends of the varistor stack 100 in the longitudinal direction of the surge arrester module 10. In some embodiments, metal plates may also be disposed between the varistor blocks 102.

[0045] A pair of electrodes 200 are made of a conductive material (e.g., aluminum, copper, or any other suitable metal). One of the electrodes 200 is electrically connected to a high-voltage potential or another surge arrester module, while the other electrode 200 is electrically connected to a ground potential or another surge arrester module. When the voltage applied to the surge arrester module 10 exceeds a critical value, current can flow between the electrodes 200 through the varistor block 102 in the varistor stack 100.

[0046] In the illustrated embodiment, each electrode 200 may be generally cylindrical. Each electrode 200 includes a first portion 204 and a second portion 206 that protrudes from the first portion 204 along the longitudinal direction of the surge arrester module 10 and extends away from the varistor stack 100. The first portion 204 includes a plurality of receiving holes 202 for receiving rods 302. The second portion 206 includes a plurality of fastening holes 208 for fastening the surge arrester module 10 to an adjacent surge arrester module or for fastening a shield to the surge arrester module 10.

[0047] Each electrode 200 includes a first surface 210 and a second surface 212 opposite to each other in the longitudinal direction of the surge arrester module 10, wherein the first surface 210 faces the varistor stack 100. In the illustrated embodiment, the first surface 210 and the second surface 212 are planar and extend perpendicular to the longitudinal direction of the surge arrester module 10. The planar first surface 210 and the second surface 212 can provide a relatively large contact area to achieve good electrical contact.

[0048] In the illustrated embodiment, the pair of electrodes 200 have the same construction. In another embodiment, the pair of electrodes 200 may have different constructions.

[0049] like Figure 1 and Figure 2A As shown, the varistor stack 100 is disposed between a pair of electrodes 200, and the pair of electrodes 200 are connected to each other by a connecting component 300, so that the electrodes 200 and the varistor stack 100 are held together in the longitudinal direction of the surge arrester module 10, and the contact pressure between the varistor blocks 102 of the varistor stack 100 is achieved.

[0050] The connection assembly 300 includes a plurality of rods 302 evenly spaced from each other around the periphery of the varistor stack 100. In the illustrated embodiment, the connection assembly 300 includes four rods 302, such as... Figure 1 As shown. However, the connecting assembly 300 may include any other suitable number of levers 302, such as three, five, or six levers 302.

[0051] like Figure 2B As shown, in the illustrated embodiment, each rod 302 includes a rod body 304 and two sleeves 306. The rod body 304 may be made of an insulating material, such as fiber-reinforced epoxy resin, by a pultrusion process. The fiber-reinforced epoxy resin may be, for example, glass fiber-reinforced epoxy resin. The sleeves 306 may be made of metal (e.g., aluminum, steel, or any other suitable metal).

[0052] In the illustrated embodiment, the rod body 304 includes two opposite end portions 312 and an intermediate portion 314 extending between the two end portions 312. Each of the two sleeves 306 has a tubular shape. The two sleeves 306 are respectively fitted over the outside of the two end portions 312 of the rod body 304 for attaching the rod 302 to a pair of electrodes 200. In the illustrated embodiment, the outer diameter of the sleeve 306 is substantially equal to the outer diameter of the intermediate portion 314, and the inner diameter of the sleeve 306 is substantially equal to the outer diameter of the end portions 312.

[0053] like Figure 2A and Figure 2B As shown, the first interlocking part 308 of the rod body 304 is in the form of a circumferential groove, and the second interlocking part 310 of the sleeve 306 is in the form of a circumferential protrusion protruding toward the inside of the sleeve 306.

[0054] To facilitate the placement of the sleeve 306 outside the end portion 312 of the rod body 304 or the insertion of the end portion 312 of the rod body 304 into the sleeve 306, the sleeve 306 is provided with at least one groove 316 for allowing at least a portion of the sleeve 306, including the second interlocking portion 310, to elastically deform, further allowing the second interlocking portion 310 to engage with the first interlocking portion 308. When the end portion 312 of the rod body 304 is initially inserted into the sleeve 306 and the rod body 304 pushes the second interlocking portion 310 of the sleeve 306, the portion of the sleeve 306 including the second interlocking portion 310 will deform radially outward. As the end portion 312 of the rod body 304 is further inserted into the sleeve 306 and the first interlocking portion 308 of the rod body 304 engages with the second interlocking portion 310 of the sleeve 306, this portion of the sleeve 306 will move radially inward, and the sleeve 306 will return to its original shape and be anchored to the rod body 304.

[0055] In the illustrated embodiment, the first interlocking portion 308 extends substantially along the entire circumference of the rod body 304 and has an annular / circular shape. The second interlocking portion 310 extends substantially along the entire circumference of the sleeve 306 and has two generally semi-circular sections.

[0056] In the illustrated embodiment, a first interlocking portion 308 is disposed between the end portion 312 and the middle portion 314 of the rod body 304. In some embodiments, the depth of the first interlocking portion 308 (i.e., the depth of the circumferential groove 308) is preferably in the range of 0.5 mm to 5 mm to reduce stress concentration at the interlocking position and allow the rod 302 to withstand greater tensile force. In some embodiments, the sleeve 306 may be further fixed to the rod body 304 by adhesive to strengthen the connection between the sleeve 306 and the rod body 304.

[0057] In the illustrated embodiment, sleeve 306 includes two grooves 316 that extend longitudinally from one end of sleeve 306 and penetrate the wall of sleeve 306. The two grooves 316 are arranged symmetrically with respect to the axis of sleeve 306. It should be understood that in other embodiments, sleeve 306 may also include any other suitable number of grooves 316, such as three or four grooves 316.

[0058] The connecting assembly 300 also includes at least one nut 318. For example... Figure 1 and Figure 2A As shown in the illustrated embodiment, the connecting assembly 300 includes a plurality of nuts 318. Each sleeve 306 is provided with external threads and threadedly connected to the corresponding nut 318. Specifically, two sleeves 306 of each rod 302 are threadedly connected to two nuts 318 for attaching the rod 302 to a pair of electrodes 200 and holding the electrodes 200 and the varistor stack 100 together. Because the sleeves 306 are made of metal, the teeth of the external threads of the sleeves 306 have sufficient strength to allow the rod 302 to withstand large tensile forces and to allow the surge arrester module 10 to be disassembled and reassembled multiple times without damaging the threaded connection, which is particularly convenient for maintaining the varistor stack 100 that needs to be disassembled for maintenance.

[0059] In the illustrated embodiment, the end portion 312 of the rod 302 and the nut 318 threadedly connected to the rod 302 do not extend beyond the second surface 212 of the pair of electrodes 200. This is in the case of two or more surge arrester modules 10 as follows: Figure 8 The series connection shown is particularly advantageous because the adjacent electrodes 200 of adjacent surge arrester modules 10 can contact each other, making the combination of surge arrester modules 10 more compact.

[0060] like Figure 2A As shown, the surge arrester module 10 may further include an electrical contact element 400 for maintaining contact pressure between the varistor blocks 102. The electrical contact element 400 is made of a conductive material (such as steel, aluminum, and copper). In the illustrated embodiment, the electrical contact element 400 is in the form of an elastic element. The electrical contact element 400 is arranged and compressed between the electrode 200 and the varistor stack 100 at the upper end of the surge arrester module 10.

[0061] In the illustrated embodiment, the opposite ends of the electrical contact element 400 abut against the first portion 204 of the electrode 200 and the metal plate 104 disposed at the upper end of the varistor stack 100, respectively. The electrical contact element 400 can press the varistor stack 100 and thus maintain the contact pressure between the varistor blocks 102.

[0062] like Figure 2AAs shown in the illustrated embodiment, the surge arrester module 10 may further include a limiting sleeve 402. The electrical contact element 400 is disposed and confined within the limiting sleeve 402, thereby preventing displacement of the electrical contact element 400 and ensuring stable electrical contact.

[0063] Figures 3A to 4B A surge arrester module 10 and its components according to a second embodiment of the present disclosure, as well as a portion of the manufacturing process of the surge arrester module 10, are shown. The surge arrester module according to the second embodiment is similar to the surge arrester module according to the first embodiment, the main difference being that the sleeve 306 of the rod 302 of the surge arrester module 10 according to the second embodiment is press-fitted to the rod body 304. The differences between the two embodiments will be described below, while their similarities will be omitted.

[0064] like Figure 3A As shown, the surge arrester module 10 according to the second embodiment includes a varistor stack 100, a pair of electrodes 200, and a coupling assembly 300. Each electrode 200 includes at least one receiving hole 202. The coupling assembly 300 includes at least one rod 302. Each rod 302 includes a rod body 304 and at least one sleeve 306. The rod body 304 extends along the longitudinal direction of the surge arrester module 10 and extends into the receiving hole 202 of the electrode 200. The rod body 304 may be made of an insulating material, such as fiber-reinforced epoxy resin, by a pultrusion process. The sleeve 306 may be made of a metal (e.g., aluminum, steel, or any other suitable metal). The rod body 304 includes a first interlock portion 308. The sleeve 306 includes a second interlock portion 310. The second interlock portion 310 is adapted to cooperate with the first interlock portion 308 to prevent relative movement of the rod body 304 and the sleeve 306 in the longitudinal direction of the surge arrester module 10.

[0065] like Figure 3B As shown in the illustrated embodiment, each rod 302 includes a rod body 304 and two sleeves 306. The two sleeves 306 are respectively fitted over the two end portions 312 of the rod body 304 for attaching the rod 302 to a pair of electrodes 200.

[0066] The connecting assembly 300 also includes at least one nut 318. For example... Figure 3A As shown, in the illustrated embodiment, the connecting assembly 300 includes a plurality of nuts 318. Each sleeve 306 is provided with external threads and threadedly connected to the corresponding nut 318. In the illustrated embodiment, the two sleeves 306 of each rod 302 are respectively threadedly connected to the two nuts 318 for attaching the rod 302 to a pair of electrodes 200 and holding the electrodes 200 and the varistor stack 100 together.

[0067] In the illustrated embodiment, the first interlocking portion 308 of the rod body 304 is in the form of a circumferential groove, and the second interlocking portion 310 of the sleeve 306 is in the form of a circumferential protrusion projecting toward the interior of the sleeve 306. In the illustrated embodiment, the first interlocking portion 308 extends substantially along the entire circumference of the rod body 304 and has an annular / circular shape. The second interlocking portion 310 extends substantially along the entire circumference of the sleeve 306 and has an annular / circular shape.

[0068] Each sleeve 306 is circumferentially pressed against the rod body 304, such that the circumferential portion of the sleeve 306 is embedded in the first interlocking part 308 and forms the second interlocking part 310. In this document, "circumferentially pressed" means that the circumferential portion of the sleeve is pressed against the rod body 304 and deforms toward the rod body 304.

[0069] In the illustrated embodiment, each sleeve 306 is fixed to the rod body 304 by being circumferentially pressed into the rod body 304 using a crimping machine. Figure 4A and Figure 4B As shown, the crimping machine may include a plurality of crimping dies 20. The plurality of crimping dies 20 are evenly spaced from each other about the axis of the rod 302. Each crimping die 20 includes an arcuate portion 22 facing the rod 302.

[0070] Before pressing the sleeve 306 to the rod body 304, adjust the pressing die 20 and / or the rod 302 so that the arcuate portion 22 of each pressing die 20 is aligned with the first interlocking portion 308 of the rod body 304. Then, move the pressing die 20 radially toward the sleeve 306 of the rod 302 and press a portion of the sleeve 306 radially into the first interlocking portion 308, and hold the pressing die 20 in a predetermined position for a certain period of time, thereby forming the second interlocking portion 310 of the sleeve 306, which engages with the first interlocking portion 308.

[0071] A portion of the sleeve 306 is circumferentially pressed into the first interlocking portion 308 of the rod body 304, making the connection between the sleeve 306 and the rod body 304 more secure, allowing the rod 302 to have a uniform stress distribution when subjected to tension, and enabling the rod 302 to withstand greater tension.

[0072] In some embodiments, the depth of the first interlocking portion 308 (i.e., the depth of the circumferential groove 308) is preferably in the range of 0.5 mm to 5 mm to reduce stress concentration at the interlocking location and allow the rod 302 to withstand greater tensile force.

[0073] Figures 5 to 7A surge arrester module 10 and its components according to a third embodiment of this disclosure are shown. The surge arrester module according to the third embodiment is similar to the surge arrester module according to the second embodiment, the main difference being the manner in which the rod 302 of the surge arrester module 10 according to the third embodiment is attached to the electrode 200. The differences between the two embodiments will be described below, and their similarities will be omitted.

[0074] like Figure 5 and Figure 6A As shown, the surge arrester module 10 according to the third embodiment includes a varistor stack 100, a pair of electrodes 200, and a coupling assembly 300. The varistor stack 100 includes a plurality of varistor blocks 102 stacked along the longitudinal direction of the surge arrester module 10. The pair of electrodes 200 are configured to clamp the varistor stack 100 therebetween in the longitudinal direction of the surge arrester module 10. Each electrode 200 includes at least one receiving hole 202. The coupling assembly 300 is configured to connect the pair of electrodes 200 and hold the pair of electrodes 200 and the varistor stack 100 together. The coupling assembly 300 includes at least one rod 302. Each rod 302 includes a rod body 304 and at least one sleeve 306. The rod body 304 extends along the longitudinal direction of the surge arrester module 10 and extends into the receiving hole 202 of the electrode 200. The rod body 304 is made of an insulating material and includes a first interlocking portion 308. At least one sleeve 306 is fitted over the rod body 304 for attaching the rod 302 to the electrode 200. The sleeve 306 is made of metal and includes a second interlock 310. The second interlock 310 is adapted to cooperate with a first interlock 308 to prevent relative movement between the rod body 304 and the sleeve 306 in the longitudinal direction of the surge arrester module 10.

[0075] like Figure 5 and Figure 6A As shown, the varistor stack 100 may include a plurality of generally cylindrical varistor blocks 102. The varistor stack 100 may also include one or more circular metal plates 104 made of conductive material to compensate for gaps between the varistor blocks 102 and mechanically reinforce the surge arrester module 10. Figure 6A As shown, three metal plates 104 are respectively disposed at opposite ends of the varistor stack 100, wherein two metal plates are located at the upper end of the varistor stack 100 and one metal plate is located at the lower end of the varistor stack 100.

[0076] like Figure 6A and Figure 7As shown, each electrode 200 may be generally cylindrical. Each electrode 200 includes a first surface 210 and a second surface 212 opposite in the longitudinal direction of the surge arrester module 10, the first surface 210 facing the varistor stack 100. In the illustrated embodiment, the first surface 210 and the second surface 212 are planar and extend perpendicular to the longitudinal direction of the surge arrester module 10.

[0077] In the illustrated embodiment, each electrode 200 includes a plurality of receiving holes 202 for receiving rods 302. Each electrode 200 may also include a plurality of fastening holes 208, wherein one fastening hole 208a is used to fasten a surge arrester module 10 to an adjacent surge arrester module 10, and other fastening holes 208b are used to fasten a shield to a surge arrester module 10, such as... Figure 5 and Figure 8 As shown. In the illustrated embodiment, each receiving hole 202 is in the form of a through hole and extends from the first surface 210 to the second surface 212. It should be understood that in other embodiments, the receiving hole 202 may also be in the form of a blind hole.

[0078] like Figure 5 As shown, the connection assembly 300 includes a plurality of rods 302, which are evenly spaced from each other around the periphery of the varistor stack 100. In the illustrated embodiment, as... Figure 6B As shown, each rod 302 includes a rod body 304 and two sleeves 306. The rod body 304 includes two opposite end portions 312 and a middle portion 314 extending between the two end portions 312. The two sleeves 306 are respectively fitted over the two end portions 312 of the rod body 304 for attaching the rod 302 to a pair of electrodes 200.

[0079] In the illustrated embodiment, the first interlocking portion 308 of the rod body 304 is in the form of a circumferential groove, and the second interlocking portion 310 of the sleeve 306 is in the form of a circumferential protrusion.

[0080] In the illustrated embodiment, each sleeve 306 may include a tubular body 320 and a shoulder 322 extending radially outward from the tubular body 320. The tubular body 320 of each sleeve 306 is circumferentially pressed against the rod body 304 such that the circumferential portion of the tubular body 320 is embedded in a first interlocking portion 308 to form a second interlocking portion 310.

[0081] like Figure 7 As shown, each receiving hole 202 includes a first receiving portion 214 for receiving a shoulder 322 of a sleeve 306 and a second receiving portion 216 for receiving a tubular body 320 of the sleeve 306. The internal dimensions of the first receiving portion 214 are larger than those of the second receiving portion 216.

[0082] In the illustrated embodiment, each receiving hole 202 includes an abutment surface 218. The abutment surface 218 is configured to abut against a shoulder 322 (e.g., the bottom surface of the shoulder 322) to prevent relative movement of the sleeve 306 and the electrode 200 in the longitudinal direction of the surge arrester module 10. The abutment surface 218 may be in the form of a stepped surface formed between the first receiving portion 214 and the second receiving portion 216.

[0083] In the illustrated embodiment, each receiving hole 202 is radially outwardly open, allowing the rod 302 to be radially inserted into the receiving hole 202. Each receiving hole 202 also includes a limiting surface 220 configured to abut against a shoulder 322 of the sleeve 306 (e.g., the outer peripheral surface of the shoulder 322) to prevent the sleeve 306 and the rod 302 from sliding away from the electrode 200 in the radial direction of the surge arrester module 10. This is particularly advantageous in cases where thermal expansion of the varistor stack 100 occurs, for example, during a short-circuit test.

[0084] like Figure 6A As shown, the surge arrester module 10 may further include an electrical contact element 400 for maintaining contact pressure between the varistor blocks 102. In the illustrated embodiment, the electrical contact element 400 is in the form of a screw, such as a set screw. In the illustrated embodiment, the fastening hole 208a is in the form of a threaded hole. The electrical contact element 400 is provided with external threads and is threadedly connected to the threaded hole 208a, wherein one end of the electrical contact element 400 abuts against the metal plate 104 on top of the varistor stack 100. The electrical contact element 400 may be displaced relative to the electrode 200 in the longitudinal direction of the surge arrester module 10 to press the metal plate 104 thereby maintaining contact pressure between the varistor blocks 102. The threaded hole 208a may be located in the center of the electrode 200, so that the varistor blocks 102 are pressed evenly.

[0085] The following will refer to Figures 5 to 7 An exemplary assembly process for the surge arrester module 10 of the third embodiment is described.

[0086] First, the varistor stack 100 can be clamped between a pair of electrodes 200. The pair of electrodes 200 can then be adjusted so that the receiving hole 202 of one electrode 200 aligns with the receiving hole 202 of the other electrode 200. Next, rods 302 can be arranged around the varistor stack 100 such that the opposite ends of each rod 302 are inserted into the corresponding receiving holes 202 of the pair of electrodes 200. Then, the electrical contact element 400 can be moved toward the varistor stack 100, gradually increasing the distance between the pair of electrodes 200. Finally, the shoulder 322 and tubular body 320 of each sleeve 306 are received in the first receiving portion 214 and the second receiving portion 216 of the corresponding receiving hole 202, respectively, with the bottom surface of the shoulder 322 abutting the abutment surface 218 of the receiving hole 202. Each rod 302 is then tensioned to hold the electrodes 200 and the varistor stack 100 together.

[0087] Compared to surge arrester modules where the rod is attached to the electrode via multiple nuts, the surge arrester module 10 of the third embodiment is easier to assemble due to fewer threaded connections, and the varistor stack 100 can be compressed more evenly.

[0088] Figure 8 A surge arrester 1 according to the present disclosure is shown. The surge arrester 1 may include at least one surge arrester module 10 and a housing 12 housing the at least one surge arrester module 10. The housing 12 may be made of polymer, ceramic, or metal. The surge arrester 1 may be applied to gas-insulated switchgear or other electrical equipment.

[0089] When surge arrester 1 is used in gas-insulated switchgear, and the operating voltage in the switchgear is too high for a single surge arrester module to withstand, surge arrester 1 may include two or more surge arrester modules 10 connected in series.

[0090] Reference Figure 6A and Figure 8 In the illustrated embodiment, the surge arrester 1 includes two surge arrester modules 10 connected in series, wherein the upper surge arrester module 10 is provided with a shield 14. In the illustrated embodiment, the second surface 212 of each electrode 200 is planar and the end of each rod 302 is fully received in the receiving hole 202 of the electrode 200, such that the second surfaces 212 of adjacent electrodes 200 of two adjacent surge arrester modules 10 connected in series are in contact with each other, thereby making the combination of surge arrester modules 10 more compact.

[0091] The foregoing discloses the technical content and features of this disclosure. However, it is conceivable that those skilled in the art can make various changes and improvements to the concepts disclosed above, based on the inventive ideas of this disclosure, but all such changes and improvements fall within the protection scope of this disclosure. The description of the above embodiments is exemplary and not restrictive, and the protection scope of this disclosure is defined by the appended claims.

[0092] The description and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The description and illustrations are not intended to be an exhaustive and comprehensive description of all elements and features of devices and systems using the structures or methods described herein. Some features described herein in the context of separate embodiments for clarity may also be provided in combination in a single embodiment. Conversely, various features described in the context of a single embodiment for brevity may also be provided individually or in sub-combinations. Furthermore, references to values ​​expressed as ranges include every value within that range. Many other embodiments will only become apparent to those skilled in the art after reading this specification. Other embodiments may be used and other embodiments may be derived from this disclosure, such that structural substitutions, logical substitutions, or other changes can be made without departing from the scope of this disclosure. Therefore, this disclosure should be considered illustrative rather than restrictive.

[0093] The description provided in conjunction with the accompanying drawings is intended to aid in understanding and describing the teachings disclosed herein, and should not be construed as limiting the scope or applicability of the teachings. However, other teachings may certainly be used in this application.

[0094] As used herein, the terms “comprising,” “including,” “containing,” “having,” “possessing,” or any other variation thereof are intended to cover non-exclusive inclusion. For example, a method, article, or apparatus that includes a list of features is not necessarily limited to those features, but may include other features not expressly listed or inherent to the aforementioned method, article, or apparatus. Furthermore, unless expressly stated to the contrary, “or” means inclusive or, not exclusive, or. For example, condition A or B is satisfied by any one of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); and both A and B are true (or exist).

[0095] Furthermore, the terms "a" or "an" are used to describe the elements and components described herein. This is merely for convenience and to give a general meaning to the scope of this disclosure. The description should be understood to include one or at least one, and the singular form of an element or component includes the plural form, or vice versa, unless otherwise stated. For example, when describing a single article, more than one article may be used instead of "single article." Similarly, in the case of describing more than one article, a single article may be used instead of "more than one article."

[0096] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Materials, methods, and examples are illustrative rather than limiting. Where certain details regarding particular materials and processing methods are not described, such details may include conventional methods, which can be found in reference books and other sources within the field of manufacturing.

[0097] While various aspects of this disclosure have been specifically shown and described with reference to the foregoing embodiments, those skilled in the art will understand that various other embodiments can be contemplated by modifying the disclosed machines, systems, and methods without departing from the spirit and scope of the disclosure. It should be understood that such embodiments fall within the scope of this disclosure as defined by the claims and any equivalents.

Claims

1. A surge arrester module (10), comprising: A varistor stack (100) comprising a plurality of varistor blocks (102) stacked along the longitudinal direction of the surge arrester module (10); A pair of electrodes (200) configured to sandwich the varistor stack (100) therebetween in the longitudinal direction, each electrode (200) including at least one receiving hole (202); as well as A coupling assembly (300) configured to couple the pair of electrodes (200) and hold the pair of electrodes (200) and the varistor stack (100) together, the coupling assembly (300) including at least one rod (302), each rod (302) including: A rod body (304) extends along the longitudinal direction and into the receiving hole (202) of the pair of electrodes (200). The rod body (304) is made of insulating material and includes a first interlocking portion (308) in the form of a circumferential groove, wherein the circumferential groove is located in a plane having a normal vector parallel to the longitudinal direction. At least one sleeve (306) is fitted over the rod body (304) for attaching the rod (302) to the electrode (200). The sleeve (306) is made of metal and includes a second interlocking portion (310) which is circumferentially protruding and adapted to engage with a first interlocking portion (308) to prevent relative movement of the rod body (304) and the sleeve (306) in the longitudinal direction. The connecting assembly (300) further includes at least one nut (318), and the sleeve (306) is threadedly connected to the nut (318).

2. The surge arrester module (10) according to claim 1, wherein, The sleeve (306) is circumferentially pressed against the rod body (304), and the circumferential portion of the sleeve (306) is deformed due to the pressing to form the second interlocking part (310).

3. The surge arrester module (10) according to claim 1, wherein, The sleeve (306) includes at least one groove (316) configured to allow at least a portion of the sleeve (306), including the second interlock (310), to elastically deform in order to engage with the first interlock (308).

4. The surge arrester module (10) according to any one of claims 1 to 3, wherein, The surge arrester module (10) also includes an electrical contact element (400) for maintaining the contact pressure between the varistor blocks (102).

5. The surge arrester module (10) according to claim 4, wherein, The electrical contact element (400) is in the form of an elastic element and is disposed between the electrode (200) and the varistor stack (100).

6. The surge arrester module (10) according to claim 4, wherein, The electrical contact element (400) is in the form of a screw and is threaded to a threaded hole in the electrode (200), wherein one end of the electrical contact element (400) abuts against the varistor stack (100).

7. The surge arrester module (10) according to any one of claims 1 to 3, wherein, The connection assembly (300) includes a plurality of rods (302) arranged around the varistor stack (100).

8. A surge arrester (1), comprising: At least one surge arrester module (10) according to any one of claims 1 to 7; as well as A housing (12) that accommodates at least one surge arrester module (10).

Images