Enhanced composite wrapped surge arresters and methods of providing such surge arresters

Abstract

A solid dielectric surge arrester includes a module assembly of a hermetically sealed composite material package. The module assembly includes at least one metal oxide varistor (MOV) block having a peripheral surface, and a material applied to the peripheral surface. The material includes a plurality of layers to allow the module assembly to withstand bending moments under long-term cyclic loads and short-term rated bending loads, the material configured to improve bending strength and provide safe short circuit failure mode discharge in a preferred direction or directions.

Description

Background Art

[0001] Lightning or surge arresters are typically connected to power lines to conduct surge current to ground. In this way, damage to lines and equipment connected close to the arrester can be reduced and / or prevented. During normal system voltage on the power line, the arrester has a very high resistance and functions as an insulator. When a system disturbance occurs, such as when a direct lightning surge and / or indirect lightning surge, switching surge or voltage rise occurs, the arrester reaches a threshold voltage, at which the resistance becomes very small and the surge current is conducted to ground through the arrester, thereby clamping and limiting the voltage rise on the system. Examples of common system disturbances include lightning strikes, switching surge currents and temporary overvoltages, which can occur in a variety of fault conditions ranging from system insulation failure to tree branches causing high impedance grounding. Surge arresters are typically used to protect system components from dangerous transient overvoltage conditions.

[0002] Under normal operating conditions, power transmission and distribution equipment is subject to voltages within a narrow and controlled range. However, system disturbances—such as lightning strikes, switching surges, and system faults—can cause transient or prolonged overvoltage conditions that significantly exceed the voltage levels experienced by the equipment during normal operating conditions. These voltage variations are often referred to as overvoltage conditions.

[0003] Without protection from overvoltage conditions, critical and expensive equipment such as transformers, switchgear, computer equipment, and motors may be damaged or destroyed by overvoltage conditions or associated current surges. Surge arresters may be used to protect system components from dangerous overvoltage conditions.

[0004] After a surge occurs, the voltage drops and the arrester typically returns to a high resistance state. However, when the arrester is overloaded or fails, the high resistance state may not be restored and the arrester may continue to provide an electrical path from the power line to ground. Eventually, the arrester will fail due to the current evolving into a short circuit state due to heating of the metal oxide varistor element, and the arrester will need to be replaced. In order to improve system reliability, conventional surge arresters need to be replaced. Summary of the invention

[0005] Embodiments herein relate to a surge arrester including a module assembly including at least one metal oxide varistor (MOV) block including a top surface, a bottom surface opposite to the top surface, and a peripheral surface between the top surface and the bottom surface. A first fabric material is formed on the peripheral surface, and the first fabric material includes a fabric including a plurality of unidirectional glass fibers, the plurality of unidirectional glass fibers being arranged substantially parallel to each other and extending from the bottom surface to the top surface.

[0006] Embodiments include a second fabric material formed on a portion of the first material. The second fabric material is configured to partially wrap the first fabric material to define an axially extending gap in the second fabric material. Some embodiments provide that the second fabric material includes a multi-directional fabric. In some embodiments, loop and / or off-axis fibers may be included. In some embodiments, a non-limiting example of a second fabric includes an 18 oz / sq. yd fabric that is a 0 / 90 woven and has a heavier tow, such as, for example, 4×5 tows per inch. In some embodiments, the fabric can be a + / - 45 woven and / or can be a stitched and / or layered material.

[0007] Embodiments herein relate to methods for providing surge arresters. This method includes an operation of providing a stack array, the stack array including at least one MOV and at least one metal block, the at least one MOV and the at least one metal block being arranged adjacent to each other to form a peripheral surface between a stack top surface and a stack bottom surface. The operation includes compressing the stack array by applying an axial compressive force at the stack top surface and the stack bottom surface, and applying a first fabric material to the peripheral surface of the stack array. In some embodiments, the compressive force is maintained by a resin curing operation. The first fabric material includes a fabric including a plurality of unidirectional glass fibers arranged substantially parallel to each other. The operation includes applying a second fabric material, the second fabric material being formed on a portion of the first fabric material. In some embodiments, the second fabric material is configured to partially wrap the first fabric material to define an end-to-end axially extending gap in the second fabric material. Some embodiments include applying a spiral wrap layer on the second fabric material. In some embodiments, the spiral wrap layer includes a plurality of filament wound hoops. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings, which are included to provide a further understanding of the present disclosure and are incorporated as a part of this application, illustrate certain non-limiting embodiments of the inventive concept. In the drawings:

[0009] Figure 1 Detailed Description of the Invention A schematic block diagram of an electrical system is illustrated, wherein electrical equipment is protected by a surge arrester according to embodiments herein.

[0010] Figure 2 is a block diagram of a surge arrester according to some embodiments.

[0011] FIG. 3A to FIG. 3E is a schematic block diagram illustrating a cut-away cross-sectional view of various embodiments of a surge arrester according to some embodiments.

[0012] Figure 4 is a schematic block diagram illustrating a stacked array in a module assembly according to some embodiments.

[0013] Figure 5 A block diagram illustrating operations for providing a surge arrester according to some embodiments.

[0014] Fig. 6A and Figure 6B Schematic block diagrams of a cut-away side view and a top view, respectively, of a surge arrester according to some embodiments. DETAILED DESCRIPTION

[0015] The inventive concept will be described more fully below with reference to the accompanying drawings, in which examples of the inventive concept are shown. However, the inventive concept can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. Specifically, these embodiments are provided so that: this disclosure will be comprehensive and complete, and the scope of the inventive concept will be fully conveyed to those skilled in the art. It should also be noted that these embodiments are not mutually exclusive. Components from one embodiment may be defaulted to being present / used in another embodiment.

[0016] The following description presents various embodiments of the disclosed subject matter. These embodiments are presented as teaching examples and should not be interpreted as limiting the scope of the disclosed subject matter. For example, some details of the described embodiments may be modified, omitted or expanded without departing from the scope of the described subject matter.

[0017] A solid dielectric arrester suitable for use in substation, transmission and distribution surge arrester applications is described. As discussed below, the material layer provides axial strength to the solid dielectric arrester while also facilitating the discharge of gases and / or plasma that may be generated when the arrester fails or fails. Therefore, the solid dielectric arrester discussed herein can be used in high voltage applications and / or applications that require the arrester to withstand significant mechanical forces. In addition, the material layer can be configured so that: in a failure mode state, the solid dielectric arrester allows gases and / or plasma to be discharged in a specific single or multiple desired directions. These desired specific directions can be considered to be preferred directions.

[0018] Some systems use air core arresters for high voltage and / or high strength applications. An air core arrester may include a housing (e.g., a reinforced plastic tube) that houses the components of the arrester and provides cantilever strength to the arrester. In an air core arrester, the internal components of the arrester (e.g., a stack of metal oxide varistors or a stack of MOVs) are held away from the housing wall so that there is an air space between the internal components and the housing wall. The presence of the air space may allow humid air to enter the arrester, causing moisture to enter the MOV block and other internal components, thereby increasing the likelihood of performance degradation and arrester failure.

[0019] In contrast, a solid dielectric arrester may not employ a housing that is separate from the internal components of the arrester. Instead, the internal components of the solid dielectric arrester may be structurally held in place at least in part by a composite material, wherein the composite material is bonded to the outer peripheral surface of the MOV block to form an interface substantially free of air between the outer peripheral surface of the MOV block and the composite material and between the weatherproof polymer housing of the arrester and the composite material. Compared to a hollow core arrester, a solid dielectric arrester may be easier to produce and may be more reliable due to the absence of an air space and a separate housing. However, due to the absence of a separate tube housing with a larger diameter, the cantilever strength of a solid dielectric arrester may be lower than that of a hollow core arrester because the stress of the bending moment increases proportionally with respect to the decrease in the distance from the center of the composite structure. In addition, as MOV technology improves, the MOV block core diameter may decrease, resulting in a further increase in mechanical stress on the composite material, which may result in the need for construction methods and materials that improve the strength of the composite material as discussed herein.

[0020] Some embodiments disclosed herein can achieve high strength solid dielectric arrester constructions. However, the introduction of international product standards requiring the withstanding of cyclic loads may render some of these designs incompatible and / or significantly reduce the rated bending moment. Compared to the prior art, some embodiments disclosed herein can enable the withstanding of cyclic load missions and provide further improvements in bending strength.

[0021] In a solid dielectric discharger, an array of metal oxide varistors (MOV blocks) and conductive spacers and conductive end terminals can be held together under the action of a compressive preload to provide electrical contact and mechanical strength between the components. In use, being subjected to a high bending moment may cause the component stack to lift on the tensile side, thereby causing edge-to-edge contact on the compression side. Some industry standards now specify a rated long-term cyclic load capacity (SLL) and a higher rated short-term static load capacity (SSL). Some embodiments provide that when alternating compressive loads occur during a cycle SL, mechanical fractures associated with material fatigue of components and / or composite layers may occur, potentially leading to failure. In addition, the quality of the electrical contact between the various internal components may be reduced due to the lifting effect, and internal partial discharges and / or poor current distribution may occur during a fault state. Both of these situations may lead to permanent damage and / or failure of the discharger. Therefore, conventional solid dielectric dischargers may not be optimally suited for high voltage applications and / or applications that subject solid dielectric dischargers to high mechanical forces.

[0022] The cantilever strength of the solid dielectric arrester can be improved by continuously providing a high axial compressive preload on the stack of MOVs and spacers during the manufacturing process of curing the composite material. The compressed stack (the stack of MOVs, conductive spacers and terminals with the coated composite layer) is wrapped circumferentially with a compression fabric layer, thereby achieving improved densification of the composite layer (fibers and resin) during the curing of the composite material. The use of a unique spiral circumferentially wrapped fabric compression material increases both the compression of the composite fiber and the pre-tensioning of the composite fiber. In addition, the bending stiffness can be further improved by using a higher modulus composite glass fiber such as discussed herein. In some embodiments, the composite material is made of a fiber-reinforced resin matrix material. The material layer can be configured to provide sufficient axial strength to allow the arrester to withstand harsh conditions while also allowing the arrester to exhaust gas and / or plasma when it fails or fails, resulting in a physically complete structure. The short-circuit current rating can be further increased by applying a wire wound ring on the surface of the composite material. For example, the arrangement of multiple axial unidirectional layers applied to the surface of MOVs and component stacks can provide high axial strength in the base layer region while not providing significant hoop strength. These layers can easily separate as the temperature rises during an end-of-life event, resulting in decomposition of the resin matrix and the creation of fiber-to-fiber openings to serve as drainage areas. The arrangement of the fibers disposed on the unidirectional layers and closer to the surface is multi-directional, each multi-directional layer provides significant resistance to arc pressure release and is therefore applied in a less than full circumferential wrap to form a small gap along each axial butt joint, the start and end of each multi-directional layer are staggered to form a bonded layer-to-layer lap joint to provide sufficient hoop strength during bending stresses while still maintaining relatively weak resin-rich layer-to-layer bonds to facilitate the formation of relatively weak adhesive bond discharge points in these specific areas during end-of-life failure modes, thereby making the solid dielectric arrester suitable for substation, transmission and distribution surge arrester applications that require the solid dielectric arrester to withstand high mechanical forces (e.g., 500 pounds to 1000 pounds of constant or nearly constant terminal load capacity, or greater and lesser cyclic loads). These applications may require solid dielectric arresters that are longer than about 12 feet, and / or these applications subject the solid dielectric arrester to bending moments of up to about 100,000 inch-pounds or more. Relative to many solid dielectric products, for a given MOV diameter, strength can be expected to increase by at least 50%.

[0023] As discussed in more detail below, the material layer may include multiple material layers that include fibers that are arranged such that when the material is applied to the MOV, a majority of the fibers are aligned with the axial direction of the MOV. Considering that the MOV and spacer cores are compressively preloaded as ridged cores, this arrangement of unidirectional fibers allows the material layer to be placed on the surface of the MOV, thereby providing cantilever strength while also allowing gas and / or plasma to be vented from the surge arrester. In contrast, applying multiple existing composite material layers, which include approximately equal amounts of fibers in multiple directions, may result in reduced (or no) gas venting. For example, overlapping material layers including fibers in multiple directions may result in fibers of one layer blocking fiber-free or relatively fiber-free areas of the layer below. Insufficient venting may cause the arrester to explode or rupture, causing the MOV and other components within the arrester to be ejected and causing damage to nearby equipment.

[0024] By using a permanently applied compression layer fabric, significant improvements have been made to strength. These fabrics are applied under high tension of at least 100 pounds per inch to 500 pounds per inch, thereby producing radial compression and promoting the improvement of composite material consolidation. These compression fabric layers can be placed in the middle layer of the composite structure, and can also be placed on the surface of the composite structure and incorporated into an excess of available resin matrix material, which becomes available due to the applied compressive load when the composite material is consolidated. By using chemical etching or laser etching to surface treat the conductive metal end electrodes to remove oxides and residual oil and other contaminants from the surface layer, further improvement of cyclic load strength can be achieved. The film or shrink film material provided in some embodiments can only withstand 10 pounds per inch to 20 pounds per inch, and also inhibits resin from flowing out of the composite layer, thereby providing a lower level of composite filling and much lower relative strength and significantly reduced cyclic fatigue strength.

[0025] In some implementations, the discharge area is formed in the material layer so that the solid dielectric discharger can discharge gas in a direction that is predictable. The specific predictable direction can be one or more desired directions and / or one or more specific directions. Directed discharge, for example, allows the discharged gas to be limited to a specific direction (multiple specific directions) or a desired direction (multiple desired directions), so that the discharged gas is guided away from adjacent or nearby equipment and / or adjacent phases, thereby reducing and / or eliminating collateral damage caused by the failure or failure of the solid dielectric discharger. Some prior art attempts to achieve directional discharge rely on breaking through a continuous cigarette-like wrapping layer that is thinner in a single direction along the top to bottom direction. However, breaking through glass reinforcements requires much greater plasma gas pressure, resulting in a much higher level of demonstration. By using the epoxy lap joints of the layers as weak breakthrough areas and discharge locations, the required pressure accumulation is much lower. In addition, by additionally utilizing the arc angles arranged along the predicted failure axis, the level of demonstration is significantly reduced (the size of the plasma cloud). A vent area is an area in the material layer that is modified so that gases generated when the surge arrester fails or malfunctions escape through the vent area.

[0026] In one general aspect, a solid dielectric surge arrester may include a module assembly. The module assembly includes at least one metal oxide varistor (MOV) block having an outer peripheral surface. The solid dielectric surge arrester also includes a composite reinforcement material applied to the outer peripheral surface, the composite reinforcement material including multiple layers to allow the module assembly to withstand bending moments under substantially continuously applied loads, and the material is configured to allow gases formed in the module assembly to be discharged when the module assembly fails. In another aspect, a solid dielectric surge arrester includes a module assembly. The module assembly includes at least one metal oxide varistor (MOV) block having an outer peripheral surface, and a material applied to the outer peripheral surface. The material includes multiple layers to allow the module assembly to withstand bending moments under cyclic loads, and the material is configured to allow gases formed in the module assembly to be discharged in a desired direction and / or in multiple desired directions.

[0027] Some embodiments may include one or more of the following elements. Some embodiments include exhaust regions along one or more axial directions of the module assembly. The exhaust region can allow gas to be exhausted unidirectionally and / or multidirectionally, and the exhaust region can be defined by a boundary or multiple boundaries formed by a layer-by-layer maze structure in the composite material, wherein at the boundary or these boundaries there is a resin-only path through the composite layered structure. The boundary or multiple boundaries in the material can have a length equal to or greater than the axial length of the MOV block. Gas can be exhausted radially outward through the boundary and perpendicular to the module assembly. A second fabric material can be applied to the outer surface of the material in the form of multiple bands, and the multiple bands are configured to constrain the composite layers and allow gas to be exhausted at the same time.

[0028] Composite materials including multiple layers can allow module assemblies to withstand bending moments greater than 20,000 inch-pounds per inch of MOV radius. As the number of unidirectional layers and possibly multiple layers of compressive material increases, the bending moments continue to increase in a manner substantially proportional to the increase in total unidirectional material thickness.

[0029] In some aspects, a solid dielectric surge arrester includes a module assembly including at least one metal oxide varistor (MOV) block having an outer peripheral surface, and a plurality of bidirectional or multidirectional material layers with staggered butt joint locations applied to the outer peripheral surface. In some embodiments, the material layers include layer-to-layer epoxy lap joints configured to allow venting of gases formed upon failure in the module assembly.

[0030] In another aspect, resin impregnated composite tows and / or tapes may be added to the surface of the composite material layer to form spaced loops that are used to hold the drainage layer in place during failure mode drainage due to a short circuit failure event.

[0031] Some embodiments may include one or more of the following features. The material layers may include a first fabric material applied to the outer peripheral surface of the at least one MOV, and a second fabric material applied to the first fabric material, the second fabric material wrapped into layers with staggered butt joints and surrounding the first fabric material. Depending on the material build thickness, single or multiple compression materials may be applied on all composite fabric layers or optionally also in intermediate layer locations.

[0032] In some embodiments, a method of assembling a solid dielectric surge arrester includes applying a material to a circumferential surface of a metal oxide varistor (MOV) block, the material configured to allow the surge arrester to withstand a bending moment under a nearly continuously applied load, and using the material to form a material layer surrounding the MOV block.

[0033] Composite enclosures provide adequate dielectric strength and insulation when used in dry indoor environments. However, to withstand outdoor environments subject to rain and pollution, it would be beneficial to provide another dielectric enclosure of silicone rubber or other insulating rubber. Although the enclosure may be an interference fit or a gap fit with an intermediate gap filler material, it may be desirable to apply a layer of silane-based primer and then directly mold and bond the high temperature vulcanized silicone rubber housing.

[0034] Now refer to Figure 1 , Figure 1 1 is a schematic block diagram of an electrical system, wherein electrical equipment is protected by a surge arrester according to embodiments herein. Figure 1 , the electrical system 100 includes an electrical device 105 protected by a surge arrester 110. In embodiments where the electrical device may be exposed to very high energy associated with switching events on the electrical device 105, the surge arrester 110 may be a station-level surge arrester capable of protecting the electrical device 105. In use and operation, the surge arrester 110 safely shunts or diverts overvoltage-induced current surges around the electrical device 105 to ground, and thereby protects the device 105 and its internal circuits from damage. The surge arrester 110 includes a protection module (module assembly) 115 that directs current to or away from the electrical device 105 based on the voltage to which the module assembly 115 is exposed. In other words, during an overvoltage period, the module assembly 115 causes current to flow through the surge arrester 110. The surge arrester 110 is connected in parallel with the electrical device 105. Furthermore, in implementations where the energy becomes excessive, the station level surge arresters are capable of withstanding a fault current of 80 kA for 12 cycles.

[0035] The module assembly 115 may include a stack (e.g., a stacked array) of one or more voltage-dependent nonlinear resistance elements, which are referred to as varistors. An example of a varistor is a metal oxide varistor (MOV) block. A varistor is characterized by having a relatively high resistance when exposed to a normal operating voltage and a much lower resistance when exposed to a larger voltage, such as associated with an overvoltage condition. The module assembly 115 may also include one or more conductive spacer elements coaxially aligned with the varistors as part of the stacked array.

[0036] Due to the varistor, the module assembly 115 can operate in a low impedance mode when exposed to an overvoltage condition, the low impedance mode providing an electrical ground current path with a relatively low impedance. Otherwise, the module assembly 115 operates in a high impedance mode, the high impedance mode providing a ground current path with a relatively high impedance. When the surge arrester 110 operates in the low impedance mode, the impedance of the ground current path is significantly lower than the impedance of the device 105 protected by the surge arrester 110. Therefore, the current flows through the current path to ground. Otherwise, the impedance is significantly higher than the impedance of the protected device 105, so that the current flows through the electrical device 105. After the overvoltage condition ends, the surge arrester 110 returns to operating in a high impedance mode, in which the impedance of the module assembly 115 is relatively high. This prevents normal current at the system frequency from following the surge current to ground along the current path through the surge arrester 110.

[0037] In some implementations, the electrical device 105 may be a transformer that converts a voltage on an input terminal of the transformer to a corresponding voltage on an output terminal of the transformer. For example, the transformer may be included in a substation that also includes the surge arrester 110 .

[0038] In such applications, the outside of the module assembly 115 may include one or more relatively thin pre-impregnated composite material layers. The pre-impregnated composite material layers provide the dielectric module assembly 115 with sufficient mechanical strength to withstand typical failure current events of a station level surge arrester while reducing the amount of material used in the station level surge arrester 110, the overall diameter of the module assembly 115, and the size of the surge arrester 110.

[0039] Now refer to Figure 2 , Figure 2 for Figure 1 Block diagram of a surge arrester. Figure 2 The surge arrester 110 includes a housing 205 in which the module assembly 115 is located. The housing 205 can protect the surge arrester 110 from environmental conditions and can be made of an electrically insulating polymer material. An insulating compound and / or a dielectric compound, such as room temperature vulcanized silicone rubber, can fill any gaps between the module assembly 115 and the inner surface of the housing 205.

[0040] In some embodiments, the housing assembly is pre-molded and the module is coated with room temperature vulcanized silicone rubber (RTV). The housing can be expanded and telescoped onto the module. In some embodiments, a silane surface treatment is applied to the module assembly 115, and then a high temperature vulcanized (HTV) silicone rubber 205 can be molded directly and bonded to the module 115. This method can also be performed using liquid silicone rubber molding (LSR).

[0041] Contact 210a is disposed in an upper terminal near the top of surge arrester 110. Similarly, contact 210b is disposed in a lower terminal near the bottom of surge arrester 110. The upper and lower terminals are connected to module assembly 115 and extend out of housing 205 to provide a series electrical path through surge arrester 110 from contact 210a to contact 210b.

[0042] In some embodiments, the arrester module may include a molded "log" of arrester modules. A log according to such an embodiment may include 1 to 10 arrester modules, depending on the module size. After molding, the silicone rubber and f / g composite are cut at each module-to-module interface and separated into individual modules. Therefore, the molded silicone rubber only encloses the same circumferential surface as the f / g composite. We then use RTV silicone rubber to bond a metal cap, such as a stainless steel cap, to each end. The terminal post can be screwed into the module end electrode on each end and retain the metal cap to form a bonded seal. In some embodiments, RTV can be a gap filler to eliminate entrapped air and bond the surfaces together.

[0043] The surge arrester 110 is connected to the line potential conductor at the contact portion 210a and is grounded at the contact portion 210b. The surge arrester 110 is also connected to the electrical device protected by the surge arrester at the contact portion 210a. More specifically, one end of the surge arrester 110 and one end of the electrical device 105, both connected to the line potential conductor, are connected at the contact portion 210a. The housing 205 is sealed around the upper and lower ends of the module assembly 115.

[0044] The module assembly 115 may include one or more MOV blocks and / or conductive blocks housed in a pre-impregnated composite structure. The pre-impregnated composite may include a matrix made of fiberglass bundles, and the spaces between the fiberglass bundles are filled with epoxy resin. The pre-impregnated composite may be applied multiple times around the MOV block. In some embodiments, a scrim layer may be applied over the pre-impregnated composite. The scrim layer may include epoxy resin and a polyester mat that provides a frame for the epoxy resin. The scrim layer provides additional resin to ensure that the module assembly 115 is an air-free solid dielectric module.

[0045] Some embodiments provide that the module assembly 115 includes a top surface 316 and a bottom surface 317 opposite the top surface 316. Some embodiments provide that the plurality of blocks in the stacked array define a peripheral surface 318 between the top surface 316 and the bottom surface 317.

[0046] Now refer to FIG. 3A to FIG. 3E , FIG. 3A to FIG. 3Eis a schematic block diagram illustrating a cut-away cross-sectional view of various embodiments of a surge arrester component according to some embodiments. Figure 3A , the surge arrester 110 may include a module assembly 115, the module assembly 115 includes at least one metal oxide varistor (MOV) block, the at least one metal oxide varistor block including a top surface 316, a bottom surface 17 opposite the top surface 316, and an outer peripheral surface 318 located between the top surface 316 and the bottom surface 317. In some embodiments, the geometry of the MOV block 305 may be a generally cylindrical disk, a polygonal and / or a linear block.

[0047] Some embodiments provide that a first fabric material 310 is formed on the peripheral surface 318, and the first fabric material 310 includes a fabric that includes a plurality of unidirectional glass fibers that are arranged substantially parallel to each other and extend from the bottom surface 317 to the top surface 316. In some embodiments, after applying the first fabric, multiple layers of compression tape may be applied. For example, in some embodiments, 6 to 8 layers of compression tape may be applied. In some embodiments, basalt fibers may be a structural dielectric insulator material that may be used independently and / or in combination with other fibers and / or other fiber types.

[0048] Some embodiments provide that a second fabric material 315 is formed on a portion of the first fabric material 310. In some embodiments, the second fabric material 315 is configured to partially wrap the first fabric material 310 to define an axially extending gap 325 in the second fabric material 315. Some embodiments provide that the fabric material layer can include various types of fabrics, including woven, stitched, thermoformed, chopped fiber, continuous fiber and / or paper, natural and synthetic, etc.

[0049] Some embodiments include a spiral wrap 320 on the second fabric material 315. In some embodiments, the spiral wrap 320 includes a plurality of filament wound loops.

[0050] Some embodiments include a third fabric material 335 formed on a portion of the second fabric material 315. In some embodiments, the third fabric material 335 is configured to partially wrap the second fabric material 315 to define an axially extending gap in the third fabric material 335. In some embodiments, the third fabric material 335 is located between the second fabric material 315 and the spiral wrap layer 320. Figure 3B , some embodiments do not include the third fabric material 335 .

[0051] In some embodiments, the axially extending gaps 325 in the second fabric material 315 and the axially extending gaps 326 in the third fabric material 335 contain resin. Figure 3C Some embodiments provide that the axially extending gaps 325 in the second fabric material 315 are aligned with the axially extending gaps 326 in the third fabric material 335 .

[0052] Reference Figure 3A , the axially extending gaps 325 in the second fabric material 315 are located at a first radial position, and the axially extending gaps 330 in the third fabric material are located at a second radial position different from the first radial position.

[0053] Reference Figure 3A Some embodiments provide that the axially extending gap 325 in the second fabric material 315 is located at a first radial position, and the axially extending gap 330 in the third fabric material 335 is located at the same radial position as the first radial position. Some embodiments provide that there can be a layer to layer overlap of about 1 / 2 inch or more in order to withstand cyclic loading.

[0054] In some embodiments, the second fabric material 315 and the third fabric material 335 are configured to define a plurality of axially extending gaps in the second fabric material 315 and the third fabric material 335. Some embodiments provide that some of the extending gaps are radially staggered relative to each other.

[0055] Reference Figure 3D , some embodiments provide that the axially extending gap 325 at the first radial position in the second fabric material 315 and the axially extending gap 326 in the third fabric material 335 partially overlap each other. In some embodiments, the axially extending gap 325 at the first radial position in the second fabric material 315 and the axially extending gap 326 in the third fabric material 335 partially overlap each other by about 1 / 4 inch to about 3 / 4 inch. In some embodiments, the gaps 325 and 326 can be separated by at least 1 / 2 inch of fabric and fabric resin bonding between the two gaps.

[0056] In some embodiments, the axially extending gap 325 in the second fabric material at the first radial position is covered by the multi-directional tape from about 3 / 4 inch to about 2 inches. Some embodiments provide that the second layer and the third layer each include a fabric including a resin matrix material reinforced with multi-directionally arranged fibers.

[0057] In some embodiments, the at least one MOV block is a component in a stack comprising a plurality of MOV blocks. In some embodiments, the at least one MOV block is a component in a stack comprising metal blocks.

[0058] Some embodiments include a compression layer formed on the second fabric material 315 and / or the third fabric material 335. In some embodiments, the compression layer includes a compression tape.

[0059] Reference Figure 3E , some embodiments provide that the axially extending gap 325 in the second fabric material 315 at the first radial position and the axially extending gap 326 in the third fabric material 335 are spaced apart from each other. In some embodiments, the axially extending gap 325 in the second fabric material 315 is located at the first radial position, and the axially extending gap 326 in the third fabric material 335 may be located at the second position. In some embodiments, the gaps 325 and 326 may be separated by at least 1 / 2 inch of fabric to fabric resin bond between the two gaps.

[0060] In some embodiments, the axially extending gap 325 at the first radial position in the second fabric material 315 is covered by the multi-directional tape from about 3 / 4 inch to about 2 inches. Some embodiments provide that the second layer and the third layer each include a fabric including a resin matrix material reinforced with multi-directionally arranged fibers.

[0061] In some embodiments, the at least one MOV block is a component in a stack comprising a plurality of MOV blocks. In some embodiments, the at least one MOV block is a component in a stack comprising metal blocks.

[0062] Some embodiments include a compression layer formed on the second fabric material 315 and / or the third fabric material 335. In some embodiments, the compression layer includes a compression tape.

[0063] Now briefly refer to Figure 4 , Figure 4 1 is a schematic block diagram illustrating a stack array in a module assembly 115 according to some embodiments. Some embodiments include one or more MOV blocks 305 and / or one or more conductive blocks 306. In some embodiments, the conductive blocks 306 include metal blocks, such as aluminum blocks.

[0064] Some embodiments provide that the module assembly 115 includes a top surface 316 and a bottom surface 317 opposite the top surface 316. Some embodiments provide that the plurality of blocks in the stacked array define a peripheral surface 318 between the top surface 316 and the bottom surface 317.

[0065] Now refer to Figure 5 , Figure 56 is a block diagram illustrating operations of providing a surge arrester according to some embodiments. The operations include providing (block 602) a stack array including at least one MOV and at least one metal block arranged adjacent to each other. In some embodiments, the stack array may form a peripheral surface disposed between a stack top surface and a stack bottom surface. The operations include compressing (block 604) the stack array by applying an axial compressive force at the stack top surface and the stack bottom surface, and applying (block 606) a first fabric material to the peripheral surface of the stack array, the first fabric material including a fabric including a plurality of unidirectional glass fibers that are arranged substantially parallel to each other and axially oriented on the module assembly 115. Some embodiments provide that the first fabric may not be included.

[0066] The operations also include applying (block 608) a second fabric material formed over a portion of the first material. Some embodiments provide that the second fabric material is configured to partially wrap around the first fabric material to define an end-to-end axially extending gap in the second fabric material.

[0067] The operation may include applying (block 610) a spiral wrap layer on the second fabric material. In some embodiments, the spiral wrap layer includes a plurality of wire wound loops. In some embodiments, the wire wound loops may be axially spaced apart from each other.

[0068] In some embodiments, the method further comprises preheating the stacked array prior to applying the first material (block 612). Some embodiments further comprise applying (block 614) an intermediate compression layer to the first material prior to applying (block 608) the second fabric material. In some embodiments, the third layer may have a gap that is staggered from the gap of the second layer. In such embodiments, the material layers may always be included, and layer 1 and / or layer 3 may be optional.

[0069] Some embodiments further include applying (block 616) a compressive layer to the second fabric material. Some embodiments further include applying (block 618) a tow band to the compressive layer.

[0070] Some embodiments include curing the resin in the first material and / or the second fabric material by applying heat to the surge arrester (block 620). In some embodiments, after curing the resin, the method further includes releasing the axial compression applied to the stack array by removing the axial compressive force at the stack top surface and the stack bottom surface (block 622).

[0071] Some embodiments further include applying (block 624) a silane primer to the compressive layer, and molding and bonding (block 626) a silicon housing to the layer formed on the stacked array. Some embodiments include installing (block 628) the silicon housing into the surge arrester housing.

[0072] In some embodiments, the operations may include at least one of adhesively bonding ethylene propylene diene monomer (EPDM) to the module assembly, mechanically sealing EPDM to the module assembly, interference fitting EPDM to the module assembly, sealing EPDM to the module assembly, applying a thermoset polymer to the module assembly, and / or applying a thermoplastic to the module assembly.

[0073] Now refer to Fig. 6A and Figure 6B , Fig. 6A and Figure 6B Schematic block diagrams of a cut-away side view and a top view, respectively, of a surge arrester according to some embodiments.

[0074] Reference Fig. 6A and Figure 6B , the surge arrester includes a module assembly 115. An insulating compound and / or a dielectric compound, such as room temperature vulcanized silicone rubber, may fill any gaps between the module assembly 115 and any inner surface of the housing.

[0075] In some embodiments, a silane surface treatment is applied to the module assembly 115, and then a high temperature vulcanized (HTV) silicone rubber can be molded and bonded directly to the module 115. This approach can also be performed using liquid silicone rubber molding (LSR).

[0076] In some embodiments, the arrester module may include a molded "log" of arrester modules. A log according to such an embodiment may include 1 to 10 arrester modules depending on the module size. After molding, the silicone rubber and f / g composite are cut at each module-to-module interface and separated into individual modules. Therefore, the molded silicone rubber only encloses the same circumferential surface as the f / g composite. We then use RTV silicone rubber to bond a metal cap, such as a stainless steel cap, to each end. The terminal post can be screwed into the module end electrode on each end and hold the metal cap to form a bonded seal. In some embodiments, RTV can be a gap filler to eliminate entrapped air and bond the surfaces together.

[0077] The surge arrester is connected to the line potential conductor and to ground. The surge arrester is also connected to the electrical device protected by the surge arrester. More specifically, the end of the surge arrester and the end of the electrical device are both connected to the line potential conductor. The module assembly 115 may include one or more MOV blocks 705 and / or conductive blocks housed in a pre-impregnated composite structure.

[0078] The module assembly 115 may include at least one metal oxide varistor (MOV) block 705 including an outer peripheral surface 718. In some embodiments, the geometry of the MOV block 705 may be a generally cylindrical disk, a polygonal and / or rectilinear block, or the like.

[0079] Some embodiments provide that a first fabric material 710 is formed on the peripheral surface 718, and the first fabric material 710 includes a fabric that includes a plurality of unidirectional glass fibers that are arranged substantially parallel to each other and extend from the bottom to the top. In some embodiments, after applying the first fabric, multiple layers of compression tape may be applied. For example, in some embodiments, 6 to 8 layers of compression tape may be applied. In some embodiments, basalt fibers may be used as a structural dielectric insulator material, which may be used independently and / or in combination with other fibers and / or other fiber types.

[0080] Some embodiments provide that the second fabric material 715 is formed on a portion of the first fabric material 710. In some embodiments, the second fabric material 715 is configured to partially wrap the first fabric material 710 to define an axially extending gap 725 in the second fabric material 715. Some embodiments provide that the fabric material layer can include various types of fabrics, including woven, stitched, thermoformed, chopped fiber, continuous fiber and / or paper, natural and synthetic, etc.

[0081] Some embodiments include a compressive resin coating and a spiral wrap layer 720 on the second fabric material 715. In some embodiments, the spiral wrap layer 720 includes a plurality of filament wound loops. In some embodiments, a multi-axial drainage layer 736 may be applied adjacent to the gap region 725 filled with epoxy or other type of resin.

[0082] In the above description of various embodiments of the inventive concept of the present invention, it is to be understood that the terms used herein are only used to describe specific embodiments and are not intended to limit the inventive concept of the present invention. Unless otherwise specified, all terms (including technical and scientific terms) used herein have the same meanings as those of ordinary skill in the art to which the inventive concept of the present invention belongs. It will also be understood that those terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meanings in the context of this specification and related fields.

[0083] When an element is referred to as being "connected", "coupled", "responsive" or a variation thereof to another element, it may be directly connected, coupled or responsive to another element, or there may be an intermediate element. In contrast, when an element is referred to as being "directly connected", "directly coupled", "directly responsive" or a variation thereof to another element, there is no intermediate element. The same reference numerals always refer to the same element. In addition, "coupled", "connected", "responsive" or a variation thereof used herein may include wireless connection, wireless connection or wireless response. As used herein, the singular forms of "one", "a kind of" and "the" are intended to also include plural forms unless the context clearly indicates otherwise. For the sake of brevity and / or clarity, well-known functions or structures may not be described in detail. The term "and / or" includes any one and all combinations of one or more associated listed items in the associated listed items.

[0084] It will be understood that, although the terms first, second, third, etc. can be used to describe various elements / operations in this article, these elements / operations should not be limited by these terms. These terms are only used to distinguish an element / operation from another element / operation. Therefore, without departing from the teaching of the inventive concept of the present invention, the first element / operation in some embodiments can be referred to as the second element / operation in other embodiments. Throughout the specification, the same reference numerals or the same reference numerals indicate the same or similar elements.

[0085] As used herein, the terms "comprising", "including", "comprising", "including", "having", "having" or variations thereof are open-ended and include one or more stated features, integers, elements, steps, components or functions, but do not exclude the presence or addition of one or more other features, integers, elements, steps, components, functions or combinations thereof.

[0086] Example implementations are described herein with reference to the block diagrams and / or flow charts of computer-implemented methods, equipment (systems and / or devices) and / or computer program products. It is to be understood that the combination of the blocks of the block diagram and / or flow chart and the blocks in the block diagram and / or flow chart can be realized by computer program instructions executed by one or more computer circuits. These computer program instructions can be provided to the processor circuits of general-purpose computer circuits, special-purpose computer circuits and / or other programmable data processing circuits to produce machines, so that the instructions executed by the processors of computers and / or other programmable data processing devices convert and control transistors, values ​​stored in memory locations and other hardware components in such circuits to realize the functions / actions specified in the block diagram and / or flow chart blocks, and thus create a device (function) and / or structure for realizing the functions / actions specified in the block diagram and / or flow chart blocks. The boxes illustrated using dotted lines can be considered optional and can correspond to different implementations in multiple implementations described herein.

[0087] These computer program instructions may also be stored in a tangible computer-readable medium, which may direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable medium produce a manufactured product, the instructions including instructions for implementing the functions / actions specified in the block diagram and / or flowchart block or multiple flowchart blocks. Therefore, the embodiments of the inventive concept of the present invention may be implemented in hardware and / or in software (including firmware, resident software, microcode, etc.) running on a processor such as a digital signal processor, which may be collectively referred to as a "circuit", "module" or a variant thereof.

[0088] It should also be noted that, in some alternative implementations, the function / action noted in the frame may not occur in the order noted in the flow chart. For example, two frames shown in succession may actually be performed substantially simultaneously, or these frames may sometimes be performed in reverse order, depending on the function / action involved. In addition, the function of a given frame of a flow chart and / or block diagram may be divided into multiple blocks, and / or the function of two or more frames of a flow chart and / or block diagram may be at least partially integrated. Finally, without departing from the scope of the inventive concept, other frames may be added / inserted between the illustrated frames, and / or frames / operations may be omitted. In addition, although some of the figures in the figure include arrows on the communication path to show the main communication direction, it is to be understood that communication may occur in the direction opposite to the arrows shown.

[0089] In the case of not departing substantially from the principles of the inventive concept of the present invention, various modifications and alterations may be made to the embodiments. All such modifications and alterations are intended to be included in the scope of the inventive concept of the present invention herein. Therefore, the subject matter disclosed above should be considered illustrative rather than restrictive, and the examples of the embodiments are intended to cover all such modifications, enhancements and other embodiments, which all fall within the spirit and scope of the inventive concept of the present invention. Therefore, to the maximum extent permitted by law, the scope of the inventive concept of the present invention will be determined by the broadest permissible interpretation of the present disclosure, including examples of embodiments and other schemes thereof, and should not be subject to the constraints or limitations of the foregoing detailed description.

Claims

1. A surge arrester, comprising: a module assembly including at least one metal oxide varistor (MOV) block including a top surface, a bottom surface opposite the top surface, and a peripheral surface between the top surface and the bottom surface; a first fabric material formed on the outer peripheral surface and comprising a fabric including a plurality of unidirectional glass fibers arranged substantially parallel to each other and extending from the bottom surface to the top surface; as well as A second fabric material is formed on a portion of the first material, wherein the second fabric material is configured to partially wrap the first fabric material to define an axially extending gap in the second fabric material.

2. The surge arrester of claim 1 further comprising a spiral tow wrap on the second fabric material, wherein: The helical tow wrap includes a plurality of filaments in the form of a bundle of tows.

3. The surge arrester according to claim 2, further comprising a third fabric material formed on a portion of the second fabric material, wherein The third fabric material is configured to partially wrap the second fabric material to define an axially extending gap in the third fabric material, wherein the third fabric material is located between the second fabric material and the spiral wrap.

4. The surge arrester according to claim 3, wherein: The axially extending gaps in the second fabric material and the axially extending gaps in the third fabric material include a resin.

5. The surge arrester according to claim 3, wherein: The axially extending gaps in the second fabric material are aligned with the axially extending gaps in the third fabric material.

6. The surge arrester according to claim 3, wherein: The axially extending gaps in the second fabric material are located at a first radial position, and the axially extending gaps in the third fabric material are located at a second radial position different from the first radial position.

7. The surge arrester according to claim 3, wherein: The axially extending gap in the second fabric material is located at a first radial position, and the axially extending gap in the third fabric material is located at the same radial position as the first radial position.

8. The surge arrester according to claim 3, wherein: The second fabric material and the third fabric material are configured to define a plurality of axially extending gaps therein, and Wherein, some of the plurality of extension gaps are radially staggered relative to each other.

9. The surge arrester according to claim 3, wherein: The axially extending gap in the second fabric material at the first radial position and the axially extending gap in the third fabric material partially overlap each other.

10. The surge arrester according to claim 9, wherein: The axially extending gaps in the second fabric material at the first radial location and the axially extending gaps in the third fabric material are offset from one another by about 1 / 4 inch to about 3 / 4 inch.

11. The surge arrester according to claim 3, wherein: The axially extending gap in the second fabric material at the first radial location is covered by the multi-directional tape from about 3 / 4 inch to about 2 inches.

12. The surge arrester according to claim 3, wherein: The second layer and the third layer each include a fabric including a resin matrix material reinforced with multi-directionally arranged fibers.

13. The surge arrester according to claim 1, wherein: The at least one MOV block is part of a stack including a plurality of MOV blocks.

14. The surge arrester according to claim 1, wherein: The at least one MOV block is a component in a stack including metal blocks.

15. The surge arrester of claim 2, further comprising a compression layer formed on the second fabric material and / or the third fabric material.

16. The surge arrester according to claim 15, wherein: The compression layer includes a compression band.

17. The surge arrester according to claim 16, wherein: The belt includes a fabric and / or a perforated belt configured to provide a compressive force and is encapsulated by a resin.

18. The surge arrester according to claim 1, wherein: The plurality of unidirectional glass fibers include basalt fibers.

19. A method of providing a surge arrester, the method comprising: providing a stack array, the stack array comprising at least one MOV and at least one metal block, the at least one MOV and the at least one metal block being arranged adjacent to each other to form a peripheral surface between a stack top surface and a stack bottom surface; compressing the stack array by applying an axial compressive force at the stack top surface and the stack bottom surface; applying a first fabric material to the outer peripheral surface of the stacked array, the first fabric material comprising a fabric including a plurality of unidirectional glass fibers arranged substantially parallel to each other and end to end; applying a second fabric material, the second fabric material formed over a portion of the first fabric material, the second fabric material configured to partially wrap around the first fabric material to define an end-to-end axially extending gap in the second fabric material; as well as A spiral wrap is applied to the second fabric material, wherein the spiral wrap includes a plurality of wire wound loops.

20. The method according to claim 19, wherein: Prior to applying the first fabric material, the method further includes preheating the stacked array.

21. The method of claim 19, further comprising applying an intermediate compression layer to the first fabric material prior to applying the second fabric material.

22. The method according to claim 21, wherein: A plurality of compression layers and a plurality of first textile material layers are applied alternately.

23. The method according to claim 21, further comprising: applying a first plurality of basalt unidirectional layers; applying a first compression wrap to the outer surface of the first plurality of basalt unidirectional layers; applying a second plurality of basalt unidirectional layers to the first compression wrap; as well as A second compression wrap is applied to the outer surface of the second plurality of basalt unidirectional plies.

24. The method according to claim 23, further comprising: applying a plurality of multi-directional layers to the second compression wrap; as well as A third compression wrap is applied to the plurality of multi-directional layers.

25. The method of claim 19, further comprising applying a compression layer to the second textile material.

26. The method of claim 22, applying a tow band to the compression layer.

27. The method according to claim 23, wherein: The tow band includes basalt fibers.

28. The method of claim 19, further comprising curing a resin in the first fabric material and / or the second fabric material by applying heat to the surge arrester.

29. The method of claim 28, after curing the resin, further comprising releasing the axial compression applied to the stack array by removing the axial compressive force at the stack top surface and the stack bottom surface.

30. The method of claim 19, further comprising: applying a silane primer to the compression layer; as well as A silicon housing is molded and bonded to the layers formed on the stacked array.

31. The method of claim 30, further comprising molding the silicon housing directly into a surge arrester.

32. The method of claim 19, further comprising at least one of adhesively bonding EPDM to the module assembly, mechanically sealing EPDM to the module assembly, interference fitting EPDM to the module assembly, sealing EPDM to the module assembly, applying a thermoset polymer to the module assembly, and / or applying a thermoplastic to the module assembly.

33. The method of claim 19, wherein: The first textile material includes basalt fibers.

34. The method of claim 19, wherein: Compressing the stack array by applying an axial compressive force at the stack top surface and the stack bottom surface includes applying an initial preload pressure of about 2400 psi to about 2800 psi.

35. The method of claim 34, wherein: The initial preload pressure was about 2600 psi.

36. The method of claim 34, wherein: Compressing the stack array by applying an axial compressive force at the stack top surface and the stack bottom surface includes reducing the preload pressure to about 870 psi to about 1070 psi.

37. The method of claim 36, wherein: The reduced preload pressure is about 970 psi.

38. A surge arrester comprising: a module assembly including at least one metal oxide varistor (MOV) block including a top surface, a bottom surface opposite the top surface, and a peripheral surface between the top surface and the bottom surface; as well as a first fabric material formed on a portion of the outer peripheral surface, wherein the first fabric material is configured to partially wrap around the outer peripheral surface to define an axially extending gap in the first fabric material, and Wherein, the first fabric material comprises a resin matrix material reinforced by multi-directionally arranged fibers.

39. The surge arrester of claim 38, further comprising a second fabric material formed on a portion of the first fabric material, wherein: The second fabric material is configured to partially wrap the first fabric material to define an axially extending gap in the second fabric material, wherein the second fabric material is located between the first fabric material and the spiral wrap.

40. The surge arrester of claim 39, further comprising a third fabric material formed on a portion of the second fabric material, wherein: The third fabric material is configured to partially wrap the second fabric material to define an axially extending gap in the third fabric material, wherein the third fabric material is located between the second fabric material and the spiral wrap.

41. The surge arrester of claim 40, further comprising a compression material encapsulated by the multi-directionally arranged fiber reinforced resin matrix material.

42. The surge arrester of claim 40, wherein: At least one of the first fabric material, the second fabric material, and the third fabric material comprises woven polypropylene having fused edges.

43. The surge arrester of claim 40, wherein: At least one of the first fabric material, the second fabric material, and the third fabric material comprises approximately 0.005 inch woven polypropylene.

44. The surge arrester of claim 40, wherein: At least one of the first fabric material, the second fabric material, and the third fabric material is configured to shrink by about 0.5% to about 7.0% at about the lowest viscosity temperature of the epoxy resin in the first fabric material, the second fabric material, and / or the third fabric material.

Images