A method for preparing a high resistance layer of a lightning arrester and a large current resistance disc

Abstract

The application relates to a lightning arrester and a preparation method of a high-resistance layer of a large-current resistance sheet, which comprises the following steps: obtaining a high-resistance layer base material with a weight of M, polyvinyl alcohol glue with a mass ratio of N, and a defoaming agent with a mass-volume ratio of L; pouring the high-resistance layer base material and the polyvinyl alcohol glue into a high-speed stirrer of a grinder to wet mill for a first time to obtain mixed slurry; and pouring the defoaming agent into the high-speed stirrer with the mixed slurry to high-speed stir for a second time to obtain high-resistance layer slurry. The high-resistance layer slurry prepared by the preparation method of the high-resistance layer of the large-current resistance sheet makes the resistance sheet have a uniform thickness and a high-performance insulating layer, effectively improves the current-carrying capacity of the resistance sheet, and can withstand 21 times of current-carrying tests of 4000A square waves; and the insulating property, current-carrying capacity and lightning resistance of the lightning arrester are improved, and the technical problems of poor insulating property and current-carrying capacity of the resistance sheet in a traditional zinc oxide lightning arrester and difficulty in coping with multiple lightning strikes are solved.

Description

Technical Field

[0001] This application relates to the field of surge arrester technology, and in particular to a method for preparing a high-resistivity layer of a surge arrester and a high-current resistive element. Background Technology

[0002] In recent years, with climate change, the frequency of multiple lightning strikes has been gradually increasing, and zinc oxide surge arrester failures caused by multiple lightning strikes have occurred repeatedly. Traditional zinc oxide surge arresters have poor current-carrying capacity and are unable to cope with multiple lightning strikes. The core component of a zinc oxide surge arrester is the zinc oxide resistance element. The high-resistivity insulation performance of the side layer of the zinc oxide resistance element manufactured under the existing formulation system is insufficient, resulting in its current-carrying capacity failing to meet the high current-carrying requirements of multiple lightning strikes. In addition, since zinc oxide surge arresters use a large-size resistance element stacked and connected in series structure, the core's fastening strength needs to be strengthened to ensure the mechanical strength and electrical reliability of the arrester core.

[0003] Surge arresters are crucial protective devices for ensuring the safe operation of power systems, serving to absorb and release lightning strike energy. Currently, zinc oxide surge arresters are the most widely used type in power systems. However, the high-resistivity insulation of zinc oxide resistor elements is relatively poor, making them prone to side flashover or pinhole breakdown under high-current impacts. Therefore, these elements cannot withstand repeated lightning strikes. Furthermore, existing surge arrester core fastening methods primarily rely on multiple insulating rods to clamp the resistor element core, with only a single top spring ensuring electrical connection. For high-current zinc oxide surge arresters using large-size resistor elements and multi-element series structures, existing fastening methods are prone to core loosening and poor electrical contact, potentially leading to increased partial discharge, internal insulation deterioration, and ultimately, arrester failure. Summary of the Invention

[0004] This application provides a method for preparing a high-resistivity layer for a surge arrester and a high-current-carrying resistor element, which solves the technical problems of poor insulation performance and poor current-carrying capacity of the resistor element in traditional zinc oxide surge arresters, making it difficult to cope with multiple lightning strikes.

[0005] To achieve the above objectives, the embodiments of this application provide the following technical solutions:

[0006] On the one hand, a method for preparing a high-resistivity layer of a high-current resistive sheet is provided, including the following steps:

[0007] Obtain a high-resistance base material with a weight of M, a polyvinyl alcohol adhesive with a mass ratio of N, and a defoamer with a mass-volume ratio of L;

[0008] The high-resistance base material and the polyvinyl alcohol adhesive are poured into the high-speed mixer of the mill and wet-milled for the first time to obtain a mixed slurry.

[0009] The defoamer is poured into the high-speed mixer containing the mixed slurry and stirred at high speed for a second time to obtain a high-resistance slurry.

[0010] Preferably, the method for preparing the high-resistivity layer of the high-current resistive sheet includes:

[0011] The high-resistivity slurry is applied to the side wall of the resistor sheet after adhesive removal using a spraying process according to the thickness data, to obtain the resistor sheet to be sintered.

[0012] The resistor sheet to be sintered is subjected to high-temperature sintering according to the temperature data and the third time to obtain the resistor sheet.

[0013] Preferably, the thickness data is 100μm~200μm, the temperature data is 1050℃~1100℃, and the third time is 120min~240min.

[0014] Preferably, the first time is 2 hours and the second time is 4 hours.

[0015] Preferably, M is 500g, N is 1:1 to 1:1.3, and L is 5000g:1ml to 5000g:2ml.

[0016] Preferably, the high-resistivity layer base material comprises raw materials in molar percentages, wherein the raw materials include 90%~97% zinc oxide, 0.1%~1% bismuth oxide, 0.1%~1% antimony trioxide, 0.1%~1% tin trioxide, 0.1%~0.5% zinc chloride and 0.05%~0.5% iron oxide.

[0017] On another front, a surge arrester is provided, including a surge arrester body assembly and cover plates covering both ends of the surge arrester body assembly. The surge arrester body assembly includes several core units and a core fastening mechanism. Each core unit includes multiple resistors connected in series with high-resistivity layers prepared by the high-resistivity layer preparation method described above for high-current-carrying resistors. The resistors of two adjacent core units are clamped and fixed together by the core fastening mechanism.

[0018] Preferably, each of the fastening core mechanisms includes a corrugated spring box, a clamping plate, and a pad. The corrugated spring box abuts against one end face of one of the core units, the pad abuts against the other end face of another core unit, and the pad abuts against the corrugated spring box. The outer wall surface of one end of the clamping plate abuts against the end faces of the corrugated spring box and the pad, respectively. The pads are located on both sides of the core unit and clamped by the pads. The pads are provided with connecting holes, and several core units are connected and fixed by passing an insulating connecting rod through all the connecting holes on the same side.

[0019] Preferably, an insulating fastener for fastening is provided between the pad and the insulating connecting rod.

[0020] Preferably, the surge arrester body assembly is covered with an insulating sleeve, one end of the surge arrester body assembly is connected to the cover plate through an elastic element, and the other end of the surge arrester body assembly is connected to the cover plate through a connecting post.

[0021] The method for preparing the high-resistivity layer of the surge arrester and high-current-carrying resistor includes obtaining a high-resistivity layer base material with a weight of M, a polyvinyl alcohol adhesive with a mass ratio of N, and a defoamer with a mass-volume ratio of L; pouring the high-resistivity layer base material and polyvinyl alcohol adhesive into a high-speed mixer of a mill for wet grinding for a first time to obtain a mixed slurry; pouring the defoamer into the high-speed mixer containing the mixed slurry for high-speed stirring for a second time to obtain a high-resistivity layer slurry. From the above technical solution, it can be seen that the embodiments of this application have the following advantages: the high-resistivity layer slurry prepared by this high-resistivity layer preparation method for the high-current-carrying resistor gives the resistor a uniform thickness and high-performance insulation layer, effectively improving the current-carrying capacity of the resistor and enabling it to withstand 21 current-carrying tests with a 4000A square wave; thereby improving the insulation, current-carrying capacity, and lightning strike resistance of the surge arrester, solving the technical problems of poor insulation performance and poor current-carrying capacity of the resistor in traditional zinc oxide surge arresters, making it difficult to cope with multiple lightning strikes.

[0022] This surge arrester uses a core-fastening mechanism to fix several core units, improving the overall strength of the arrester assembly. The use of resistor elements with high-resistance insulating layers enhances the arrester's ability to withstand multiple lightning strikes. By improving the lightning strike resistance of the core units and increasing the core strength, the arrester's performance is improved, ensuring stable operation under multiple lightning strikes. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart illustrating the steps of the high-resistivity layer fabrication method for the high-current resistive chip described in the embodiments of this application.

[0025] Figure 2 This is a schematic diagram of the surge arrester described in the embodiments of this application. Detailed Implementation

[0026] To make the inventive objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] In the description of the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0028] In the embodiments of this application, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0029] Currently, there are four types of high-resistivity side layers for zinc oxide resistors. The first type uses an inorganic and organic insulating layer; the second type uses an inorganic insulating layer and glass glaze; the third type uses only glass glaze; and the fourth type uses silicone rubber coating. Among these, the type using an inorganic and organic insulating layer is the mainstream. Different formulations and processes require different high-resistivity layer formulations and processes for zinc oxide resistors; no single high-resistivity layer is suitable for all types of zinc oxide resistors. Regarding the coating of the high-resistivity layer paste, roller coating is currently commonly used. This method makes it difficult to control the thickness and uniformity of the high-resistivity layer, potentially leading to problems such as excessive coating thickness or uneven coating, which affects the side insulation performance of the resistor and limits its current-carrying capacity.

[0030] Currently, surge arrester core fastening involves using multiple insulated rods to clamp the resistor element column. The ends of the insulated rods are threaded, and the resistor element core is secured by a top clamping plate and insulated nuts. A spring at the top of the core connects it to a cover plate, ensuring electrical connection between the core and the external environment. However, this type of surge arrester core fastening is prone to loosening and poor electrical contact, especially with large resistor elements or multiple elements connected in series.

[0031] This application provides a method for preparing a high-resistivity layer for a surge arrester and a high-current-carrying resistor element, which solves the technical problems of poor insulation performance and poor current-carrying capacity of the resistor element in traditional zinc oxide surge arresters, making it difficult to cope with multiple lightning strikes.

[0032] Example 1:

[0033] Figure 1 This is a flowchart illustrating the steps of the high-resistivity layer fabrication method for the high-current resistive chip described in the embodiments of this application.

[0034] like Figure 1 As shown in the figure, this application provides a method for fabricating a high-resistivity layer of a high-current resistive sheet, including the following steps:

[0035] S1. Obtain a high-resistance base material with a weight of M, a polyvinyl alcohol adhesive with a mass ratio of N, and a defoamer with a mass-volume ratio of L.

[0036] It should be noted that the materials required for preparing the high-resistivity layer are obtained in step S1. In this embodiment, M is preferably 500g, N is preferably 1:1 to 1:1.3, and L is preferably 5000g:1ml to 5000g:2ml.

[0037] S2. Pour the high-resistance base material and polyvinyl alcohol adhesive into the high-speed mixer of the mill and wet grind them for the first time to obtain a mixed slurry.

[0038] It should be noted that in step S2, the high-resistance base material and polyvinyl alcohol adhesive obtained in step S1 are wet-milled in a mill to obtain a mixed slurry. In this embodiment, the initial time is preferably 2 hours. The high-speed agitator is preferably a spherical agitator.

[0039] S3. Pour the defoamer into a high-speed mixer containing the mixed slurry and mix at high speed for the second time to obtain a high-resistance slurry.

[0040] It should be noted that in step S3, the defoamer obtained in step S1 is poured into the mixed slurry obtained in step S2 and stirred in the high-speed agitator of the mill for a second time to obtain a high-resistivity layer slurry, which provides material for preparing a resistor sheet with a uniform thickness and high-performance insulating layer. In this embodiment, the second time is preferably selected as 4 hours. The high-resistivity layer slurry prepared by this high-resistivity layer preparation method for high-current-carrying resistor sheets gives the resistor sheet a uniform thickness and high-performance insulating layer, effectively improving the current-carrying capacity of the resistor sheet, which can withstand 21 current-carrying tests of a 4000A square wave.

[0041] This application provides a method for preparing a high-resistivity layer for a high-current-carrying resistor. The method includes obtaining a high-resistivity layer base material with a weight of M, polyvinyl alcohol adhesive with a mass ratio of N, and an antifoaming agent with a mass-to-volume ratio of L; pouring the high-resistivity layer base material and polyvinyl alcohol adhesive into a high-speed mixer of a mill and wet-milling for a first time to obtain a mixed slurry; pouring the antifoaming agent into the high-speed mixer containing the mixed slurry and high-speed stirring for a second time to obtain a high-resistivity layer slurry. The high-resistivity layer slurry prepared by this method gives the resistor a uniform thickness and high-performance insulating layer, effectively improving the resistor's current-carrying capacity and enabling it to withstand 21 current-carrying tests with a 4000A square wave; thereby improving the insulation, current-carrying capacity, and lightning strike resistance of the surge arrester, solving the technical problems of poor insulation performance and poor current-carrying capacity of resistors in traditional zinc oxide surge arresters, making it difficult to cope with multiple lightning strikes.

[0042] like Figure 1 As shown, in one embodiment of this application, the method for fabricating the high-resistivity layer of the high-current-pass resistive sheet includes:

[0043] S4. Apply the high-resistivity slurry to the side wall of the resistor sheet after glue removal using a spraying process according to the thickness data to obtain the resistor sheet to be sintered; sinter the resistor sheet to be sintered at high temperature according to the temperature data and the third time to obtain the resistor sheet.

[0044] It should be noted that the high-resistivity layer preparation method for this high-current-carrying resistor sheet involves coating the side of the resistor sheet with a high-resistivity slurry using a spraying process, followed by high-temperature sintering at 850℃ to form a resistor sheet with uniform thickness and a high-performance insulating layer. This improves the side insulation performance of the resistor sheet, effectively enhancing its current-carrying capacity, thereby improving the current-carrying capacity and insulation performance of the surge arrester. In this embodiment, the preferred thickness is 100μm~200μm, the preferred temperature is 1050℃~1100℃, and the preferred time is 120min~240min. The resistor sheet is preferably a zinc oxide resistor sheet. The high-resistivity slurry is sintered at high temperature to form a high-performance insulating layer that integrates with the resistor sheet.

[0045] In one embodiment of this application, the high-resistivity layer base material comprises raw materials in molar percentages, including 90%~97% zinc oxide, 0.1%~1% bismuth oxide, 0.1%~1% antimony trioxide, 0.1%~1% tin trioxide, 0.1%~0.5% zinc chloride, and 0.05%~0.5% iron oxide.

[0046] It should be noted that the high-resistance layer base material is composed of raw materials in molar percentage.

[0047] Example 2:

[0048] Figure 2This is a schematic diagram of the surge arrester described in the embodiments of this application.

[0049] like Figure 2 As shown, this application provides a surge arrester, including a surge arrester body assembly and cover plates 10 covering both ends of the surge arrester body assembly. The surge arrester body assembly includes several core units and a core fastening mechanism. Each core unit includes multiple resistors 20 connected in series with high-resistivity layers prepared by the above-mentioned high-resistivity layer preparation method of the high-current-carrying resistors. The resistors 20 of two adjacent core units are clamped and fixed together by the core fastening mechanism.

[0050] It should be noted that the method for preparing the high-resistivity layer of the high-current-carrying resistor has been described in Example 1, and will not be repeated in this example. The surge arrester uses a core-fastening mechanism to fix several core units, improving the fastening strength of the surge arrester body assembly. The use of a resistor with an insulating high-resistivity layer enhances the surge arrester's ability to withstand multiple lightning strikes. Improving the lightning strike resistance and core strength of the core units enhances the surge arrester's performance, ensuring stable operation under multiple lightning strikes. In this example, the number and position of the core units and the core-fastening mechanism in the surge arrester body assembly can be adjusted according to actual needs, without being limited by the surge arrester's form or structure. The series connection structure of the resistor units and the core-fastening mechanism in each core unit of the surge arrester body assembly can be used in various types of zinc oxide surge arresters, not limited to a single surge arrester type and voltage level.

[0051] like Figure 2 As shown, in one embodiment of this application, each fastening core mechanism includes a corrugated spring box 31, a clamping plate 32, and a pad 33. The corrugated spring box 31 abuts against one end face of a core unit, the pad 33 abuts against the other end face of another core unit, and the pad 33 abuts against the corrugated spring box 31. The outer wall surface of one end of the clamping plate 32 abuts against the end faces of the corrugated spring box 31 and the pad 33, respectively. The two sides of the core unit are clamped by the pad 33. The pad 33 is provided with a connecting hole 331. Several core units are connected and fixed by passing through all the connecting holes 331 on the same side by an insulating connecting rod 40.

[0052] It should be noted that the insulating connecting rod 40 can be selected as a fully threaded insulating rod, and the connecting hole on the corresponding pad 33 is provided with an internal thread that matches the insulating connecting rod 40. In each fastening core mechanism, a groove 34 matching the clamping plate 32 is formed between the corrugated spring box 31 and the pad 33. In summary, each pair of core units is clamped and fixed by a fastening core mechanism, which greatly improves the fastening strength of the core units in the surge arrester. Specifically, the surge arrester uses the corrugated spring box 31, clamping plate 32, and pad 33, along with the insulating connecting rod 40, to individually fix the core units, thereby improving the fastening strength of the surge arrester body assembly in the surge arrester.

[0053] In one embodiment of this application, an insulating fastener 50 for fastening is provided between the pad 33 and the insulating connecting rod 40.

[0054] It should be noted that the insulating fastener 50 can be selected as an insulating nut. Each core unit column is pressed with a corrugated spring box 31 and a clamping plate 32. After each core unit is pressed by the corrugated spring, the insulating fastener 50 on the clamping plate 32 is tightened, which serves to secure each core unit.

[0055] In one embodiment of this application, the surge arrester body assembly is wrapped with an insulating sleeve 60, one end of the surge arrester body assembly is connected to the cover plate 10 through an elastic element 70, and the other end of the surge arrester body assembly is connected to another cover plate 10 through a connecting post 80.

[0056] It should be noted that the elastic element 70 can be a spring. The connecting post 80 can be a T-shaped connector.

[0057] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0058] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0059] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing a high-resistivity layer of a high-current resistive sheet, characterized in that, Includes the following steps: Obtain a high-resistance base material with a weight of M, a polyvinyl alcohol adhesive with a mass ratio of N, and a defoamer with a mass-volume ratio of L; wherein M is 500g, N is 1:1 to 1:1.3, and L is 5000g:1ml to 5000g:2ml. The high-resistance base material and the polyvinyl alcohol adhesive are poured into the high-speed mixer of the mill and wet-milled for the first time to obtain a mixed slurry. The defoamer is poured into the high-speed mixer containing the mixed slurry and stirred at high speed for a second time to obtain a high-resistance slurry. The high-resistivity slurry is applied to the side wall of the resistor sheet after adhesive removal using a spraying process according to the thickness data, to obtain the resistor sheet to be sintered. The resistor sheet to be sintered is subjected to high-temperature sintering according to the temperature data and the third time to obtain the resistor sheet; The high-resistivity layer base material comprises raw materials in molar percentages, including 90%~97% zinc oxide, 0.1%~1% bismuth oxide, 0.1%~1% antimony trioxide, 0.1%~1% tin trioxide, 0.1%~0.5% zinc chloride and 0.05%~0.5% iron oxide; Specifically, the resistor sheet to be sintered is sintered at a high temperature of 850°C to form a resistor sheet with uniform thickness and a high-performance insulating layer, so that the resistor sheet can withstand the current carrying capacity of 21 current carrying tests of 4000A square wave.

2. The method for preparing the high-resistivity layer of the high-current resistive sheet according to claim 1, characterized in that, The thickness data is 100μm~200μm, the temperature data is 1050℃~1100℃, and the third time is 120min~240min.

3. The method for preparing the high-resistivity layer of the high-current resistive sheet according to claim 1, characterized in that, The first time is 2 hours, and the second time is 4 hours.

4. A surge arrester, characterized in that, The device includes a surge arrester body assembly and cover plates covering both ends of the surge arrester body assembly. The surge arrester body assembly includes several core units and a core fastening mechanism. Each core unit includes multiple resistors connected in series, which have an insulating high-resistivity layer prepared by the high-resistivity layer preparation method of the high-current-carrying resistor as described in any one of claims 1-3. The resistors of two adjacent core units are clamped and fixed together by the core fastening mechanism.

5. The surge arrester according to claim 4, characterized in that, Each of the fastening core mechanisms includes a corrugated spring box, a clamping plate, and a pad. The corrugated spring box abuts against one end face of one of the core units, the pad abuts against the other end face of another core unit, and the pad abuts against the corrugated spring box. The outer wall surface of one end of the clamping plate abuts against the end faces of the corrugated spring box and the pad, respectively. The pads are located on both sides of the core unit and are clamped by the pads. The pads are provided with connecting holes, and several core units are connected and fixed by passing an insulating connecting rod through all the connecting holes on the same side.

6. The surge arrester according to claim 5, characterized in that, An insulating fastener is provided between the pad and the insulating connecting rod for securing them.

7. The surge arrester according to claim 4, characterized in that, The surge arrester body assembly is covered with an insulating sleeve. One end of the surge arrester body assembly is connected to the cover plate through an elastic element, and the other end of the surge arrester body assembly is connected to the cover plate through a connecting post.

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