Lightning protection and overvoltage protection device

Abstract

The invention discloses a lightning protection and overvoltage protection device, which relates to the technical field of circuit protection and comprises an outer shell, a lightning arrester arranged at the top of the outer shell, an overvoltage protection component and a protector thermal inductance heat dissipation mechanism, and the overvoltage protection component and the protector thermal inductance heat dissipation mechanism are arranged in an inner cavity. The overvoltage protection assembly comprises a plurality of piezoresistor columns, the bottoms of the piezoresistor columns are grounded through conductive copper sheets, and the tops are connected with the main circuit; the protector thermal induction heat dissipation mechanism comprises an air storage tank and an airflow pipeline communicated with the air storage tank, and a plunger valve assembly driven by a thermal induction liquid pipe is arranged on the pipeline. The overvoltage protection assembly can be integrally pulled through the design of a sliding rail, all electrical connections are automatically disconnected when the overvoltage protection assembly is pulled out, and rapid and safe maintenance and replacement are achieved. The problem that the piezoresistor is damaged due to overheating is effectively solved, and the reliability, the safety and the maintainability of the protection device are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of circuit protection technology, specifically to a lightning strike and overvoltage protection device. Background Technology

[0002] Outdoor power facilities (such as distribution cabinets and substations) are frequently threatened by lightning strikes and operational overvoltages, and their protection devices typically use varistors as core components. In actual operation, especially in areas prone to lightning strikes or areas with frequent power grid fluctuations, varistors generate significant Joule heating due to frequent energy dissipation. If this heat cannot be dissipated in time, the component temperature will continue to rise, leading to performance degradation or even thermal breakdown, causing the protection function to fail and directly threatening the safety of power equipment.

[0003] Currently, most common heat dissipation methods are passive, such as relying on natural cooling with heat sinks or air convection inside the cabinet. These methods have low heat dissipation efficiency and slow response, making it difficult to cope with the rapid temperature rise caused by sudden or continuous large energy surges. In addition, although some solutions mention adding fans for forced air cooling, these usually require continuous power supply or rely on external control, which not only increases energy consumption but also fails to achieve precise and automatic triggering linked to the actual temperature of the varistor, resulting in insufficient reliability.

[0004] On the other hand, existing protection devices often present maintenance inconveniences when varistors need to be replaced due to deterioration or damage. Most devices use fixed wiring or bolted connections, requiring manual disassembly of electrical connections during replacement, which is cumbersome and poses a safety risk of accidental contact with live parts. During maintenance, the entire protection circuit often needs to be de-energized, affecting continuous system operation. Although modular designs have emerged, they may still lack effective automatic electrical isolation mechanisms during insertion and removal, posing risks of arcing or poor contact. Therefore, there is an urgent need in the existing technology for an overvoltage protection device that can achieve efficient active heat dissipation and automatic safe disconnection during maintenance to solve the problem of varistor overheating damage and enable fast, safe, and uninterrupted maintenance and replacement, thereby improving the reliability, safety, and maintainability of the protection system. Summary of the Invention

[0005] The purpose of this invention is to provide a lightning and overvoltage protection device that can achieve efficient active heat dissipation and automatic safe disconnection during maintenance, so as to solve the problem of overheating damage to varistors and achieve fast, safe, and uninterrupted maintenance and replacement.

[0006] This invention is achieved through the following technical solution: A lightning strike and overvoltage protection device includes a housing, a surge arrester is provided on the top of the housing, and an overvoltage protection component and a heat dissipation mechanism for the protector are provided inside the housing. The overvoltage protection component includes multiple varistor columns arranged side by side. The bottom of the multiple varistor columns is grounded through a conductive copper sheet, and the top of the multiple varistor columns is connected to the external main circuit. The protector's thermal cooling mechanism includes an air tank and an airflow pipe connected to the air tank for injecting high-pressure gas into the varistor column. The airflow pipe is equipped with a plunger valve assembly that is automatically controlled to open and close based on temperature sensing. The plunger valve assembly is thermally associated with the corresponding varistor column. When the temperature of the varistor column rises to a set threshold, the plunger valve assembly automatically opens, allowing the high-pressure gas in the air tank to be injected into the corresponding varistor column to achieve active heat dissipation.

[0007] As a further provision of the above scheme, the airflow pipeline includes a main air pipe connected to the air storage tank, and the main air pipe is provided with an outlet branch pipe corresponding to each varistor column, and the outlet branch pipe is provided with an exhaust hole facing the varistor column.

[0008] As a further provision of the above scheme, the plunger valve assembly includes a plunger valve tube connected to the outlet branch pipe. Inside the plunger valve tube, a movable plunger for opening and closing the outlet branch pipe is connected by an elastic element, and the movable plunger has a connecting hole. One end of the plunger valve tube is connected to a heat-sensing liquid tube, which extends to the side of the corresponding piezoresistive column and is thermally coupled to it through heat-absorbing fins. The heat-sensing liquid tube is filled with a thermally expanding liquid medium.

[0009] As a further feature of the above scheme, an expansion section is provided at the upstream end of the heat-sensing liquid pipe.

[0010] As a further feature of the above solution, the overvoltage protection component also includes an insulating mounting plate. The conductive copper sheet is embedded and fixed on the upper surface of the insulating mounting plate. The insulating mounting plate and the conductive copper sheet have multiple mounting holes. The lower end of the varistor column is provided with a metal threaded section that penetrates the mounting hole. The upper end of the metal threaded section is provided with a conductive ring. A fastening nut is threaded onto the metal threaded section located below the insulating mounting plate. By tightening the fastening nut, the conductive ring is tightly pressed against the upper surface of the conductive copper sheet to achieve circuit connection.

[0011] As a further feature of the above scheme, slide rails are provided on the inner walls of both sides of the outer shell, and sliders that cooperate with the slide rails are provided at both ends of the insulating mounting plate; elastic pressing plates are provided on the side ends of the conductive copper sheet, and a grounding copper sheet is fixedly provided in the inner cavity of the outer shell, and a grounding wire is connected to the grounding copper sheet to ensure the safe conduction of high voltage to the ground; and an embedded groove is provided on the grounding copper sheet to interact with the protrusions on the elastic pressing plate.

[0012] As a further feature of the above solution, each of the varistor columns is provided with an upwardly protruding contact piece at its top, and the top of the inner cavity of the outer shell is provided with multiple conductive flaps that are connected to the external main circuit, and the conductive flaps are provided with elastic upper recesses that are adapted to the contact pieces; when the overvoltage protection component is pushed into the working position, the contact piece is embedded in the corresponding elastic upper recess to achieve electrical connection and mechanical engagement; when the overvoltage protection component is withdrawn, the contact piece disengages from the elastic upper recess.

[0013] As a further feature of the above scheme, the bottom of the surge arrester is connected to a grounding wire that is connected to a grounding copper sheet.

[0014] As a further feature of the above solution, the opening of the outer casing is provided with an easy-to-operate maintenance door.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The lightning and overvoltage protection device disclosed in this invention, through the incorporation of a heat-sensing liquid pipe and plunger valve assembly thermally coupled to the varistor column, can sense its operating temperature in real time. When the varistor column experiences a rapid temperature rise due to a sudden or sustained high-energy impact, it automatically triggers high-pressure gas jet cooling. This heat dissipation method is rapid in response, precise in direction, and highly effective in cooling, effectively preventing performance degradation or thermal breakdown of the varistor caused by heat accumulation. It solves the fundamental problem of low efficiency in traditional passive heat dissipation, ensuring the long-term stable operation of the protection device under frequent overvoltage or lightning strike conditions.

[0016] Furthermore, by setting an expansion section upstream of the heat-sensing liquid pipe, the liquid medium must absorb sufficient heat and expand to fill the expansion section before it can actuate the plunger valve. This design gives the heat dissipation system a certain "thermal inertia" or "delayed triggering" characteristic, which can effectively avoid false opening caused by slight instantaneous temperature rise of the varistor or fluctuations in ambient temperature, thus improving the stability and reliability of the heat dissipation system.

[0017] The overvoltage protection component in this invention adopts a sliding modular design, connected to the housing via a slide rail; during replacement or maintenance, it can simply be pulled out. During this process, the elastic pressing plate on the conductive copper sheet side automatically separates from the grounding copper sheet, and simultaneously, the contact plate at the top of the varistor column also detaches from the conductive tab, achieving omnidirectional automatic electrical disconnection. This design avoids the risk of maintenance personnel manually disassembling live wires, allowing maintenance without disconnecting the main circuit, significantly improving operational safety and maintenance efficiency.

[0018] This invention integrates a surge arrester, overvoltage protection component, and intelligent heat dissipation mechanism into a single housing, forming an integrated protection module that simplifies on-site installation and wiring. Simultaneously, after the overvoltage protection component is pushed into the working position, the electrical connection achieves self-locking and mechanical positioning through the engagement of the protruding part of the elastic pressing plate with the groove of the grounding copper plate, and the engagement of the contact piece with the elastic upper recess of the conductive fold, ensuring reliable contact and eliminating the need for additional tightening steps. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a frontal perspective view of the present invention; Figure 2 This is a schematic diagram of the internal planar structure of the present invention from the front view. Figure 3 This is a three-dimensional structural diagram of the back of the present invention; Figure 4 This is a first-angle three-dimensional structural diagram of the outer shell and its internal protector heat dissipation mechanism in this invention. Figure 5 This is a second-angle three-dimensional structural diagram of the outer shell and its internal protector heat dissipation mechanism in this invention; Figure 6 This is a three-dimensional structural diagram of the overvoltage protection component in this invention; Figure 7 This is a three-dimensional schematic diagram of the thermal sensing and heat dissipation mechanism of the protector in this invention; Figure 8 This is a three-dimensional schematic diagram of the conductive copper sheet in Embodiment 2 of the present invention; Figure 9 This is a schematic diagram of the internal planar structure of the plunger valve tube in this invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The following will refer to the appendix... Figures 1-9 This application will be described in detail with reference to the embodiments. Example 1

[0023] like Figures 1-3 As shown, Embodiment 1 discloses a lightning strike and overvoltage protection device. The device is designed with an integrated modular structure, suitable for top-mounting of equipment such as outdoor distribution cabinets and substations. It includes a housing 10, with a surge arrester 20 mounted on the top of the housing 10. An inspection door 30 is hinged to the opening on the front side of the housing 10, facilitating the installation and subsequent maintenance of internal components by operators.

[0024] An overvoltage protection component 40 and a protector thermal sensing and heat dissipation mechanism 50 are provided inside the outer casing 10. When a large amount of heat is generated inside the overvoltage protection component 40 due to the Joule heating effect, the protector thermal sensing and heat dissipation mechanism 50 can actively start heat dissipation to prevent the varistor column in the overvoltage protection component 40 from being damaged due to overheating.

[0025] like Figure 6 As shown, the overvoltage protection assembly 40 includes an insulating mounting plate 401 fixedly installed inside the housing 10. A conductive copper sheet 402 is embedded and fixed on the upper surface of the insulating mounting plate 401. Three mounting holes 403 are correspondingly opened on the insulating mounting plate 401 and the conductive copper sheet 402, and a varistor post 404 is detachably installed in each mounting hole 403. Specifically, a metal threaded section 405 penetrating the mounting hole 403 is provided at the lower end of the varistor post 404, and a conductive ring 406 is provided at the upper end of the metal threaded section 405 to press tightly against the conductive copper sheet 402. A fastening nut 407 is threaded onto the metal threaded section 405 located below the insulating mounting plate 401. During installation, the metal threaded section 405 of the varistor post 404 is passed through the mounting hole 403, and the fastening nut 407 is tightened, so that the conductive ring 406 is tightly pressed against the upper surface of the conductive copper sheet 402, achieving circuit connection.

[0026] like Figure 2 and Figure 5 As shown, a grounding copper plate 409 is connected to one side of the inner wall of the outer casing 10 via an insulating block 408, and the side end of the conductive copper plate 402 is electrically connected to the grounding copper plate 409. A grounding wire 410 extending from the lower end of the outer casing 10 is connected to the grounding copper plate 409. The tops of the three varistor columns 404 are respectively connected to the corresponding circuits in external distribution cabinets, substations, and other equipment via conductive mechanisms. In addition, a grounding wire 201 is also connected to the bottom of the surge arrester 20, which is connected to the grounding copper plate 409, so that both the surge arrester 20 and the overvoltage protection component 40 have a grounding discharge channel, ensuring that high voltage can be safely conducted to the ground.

[0027] like Figure 2 , Figure 7 and Figure 9 As shown, the thermal sensing and heat dissipation mechanism 50 of the protector includes a high-pressure gas tank 501 fixedly installed below the overvoltage protection component 40, which stores high-pressure nitrogen or high-pressure carbon dioxide. A main gas pipe 502 is connected to the high-pressure gas tank 501, which extends to the upper rear side of the overvoltage protection component 40 and branches into three gas outlet branches 503. Each gas outlet branch 503 corresponds to a varistor post 404, and an exhaust port 504 is provided on the gas outlet branch 503 facing the corresponding varistor post 404.

[0028] A plunger valve tube 505 is provided at the connection between each outlet branch pipe 503 and the main gas pipe 502. A movable plunger 507 is connected inside the plunger valve tube 505 via an elastic element 506. The movable plunger 507 has a connecting hole 5071 for connecting the outlet branch pipe 503 and the main gas pipe 502. A heat-sensitive liquid tube 508 is connected to the end of the plunger valve tube 505 away from the elastic element 506. The heat-sensitive liquid tube 508 is filled with a thermally expanding and contracting liquid medium, such as mercury, kerosene, or alcohol. The heat-sensitive liquid tube 508 extends to the side of the corresponding varistor column 404 and has multiple heat-absorbing fins 509 arranged close to the varistor column 404 to enhance heat absorption efficiency.

[0029] In addition, to prevent the pressure-sensitive resistor column 404 from falsely triggering heat dissipation due to slight temperature rise, the upper end of the thermal sensing liquid pipe 508 is provided with a larger diameter expansion section 510. When the liquid medium initially expands slightly in volume due to heating, it will first fill the expansion section 510. Only after the volume expands further due to continued heating will it enter the plunger valve pipe 505 and push the movable plunger 507 to move, thereby delaying the opening of the valve and improving the accuracy of control.

[0030] The specific working principle of the lightning strike and overvoltage protection device disclosed in Embodiment 1 is as follows: When the main circuit encounters an overvoltage, the overvoltage protection component 40 switches from a near-open circuit state to a conducting state, conducting the overvoltage to the ground through the conductive copper sheet 402, the grounding copper sheet 409, and the grounding wire 410. When struck by lightning, the lightning current can be discharged to the ground through the surge arrester 20 via the grounding conductor 201, the grounding copper sheet 409, and the grounding wire 410.

[0031] Furthermore, under conditions of frequent overvoltage, the varistor column 404 generates a large amount of heat due to continuous current flow, causing its temperature to rise. At this time, the heat-absorbing fins 509 rapidly absorb heat and transfer it to the liquid medium in the heat-sensing liquid pipe 508, causing the liquid medium to expand due to heat. The expanding liquid medium overcomes the resistance of the elastic element 506, pushing the movable plunger 507 to move, aligning its connecting hole 5071 with the gas path, thereby opening the corresponding gas outlet branch pipe 503.

[0032] After the gas path is opened, the gas in the high-pressure gas tank 501 is quickly ejected through the exhaust port 504. On the one hand, the gas absorbs heat due to adiabatic expansion, which lowers the local ambient temperature. On the other hand, the airflow quickly carries away the heat from the surface of the varistor column 404, achieving efficient cooling and ensuring the long-term stable operation of the overvoltage protection component 40. Example 2

[0033] Example 2 discloses a lightning strike and overvoltage protection device optimized based on the technical solution in Example 1. The similarities between it and Example 1 will not be described again.

[0034] like Figures 4-6 As shown, in this embodiment 2, a slide rail 101 is fixedly installed on each of the left and right inner sidewalls of the outer casing 10. Slider blocks 411 that cooperate with the slide rails 101 are correspondingly installed at both ends of the insulating mounting plate 401. A handle 412 is also provided in the middle of the front side of the insulating mounting plate 401. When a component in the overvoltage protection assembly 40 is damaged and needs replacement or maintenance, the entire assembly can be directly pulled out along the slide rail 101 using the handle 412, making the replacement and maintenance process more convenient.

[0035] To facilitate the automatic disconnection of the overvoltage protection component 40 from the circuit during maintenance, the following design is implemented in this embodiment 2. Firstly, an elastic pressing sheet 4021 is provided on the side end of the conductive copper sheet 402, with a protrusion 4022 on the elastic pressing sheet 4021. A corresponding embedding groove adapted to the protrusion 4022 is provided on the grounding copper sheet 409. Secondly, an upwardly protruding contact piece 4041 is provided at the top of each varistor column 404. Multiple conductive flaps 414 are fixed to the top wall of the housing 10 via an insulating plate 413. Each conductive flap 414 is connected to a connector-equipped wire 415 extending out of the housing 10, which is used to connect to the external main circuit. Finally, an elastic upper recess 416 adapted to the contact piece 4041 is provided at the front end of the conductive flap 414.

[0036] In this embodiment 2, through the above-mentioned optimized design, when the insulating mounting plate 401 is pulled outward along the slide rail 101, the protrusion 4022 of the elastic pressing sheet 4021 separates from the embedded groove of the grounding copper sheet 409. At the same time, the contact piece 4041 at the top of each varistor column 404 also comes out from the elastic upper recess 416 of the conductive fold 414, thereby achieving complete electrical disconnection of the entire overvoltage protection assembly 40 while physically disengaging.

[0037] After replacement or maintenance is completed, push the insulating mounting plate 401 back inward. When the insulating mounting plate 401 is pushed to the set position, the protrusion 4022 of the elastic pressing sheet 4021 is embedded into the groove of the grounding copper sheet 409 to achieve electrical connection and mechanical engagement. At the same time, each contact piece 4041 is also engaged in the elastic upper recess 416 of the corresponding conductive tab 414, which not only restores the circuit connection but also realizes the positioning of the components. No additional fasteners are needed for locking, simplifying the installation process.

[0038] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lightning strike and overvoltage protection device, comprising a housing, characterized in that, A surge arrester is installed on the top of the housing, and an overvoltage protection component and a protector thermal heat dissipation mechanism are installed inside the housing. The overvoltage protection component includes multiple varistor columns arranged side by side. The bottom of the multiple varistor columns is grounded through a conductive copper sheet, and the top of the multiple varistor columns is connected to the external main circuit. The protector's thermal cooling mechanism includes an air tank and an airflow pipe connected to the air tank for injecting high-pressure gas into the varistor column. The airflow pipe is equipped with a plunger valve assembly that is automatically controlled to open and close based on temperature sensing. The plunger valve assembly is thermally associated with the corresponding varistor column. When the temperature of the varistor column rises to a set threshold, the plunger valve assembly automatically opens, allowing the high-pressure gas in the air tank to be injected into the corresponding varistor column to achieve active heat dissipation.

2. The lightning strike and overvoltage protection device according to claim 1, characterized in that, The airflow pipeline includes a main air pipe connected to the air storage tank. The main air pipe is provided with an outlet branch pipe corresponding to each varistor column. The outlet branch pipe has an exhaust hole facing the varistor column.

3. The lightning strike and overvoltage protection device according to claim 2, characterized in that, The plunger valve assembly includes a plunger valve tube connected to the outlet branch pipe. Inside the plunger valve tube, a movable plunger for opening and closing the outlet branch pipe is connected by an elastic element, and the movable plunger has a connecting hole. One end of the plunger valve tube is connected to a heat-sensitive liquid tube, which extends to the side of the corresponding piezoresistive column and is thermally coupled to it through heat-absorbing fins. The heat-sensitive liquid tube is filled with a thermally expanding liquid medium.

4. The lightning strike and overvoltage protection device according to claim 3, characterized in that, An expansion section is provided at the upstream end of the thermal induction liquid pipe.

5. The lightning strike and overvoltage protection device according to claim 1, characterized in that, The overvoltage protection component also includes an insulating mounting plate. The conductive copper sheet is embedded and fixed on the upper surface of the insulating mounting plate. The insulating mounting plate and the conductive copper sheet have multiple mounting holes. The lower end of the varistor column is provided with a metal threaded section that passes through the mounting hole. The upper end of the metal threaded section is provided with a conductive ring. A fastening nut is threaded onto the metal threaded section located below the insulating mounting plate. The conductive ring is tightly pressed onto the upper surface of the conductive copper sheet by the tightening action of the fastening nut to achieve circuit connection.

6. The lightning strike and overvoltage protection device according to claim 5, characterized in that, The inner walls on both sides of the outer casing are provided with slide rails, and both ends of the insulating mounting plate are provided with sliders that cooperate with the slide rails; the side end of the conductive copper sheet is provided with an elastic pressing sheet, and a grounding copper sheet is fixedly provided in the inner cavity of the outer casing, and a grounding wire is connected to the grounding copper sheet to ensure that the high voltage is safely conducted to the ground; the grounding copper sheet is provided with an embedded groove that interacts with the protrusion on the elastic pressing sheet.

7. The lightning strike and overvoltage protection device according to claim 6, characterized in that, Each of the varistor columns is provided with an upwardly protruding contact piece at the top, and the top of the inner cavity of the outer shell is provided with multiple conductive flaps connected to the external main circuit, and the conductive flaps are provided with elastic upper recesses that are adapted to the contact pieces. When the overvoltage protection component is pushed into the working position, the contact piece is embedded in the corresponding elastic upper recess to achieve electrical connection and mechanical engagement; when the overvoltage protection component is pulled out, the contact piece disengages from the elastic upper recess.

8. The lightning strike and overvoltage protection device according to claim 6, characterized in that, The bottom of the surge arrester is connected to a grounding wire that is connected to a grounding copper plate.

9. The lightning strike and overvoltage protection device according to claim 1, characterized in that, The outer casing has an access door at its opening for easy operation.

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