Self-heating sealing ring for low-temperature and high-voltage power equipment and power equipment

Abstract

The present invention provides a self-heating sealing ring for low-temperature, high-voltage power equipment and the power equipment, relating to the field of power equipment. Aiming at the problem that sealing rings of power equipment in cold and high-altitude areas are prone to aging and failure, the present invention utilizes the alternating magnetic field surrounding the power equipment to heat the conductor in the sealing ring base by electromagnetic induction heating, thereby heating the sealing ring base from the inside, reducing the temperature difference between the inner and outer rings of the sealing ring, increasing the overall temperature of the sealing ring, slowing down the hardening, cracking, deterioration or failure of rubber seals, and ensuring the sealing performance of the equipment.

Description

Technical Field

[0001] The present invention relates to the field of power equipment, and in particular to a self-heating sealing ring for low-temperature and high-voltage power equipment and the power equipment. Background Art

[0002] Rubber seals are commonly used at the connections of oil- and gas-filled equipment in power systems. Rubber products achieve their sealing function when the material is in its highly elastic state. EPDM or NBR are commonly used as housing seals in high-voltage oil- and gas-insulated equipment. Due to the poor thermal conductivity of rubber seals, when the equipment operates in low-temperature environments, the external temperature of the rubber seals approaches the ambient temperature. In cold regions, temperatures can reach below -50°C. This causes commonly used rubber seals to harden and crack, eventually deteriorating and failing. This can lead to oil and gas leaks within the equipment, and the infiltration of impurities such as external gases and moisture, causing equipment malfunctions or even failure.

[0003] A Chinese patent (publication number CN106764162B, publication date 20170531) discloses a rubber heating seal for preventing freezing and blockage of water supply and drainage pipes. The heat-conducting frame includes an insulating plate and a heat-conducting copper plate attached to the lower surface of the insulating plate. The insulating plate is provided with a heating wire mounting groove surrounding the insulating plate. The heating wire is installed in the heating wire mounting groove. The heating wire circuit is controlled by a thermostat to be conductive and heated according to demand to prevent freezing of the pipes. However, the heat-conducting seal requires connection to a thermostat for power supply and heating, and the wires need to be led out of the heat-conducting frame, which destroys the integrity and integrity of the exterior of the heat-conducting frame. The lead-out position becomes a weak point and is damaged by external environmental influences, resulting in poor weather resistance. Due to the need for lead-out wires, it can only be installed end-to-end, which is inconvenient to install in a small space. The reliance on the thermostat to achieve active electric heating makes it difficult to apply to working conditions where it is inconvenient to maintain the position or a large number of electrical systems. Summary of the Invention

[0004] The purpose of the present invention is to address the defects of the prior art and provide a self-heating sealing ring and power equipment for low-temperature and high-voltage power equipment. The alternating magnetic field around the power equipment is used to heat the conductor in the sealing ring base by electromagnetic induction heating, thereby heating from the inside of the sealing ring base, reducing the temperature difference between the inner and outer rings of the sealing ring, increasing the overall temperature of the sealing ring, slowing down the hardening, cracking, deterioration or failure of rubber seals, and ensuring the sealing performance of the equipment.

[0005] The first object of the present invention is to provide a self-heating sealing ring for low-temperature and high-voltage power equipment, which adopts the following scheme:

[0006] It includes a sealing ring base and a conductor located inside the sealing ring base. The conductor is distributed along the sealing ring base in an annular direction. The conductor forms a closed conductive loop in the sealing ring base for heating the sealing ring base through electromagnetic induction self-heating.

[0007] Furthermore, the conductor is covered with an insulating layer.

[0008] Furthermore, the conductors are distributed in an annular direction along the sealing ring base and connected end to end to form a closed ring.

[0009] Furthermore, the conductor is in a spiral shape, and the axis of the spiral conductor coincides with or is concentric with the axis of the sealing ring base.

[0010] Furthermore, the conductor is provided with openings, and the openings also form a closed conductive loop in a circular direction.

[0011] Furthermore, the conductor is in the form of a hollow tubular ring, and the openings are distributed on the ring wall of the hollow ring.

[0012] Furthermore, there are a plurality of openings, which are circular or polygonal, so that the conductor forms a hollow structure.

[0013] Furthermore, the opening is a hexagonal hole.

[0014] Furthermore, the conductor and the sealing ring base deform together to maintain the relative position of the conductor and the sealing ring base.

[0015] A second object of the present invention is to provide an electric power device, utilizing the self-heating sealing ring for low-temperature and high-voltage electric power devices as described in the first object.

[0016] Compared with the prior art, the present invention has the following advantages and positive effects:

[0017] In response to the current problem that sealing rings of power equipment in high-altitude and cold areas are prone to aging and failure, the alternating magnetic field around the power equipment is used to make the conductor in the sealing ring base heat up due to the effect of electromagnetic induction heating, thereby heating from the inside of the sealing ring base, reducing the temperature difference between the inner and outer rings of the sealing ring, increasing the overall temperature of the sealing ring, slowing down the hardening, cracking, deterioration or failure of rubber seals, and ensuring the sealing performance of the equipment.

[0018] To address the inconvenience of installation and poor weather resistance of existing actively heated seals, the conductor utilizes electromagnetic induction heating to heat the seal from within. This self-heating method eliminates the need for an external power source and complex temperature control equipment, avoiding the problems associated with external wires and thermostats in existing technologies, and preventing damage to the integrity of the gasket. This allows the seal to fit into a variety of confined spaces and facilitates installation.

[0019] The conductor is distributed circumferentially along the sealing ring base and connected end to end to form a closed ring, or it is spiral-shaped with its axis coinciding or concentric with the axis of the sealing ring base. Various structural forms, such as openings in the conductor that also form a closed conductive loop, ensure that the conductor can effectively induce the alternating magnetic field to generate heat, and also make the conductor structure more reasonable and adaptable to different application scenarios and needs. The conductor and the sealing ring base deform together, maintaining the relative position of the conductor and the sealing ring base. During operation, even if the sealing ring is subjected to certain deformation or external forces, the conductor can still operate normally and continue to exert its self-heating function, ensuring the stability and reliability of the sealing ring.

[0020] The openings form a hollow structure, which ensures the integrity of the conductive circuit while reducing the weight of the sealing ring and the equipment load; the heat generated by the conductor through electromagnetic induction can be more evenly transferred to the sealing ring base through the hollow structure, reducing local temperature differences, improving the overall heating effect, and facilitating uniform heat distribution; while ensuring the function of the conductor, the hollow structure reduces the use of conductor materials and reduces costs. The hollow structure of the conductor is also filled with the sealing ring base inside and outside, which can occupy the space of the hollow part without affecting the sealing performance, making the entire structure more compact and effectively utilizing the space. The structure in which the conductor and the sealing ring base are nested with each other enables the two to work together better when deformed, and jointly adapt to various stresses and working conditions during equipment operation, thereby enhancing the stability and reliability of the entire sealing ring structure.

[0021] The opening shape of the hexagonal hole will make the distribution of the magnetic field inside the conductor more in line with the requirements, which is beneficial to improving the efficiency of electromagnetic induction, making the conductor heat more effectively, and indirectly increasing the heating performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0023] Figure 1 This is a schematic structural diagram of a self-heating sealing ring with a spiral conductor for low-temperature and high-voltage power equipment in one or more embodiments of the present invention.

[0024] Figure 2 This is a schematic structural diagram of a self-heating sealing ring for low-temperature, high-voltage power equipment having hexagonal openings in one or more embodiments of the present invention.

[0025] Figure 3 Schematic diagram comparing the surface temperature of the sealing ring under different types of conductors in one or more embodiments of the present invention.

[0026] Among them, 1. sealing ring base; 2. conductor; 3. opening. DETAILED DESCRIPTION

[0027] Example 1

[0028] In a typical embodiment of the present invention, Figure 1-Figure 3 As shown, a self-heating sealing ring for low-temperature and high-voltage power equipment is provided.

[0029] In order to improve the damage to the sealing ring caused by low temperature during the operation of power equipment in a cold environment, this embodiment provides a self-heating sealing ring for low-temperature and high-voltage power equipment. By sealing a conductor 2 that can generate eddy currents inside the sealing ring base 1, the conductor 2 uses the electromagnetic induction heating effect to achieve self-heating under the action of the leakage magnetic field of the power equipment, thereby heating the seal and achieving self-heating of the entire sealing ring, reducing the temperature difference between the inside and outside of the rubber sealing ring, and improving the overall temperature of the self-heating sealing ring used for low-temperature and high-voltage power equipment.

[0030] like Figure 1 and Figure 2 As shown, the self-heating seal ring for low-temperature, high-voltage power equipment includes a seal ring base 1 and a conductor 2. Based on the principle of electromagnetic induction, an alternating magnetic field exists around the power equipment, generating eddy currents in conductor 2, causing it to heat. Typically, seals are installed at the joints of the equipment casing, where a certain density of leakage magnetic field exists. This embodiment utilizes the electromagnetic induction heating effect to increase the temperature of the self-heating seal ring for low-temperature, high-voltage power equipment. In this embodiment, "low-temperature" refers to the extreme low-temperature environments that power equipment may encounter when operating in cold and high-altitude areas, typically reaching temperatures below -50°C. "High voltage" refers to the voltage range applicable to high-voltage power equipment in this embodiment, typically above 1000V. In this embodiment, high-voltage power equipment primarily involves voltage levels of 110kV and above (such as 110kV, 220kV, and 500kV). Typical application scenarios include high-voltage transmission and transformation equipment and GIS (gas-insulated switchgear).

[0031] The hardness of the seal of the high-voltage power equipment housing is above 60 HA, the cross-sectional diameter of the O-ring used is greater than 200mm, and the cross-sectional area of ​​the rectangular side corresponding to the rectangular sealing ring used is also greater than 200mm2. In this regard, the self-heating sealing ring for low-temperature and high-voltage power equipment in this embodiment can be configured as an O-ring or a rectangular sealing ring according to needs, and the cross-sectional size can also meet the requirements of high-voltage power equipment. At the same time, a conductor 2 that can generate eddy currents is integrated and packaged in the sealing ring base 1. The conductor 2 forms a closed conductive loop in the sealing ring base 1. Since the conductor 2 has resistance, heat is generated when current passes through it. The conductor 2 senses the alternating magnetic field during the operation of the equipment to generate eddy current heating, thereby realizing self-heating of the self-heating sealing ring for low-temperature and high-voltage power equipment, reducing the temperature difference between the inside and outside of the sealing ring base 1, and increasing the temperature of the self-heating sealing ring for low-temperature and high-voltage power equipment to resist the external low temperature and slow down the degradation and failure of the sealing ring.

[0032] By increasing the overall temperature of the sealing ring through self-heating, this technology effectively mitigates the hardening, cracking, deterioration, or failure of rubber seals caused by low temperatures, maintaining the elasticity and flexibility of the rubber, thereby ensuring the sealing performance of the equipment and preventing oil and gas leakage, as well as the infiltration of impurities such as external gases and moisture, which could cause equipment failure. This system does not rely on external heating equipment or thermostats, but utilizes the alternating magnetic field surrounding the power equipment to generate heat. It is suitable for use in electrical systems in locations that are difficult to access and in large-scale deployments, demonstrating high adaptability and reliability.

[0033] In one implementation of this embodiment, conductor 2 is coated with an insulating layer. In this embodiment, the implanted conductor 2 is an insulated wire. The conductor 2 within the wire can be a copper core, aluminum core, silver core, or gold core. The metal of conductor 2 within the wire has excellent electrical conductivity and can effectively generate electromagnetic induction heating. Copper cores are a common choice due to their excellent electrical conductivity, high mechanical strength, and strong corrosion resistance. Aluminum cores are lightweight and low-cost. Silver and gold cores offer better electrical conductivity but are more expensive and are generally used in specialized applications with extremely high performance requirements.

[0034] Furthermore, to ensure both a heating effect and the required sealing performance of the seal ring, the cross-sectional diameter of the conductor 2 embedded in the seal ring base 1 is set to 5% to 35% of the minimum cross-sectional diameter of a self-heating seal ring for low-temperature, high-voltage power equipment. If the cross-sectional dimensions of the conductor 2 are too small, insufficient heat will be generated, failing to effectively heat the seal ring base 1 and preventing low-temperature degradation of the rubber seal. If the cross-sectional dimensions are too large, this will increase costs while also affecting the overall structure and sealing performance of the seal ring, reducing its elasticity and making it difficult to achieve a good seal.

[0035] The implanted conductors 2 are connected end to end to form a closed loop, allowing the current generated by electromagnetic induction to flow continuously through the conductors 2, thereby generating continuous heat. Conductors 2 are completely enclosed within the sealing ring base 1, protecting them from environmental corrosion and damage, extending their service life, and ensuring the appearance and sealing performance of the sealing ring.

[0036] It should be pointed out that the implanted conductor 2 has the characteristic of overall deformation without displacement. When the compression of the rubber ring is 25%-30%, the implanted conductor 2 does not produce axial and radial displacement. The rubber sealing ring will be subjected to a certain compressive force in actual use and will deform. If the implanted conductor 2 is displaced in this case, it may cause the relative position between the conductor 2 and the sealing ring base 1 to change, affecting the uniformity of the heating effect, and may even cause the conductor 2 to break, short-circuit, and other problems, thereby affecting the performance and service life of the entire sealing ring. Ensuring that the conductor 2 does not displace and that the conductor 2 deforms and adapts to the sealing ring base 1 can ensure that under various working conditions, the conductor 2 can stably generate heat and evenly heat the sealing ring base 1 to maintain the sealing performance of the sealing ring.

[0037] In another implementation of this embodiment, conductors 2 are distributed circumferentially along the sealing ring base 1 and connected end to end to form a closed ring. This ensures that the conductors 2 embedded in the sealing ring base 1 have the same shape as the sealing ring, facilitating uniform heat generation through electromagnetic induction and enabling relatively uniform heating of the sealing ring base 1. This closed ring structure generates a relatively stable and uniform induced current in an alternating magnetic field, thereby generating relatively uniform heat along the entire circumference, avoiding localized overheating or overcooling and facilitating consistent overall performance of the sealing ring.

[0038] The diameter of the closed annular cross-section formed by the conductor 2 is less than 80% of the cross-sectional diameter of the self-heating sealing ring for low-temperature, high-voltage power equipment, and is greater than 30% of the cross-sectional diameter of the self-heating sealing ring for low-temperature, high-voltage power equipment, thereby preventing the conductor 2 from being too close to the outer and inner edges of the self-heating sealing ring for low-temperature, high-voltage power equipment, reducing external extrusion or wear, and affecting its performance and safety.

[0039] When the axis of the annular distribution corresponding to conductor 2 coincides with the axis of the annular distribution corresponding to the self-heating sealing ring used for low-temperature, high-voltage power equipment, heating uniformity can be ensured, and the temperature variation of the self-heating sealing ring used for low-temperature, high-voltage power equipment in the circumferential direction is small. In addition, the offset of the axis of conductor 2 relative to the axis of the self-heating sealing ring used for low-temperature, high-voltage power equipment in the outer diameter direction is set to no more than 30%, thereby reducing the problem of the sealing ring base 1 wrapping the conductor 2 too thinly in some positions. At the same time, the position of conductor 2 can be fine-tuned according to the specific equipment structure and magnetic field distribution to better utilize the magnetic field energy and improve the heating effect. Excessive offset leads to uneven heating inside the sealing ring, affecting the sealing performance.

[0040] In another implementation form of this embodiment, as Figure 1 As shown, the conductor 2 is in the shape of a spiral, and the axis of the spiral conductor 2 coincides with or is concentric with the axis of the sealing ring base 1. The design of the spiral conductor 2 helps to more flexibly adjust the distribution of electromagnetic induction and the pattern of heat generation. When the axis of the spiral conductor 2 coincides with or is concentric with the axis of the sealing ring base 1, a relatively uniform magnetic field distribution can be formed inside the sealing ring, thereby generating relatively uniform heat, which can enable heat to be more evenly transferred in both the circumferential and radial directions of the sealing ring. Compared to a simple annular conductor 2, the spiral shape increases the interaction area and path length between the conductor 2 and the magnetic field, which will improve the efficiency of electromagnetic induction, thereby more effectively heating the sealing ring base 1.

[0041] The pitch of the spiral conductor 2 can be 1mm-10mm, which ensures the electromagnetic induction effect while making the heat more evenly distributed inside the sealing ring. The specific pitch can be optimized and adjusted according to factors such as the size and material of the sealing ring and the parameters of the electromagnetic induction equipment.

[0042] The diameter corresponding to the cross-section of conductor 2 can be set to 50% to 80% of the cross-sectional diameter of the self-heating sealing ring for low-temperature, high-voltage power equipment to ensure the performance of the self-heating sealing ring for low-temperature, high-voltage power equipment. At the same time, similar to the previous implementation, the axial position of the implanted conductor 2 coincides with the axial position of the self-heating sealing ring for low-temperature, high-voltage power equipment, or the axial position of the implanted conductor 2 is offset by no more than 50% in the direction of the outer diameter of the self-heating sealing ring for low-temperature, high-voltage power equipment. The coincidence of the axes helps to ensure heating uniformity. The deviation of no more than 50% in the direction of the outer diameter of the sealing ring is allowed so that in some special cases, the position of conductor 2 can be adjusted according to the actual magnetic field distribution and equipment structural characteristics to better utilize the magnetic field energy and improve heating efficiency.

[0043] It can be understood that, in this embodiment, the axis of the conductor 2 refers to the axis in the direction in which the conductor 2 extends into a ring, and the cross section of the conductor 2 refers to the cross section perpendicular to the axis of the conductor 2 .

[0044] In another implementation form of this embodiment, an opening 3 is provided on the conductor 2, and the opening 3 also forms a closed conductive loop in a circumferential direction. On the one hand, the opening 3 changes the effective conductive area of ​​the conductor 2, increases the number of closed conductive loops formed, and enhances the local electromagnetic induction effect, thereby generating more heat. On the other hand, the circumferential closed conductive loop ensures the overall conductive continuity, so that the electromagnetic induction can be carried out continuously and stably, providing a stable heat source for heating the sealing ring base 1.

[0045] Conductor 2 forms a hollow tubular ring with openings 3 distributed throughout the ring wall, optimizing electromagnetic induction and heating. This hollow structure reduces conductor 2's weight and, to a certain extent, alters the magnetic field distribution, making it more evenly distributed within and around the ring, thereby improving heating uniformity.

[0046] The opening 3 forms a hollow structure, which reduces the weight of the sealing ring and the equipment load while ensuring the integrity of the conductive circuit; the heat generated by the conductor 2 through electromagnetic induction heating can be more evenly transferred to the sealing ring base 1 through the hollow structure, reducing local temperature differences, improving the overall heating effect, and facilitating uniform heat distribution.

[0047] While ensuring the function of the conductor 2, the hollow structure reduces the amount of material used in the conductor 2 and reduces the cost. The hollow structure of the conductor 2 is also filled with the sealing ring matrix 1 both inside and outside. It can occupy the space of the hollow part without affecting the sealing performance, making the entire structure more compact and effectively utilizing the space. The structure in which the conductor 2 and the sealing ring matrix 1 are nested with each other enables the two to work together better during deformation, jointly adapt to various stresses and working condition changes during the operation of the equipment, and enhance the stability and reliability of the entire sealing ring structure.

[0048] The opening 3 is designed to be circular or polygonal to form a hollow structure, which increases the interaction area between the conductor 2 and the magnetic field and can also change the distribution pattern of the magnetic field to adapt to the heating requirements of the sealing ring.

[0049] like Figure 2 As shown, the implanted conductor 2 is a hollowed-out circular ring with the same overall shape as the sealing ring. The side length of the hexagonal hole in the hollowed-out position is 1mm-10mm. The outer diameter of the ring corresponding to the hollowed-out circular ring structure is 50% to 80% of the outer diameter of the corresponding ring of the self-heating sealing ring used for low-temperature, high-voltage power equipment. The axis position of the implanted conductor 2 coincides with the axis position of the self-heating sealing ring used for low-temperature, high-voltage power equipment, or the axis position of the implanted conductor 2 is offset by no more than 50% in the direction of the outer diameter of the self-heating sealing ring used for low-temperature, high-voltage power equipment.

[0050] In another implementation of this embodiment, the conductor 2 is provided with openings 3 to form a hollow structure. The openings 3 are diamond-shaped holes with a side length of 1 mm to 10 mm.

[0051] Simulate the magnetic field strength at the flange of 110kV GIS outdoor equipment and conduct self-heating effect tests of different types of conductor 2 implantation under different ambient temperature conditions, such as Figure 3 shown.

[0052] The magnetic field strength at the flange of 110kV GIS outdoor equipment was simulated, ranging from 50 to 200 μT (microtesla) under different load working conditions. The test used 150μT under rated operating conditions. The compression rate of the self-heating sealing ring used for low-temperature and high-voltage power equipment was 25%, and compression was performed using a metal mold. The self-heating sealing ring used for low-temperature and high-voltage power equipment with different forms of conductors embedded inside was placed in a variable temperature environment containing a 150μT magnetic field. The temperature change range was -55℃ to 10℃. After each temperature change, the surface temperature of the sealing ring was tested after keeping the temperature and magnetic field stable for 2 hours. The test interval was 5℃. The test results are as follows: Figure 3 shown.

[0053] The self-heating effect of the hollow ring structure formed by opening hexagonal holes on the conductor 2 is the best, and the difference between the surface temperature of the rubber ring and the ambient temperature is 17.2°C. The self-heating effect of the hollow ring structure formed by opening diamond holes on the conductor 2 is similar to that of the hexagonal hollow ring; the surface temperatures of the self-heating sealing rings implanted in the closed ring conductor 2 and the spiral linear conductor 2 for low-temperature and high-voltage power equipment are similar, and the self-heating effects are similar.

[0054] Example 2

[0055] In another typical embodiment of the present invention, Figure 1-Figure 3 As shown, an electric power device is provided.

[0056] The power equipment adopts the self-heating sealing ring used for low-temperature and high-voltage power equipment as in Example 1.

[0057] In view of the problem that the sealing rings of power equipment in high-altitude and cold areas are prone to aging and failure, the alternating magnetic field around the power equipment is used to make the conductor 2 in the sealing ring base 1 heat up by the effect of electromagnetic induction heating, thereby heating from the inside of the sealing ring base 1, reducing the temperature difference between the inner and outer rings of the sealing ring, increasing the overall temperature of the sealing ring, slowing down the hardening, cracking, deterioration or failure of rubber seals, and ensuring the sealing performance of the equipment.

[0058] The good effect achieved by the power equipment comes from the self-heating sealing ring used for low-temperature and high-voltage power equipment. This part has been explained in Example 1 and will not be repeated here.

[0059] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A self-heating sealing ring for low-temperature and high-voltage power equipment, characterized in that: The seal is installed at the joint of the equipment casing, and includes a sealing ring base and a conductor located inside the sealing ring base. The conductor is distributed circumferentially along the sealing ring base, and the conductor forms a closed conductive loop in the sealing ring base, which is used to heat the sealing ring base through self-heating by electromagnetic induction; the conductor is provided with openings, and the openings also form a closed conductive loop in the circumferential direction. The conductor is a hollow tubular ring, and the openings are distributed on the ring wall of the hollow ring, which changes the distribution of the magnetic field to a certain extent; there are multiple openings, and the openings are circular or polygonal, so that the conductor forms a hollow structure.

2. The self-heating sealing ring for low-temperature and high-voltage power equipment according to claim 1, characterized in that: The conductor is covered with an insulating layer.

3. The self-heating sealing ring for low-temperature and high-voltage power equipment according to claim 1, characterized in that: The conductors are distributed in an annular direction along the sealing ring base and connected end to end to form a closed annular shape.

4. The self-heating sealing ring for low-temperature and high-voltage power equipment according to claim 3, characterized in that: The conductor is in a spiral shape, and the axis of the spiral conductor coincides with or is concentric with the axis of the sealing ring base.

5. The self-heating sealing ring for low-temperature and high-voltage power equipment according to claim 1, characterized in that: The opening is a hexagonal hole.

6. The self-heating sealing ring for low-temperature and high-voltage power equipment according to claim 3, characterized in that: The conductor and the sealing ring base are deformed together to maintain the relative position of the conductor and the sealing ring base.

7. An electric power device, characterized in that: A self-heating sealing ring for low-temperature and high-voltage power equipment is used as described in any one of claims 1 to 6.

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