Arc extinguishing device for load switch and environment-friendly gas insulation ring main unit

Abstract

The utility model provides an arc extinguishing device for a load switch and an environment-friendly gas insulation ring main unit, the arc extinguishing device comprises an arc suction pipe, a vacuum storage chamber, a vacuumizing pump and an exhaust pipe, the inlet of the arc suction pipe is right opposite to the contact position of a moving contact and a static contact of the load switch; an outlet of the arc suction pipe is communicated with an inlet of the vacuum storage chamber, an outlet of the vacuum storage chamber is communicated with an inlet of the exhaust pipe, and the vacuumizing pump is installed on the exhaust pipe. And a first valve and a second valve are respectively arranged at an inlet and an outlet of the vacuum storage chamber. According to the utility model, vacuum arc absorption is adopted for arc extinguishing, no foreign gas is introduced, and arc extinguishing can be rapidly carried out; compared with a traditional arc extinguishing mode of compressed gas, the arc extinguishing device can prevent the insulating air in the box from going bad due to long-term compression, thereby guaranteeing the performance of the insulating air. And air does not need to be compressed repeatedly, a high-speed action mechanism is omitted, and the requirement for device manufacturing materials is lowered.

Description

Technical Field

[0001] The present application relates to the technical field of arc extinguishing of load switches, and in particular to an arc extinguishing device for load switches and an environmentally friendly gas-insulated ring network cabinet. Background Art

[0002] As a key power distribution equipment, gas insulated ring main unit is widely used in power systems. At present, the insulating medium of most ring main unit gas filling units is greenhouse gas SF6, and its carbon emissions have caused serious pollution and damage to the environment. In order to reduce and eliminate the damage caused by SF6 to the environment, people are vigorously promoting environmentally friendly gas insulated ring main units. Dry air, as a zero-carbon emission environmentally friendly insulating gas, has the advantages of wide sources, easy processing, and low price, and has been used in ring main units.

[0003] However, the electrical strength of dry air is about 0.33 times that of SF6 gas insulation strength, and its arc extinguishing ability can only reach 0.01 times that of SF6 gas. Its weak insulation performance leads to the risk of arc being difficult to extinguish when the load switch in the dry air insulated ring main unit breaks large currents, which increases the probability of failure and accidents of the dry air insulated ring main unit during operation.

[0004] Traditional arc extinguishing devices generally use compressed gas to extinguish arcs, but the insulating air in the box is prone to deterioration due to long-term compression, such as N2+O2=2NO, which reduces the performance of the insulating air and affects the safe operation of the ring network cabinet. Summary of the invention

[0005] The present application provides an arc extinguishing device for a load switch and an environmentally friendly gas-insulated ring main unit, which solves the problem that the traditional compressed gas arc extinguishing method causes the insulating air in the box to easily deteriorate due to long-term compression, thereby reducing the performance of the insulating air.

[0006] The first aspect of the present application provides an arc extinguishing device for a load switch, comprising an arc absorbing tube, a vacuum storage chamber, a vacuum pump and an exhaust pipe, wherein the inlet of the arc absorbing tube is opposite to the contact position between the moving contact and the static contact of the load switch, the outlet of the arc absorbing tube is connected with the inlet of the vacuum storage chamber, the outlet of the vacuum storage chamber is connected with the inlet of the exhaust pipe, and the vacuum pump is installed on the exhaust pipe; the inlet and outlet of the vacuum storage chamber are respectively provided with a first valve and a second valve.

[0007] In the technical solution provided by the present application, by setting an arc-absorbing tube, a vacuum storage chamber, a vacuum pump and an exhaust pipe, the first valve can be closed in advance and the second valve can be opened, the vacuum storage chamber can be evacuated by the vacuum pump, and then the second valve can be closed; before the load switch needs to be opened and closed, the first valve is opened first, and the negative pressure generated by the vacuum storage chamber will make the arc-absorbing tube have an air-absorbing function, and a negative pressure is generated at the entrance of the arc-absorbing tube, and then the load switch is disconnected or closed, and the arc generated at the moment of disconnection or closing of the load switch will be sucked into the arc-absorbing tube, thereby achieving the effect of arc extinguishing; the present application adopts vacuum arc absorption to extinguish the arc, does not introduce any impurity gas, and can extinguish the arc quickly; compared with the traditional compressed gas arc extinguishing method, it can avoid the deterioration of the insulating air in the box due to long-term compression, thereby ensuring the performance of the insulating air. And there is no need to compress the air repeatedly, reducing the high-speed action mechanism and the requirements for the manufacturing materials of the device.

[0008] In some embodiments, the arc extinguishing device also includes a controller and a current transformer, the current transformer is used to monitor the current passing through the load switch; the controller is respectively connected to the current transformer, the actuator of the load switch, the first valve, the second valve, and the vacuum pump; when the current transformer detects that the current exceeds the current value that the load switch can withstand, the controller automatically controls the first valve to open, and then delays the control of the load switch to disconnect, and uses the negative pressure of the vacuum storage chamber to extinguish the arc generated at the moment the load switch is disconnected; after the arc is extinguished, the controller can automatically control the first valve to close and the second valve to open, and control the vacuum pump to operate to vacuum the vacuum storage chamber, and then close the second valve after the vacuum is completed, and use the vacuum storage chamber to store the vacuum for use in the next arc extinguishing.

[0009] In some embodiments, an air pressure sensor is provided in the vacuum storage chamber, and the air pressure sensor is connected to a controller for monitoring the vacuum state in the vacuum storage chamber. When the air pressure sensor detects that the vacuum degree in the vacuum storage chamber meets a preset value, the controller controls the vacuum pump to stop running; otherwise, the controller controls the vacuum pump to continue running.

[0010] In some embodiments, the first valve is a manual-automatic integrated valve. The first valve is designed as a manual-automatic integrated valve. On the one hand, the current value flowing through the load switch can be monitored by a current transformer. When the current value is too large, the controller can automatically control the first valve to open to prepare for arc extinguishing, and then control the load switch to disconnect, which can well cope with the abnormal situation of excessively high current value and ensure the safe operation of the load switch; on the other hand, when the load switch is opened or closed in a planned manner, the first valve can be manually opened to prepare for arc extinguishing, and then the opening and closing action of the load switch can be executed to meet the daily opening and closing needs of the load switch, and when the automatic control of the first valve fails, the opening and closing action of the first valve can also be executed by manual control, thereby ensuring the reliability of the arc extinguishing device.

[0011] In some embodiments, a temperature sensor connected to a controller is provided on one side of the load switch for monitoring the air temperature near the load switch. By setting a temperature sensor on one side of the load switch, the air temperature near the load switch can be monitored in real time. When the monitored temperature value exceeds a threshold value, the controller automatically opens the first valve, then delays opening the second valve and controls the vacuum pump to start running. The vacuum pump continuously generates negative pressure, so that the arc-absorbing tube sucks in the high-temperature air near the load switch contacts and discharges it from the outlet of the exhaust pipe, thereby accelerating the gas flow in the box, quickly cooling the contacts of the load switch, and improving the reliability and stability of the load switch operation.

[0012] In some embodiments, a heat sink is provided at the outlet of the exhaust pipe. By providing the heat sink at the outlet of the exhaust pipe, the heat in the high-temperature air discharged from the exhaust pipe can be quickly absorbed and the heat can be transferred to the box body, thereby improving the heat dissipation efficiency.

[0013] In some embodiments, the arc-absorbing tube is made of polytetrafluoroethylene material, which has good high temperature resistance and insulation properties.

[0014] In some embodiments, the arc-absorbing tube is a reducer tube, and the inner diameter of the inlet of the arc-absorbing tube is smaller than the inner diameter of the outlet. By designing the arc-absorbing tube as a reducer tube with a small inner diameter at the inlet and a large inner diameter at the outlet, on the one hand, the suction force at the inlet of the arc-absorbing tube can be enhanced, thereby improving the arc-absorbing effect; on the other hand, since the inner diameter of the outlet of the arc-absorbing tube is large and the suction force is small, the opening and closing of the first valve is easier, and the response time of the first valve can be further improved.

[0015] In some embodiments, the inner diameter of the arc-absorbing tube increases uniformly from the inlet to the outlet, with the purpose of making the air pressure change in the arc-absorbing tube more uniform, thereby reducing the noise generated during vacuum suction.

[0016] A second aspect of the present application provides an environmentally friendly gas-insulated ring main unit, comprising the above-mentioned arc extinguishing device, wherein the arc extinguishing device is installed in a charging unit of the environmentally friendly gas-insulated ring main unit.

[0017] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings in this application are used to illustrate preferred embodiments, so that those skilled in the art can clearly understand various other advantages and benefits, and should not be considered as limitations of this application. In addition, the same reference numerals are used throughout the drawings to represent the same or similar components.

[0019] Figure 1 This is a structural schematic diagram of an arc extinguishing device for a load switch in one embodiment of the present application;

[0020] Icons: 1. Arc absorption tube; 2. Vacuum storage chamber; 3. Vacuum pump; 4. Exhaust pipe; 5. Load switch; 6. First valve; 7. Second valve; 8. Air pressure sensor; 9. Temperature sensor; 10. Heat sink; 11. Inflatable unit. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0022] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two (including two), unless otherwise clearly and specifically defined.

[0024] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0025] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0026] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0027] See also Figure 1 In a first aspect, an embodiment of the present application provides an arc extinguishing device for a load switch, comprising an arc absorbing tube 1, a vacuum storage chamber, a vacuum pump 3 and an exhaust pipe 4, wherein the inlet of the arc absorbing tube 1 is opposite to the contact position between the moving contact and the static contact of the load switch 5, the outlet of the arc absorbing tube 1 is connected with the inlet of the vacuum storage chamber 2, the outlet of the vacuum storage chamber 2 is connected with the inlet of the exhaust pipe 4, and the vacuum pump 3 is installed on the exhaust pipe 4; the inlet and outlet of the vacuum storage chamber 2 are respectively provided with a first valve 6 and a second valve 7.

[0028] In the technical solution provided by the present application, by setting the arc-absorbing tube 1, the vacuum storage chamber, the vacuum pump 3 and the exhaust pipe 4, the first valve 6 can be closed in advance and the second valve 7 can be opened, the vacuum storage chamber 2 can be evacuated by the vacuum pump 3, and then the second valve 7 can be closed; before the load switch 5 needs to be opened and closed, the first valve 6 is opened first, and the negative pressure generated by the vacuum storage chamber 2 will make the arc-absorbing tube 1 have an air-absorbing function, and a negative pressure is generated at the entrance of the arc-absorbing tube 1, and then the load switch 5 is disconnected or closed, and the arc generated at the moment of disconnection or closing of the load switch 5 will be sucked into the arc-absorbing tube 1, thereby achieving the effect of arc extinguishing; the present application adopts vacuum arc absorbing to extinguish the arc, does not introduce any impurity gas, and can extinguish the arc quickly; compared with the traditional compressed gas arc extinguishing method, it can avoid the deterioration of the insulating air in the box due to long-term compression, thereby ensuring the performance of the insulating air. And there is no need to repeatedly compress the air, reduce the high-speed action mechanism, and reduce the requirements for the manufacturing materials of the device.

[0029] In a specific implementation, the inlet end of the arc-absorbing tube 1 is fixed to one side of the static contact of the load switch 5 through a high-temperature resistant insulating bracket.

[0030] In some embodiments, the arc extinguishing device also includes a controller and a current transformer, wherein the current transformer is used to monitor the current passing through the load switch 5; the controller is respectively connected to the current transformer, the actuator of the load switch 5, the first valve 6, the second valve 7, and the vacuum pump 3; when the current transformer detects that the current exceeds the current value that the load switch 5 can withstand, the controller automatically controls the first valve 6 to open, and then delays the control of the load switch 5 to disconnect (the delay time can be flexibly adjusted according to actual conditions), and uses the negative pressure of the vacuum storage chamber 2 to extinguish the arc generated at the moment the load switch 5 is disconnected; after the arc is extinguished, the controller can automatically control the first valve 6 to close and the second valve 7 to open, and control the vacuum pump 3 to run to vacuum the vacuum storage chamber 2, and then close the second valve 7 after the vacuum is completed, and use the vacuum storage chamber 2 to store the vacuum for the next arc extinguishing use.

[0031] In some embodiments, an air pressure sensor 8 is provided in the vacuum storage chamber 2, and the air pressure sensor 8 is connected to the controller for monitoring the vacuum state in the vacuum storage chamber 2. When the air pressure sensor 8 detects that the vacuum degree in the vacuum storage chamber 2 meets the preset value, the controller controls the vacuum pump 3 to stop running; otherwise, the controller controls the vacuum pump 3 to continue running.

[0032] In some embodiments, the first valve 6 is a manual-automatic valve (in this embodiment, a QT971X-16 manual-automatic valve can be used, and in the specific implementation process, other types of manual-automatic valves can also be selected according to actual conditions). The first valve 6 is designed as a manual-automatic valve. On the one hand, the current value flowing through the load switch 5 can be monitored by a current transformer. When the current value is too large, the controller can automatically control the first valve 6 to open to prepare for arc extinguishing, and then control the load switch 5 to disconnect, which can well deal with the abnormal situation of excessive current value and ensure the safe operation of the load switch 5; on the other hand, when the load switch 5 is opened or closed in a planned manner, the first valve 6 can be manually opened to prepare for arc extinguishing, and then the opening and closing action of the load switch 5 is executed to meet the daily opening and closing needs of the load switch 5, and when the automatic control of the first valve 6 fails, the opening and closing action of the first valve 6 can also be performed by manual control, thereby ensuring the reliability of the arc extinguishing device.

[0033] In a specific embodiment, the arc extinguishing device needs to act quickly during the arc extinguishing process, within milliseconds (ms), otherwise the arc will be difficult to extinguish; therefore, the electronic control execution response time of the first valve 6 in this embodiment is 1 to 5 ms. Under the control of the controller, the first valve 6 can complete the opening action within milliseconds, thereby meeting the arc extinguishing requirements.

[0034] In some embodiments, a temperature sensor 9 connected to the controller is provided on one side of the load switch 5 for monitoring the air temperature near the load switch 5 .

[0035] Since the convection heat transfer coefficient of dry air is lower than that of SF6, the temperature of the solid heating mechanism (i.e., the contact of the load switch 5) in the inflation unit 11 in the dry air insulated ring network cabinet will be higher than the temperature in the SF6 gas ring network cabinet. Temperature rise is an important indicator that affects the safety performance of the switchgear. If the temperature in the switchgear rises too high and too fast, the physical and chemical properties of the component materials will change, and the mechanical and electrical properties will decrease, which will lead to failures and even serious accidents. According to statistics, heating failures occur at a high proportion in switchgear failures and are the main type of failures. For dry air insulated ring network cabinets, due to the use of a compact sealed air box structure, it is not conducive to heat dissipation, and the heat dissipation performance of dry air is inferior to that of SF6. Therefore, temperature rise will increase the possibility of failure of the dry air insulated ring network cabinet and affect the service life of the dry air insulated ring network cabinet. In this embodiment, a temperature sensor 9 is arranged on one side of the load switch 5 to monitor the air temperature near the load switch 5 in real time. When the monitored temperature value exceeds the threshold value, the controller automatically opens the first valve 6, then delays the opening of the second valve 7 and controls the vacuum pump 3 to start running (the delay time can be flexibly adjusted according to actual conditions). The vacuum pump 3 continuously generates negative pressure, so that the arc-absorbing tube 1 sucks in the high-temperature air near the contacts of the load switch 5 and discharges it from the outlet of the exhaust pipe 4, which speeds up the gas flow in the box, can quickly cool the contacts of the load switch 5, and improves the reliability and stability of the operation of the load switch 5.

[0036] In a specific implementation, the temperature sensor 9 may be an infrared temperature sensor. The use of such a non-contact temperature sensor can ensure the safe operation of the temperature sensor 9 .

[0037] In a specific embodiment, a heat sink 10 is provided at the outlet of the exhaust pipe 4. By providing the heat sink 10 at the outlet of the exhaust pipe 4, the heat in the high-temperature air discharged from the exhaust pipe 4 can be quickly absorbed and the heat can be transferred to the box, thereby improving the heat dissipation efficiency.

[0038] In some embodiments, the arc-absorbing tube 1 is made of polytetrafluoroethylene material, which has good high temperature resistance and insulation properties.

[0039] In some embodiments, the arc-absorbing tube 1 is a reducer, and the inner diameter of the inlet of the arc-absorbing tube 1 is smaller than the inner diameter of the outlet. By designing the arc-absorbing tube 1 as a reducer with a small inner diameter of the inlet and a large inner diameter of the outlet, on the one hand, the suction force at the inlet of the arc-absorbing tube 1 can be enhanced (under the same flow rate, the smaller the inner diameter of the air pipe, the faster the flow rate, and the greater the negative pressure suction force generated), thereby improving the arc absorption effect; on the other hand, since the inner diameter of the outlet of the arc-absorbing tube 1 is large and the suction force is small, the opening and closing of the first valve 6 is easier, and the response time of the first valve 6 can be further improved.

[0040] In some embodiments, the inner diameter of the arc-absorbing tube 1 increases uniformly from the inlet to the outlet, with the purpose of making the air pressure change in the arc-absorbing tube 1 more uniform, thereby reducing the noise generated during vacuum suction.

[0041] A second aspect of an embodiment of the present application provides an environmentally friendly gas-insulated ring main unit, comprising the above-mentioned arc extinguishing device, wherein the arc extinguishing device is installed in a charging unit 11 of the environmentally friendly gas-insulated ring main unit.

[0042] The working process of the arc extinguishing device in this embodiment is as follows:

[0043] The vacuum pump 3 performs vacuum operation on the vacuum storage chamber in advance, the controller controls the first valve 6 to close, the second valve 7 to open, and controls the vacuum pump 3 to start running. At the same time, the vacuum degree in the vacuum storage chamber 2 is monitored in real time through the air pressure sensor 8. When the vacuum degree reaches the preset value, the second valve 7 is controlled to close, and the vacuum pump 3 is controlled to stop running.

[0044] When encountering an emergency (such as the current flowing through the load switch 5 exceeds the threshold), the controller automatically controls the first valve 6 to open, and delays the drive of the load switch 5 to disconnect. The negative pressure at the entrance of the arc-absorbing tube 1 will quickly extinguish the arc generated at the moment the load switch 5 contacts are disconnected, thereby ensuring the safe operation of the load switch 5.

[0045] When the temperature sensor 9 detects that the temperature near the load switch 5 exceeds the threshold, the controller automatically controls the first valve 6 to open, delays the control of the second valve 7 to open and controls the vacuum pump 3 to start running, and sucks the high-temperature air near the load switch 5 through the arc-absorbing tube 1 and discharges it from the outlet of the exhaust pipe 4. The heat in the high-temperature air will be transferred to the heat sink 10, thereby accelerating the heat dissipation of the contacts of the load switch 5; during the heat dissipation period, if it is necessary to disconnect the contacts of the load switch 5, they can be disconnected directly. At this time, the arc-absorbing tube 1 has the functions of absorbing the arc and dissipating heat at the same time.

[0046] When the contacts of the load switch 5 are opened in a planned manner, the first valve 6 can be opened first to put the arc-absorbing tube 1 in an air-absorbing state, and then the contacts of the load switch 5 are disconnected, and the negative pressure at the inlet of the arc-absorbing tube 1 is used to extinguish the arc generated at the moment the contacts of the load switch 5 are disconnected.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. An arc extinguishing device for a load switch, characterized in that: The invention comprises an arc-absorbing tube (1), a vacuum storage chamber, a vacuum pump (3) and an exhaust pipe (4); the inlet of the arc-absorbing tube (1) is directly opposite to the contact position between the moving contact and the static contact of the load switch (5); the outlet of the arc-absorbing tube (1) is connected to the inlet of the vacuum storage chamber (2); the outlet of the vacuum storage chamber (2) is connected to the inlet of the exhaust pipe (4); the vacuum pump (3) is installed on the exhaust pipe (4); the inlet and outlet of the vacuum storage chamber (2) are respectively provided with a first valve (6) and a second valve (7).

2. The arc extinguishing device for a load switch according to claim 1, characterized in that: The arc extinguishing device also includes a controller and a current transformer, wherein the current transformer is used to monitor the current passing through the load switch (5); the controller is respectively connected to the current transformer, the actuator of the load switch (5), the first valve (6), the second valve (7), and the vacuum pump (3).

3. The arc extinguishing device for a load switch according to claim 2, characterized in that: An air pressure sensor (8) is provided in the vacuum storage chamber (2); the air pressure sensor (8) is connected to a controller and is used to monitor the vacuum state in the vacuum storage chamber (2).

4. The arc extinguishing device for a load switch according to claim 2, characterized in that: The first valve (6) is a manual-automatic integrated valve.

5. The arc extinguishing device for a load switch according to claim 2, characterized in that: A temperature sensor (9) connected to the controller is provided on one side of the load switch (5) for monitoring the air temperature near the load switch (5).

6. The arc extinguishing device for a load switch according to claim 5, characterized in that: A heat sink (10) is provided at the outlet of the exhaust pipe (4).

7. The arc extinguishing device for a load switch according to claim 1, characterized in that: The arc-absorbing tube (1) is made of polytetrafluoroethylene material.

8. The arc extinguishing device for a load switch according to claim 1, characterized in that: The arc-absorbing tube (1) is a diameter-reducing tube, and the inner diameter of the inlet of the arc-absorbing tube (1) is smaller than the inner diameter of the outlet.

9. The arc extinguishing device for a load switch according to claim 8, characterized in that: The inner diameter of the arc-absorbing tube (1) increases uniformly from the inlet to the outlet.

10. An environmentally friendly gas insulated ring main unit, characterized in that: It comprises an arc extinguishing device as claimed in any one of claims 1 to 9, wherein the arc extinguishing device is installed in a charging unit (11) of an environmentally friendly gas-insulated ring main unit.

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