CN205304075U - Air insulation high tension switchgear - Google Patents

Abstract

The utility model discloses an air-insulated high-voltage switchgear, the specific structure of which comprises: a combined switch room, an instrument and mechanism room and a cable room; for dry air. The relative pressure of the gas in the sealed air chamber is 0.01-0.04 MPa. The utility model not only has reasonable structure, flexible wiring mode, no greenhouse gas emission, environmental protection, and low cost, but also has excellent insulation performance and strong adaptability to the environment, and can prevent the main circuit in the primary combination switch room of the high-voltage switchgear from being subjected to external harsh conditions. environmental impact.

Description

An air-insulated high-voltage switchgear

technical field

The utility model relates to the technical field of high-voltage switch cabinets, in particular to an air-insulated high-voltage switch cabinet.

Background technique

AC metal-enclosed high-voltage switchgear (usually referred to as high-voltage switchgear) is one of the most widely used electrical equipment in power systems, and is widely used in power generation systems, power distribution systems and power supply terminals in production and life.

At present, the cabinet of the existing high-voltage switchgear is usually equipped with a primary combination switch room (also known as a bus room), an instrument and mechanism room, and a cable room. The primary combination switch room is equipped with an upper bus bar and a The lower bus bar connected to the cable room, and the primary components such as the upper bus bar, disconnector, circuit breaker, lower bus bar, grounding switch, grounding bus bar, load switch, etc. are usually located in the primary combination switch room. In order to meet different application requirements, there are various types of high-voltage switchgears on the market. In terms of arc extinguishing methods, the switching devices (such as high-voltage circuit breakers) in the high-voltage switchgear basically adopt the vacuum arc extinguishing method, that is, vacuum is used as the breaking arc extinguishing method and the fracture insulation medium after disconnection. In terms of external insulation medium, high-voltage switchgear mainly has various insulation methods such as SF6 gas insulation, solid insulation, air insulation, and composite insulation based on air insulation. These insulation methods have their own characteristics. Each insulation method has its own characteristics. There is a large market holding capacity.

In the existing technology, high-voltage switchgears insulated with SF6 gas are not only costly, but also SF6 gas is a greenhouse gas that is extremely difficult to attenuate and has an impact far exceeding that of _CO2 . Once leaked, it will bring serious harm to the environment, and regular inspections are required for leaks ; more importantly, when the large current is broken, the strong arc discharge will cause some toxic gases with strong reaction ability in the SF6 gas. These toxic gases not only have hidden dangers of leakage, but also cause corrosion to cables and electrode materials. , so this kind of high-voltage switchgear must be limited in use. Except for the high-voltage switchgear with SF6 gas insulation, the main circuit of the existing high-voltage switchgear is generally not sealed, so the insulation of the main circuit of the high-voltage switchgear is easily affected by the external environment, for example: in high altitude, severe cold, In harsh environments such as humidity and pollution, there will be great circuit safety hazards between high-voltage devices inside the high-voltage switchgear.

Contents of the invention

Aiming at the above-mentioned deficiencies in the prior art, the utility model provides an air-insulated high-voltage switchgear, which not only has reasonable structure, flexible wiring mode, no greenhouse gas emission, environmental protection, and low cost, but also has excellent insulation performance and is environmentally friendly. The adaptability is strong, which can prevent the main circuit in the primary combined switch room from being affected by the external harsh environment.

The purpose of this utility model is achieved by the following technical solutions:

An air-insulated high-voltage switchgear, including: a combined switch room, an instrument and mechanism room, and a cable room. The chamber as a whole is a sealed air chamber, and the gas filled in the sealed air chamber is dry air.

Preferably, the relative pressure of the gas in the sealed air chamber is 0.01-0.04 MPa.

Preferably, it also includes: a pressure relief chamber; the instrument and mechanism chamber is arranged in front of the primary combination switch chamber and above the cable chamber; and the pressure relief chamber is arranged below the primary combination switch chamber and behind the cable chamber; A pressure relief device for releasing the pressure of the sealed air chamber is arranged in the pressure relief chamber.

Preferably, the primary elements in the airtight chamber include an upper busbar, a disconnector, a circuit breaker, a lower busbar, a grounding switch and a grounding busbar; an upper busbar bushing is arranged on the top plate of the primary combined switch room; the primary combined switch room and the cable The lower busbar casing is arranged on the partition between the chambers; the upper busbar extends into the primary combination switch room through the upper busbar casing, and is electrically connected with the input end of the isolating switch; the output end of the isolating switch is connected with the input end of the circuit breaker The output terminal of the circuit breaker is electrically connected to the lower busbar; the lower busbar is electrically connected to the cable in the cable room through the lower busbar bushing; the input terminal of the grounding switch is electrically connected to the output terminal of the isolating switch or the input terminal of the circuit breaker. connected, and the grounding bus is electrically connected to the output terminal of the grounding switch.

Preferably, the isolating switch and the grounding switch are an integrated three-position isolating and grounding switch; the three-position isolating and grounding switch includes: a common movable contact for isolating and grounding, a static contact for the isolating switch, and a static contact for the grounding switch; The upper busbar is electrically connected to the static contact of the isolating switch, the grounding busbar is electrically connected to the static contact of the grounding switch, the common movable contact of the isolated ground is electrically connected to the input end of the circuit breaker, and the common movable contact of the isolated ground is connected to the static contact of the isolating switch Switching between the static contact of the grounding switch.

Preferably, the primary elements in the sealed air chamber include an upper busbar, a disconnector, a load switch, a lower busbar, a grounding switch and a grounding busbar; an upper busbar bushing is arranged on the top plate of the primary combined switch room; the primary combined switch room and the cable The lower busbar bushing is set on the partition between the chambers; the upper busbar extends into the primary combined switch room through the upper busbar bushing, and is electrically connected to the input end of the isolating switch; the output end of the isolating switch is connected to the input of the load switch The output end of the load switch is electrically connected to the lower busbar; the lower busbar is electrically connected to the cable in the cable room through the lower busbar bushing; the input end of the grounding switch is electrically connected to the output end of the isolating switch or the input end of the load switch connection, while the grounding bus is electrically connected to the output terminal of the grounding switch.

Preferably, the isolating switch and the grounding switch are an integrated three-position isolating and grounding switch; the three-position isolating and grounding switch includes: a common movable contact for isolating and grounding, a static contact for the isolating switch, and a static contact for the grounding switch; The upper bus bar is electrically connected to the static contact of the isolating switch, the grounding bus bar is electrically connected to the static contact of the grounding switch, the common moving contact of the isolated ground is electrically connected to the input end of the load switch, and the common moving contact of the isolated ground is connected to the static contact of the isolating switch Switching between the static contact of the grounding switch.

Preferably, the instrument and mechanism room includes an instrument room and a mechanism room; the instrument room is located directly above the mechanism room.

It can be seen from the above-mentioned technical solution provided by the utility model that the air-insulated high-voltage switchgear provided by the embodiment of the utility model sets the primary combined switch chamber as a sealed air chamber as a whole, and the primary components in the primary combined switch room and the space between these components The electrical connection positions of all are in the sealed air chamber, and dry air is used as the outer insulating medium in the sealed air chamber, and the relative pressure of the gas in the sealed air chamber is 0.01-0.04MPa, which not only overcomes the problem of using SF6 gas in the prior art As an external insulating medium, there are disadvantages such as high cost, serious damage to the environment after leakage, and possible production of toxic gases. It also improves the adaptability of the high-voltage switchgear to the environment, so that the main circuit in the primary combined switchgear can avoid being affected by the external harsh environment. It can work safely and reliably in harsh environments such as high altitude, severe cold, humidity, and dirt.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention , those skilled in the art can also obtain other drawings based on these drawings without creative work.

Figure 1 is a schematic diagram of the unit cabinet structure of the air-insulated high-voltage switchgear provided by the embodiment of the utility model;

Fig. 2 is a schematic diagram 2 of the unit cabinet structure of the air-insulated high-voltage switchgear provided by the embodiment of the utility model;

Fig. 3 is a structural schematic diagram 1 of the shared cabinet of the air-insulated high-voltage switchgear provided by the embodiment of the utility model;

Fig. 4 is a structural schematic diagram 2 of the shared cabinet of the air-insulated high-voltage switchgear provided by the embodiment of the utility model;

The meanings of the symbols in the figure are: A, primary combination switch room, B, instrument and mechanism room, B1, instrument room, B2, mechanism room, C, pressure relief room, D, cable room, 1, upper busbar bushing, 2. Upper busbar, 31. Common movable contact for isolation and grounding, 32. Static contact of isolation switch, 33. Static contact of grounding switch, 4. Circuit breaker, 5. Lower busbar, 6. Lower busbar bushing, 7. Grounding Bus bar, 8, grounding bolt, 9, pressure relief device.

detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. . Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present utility model.

The air-insulated high-voltage switchgear provided by the utility model is described in detail below.

As shown in Figure 1, Figure 2, Figure 3 and Figure 4, an air-insulated high-voltage switchgear, its specific structure may include: a combined switch room, an instrument and mechanism room, and a cable room. The upper bus bar connected to the outside of the switchgear and the lower bus bar connected to the cable room; the primary combination switch room is a sealed air room as a whole, and the gas filled in the sealed air room is dry air.

Specifically, the air-insulated high-voltage switchgear sets the primary combined switch chamber as a sealed air chamber, and the sealed air chamber is filled with dry air as an external insulating medium, so the primary elements in the primary combined switch chamber (these primary elements can be Including busbar, isolating switch, circuit breaker, grounding switch, grounding busbar, etc.) and the electrical connection positions between these components are all under the insulation protection of dry air, so that the main circuit and grounding circuit in the primary combination switch room will not be affected. Influenced by the harsh external environment, it can work more safely and reliably in harsh environments such as high altitude, severe cold, humidity, and pollution, and prolong the service life of each component in the primary combination switch room. At the same time, dry air is used instead of SF6 gas as the external insulation medium, which can overcome the high cost of using SF6 gas as the external insulation medium in the prior art, serious damage to the environment after leakage, possible production of toxic gases, and the need for on-site gas leakage Detection and other shortcomings, so that under the condition of ensuring that the high-voltage switchgear has good insulation performance, it can achieve no greenhouse gas emissions, stable and reliable performance, and reduce costs.

Among them, the components of the air-insulated high-voltage switchgear may include the following implementations:

(1) The relative pressure of the gas in the sealed air chamber (that is, the primary combined switch chamber) is preferably 0.01-0.04MPa (the relative pressure refers to the high pressure in the sealed air chamber based on the external atmospheric pressure of the high-voltage switchgear) In actual production, the external atmospheric pressure of the high-voltage switchgear can adopt the standard atmospheric pressure of 20°C and 101.3kPa), that is to say, the dry air in the sealed air chamber is preferably slightly positive pressure, which can not only Prevent the air with lower external pressure from entering the sealed air chamber, and reduce the probability of gas leakage in the sealed air chamber; if the relative pressure of the gas in the sealed air chamber is greater than 0.04MPa, the sealed air chamber will The chances of gas leaks will increase dramatically. It should be noted that even if the air pressure in the sealed air chamber is the same as the external atmospheric pressure of the high-voltage switchgear, the air-insulated high-voltage switchgear can still maintain a high dielectric strength and will not affect normal operation.

(2) The air-insulated high-voltage switchgear may also include: a pressure relief room; the instrument and mechanism room is located in front of the primary combination switch room and above the cable room, and the pressure relief room is located below the primary combination switch room. And it is located at the rear of the cable room, so that setting the pressure relief chamber under the primary combination switch room can facilitate the pressure relief of the primary combination switch room, and setting the cable room under the front and bottom of the primary combination switch room can facilitate the installation of cables.

In practical applications, it is best to divide the instrument and mechanism room into two independent compartments, the instrument room and the mechanism room, and the instrument room is preferably located directly above the mechanism room, which not only facilitates the operation and operation of the mechanisms in the mechanism room Maintenance, and it is also convenient to observe and debug the instruments in the instrument room. The pressure relief chamber can be provided with a pressure relief device for depressurizing the sealed air chamber, and the pressure relief device is preferably fixed on the partition between the primary combination switch chamber and the pressure relief chamber, which not only facilitates the The pressure relief device is installed and overhauled, and the convenience of pressure relief for the primary combination switch room is further improved.

(3) The primary components in the sealed air chamber of the air-insulated high-voltage switchgear may include an upper busbar, an isolating switch, a circuit breaker, a lower busbar, a grounding switch and a grounding busbar.

There is an upper busbar sleeve on the top plate of the primary combined switch room, and the sealing treatment is carried out between the top plate of the primary combined switch room and the upper bus bar sleeve; and the lower bus sleeve is set on the partition between the primary combined switch room and the cable room Tube, seal between the partition between the primary combination switch room and the cable room and the lower busbar bushing.

The upper busbar passes through the upper busbar bushing and extends into the primary combination switch chamber (in actual production, the upper busbar and the upper busbar bushing are usually cast into one piece, and there is no gap between the upper busbar and the upper busbar bushing, so this Good airtightness between the upper busbar and the upper busbar casing can be guaranteed), and it is electrically connected to the input end of the isolating switch; the output end of the isolating switch is electrically connected to the input end of the circuit breaker, and the output end of the circuit breaker is electrically connected to the The lower busbar is electrically connected; the lower busbar is electrically connected to the cables in the cable room through the lower busbar bushing (in actual production, the lower busbar and the lower busbar bushing are usually cast into one piece, and the lower busbar and the lower busbar bushing are There is also no gap, so this can ensure good airtightness between the lower busbar and the lower busbar bushing).

The input terminal of the grounding switch is electrically connected with the output terminal of the isolating switch or the input terminal of the circuit breaker, so that when the grounding switch is closed, the circuit breaker is connected in series to the grounding circuit, and the vacuum interrupter of the circuit breaker can replace the grounding switch for closing Short-circuit operation, which overcomes the shortcomings of the grounding switch that cannot quickly close the grounding current many times and needs maintenance after closing the short circuit, and prolongs the service life of the grounding switch. In actual production, one end of the grounding busbar is electrically connected to the output end of the grounding switch, while the other end of the grounding busbar is electrically connected to the grounding bolt fixed on the metal shell or metal partition to realize the grounding operation of the grounding loop. Thus ensuring the safety of operation and maintenance personnel. It should be noted that, according to different circuit requirements, the air-insulated high-voltage switchgear can replace the circuit breaker with a load switch.

(4) In the circuit in the sealed air chamber described in (3) above, the isolating switch and the grounding switch may be an integrated three-position isolating and grounding switch; the specific structure of the three-position isolating and grounding switch may include: Isolation and grounding common moving contact, isolating switch static contact and grounding switch static contact, the upper busbar is electrically connected to the isolating switch static contact, the grounding busbar is electrically connected to the grounding switch static contact, and the isolation and grounding common moving contact is connected to the circuit breaker The input end of the grounding switch is electrically connected, and the common moving contact of the isolation grounding switch is switched between the static contact of the isolation switch and the static contact of the grounding switch, so as to realize the closing operation of the isolating switch and the closing switch of the grounding switch. The structural design of the three-position isolating and grounding switch reduces the number of connecting parts while ensuring that the isolation function and the grounding function remain unchanged, so that the connection structure of each component is more concise, compact and reliable, and the volume is smaller.

In summary, the embodiment of the utility model not only has reasonable structure, flexible wiring mode, no greenhouse gas emission, environmental protection, and low cost, but also has excellent insulation performance and strong adaptability to the environment, which can avoid the main circuit in the primary combination switch room. affected by the harsh external environment.

In order to more clearly demonstrate the technical solutions and technical effects provided by the utility model, the air-insulated high-voltage switchgear provided by the utility model embodiment is described in detail below with reference to specific embodiments and drawings.

Example 1

As shown in Figure 1 and Figure 2, a unit cabinet-type air-insulated high-voltage switchgear, its specific structure includes: a combined switch room A, instrument and mechanism room B, pressure relief room C and cable room D; instrument and mechanism room B is set in front of the primary combined switch room A and above the cable room D, while the pressure relief chamber C is set under the primary combined switch room A and behind the cable room D.

Specifically, each component of the air-insulated high-voltage switchgear includes the following embodiments:

(1) The instrument and mechanism room B is divided into two independent compartments, the instrument room B1 and the mechanism room B2, and the instrument room B1 is located directly above the mechanism room B2; this not only facilitates the operation of the mechanisms in the mechanism room B2 and maintenance, but also facilitates the observation and debugging of the instruments in the instrument room B1.

(2) The primary combined switch chamber C is a sealed air chamber as a whole, and the gas in the sealed air chamber is dry air, and the relative pressure of the gas in the sealed air chamber is 0.01-0.04MPa, so the primary combined switch chamber C The primary components such as the upper bus bar 2, the common moving contact 31 for isolation and grounding, the static contact 32 of the isolating switch, the static contact 33 of the grounding switch, the circuit breaker 4, the lower bus bar 5, and the grounding bus bar 7, and the electrical connection positions between these components are all in the Under the insulation protection of slightly positive pressure dry air, this can not only overcome the shortcomings of using SF6 gas as the external insulating medium in the prior art, but also prevent the main circuit and grounding circuit in the primary combined switch room C from being affected by external Influenced by harsh environments, it can work more safely and reliably in harsh environments such as high altitude, severe cold, humidity, and pollution, and prolongs the service life of each component in the primary combined switch room C.

(3) The primary components in the primary combination switch room C include the upper busbar 2, the three-position isolation grounding switch, the circuit breaker 4, the lower busbar 5 and the grounding busbar 6, and the three-position isolation grounding Head 31, isolating switch static contact 32 and earthing switch static contact 33. An upper busbar bushing 1 is fixed on the top plate of the primary combined switch room A, and a lower busbar bushing 6 is fixed on the partition between the primary combined switch room A and the cable room D. The upper busbar 2 passes through the upper busbar casing 1 and extends into the primary combination switch room A, and is electrically connected with the static contact 32 of the isolating switch; one end of the grounding busbar 7 is electrically connected with the static contactor 33 of the grounding switch, and the grounding busbar 7 The other end is electrically connected with the grounding bolt 8 fixed on the metal partition; the common movable contact 31 of the isolation ground is electrically connected with the input end of the circuit breaker 4, and the common movable contact 31 of the isolation ground is connected between the static contact 32 of the isolation switch and the input end of the circuit breaker 4. Switching between the static contacts 33 of the grounding switch, so as to realize the closing operation of the isolating switch or the closing switch of the grounding switch; the output end of the circuit breaker 4 is electrically connected to the lower busbar 5; the lower busbar 5 passes through the lower busbar bushing 6 and the cable chamber Cables inside D are electrically connected.

When the common movable contact 31 for isolation and grounding is closed with the static contact 32 of the isolating switch, the isolating switch is closed, the grounding switch is disconnected, and the upper busbar 2 is connected to the main circuit; When closed, the grounding switch is closed, the isolating switch is opened, and the circuit breaker 4 is connected in series to the grounding circuit. The vacuum interrupter of the circuit breaker 4 can replace the grounding switch for closing and short-circuiting operations, which overcomes the problem that the grounding switch cannot be closed multiple times quickly. Shortcomings such as closing the grounding current and needing maintenance after closing the short circuit prolong the service life of the grounding switch. It should be noted that, according to different circuit requirements, the air-insulated high-voltage switchgear can replace the circuit breaker with a load switch. The structural design of the three-position isolating and grounding switch reduces the number of connecting parts while ensuring that the isolation function and the grounding function remain unchanged, so that the connection structure of each component is more concise, compact and reliable, and the volume is smaller.

(4) The pressure relief chamber C is located below the primary combination switch chamber A, and a pressure relief device for depressurizing the sealed air chamber is fixed on the partition between the primary combination switch chamber A and the pressure relief chamber C 9. This not only facilitates the installation and maintenance of the pressure relief device 9, but also further improves the convenience of depressurizing the primary combined switch chamber A.

It can be seen that the unit cabinet-type air-insulated high-voltage switchgear provided by the embodiment of the utility model not only has reasonable structure, flexible wiring mode, no greenhouse gas emission, green environmental protection, and low cost, but also has excellent insulation performance and strong adaptability to the environment , which can prevent the main circuit in the primary combination switch room from being affected by the external harsh environment.

Example 2

As shown in Fig. 3 and Fig. 4, the specific structure of an air-insulated high-voltage switchgear with a common cabinet type is basically similar to that of Embodiment 1. The main difference is that the main circuit and the grounding circuit in the primary combined switch room C are both Two sets, they share a sealed air chamber.

It can be seen that the common cabinet type air-insulated high-voltage switchgear provided by the embodiment of the utility model not only has reasonable structure, flexible wiring mode, no greenhouse gas emission, green environmental protection, and low cost, but also has excellent insulation performance and adaptability to the environment Strong, which can prevent the main circuit in the primary combination switch room from being affected by the external harsh environment.

In summary, the utility model not only has reasonable structure, flexible wiring, no greenhouse gas emission, environmental protection, and low cost, but also has excellent insulation performance and strong adaptability to the environment, which can prevent the main circuit in the primary combined switch room from being damaged. Influenced by harsh external environment.

The above is only a preferred embodiment of the utility model, but the scope of protection of the utility model is not limited thereto, and any person familiar with the technical field can easily think of All changes or replacements should fall within the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be based on the protection scope of the claims.

Claims (8)

1. An air-insulated high-voltage switchgear, comprising: a combined switch room, an instrument and mechanism room, and a cable room. The combined switch room is provided with an upper busbar connected to the outside of the high-voltage switchgear and a lower busbar connected to the cable room. The feature is that the primary combination switch chamber is a sealed air chamber as a whole, and the gas filled in the sealed air chamber is dry air. 2. The air-insulated high-voltage switchgear according to claim 1, wherein the relative pressure of the gas in the sealed air chamber is 0.01-0.04 MPa. 3. The air-insulated high-voltage switchgear according to claim 1 or 2, further comprising: a pressure relief chamber; the instrument and mechanism chamber is located in front of the primary combined switch chamber and above the cable chamber; The pressure chamber is arranged under the primary combination switch chamber and behind the cable chamber; a pressure relief device for depressurizing the sealed air chamber is provided in the pressure relief chamber. 4. The air-insulated high-voltage switchgear according to claim 1 or 2, wherein the primary elements in the sealed air chamber include an upper busbar, a disconnector, a circuit breaker, a lower busbar, a grounding switch and a grounding busbar; The upper busbar bushing is arranged on the top plate of the primary combined switch room; the lower busbar bushing is set on the partition between the primary combined switch room and the cable room; The upper busbar goes through the upper busbar bushing into the primary combination switch room and is electrically connected to the input end of the isolating switch; the output end of the isolating switch is electrically connected to the input end of the circuit breaker, and the output end of the circuit breaker is electrically connected to the lower busbar electrical Connection; the lower busbar passes through the lower busbar casing and is electrically connected to the cable in the cable room; The input end of the grounding switch is electrically connected to the output end of the isolating switch or the input end of the circuit breaker, and the grounding bus bar is electrically connected to the output end of the grounding switch. 5. The air-insulated high-voltage switchgear according to claim 4, wherein the isolating switch and the grounding switch are integrated three-position isolating and grounding switches; The three-position isolating grounding switch includes: isolating and grounding common movable contact, isolating switch static contact and grounding switch static contact; the upper busbar is electrically connected to the isolating switch static contact, and the grounding busbar is electrically connected to the grounding switch static contact. The common moving contact for isolation and grounding is electrically connected to the input end of the circuit breaker, and the common moving contact for isolation and grounding is switched between the static contact of the isolation switch and the static contact of the grounding switch. 6. The air-insulated high-voltage switchgear according to claim 1 or 2, wherein the primary elements in the sealed air chamber include an upper busbar, a disconnector switch, a load switch, a lower busbar, a grounding switch and a grounding busbar; The upper busbar bushing is arranged on the top plate of the primary combined switch room; the lower busbar bushing is set on the partition between the primary combined switch room and the cable room; The upper busbar goes through the upper busbar bushing into the primary combination switch room and is electrically connected to the input end of the isolating switch; the output end of the isolating switch is electrically connected to the input end of the load switch, and the output end of the load switch is electrically connected to the lower busbar electrical Connection; the lower busbar passes through the lower busbar casing and is electrically connected to the cable in the cable room; The input end of the grounding switch is electrically connected to the output end of the isolation switch or the input end of the load switch, and the grounding bus bar is electrically connected to the output end of the grounding switch. 7. The air-insulated high-voltage switchgear according to claim 6, wherein the isolating switch and the grounding switch are integrated three-position isolating and grounding switches; The three-position isolating and grounding switch includes: isolating and grounding common movable contacts, isolating switch static contacts and grounding switch static contacts; the upper busbar is electrically connected to the isolating switch static contacts, and the grounding busbar is electrically connected to the grounding switch static contacts The common movable contact of isolation and grounding is electrically connected with the input end of the load switch, and the common moving contact of isolation and grounding is switched between the static contact of the isolation switch and the static contact of the grounding switch. 8. The air-insulated high-voltage switchgear according to claim 1 or 2, wherein the instrument and mechanism room includes an instrument room and a mechanism room; the instrument room is located directly above the mechanism room.