CN205753147U - A 12kV current-carrying 1250A solid insulated switchgear - Google Patents

Abstract

The utility model discloses a 12kV solid insulated switch cabinet with a current carrying capacity of 1250A, including a box body, an insulating square cylinder is arranged in the middle of the box body, and a vacuum switch, an isolating switch and a grounding switch are arranged in the insulating square cylinder respectively. A metal shielding grounding layer is arranged on the outside of the insulating square cylinder, and the spring energy storage operating mechanism and the locking mechanism are arranged on one side of the insulating square cylinder, and are respectively connected to the vacuum switch, the isolating switch and the grounding switch. The utility model patent adopts a through-bundled busbar structure, which can ensure sufficient conductive cross-section regardless of the front and rear end wiring of the incoming and outgoing line system. The strap contact finger technology is adopted, and the contacts are evenly distributed, which reduces the conductor length, reduces the overall loop resistance, avoids the problem of uneven conduction in large current electrical contact, and solves the problem of inaccurate crimping caused by thermal deformation of the conductor, and the problem of malignant deformation caused by heating further. The rated current level of the 12kV solid insulated switch cabinet reaches 1250A.

Description

A 12kV current-carrying 1250A solid insulated switchgear

technical field

The utility model relates to the field of power transmission and distribution switch cabinets, in particular to a 12kV current-carrying 1250A solid insulation switch cabinet.

Background technique

The solid insulated ring network cabinet is a combination of three technologies: insulated busbar, combined unit miniaturization, and external solid sealing. The switch and high-voltage live parts are sealed and encapsulated with solid insulating materials such as epoxy resin. It is a new type of power distribution equipment that is mainly insulated from body to ground and phase to phase, and the conductive or semi-conductive shielding layer on its outer surface is reliably grounded. It is generally used by the State Grid and China Southern Power Grid.

With the popularization and application of domestic solid insulation cabinets in recent years, some of them have replaced expensive imported solid insulation cabinets, and have made indelible contributions to the revitalization of famous industries and the realization of the "Chinese Dream". However, the problems existing in domestic solid insulation cabinets should not be ignored. Throughout the production situation of domestic solid insulation cabinets, in addition to the two types of solid insulation cabinet structures: integral type and A, B, and C phase separation types, the internal component layout of each design manufacturer is different, and the quality of solid insulation cabinets varies. For example: Most design manufacturers are limited to no technical force, domestic professional software, and the main insulation module has not carried out simulation research on stress, electric field, partial discharge, electric field shielding, etc., and rely on experience to design; another example: most of the vacuum interrupters in the main insulation module It is arranged vertically, and the operating mechanism is placed on the upper part of the main insulation module; the busbar connection method used on the main insulation module is an external tapered connection. Since the operating mechanism is placed on the upper part of the main insulation module, and the solid insulation ring network cabinet must ensure a cable connection height of more than 650mm, the operating height of the solid insulation ring network cabinet is too high; the size is also large.

The existing design has the following disadvantages:

1. At present, almost all domestic solid insulation cabinets use a slightly cylindrical cable insulation terminal structure for the cable entry and exit lines, which can only pass a rated current of 630A, and the scope of use of the solid insulation cabinet is limited. The incoming and outgoing cables of the solid insulation cabinet are connected by copper bolts at the cable heads of slightly cylindrical terminals to realize current conduction. The conductive effective cross-sectional area of the M16 bolt is 154mm ² , and there is no problem passing the rated current of 630A. However, when the branch leads are connected in series and the rated current is 1250A, the heat generated by the current connection structure of the cable head and the bus bar will increase by at least 50 %. Cold deformation problem: Due to the gravity of the cable, the cable will drop. Under the action of the cable drop, the part of the terminal post will have a cold deformation problem. The contact bolt will be separated from the upper end of the terminal, and the thread will be relatively deformed, resulting in an unbalanced thread contact pressure. As the contact pressure on the upper part of the thread becomes smaller; the lower part is squeezed and the contact area is reduced, resulting in an increase in contact resistance, especially once these gaps are affected by condensation, rust and oxidation will occur, and the oxide will further accelerate this malignant process. cycle, so that the corrosion is so severe that it cannot withstand the normal rated current. Thermal deformation problem, the connecting part of the cable terminal and the terminal pile is heated due to the influence of the current in the running state, and the metal parts expand. When the load decreases, the temperature of the metal parts decreases, and the cold and heat expand and contract. Permanent deformation, relaxation of the overall contact part, resulting in increased contact resistance and increased heat generated by stimulation. It should be important and necessary to improve the structure of the insulation terminal head of the incoming and outgoing wires of high-current cables.

2. There are too many edges and corners in the shape of the conductive parts and there are no effective measures to change the defects of the concentration of the electric field, resulting in a reduction in the life of the insulating parts. Generally, the insulating material is affected by the electric field in about three years, resulting in obvious discharge phenomena. Some key parts are deformed and aged, resulting in ground faults and phase-to-phase short-circuit faults. Therefore, when there is no conductive or semi-conductive shielding layer on the outside of the solid insulator, there is a safety hazard that the induced current cannot be touched by human hands; and when the solid insulator is grounded with a conductive or semi-conductive shielding layer on the outside, the partial discharge index exceeds the industry standard requirements. .

3. With the blade-shaped structure of the isolating switch, the problem of partial discharge cannot be solved. The blade is inserted into the static contact. Due to the large force, it cannot be fully inserted, the contact is incomplete, and the dynamic and thermal stability is poor. The air insulation gap of the original structure is too small, the insulation creepage distance is too small, and there is no room for improvement. prevent the device from functioning properly at high altitudes.

4. The distance between the vacuum interrupter of some traditional solid insulated cabinets and the connecting busbar is not enough. During the arcing period, the longitudinal magnetic field between the contacts is attracted by the magnetic field of the connecting busbar instead of forming a uniform rotating magnetic field, which is easy to melt the copper-chromium alloy contacts.

5. Most of the moving and static contacts of the isolating switch designed in some solid cabinets are installed on an insulator, whether there is grounding isolation in the middle, leakage current passes through, and there is a problem of false fracture. After the switchgear has been used for several years, the insulation level of the switchgear has decreased year by year due to discharge, attached particles, etc., which eventually leads to equipment insulation failure. Therefore, GB1985-2003 "High Voltage Isolating Switches and Grounding Switches" clearly stipulates that there should be no dangerous leakage current between the isolation fractures.

6. Some solid insulated cabinets use two-position isolating switches, and some products use three-position isolating switches, or are equipped with independent grounding switches. The use of a three-position isolating switch can solve the grounding problem of fully insulated equipment, but it will lead to too long travel of the moving contact and increase the height or depth of the equipment.

Utility model content

In view of the above problems, the utility model aims to provide a safe and stable 12kV current-carrying 1250A solid insulated switchgear.

In order to achieve this technical purpose, the solution of this utility model is: a 12kV current-carrying 1250A solid insulated switchgear, including a box body, a panel, a locking mechanism, a spring energy storage operating mechanism, a busbar seat, an outgoing line insulating seat, and an insulating square cylinder. The middle part of the box is provided with an insulating square cylinder consisting of an upper insulating base and a lower insulating base, and a polytetrafluoroethylene is arranged in a labyrinth structure between the upper insulating base and the lower insulating base to increase the insulation creepage distance. Vinyl insulating board, the upper insulating base and the lower insulating base are respectively provided with a vacuum switch, an isolating switch, a grounding switch, a busbar seat, and an outgoing line insulating seat, and a spring energy storage operating mechanism is arranged outside the insulating square cylinder. The spring energy storage operating mechanism is drivingly connected to the locking mechanism, and the locking mechanism is drivingly connected to the vacuum switch, the isolation switch and the grounding switch respectively;

The vacuum switch, isolating switch, and grounding switch are respectively electrically connected to the conductive rod. The upper part of the box is provided with a busbar seat, the bottom of the box is provided with an outlet insulating seat, and the front of the box is provided with a transparent observation panel for easy observation. window;

The isolating switch includes isolating static contacts, isolating moving contacts, insulating sleeves, and isolating connecting ends. The isolating static contacts are fixed to the insulating square cylinder. The head is inserted into the isolated static contact through horizontal movement, and the tail end of the isolated static contact is covered with an insulating sleeve for increasing the creepage distance. The tail end of the isolated movable contact is fixedly connected to the isolated connection end. The locking mechanism is driven and connected to the isolation connection end, the isolation static contact is electrically connected to the conductive rod, and the insulating sleeve is an umbrella skirt structure;

The grounding switch includes a grounding static contact, a grounding movable contact, and a grounding connection end. The grounding static contact is arranged at the front end of the grounding movable contact, and the tail end of the grounding movable contact is fixedly connected to the isolation connection end. The above-mentioned locking mechanism is driven and connected to the ground connection end;

The vacuum switch includes an air compartment, a vacuum interrupter, and a circuit breaker insulation pull rod. The air compartment is arranged between the vacuum interrupter and the isolation switch, and the vacuum interrupter is horizontally arranged at a safe distance from the bus base. Below, the end of the vacuum interrupter is connected to the insulating pull rod of the circuit breaker.

As a preference, the isolated movable contact and the isolated static contact are both cylindrical structures, the two sets of isolated movable contacts are combined in a U-shaped structure, and the front ends of the two isolated movable contacts are respectively connected to a set of isolated static contacts. Set in parallel between group isolated static contacts.

Preferably, spring contact fingers are respectively arranged on the bus bar seat and the static grounding contact.

As a preference, the outlet insulating seat includes an insulating shielding layer, a stress sleeve, an insulating cover, a fixing nut, and a sealing window for a live display, one end of the conductive rod is nested and fixed in the insulating shielding layer, and the lower end of the insulating shielding layer is provided with Stress sleeve, the outgoing cable passes through the stress sleeve and is electrically connected to the conductive rod. Two sets of outgoing cables are connected to the tail end of the conductive rod. The outgoing cable is fixedly connected to the conductive rod through a fixing nut, and an insulating Covering, the tail end of the conductive rod is also connected with a live display sealing window for displaying the charging condition of the conductive rod.

Preferably, the outside of the insulating square cylinder is spray-coated with a semiconductive layer with a resistivity of 10 ⁸ -10 ¹² Ω.

Preferably, the conducting rod, the isolating movable contact and the grounding movable contact are all flexible transition structures without sharp corners.

Preferably, the upper insulating base and the lower insulating base joint of the insulating square cylinder are provided with an O-ring for isolating moist gas.

Preferably, an intelligent controller and a sensor are further arranged in the box, and the sensor is electrically connected to the intelligent controller.

The beneficial effect of the utility model is that the conductive rod of the utility model patent application and the outgoing cable are connected by an outgoing line insulating seat structure that runs through the cluster busbar, so that sufficient conductive cross-section can be guaranteed no matter the wiring at the front and rear ends of the incoming and outgoing line system , after adopting the outgoing line insulation seat of this structure, the rated current of the incoming and outgoing cable joints is increased from 630A to 1250A, and at the same time, the heat generation of the equipment is reduced, and the operating life of the equipment is improved;

All the internal conductive parts adopt flexible transition without obvious sharp corners, which overcomes the sharp discharge phenomenon caused by the concentration of electric field, so that the partial discharge is significantly reduced. , the overall electric field is uniform; after the enclosure is grounded with a conductive or semi-conductive shielding layer, the partial discharge meets the requirements of the industry standard;

The vacuum interrupter adopts a horizontal layout structure that deviates from the safe distance of the busbar seat to avoid the interference of the busbar magnetic field. The longitudinal magnetic field generated by the contact gap during the arcing of the vacuum interrupter can make the arc evenly distributed on the contact surface and maintain a low arc voltage. , so that the vacuum interrupter has a high post-arc dielectric strength recovery speed, small arc energy and small corrosion rate, which improves the ability and service life of the vacuum interrupter to break the current. Increase the conductive cross-section, evenly distribute the contacts, reduce the overall circuit resistance, avoid the problem of uneven conduction in the high-current electrical contact, and solve the problem of crimping and less contact caused by thermal deformation of the conductor and the further heating and vicious deformation caused by it. Problem, in the case of the same conductive cross-section, the current-carrying capacity is significantly improved;

The isolating switch adopts a double-fracture, double-cylindrical isolating movable contact horizontally moving to insert the isolating static contact spring finger flexible connection structure. There is a safe air insulation gap between the upper and lower isolated moving contacts, there is no problem of false fracture leakage current passing through, and the moving stroke of the moving contact is reduced by half; in line with the clear provisions in GB1985-2003 "High Voltage Isolating Switches and Grounding Switches": "Isolation There should be no dangerous leakage current between the fractures." Requirements.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is the structural representation of the front view of the utility model;

Fig. 3 is the structural schematic diagram of the outlet insulating seat of the present utility model;

Fig. 4 is the local structure schematic diagram of the isolating switch of the present utility model;

Fig. 5 is the structural representation of the top view surface of the utility model;

Fig. 6 is a structural schematic diagram of the spring contact fingers of the bus seat part of the utility model;

Fig. 7 is a schematic structural view of the combination of the upper insulating base and the lower insulating base of the present invention.

detailed description

Below in conjunction with accompanying drawing and specific embodiment the utility model is described in further detail.

As shown in Figures 1-7, the specific embodiment of the utility model is a 12kV current-carrying 1250A solid insulated switchgear, including a box body 1, a panel 13, a locking mechanism 3, a spring energy storage operating mechanism 2, and a busbar seat 9. Outlet insulating seat 7, the middle part of the box body 1 is provided with an insulating square cylinder composed of an upper insulating base 12 and a lower insulating base 11, and the increase between the upper insulating base 12 and the lower insulating base 11 A polytetrafluoroethylene insulating board 14 is arranged in the labyrinth groove of the insulation creepage distance, and the upper insulating base 12 and the lower insulating base 11 are respectively provided with a vacuum switch 4, an isolating switch 5, a grounding switch 6, and a bus bar seat. 9. Outlet insulating seat 7, a spring energy storage operating mechanism 2 is arranged outside the insulating square cylinder, and the spring energy storage operating mechanism 2 is drivingly connected to the locking mechanism 3, and the locking mechanism 3 is respectively connected to the vacuum switch 4, The isolating switch 5 and the grounding switch 6 are driven and connected. All the live parts of this application are enclosed in an insulating box, which cannot be touched by people, which ensures the safety of the operator; as shown in Figure 7, the labyrinth groove between the upper and lower insulating Vinyl fluoride insulation board can increase insulation creepage distance. As shown in Figure 5, the box body 1 contains a three-phase combined electrical insulation square cylinder of A, B, and C, and each phase insulation square cylinder is composed of an upper insulating base and a lower insulating base; where A , B, C phase bus base and A, B, C phase upper insulation base are solid insulation whole, and are arranged according to the phase sequence left, middle, right, rear, middle, front.

The vacuum switch 4, the isolating switch 5, and the grounding switch 6 are electrically connected to the conductive rod 8 respectively, the upper part of the box body 1 is provided with a bus bar seat 9, and the inner bottom of the box body 1 is provided with an outgoing line insulating seat 7. The front of the box body 1 is provided with a transparent observation window for easy observation. Through the transparent observation window set in the direction of the insulating box facing the panel, the operator can see the opening and closing position of the grounding switch of the isolating switch.

The isolating switch 5 includes an isolating static contact 51, an isolating movable contact 52, an insulating sleeve 53, and an isolating connection end 54. The isolating static contact 51 is fixed to the insulating square cylinder, and the top of the isolating static contact is provided with a spring The contact finger, the isolated movable contact 52 is inserted into the isolated static contact 51 through horizontal movement, and the tail end of the isolated static contact 51 is covered with an insulating sleeve 53 for increasing the creepage distance. The isolated movable contact The tail end of 52 is fixedly connected to the isolation connection end 54, the locking mechanism 3 is drivingly connected to the isolation connection end 54, the isolation static contact 51 is electrically connected to the conductive rod 8, and the insulating sleeve 53 is an umbrella skirt structure. The inner and outer sides of the insulating sleeve adopt shed-like paths to form a large creepage distance.

The grounding switch 6 includes a grounding static contact 61, a grounding movable contact 62, and a grounding connection end 63. The grounding static contact 61 is arranged at the front end of the grounding movable contact 62, and the tail end of the grounding movable contact 62 is connected to The isolation connection end 54 is fixedly connected, and the locking mechanism 3 is drivingly connected to the ground connection end 63;

As shown in Figures 1 and 4, the vacuum switch 4 includes an air compartment 41, a vacuum interrupter 42, and a circuit breaker insulating rod 43, and the air compartment 41 is arranged between the vacuum interrupter 42 and the isolating switch 5 , the vacuum interrupter 42 is horizontally arranged below the safety distance of the bus base 9 , and the tail end of the vacuum interrupter 42 is connected with a circuit breaker insulation pull rod 43 . Lighting lamp beads are also arranged in the air isolation chamber. The vacuum interrupter adopts a horizontal layout structure away from the safe distance of the bus base to avoid bus magnetic field interference. The longitudinal magnetic field generated by the gap between the contacts of the vacuum interrupter during arcing can make the arc evenly distributed on the contact surface and maintain a low arc voltage, so that the vacuum interrupter has a higher post-arc dielectric strength recovery speed and a small Arc energy and small corrosion rate. This design improves the current breaking capability and service life of the vacuum interrupter.

In order to improve the safety performance and reduce the motion-shaped stroke, the isolated movable contact 52 and the isolated static contact 51 are all cylindrical structures, and the two sets of isolated movable contacts 52 are combined in a U-shaped structure, and the front ends of the two isolated movable contacts 52 are respectively Each connection has a set of isolated static contacts 51, and the two sets of isolated static contacts 51 are arranged in parallel. Double-fracture, double-cylindrical moving contacts horizontally inserted into the isolation static contact spring contact finger flexible connection structure, there is a safe air insulation gap between the upper and lower isolation moving contacts, there is no problem of leakage current through false fractures, and the moving contacts are isolated at the same time The movement stroke of the head is reduced by half, and at the same time, sufficient air insulation gap is ensured, which meets the requirements of GB1985-2003 "High Voltage Isolating Switch and Grounding Switch": "There should be no dangerous leakage current between the isolation fractures."

In order to improve the stability of the connection, spring contact fingers 10 are respectively provided on the bus bar seat 9 and the static ground contact 61 . A spring contact finger 10 is provided on the top of the isolated static contact 51 . Through the spring contact fingers, the connection between the isolating static contact and the grounding static contact and the conductive rod can be made more stable. The strap contact function can be realized through the spring contact finger, which greatly increases the conductive cross section, and at the same time, the contacts are evenly distributed, reducing the length of the conductor, reducing the overall circuit resistance, avoiding the problem of uneven conduction in high-current electrical contact, and solving the thermal deformation of the conductor. Incorrect crimping And the further heating and malignant deformation caused by it. As shown in Figure 6, the bus bar seat also adopts a spring contact finger structure, which can greatly increase the conductive cross-section, and at the same time, the contacts are evenly distributed, reducing the length of the conductor, reducing the overall circuit resistance, and avoiding uneven conduction in high-current electrical contacts.

As shown in Figure 3, in order to ensure the stable connection between the conductive rod and the cable, the outlet insulating seat 7 includes an insulating shielding layer 71, a stress sleeve 72, an insulating cover 74, a fixing nut 73, and a live display sealing window 75. One end of the rod 8 is nested and fixed in the insulating shielding layer 71, the lower end of the insulating shielding layer 71 is provided with a stress sleeve 72, and the tail end of the conductive rod 8 is connected with two sets of outgoing cables 75, and the outgoing cables 75 pass through the stress sleeve 72 is electrically connected with the conductive rod 8, and the outgoing cable 75 is fixedly connected with the conductive rod 8 through the fixing nut 73. The fixing nut 73 is also covered with an insulating cover 74, and the tail end of the conductive rod 8 is also connected with a The charged display seal window 76 of the conductive rod charged situation. The conductive pole of the present application is connected with the outgoing cable by an outgoing line insulating seat structure that runs through the cluster busbar. Regardless of the wiring at the front and rear ends of the incoming and outgoing line system, sufficient conductive cross-sections can be guaranteed. After using the outgoing line insulating seat of this structure, the The rated current of the inlet and outlet cable joints is increased from 630A to 1250A.

In order to ensure the grounding of the insulating square cylinder and improve safety performance, the outside of the insulating square cylinder (ie, the upper insulating base 12 and the lower insulating base 11 ) is sprayed with a semiconductive layer with a resistivity of 10 ⁸ -10 ¹² Ω. The semi-conductive layer sprayed on the exposed surface of the insulating square tube can realize the grounding function, effectively eliminate the electrostatic induction, shield the internal electric field, and reduce the effect of partial discharge, so that the partial discharge meets the requirements of the industry standard.

In order to reduce the tip discharge phenomenon, the conductive rod 8, the isolating movable contact 52 and the grounding movable contact 62 are all flexible transitional structures without sharp corners. This application adopts flexible transitions on all internal conductive parts such as conductive rods, isolation movable contacts and grounding movable contacts, without obvious sharp corners, which overcomes the phenomenon of sharp discharge caused by electric field concentration, and significantly reduces partial discharge.

In order to increase the airtightness of the box, the combination of the upper insulating base 12 and the lower insulating base 11 of the insulating square cylinder is provided with an O-ring for isolating moist gas. Solve the problem of condensation affecting the insulation of solid insulated switchgear under high altitude conditions, and better solve the problem of low yield of insulating square tubes due to the constraints of production technology, materials, and inserts.

In order to facilitate the needs of different customers, an intelligent controller and a sensor are also arranged in the box 1, and the sensor is electrically connected to the intelligent controller. According to different needs, users can choose a variety of intelligent controllers such as FTU and other related sensor equipment to achieve different levels of control, measurement and protection functions.

According to the utility model patent, the conductive rod of this application and the outgoing cable are connected by an outgoing line insulation seat structure that runs through the cluster busbar. Regardless of the connection at the front and rear ends of the incoming and outgoing line system, sufficient conductive cross-section can be guaranteed. The outgoing line insulation using this structure After the seat, the rated current of the inlet and outlet cable joints is increased from 630A to 1250A, and at the same time, the heat generation of the equipment is reduced, and the operating life of the equipment is improved;

All the internal conductive parts adopt flexible transition without obvious sharp corners, which overcomes the sharp discharge phenomenon caused by the concentration of the electric field, so that the partial discharge is significantly reduced. The overall electric field is uniform; after the enclosure is grounded with a conductive or semi-conductive shielding layer, the partial discharge meets the requirements of the industry standard;

The vacuum interrupter adopts a horizontal layout structure that deviates from the safe distance of the busbar seat to avoid the interference of the busbar magnetic field. The longitudinal magnetic field generated by the contact gap during the arcing of the vacuum interrupter can make the arc evenly distributed on the contact surface and maintain a low arc voltage. , so that the vacuum interrupter has a high post-arc dielectric strength recovery speed, small arc energy and small corrosion rate, which improves the ability and service life of the vacuum interrupter to break the current. Increase the conductive cross-section, evenly distribute the contacts, reduce the overall circuit resistance, avoid the problem of uneven conduction in high-current electrical contacts, and solve the problem of unreal crimping, less point contact and further heating and vicious deformation caused by thermal deformation of conductors , in the case of the same conductive cross-section, the current-carrying capacity is significantly improved;

The isolating switch adopts a double-fracture, double-cylindrical isolating movable contact horizontally moving to insert the isolating static contact spring finger flexible connection structure. There is a safe air insulation gap between the upper and lower isolated moving contacts, there is no problem of false fracture leakage current passing through, and the moving stroke of the moving contact is reduced by half; in line with the clear provisions in GB1985-2003 "High Voltage Isolating Switches and Grounding Switches": "Isolation There should be no dangerous leakage current between the fractures." Requirements.

The utility model is more in line with the requirement of the compactness of the solid insulation ring main unit. The 12kV current-carrying 1250A solid insulated switchgear means that one switchgear can be used as two 630A switchgears, bringing good news to users and meeting the wider power consumption fields of national construction. Accelerate the elimination of SF ₆ gas-insulated ring network cabinets and promote the development of low-carbon ecological economy. The solid-sealed spine insulation structure of the vacuum interrupter of the traditional solid insulation cabinet is changed into a fence insulation structure. Enlarged shed skirt insulation structure and cylindrical through cluster bus cable entry and exit conductor device. Make it a real high-current solid insulation cabinet suitable for plateau environmental working conditions.

The above are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any minor modifications, equivalent replacements and improvements made to the above embodiments according to the technical essence of the present utility model shall be included in the Within the scope of protection of the technical solution of the utility model.

Claims (8)

1. A 12kV current-carrying 1250A solid insulated switchgear, characterized in that it includes a box body, a panel, a locking mechanism, a spring energy storage operating mechanism, a busbar seat, an outgoing line insulation seat, and an insulating square cylinder. The middle part of the box body is set by An insulating square tube composed of an upper insulating base and a lower insulating base. A polytetrafluoroethylene insulating board is arranged in a labyrinth structure that increases the insulation creepage distance between the upper insulating base and the lower insulating base. The insulating base and the lower insulating base are respectively equipped with a vacuum switch, a disconnector, a grounding switch, a bus bar seat, and an outlet insulating seat, and a spring energy storage operating mechanism is arranged outside the insulating square cylinder, and the spring energy storing operating mechanism is connected to the The locking mechanisms are driven and connected, and the locking mechanisms are respectively connected to the vacuum switch, the isolation switch, and the grounding switch; The vacuum switch, isolating switch, and grounding switch are respectively electrically connected to the conductive rod. The upper part of the box is provided with a busbar seat, the bottom of the box is provided with an outlet insulating seat, and the front of the box is provided with a transparent observation panel for easy observation. window; The isolating switch includes isolating static contacts, isolating moving contacts, insulating sleeves, and isolating connecting ends. The isolating static contacts are fixed to the insulating square cylinder. The head is inserted into the isolated static contact through horizontal movement, and the tail end of the isolated static contact is covered with an insulating sleeve for increasing the creepage distance. The tail end of the isolated movable contact is fixedly connected to the isolated connection end. The locking mechanism is driven and connected to the isolation connection end, the isolation static contact is electrically connected to the conductive rod, and the insulating sleeve is an umbrella skirt structure; The grounding switch includes a grounding static contact, a grounding movable contact, and a grounding connection end. The grounding static contact is arranged at the front end of the grounding movable contact, and the tail end of the grounding movable contact is fixedly connected to the isolation connection end. The above-mentioned locking mechanism is driven and connected to the ground connection end; The vacuum switch includes an air compartment, a vacuum interrupter, and a circuit breaker insulation pull rod. The air compartment is arranged between the vacuum interrupter and the isolation switch, and the vacuum interrupter is horizontally arranged at a safe distance from the bus base. Below, the end of the vacuum interrupter is connected to the insulating pull rod of the circuit breaker. 2. The 12kV current-carrying 1250A solid insulated switchgear according to claim 1, characterized in that: the isolated movable contact and the isolated static contact are both cylindrical structures, and the two sets of isolated movable contacts are combined in a U-shaped structure The front ends of the two sets of isolated moving contacts are respectively connected with a set of isolated static contacts, and the two sets of isolated static contacts are arranged in parallel. 3. The 12kV current-carrying 1250A solid insulated switchgear according to claim 1, characterized in that spring contact fingers are respectively provided on the bus base and the grounding static contact. 4. The 12kV current-carrying 1250A solid insulated switchgear according to claim 1, characterized in that: the outgoing line insulating seat includes an insulating shielding layer, a stress sleeve, an insulating cover, a fixing nut, and a live display sealing window, and the conductive One end of the rod is nested and fixed in the insulating shielding layer, the lower end of the insulating shielding layer is provided with a stress sleeve, and the outgoing cable passes through the stress sleeve and is electrically connected to the conductive rod. The cable is fixedly connected to the conductive rod through the fixing nut, and the fixing nut is covered with an insulating cover, and the tail end of the conductive rod is also connected with a live display sealing window for displaying the electrification of the conductive rod. 5. The 12kV current-carrying 1250A solid insulated switchgear according to claim 1, characterized in that: the outside of the insulating square cylinder is sprayed with a semi-conductive layer with a resistivity of 10 ⁸ -10 ¹² Ω. 6. The 12kV current-carrying 1250A solid insulated switchgear according to claim 1, characterized in that: the conductive rod, the isolating movable contact and the grounding movable contact are all flexible transition structures without sharp corners. 7. The 12kV current-carrying 1250A solid insulated switchgear according to claim 1, characterized in that: the joint of the upper insulating base and the lower insulating base of the insulating square cylinder is provided with an O-ring for isolating moist gas . 8. The 12kV current-carrying 1250A solid insulated switchgear according to claim 1, characterized in that: an intelligent controller and a sensor are also arranged in the box, and the sensor is electrically connected to the intelligent controller.