CN111192787B - A medium voltage gas insulated load switch - Google Patents

Abstract

The invention relates to a medium-voltage gas-insulated load switch, which comprises a static knife, a movable knife, a ground knife, an arc suppression coil, a static knife insulating beam, a movable knife insulating shaft, a ground knife insulating beam, a front plate, a rear plate, a rotating shaft and the like. The static knife is fixed on the static knife insulating beam, and the arc suppression coil is fixed at the lower part of the bus connecting surface of the static knife. The movable knife is arranged in the movable knife insulating shaft, and the movable knife insulating shaft rotates. The outer end of the movable knife is connected with the static knife or the ground knife, and the other end of the movable knife is positioned in a movable knife groove of the movable knife insulating shaft and is connected with the movable knife supporting seat through a shaft pin. The shaft pin and the rotating shaft are positioned on the same axis. The movable knife supporting seat is fixed on the movable knife insulating beam. The ground knife is fixed on the ground knife insulating beam. The load switch adopts an assembled structure, is simple and is easy to assemble; the electric field distribution is optimized, the partial discharge capacity of the product is reduced, and the service life of the product is prolonged; the insulating beam has good universality, light weight and high strength.

Description

A medium voltage gas insulated load switch

Technical Field

The invention relates to a medium-voltage gas-insulated load switch, belonging to the technical field of switch medium-voltage electrical equipment.

Background Art

Medium-voltage gas-insulated load switches (voltage level of 10kV-40.5kV) are the main distribution switchgear in the current distribution network. Its typical application is the medium-voltage sulfur hexafluoride gas-insulated metal-enclosed ring network cabinet, which integrates load switches, disconnectors, and grounding switches. There are already many public documents about this type of load switch. For example, document CN201478186U discloses a gas-insulated load switch that is equipped with an arc-starting tongue made of conductive material and a plate-like structure on the side of the separation between the moving knife rod and the static knife head. The arc-starting tongue is conductively connected to the static knife bus through an arc-extinguishing coil composed of multiple turns of wire. The direction of the magnetic lines of force generated in the center of the arc-extinguishing coil is as close as possible to the direction of the moving knife rod in the arc-starting stroke. Document CN201820690U, a high-voltage gas-insulated load switch, comprising a static knife busbar and a moving knife busbar mounted on an insulator, a static knife head connected to the static knife busbar, and a moving knife rod fixing seat and a moving knife rod connected to the moving knife busbar, a grounding knife head, a grounding busbar, and an insulating pull rod, a driving shaft and a crank arm for controlling the rotation of the moving knife rod, the insulating pull rod, the driving shaft and the crank arm drive the moving knife rod to realize the three states of closing, opening and grounding of the load switch, and a magnetic arc coil is installed above the opening motion track of the moving knife rod of each phase of the load switch; a voltage grading member is installed on both sides of the moving knife rod of each phase of the load switch; the moving knife rod, the static knife head and the magnetic arc coil of each phase of the load switch are isolated by an isolation cover. The existing load switch has the disadvantages of complex structural electric field distribution, difficult assembly and adjustment, and high cost.

Summary of the invention

The purpose of the present invention is to provide a medium voltage gas insulated load switch which has a simple structure, is easy to assemble and has a small size.

To achieve the above-mentioned purpose, the technical scheme of the present invention is: a medium-voltage gas-insulated load switch, including a static knife, a moving knife, a ground knife, an arc suppression coil, a static knife insulation beam, a moving knife insulation beam, a moving knife insulation shaft, a ground knife insulation beam, a front plate, a rear plate, a rotating shaft, etc. The static knife is fixed on the static knife insulation beam, and the arc suppression coil is fixed on the lower part of the busbar connection surface of the static knife. The moving knife is installed in the moving knife insulation shaft and rotates with the moving knife insulation shaft. The outer end of the moving knife is connected to the static knife or the ground knife, and the other end is located in the moving knife groove of the moving knife insulation shaft, and is connected to the moving knife support seat through an axle pin. The axle pin and the rotating shaft are located on the same axis. The moving knife support seat is fixed on the moving knife insulation beam. The ground knife is fixed on the ground knife insulation beam. The three-phase ground knife can be connected together through a grounding copper bar, and then connected to the rear plate, and connected to the ground wire through a stainless steel gas box; the ground knife can also be connected to the ground wire through a copper conductor in phase (mainly used in test cabinets).

The front and rear plates are cut and formed by steel plates. The front and rear plates have the same size and opening positions. There is a fixing hole for the static knife insulation beam on the upper part of one side of the front plate, a fixing hole for the moving knife insulation beam on the lower part of the same side, and a fixing hole for the ground knife insulation beam in the middle of the other side. There is a shaft fixing hole in the middle of the front plate, which is connected to the shaft through a bearing. There are switch fixing holes at the four corners of the front plate, and there are hooks on the rear plate, which are used to fix the load switch in the ring network cabinet gas box.

The static knife is a rectangular parallelepiped, with the upper part being the busbar connection surface and the lower part being the static knife surface. There is an arc extinguishing coil connection hole at the lower part of the busbar connection surface and a busbar connection hole at the upper part. The arc extinguishing coil connection hole is used to install the arc extinguishing coil. The busbar connection hole is used to fix the busbar of the ring network cabinet. There are two static knife screw holes at the rear of the static knife surface for fixing the static knife and the static knife insulation beam. The static knife surface is thicker than the busbar connection surface. The static knife surface is formed by stamping to improve strength. The static knife surface has a silver-plated layer with a thickness of 8-20 microns.

The arc extinguishing coil includes an arc-striking tongue, a metal ring, a plastic ring, a coil winding, an insulating layer, and a clamp. The metal ring is fixed to the plastic ring by a countersunk screw. The coil winding is located between the plastic ring and the clamp. There is an insulating layer between the clamp and the metal ring. There is an arc-striking tongue on the metal ring. There is an extension end of the clamp above the arc-striking tongue. There are fastening holes and fixing holes on the extension end. Bolts pass through the fastening holes to fasten the clamp to the coil winding. The fixing hole is used to connect with the static knife.

The static blade insulation beam is made of insulating injection molding material and processed by mold. There are bosses at both ends of the static blade insulation beam, and there are inserts inside that are connected to the front plate and the rear plate by bolts. Triangular prisms or cylinders for process positioning can also be set at both ends of the static blade insulation beam to cooperate with the process holes or grooves of the front plate or the rear plate, the purpose of which is to improve the installation accuracy. There is an insulating support layer on the static blade insulation beam to fix the static blade. There are 2 static blade fixing holes in the middle of the insulating support layer, and a static blade installation groove at the bottom for bolt fixing. There are insulating ribs around the static blade installation groove to avoid the bolts being exposed and affecting the electric field distribution. The static blade insulation beam is composed of nylon and glass fiber to form an insulation layer, which not only ensures electrical insulation, but also improves the strength and toughness of the insulation beam.

The moving knife insulating beam and the ground knife insulating beam have the same appearance and structure as the static knife insulating beam and can be produced in a unified manner using a mold, thereby improving the consistency and interchangeability of the insulating beams.

The main body of the moving knife insulating shaft is cylindrical, with a spline groove on the left end connected to the rotating shaft, and a rear shaft on the right end connected to the rear plate. There is a moving knife square hole on the moving knife insulating shaft, and below the moving knife square hole is a moving knife groove, and there are reinforcing ribs around the moving knife square hole. There are also insulating cross partitions on the moving knife insulating shaft, and there are grooves between the insulating cross partitions, which ensures the strength of the insulating shaft while reducing the weight of the moving knife insulating shaft.

The present invention adopts a static knife insulating beam, a moving knife insulating beam, and a ground knife insulating beam to connect with the front plate and the rear plate respectively by bolts to realize the assembled structure of the load switch. Compared with the existing load switch adopting the steel bracket welding mode, it reduces the mode of installing insulators on the bracket, then installing the busbar connection copper bar, and then installing the static knife copper parts, reduces the deformation of the frame caused by welding, and reduces the installation links and static knife adjustment links. The arc extinguishing coil eliminates the bracket that needs to be welded in the prior art, and there is no need to adjust the arc tongue angle. The clamp fastening end is adjusted to the static knife side to optimize the electric field distribution.

The beneficial effects of the present invention are: 1. The switch adopts an assembled structure, which is simple and easy to assemble; 2. The electric field distribution is optimized, the local discharge of the product is reduced, and the life of the product is increased; 3. The insulating beam has good versatility, light weight and high strength.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic diagram of a load switch of the present invention;

Figure 2 is a cross-sectional view of the load switch of the present invention;

Figure 3 is a top view of the load switch of the present invention;

Figure 4 is a right side view of the load switch of the present invention;

Figure 5 is a schematic diagram of the static knife of the present invention;

Figure 6 is a cross-sectional view of the static knife of the present invention;

Figure 7 is a cross-sectional view of the arc suppression coil of the present invention;

Figure 8 is a front view of the static blade insulating beam of the present invention;

Figure 9 is a cross-sectional view of the static blade insulating beam A-A of the present invention;

FIG10 is a schematic diagram of the insulating shaft of the movable knife of the present invention.

Description of the attached figures: 1. Stationary knife, 1.1. Busbar connection surface, 1.2. Stationary knife surface, 1.3. Stationary knife screw hole, 1.4. Arc extinguishing coil connection hole, 1.5. Busbar connection hole, 2. Arc extinguishing coil, 2.1. Arc-starting tongue, 2.2. Fixing hole, 2.3. Fastening hole, 2.4. Metal ring, 2.5. Plastic ring, 2.6. Countersunk screw, 2.7. Insulation layer, 2.8. Hoop, 2.9. Coil winding, 3. Moving knife, 3.1. Voltage equalizing piece, 3.2. Moving knife support seat, 4. Ground knife, 5. Grounding copper bar, 5.1. Grounding pad, 6. Stationary knife insulation beam, 6.1. Convex Table, 6.2, insulating support layer, 6.3, fixed hole of static knife, 6.4, insulating partition, 6.5, insulating layer, 6.6, static knife installation groove, 6.7, insulating rib, 7, insulating beam of ground knife, 8, front plate, 8.1, fixed hole of static knife insulating beam, 8.2, fixed hole of moving knife insulating beam, 8.3, fixed hole of ground knife insulating beam, 8.4, fixed hole of switch, 9, rear plate, 9.1, hook, 10, insulating shaft of moving knife, 10.1, square hole of moving knife, 10.2, groove of moving knife, 10.3, rear shaft, 10.4, reinforcing rib, 10.5, insulating cross partition, 11, rotating shaft, 12, insulating beam of moving knife.

DETAILED DESCRIPTION

The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

Embodiment 1:

As shown in Fig. 1, Fig. 2, Fig. 3 and Fig. 4, a medium-voltage gas-insulated load switch comprises a stationary knife 1, a moving knife 3, a ground knife 4, an arc-extinguishing coil 2, a stationary knife insulating beam 6, a moving knife insulating beam 12, a moving knife insulating shaft 10, a ground knife insulating beam 7, a front plate 8, a rear plate 9, a rotating shaft 11 and the like. The stationary knife insulating beam 6, the moving knife insulating beam 12 and the ground knife beam are respectively fixed to the front plate 8 and the rear plate 9 by bolts. The moving knife insulating shaft 10 is fixed to the front plate and the rear plate via the rotating shaft 11 and the bearing. The stationary knife 1 is fixed to the stationary knife insulating beam 6, and the arc-extinguishing coil 2 is fixed to the lower part of the busbar connection surface 1.1 of the stationary knife 1. A spacer can be added between the stationary knife 1 and the stationary knife insulating beam 6 to adjust the distance between the stationary knife and the moving knife. The moving knife 3 is installed in the moving knife square hole 10.1 of the moving knife insulating shaft 10 and rotates with the moving knife insulating shaft 10. The outer end of the moving knife 3 is connected to the static knife 1 or the ground knife 4, and the other end is located in the moving knife groove 10.2 of the moving knife insulating shaft 10, and is connected to the moving knife support seat 3.2 through an axle pin. The axle pin and the rotating shaft are located on the same axis. The moving knife support seat 3.2 is fixed on the moving knife insulating beam 12. A pad can also be added between the moving knife support seat 3.2 and the moving knife insulating beam 12. The ground knife 4 is fixed on the ground knife beam. The three-phase ground knife 4 can be connected together through the grounding copper busbar 5, and then connected to the front plate 8 or the rear plate 9, and connected to the ground wire through the stainless steel gas box. A grounding pad 5.1 can also be added between the grounding copper busbar 5 and the ground knife beam to adjust the distance between the ground knife and the moving knife beam. The ground knife beam can be made of metal, or a ground knife insulating beam 7 can be used. In a test cabinet for cable testing, only the ground knife insulating beam 7 can be used.

As shown in Figure 2, the stationary blade 1, the moving blade 3, and the moving blade support seat 3.2 are located on the same center line. The load switch adopts an assembled structure and does not require welding. There is no frame deformation caused by welding, which leads to the need to adjust the axis deviation of the moving blade. The moving blade 3 is directly connected to the moving blade support seat 3.2, and the moving blade is driven to rotate through the square hole of the moving blade. Therefore, the slight deformation of the insulating shaft of the moving blade does not affect the positioning accuracy of the moving blade, thereby reducing the difficulty of assembling the moving blade. Equalizing parts 3.1 are provided on both sides of the upper end of the moving blade, which mainly solves the problem of electric field concentration caused by bolts on the upper end of the moving blade, surface burrs, etc. For the 12kV voltage level, the equalizing part 3.1 can be omitted. For the 24kV and 40.5kV voltage levels, the uniformizing part 3.1 is required.

As shown in FIG4 , the front plate 8 and the rear plate 9 are cut and formed by 8-10 mm thick steel plates. As shown in FIG1 , the short side of the rear plate 9 has a 90-degree folded edge, and a hook 9.1 is provided on the upper part of the folded edge. The size and opening position of the front plate 8 and the rear plate 9 are the same. There is a fixed hole 8.1 for the static knife insulation beam on the upper part of one side of the front plate 8, a fixed hole 8.2 for the moving knife insulation beam on the lower part of the side, and a fixed hole 8.3 for the ground knife insulation beam on the middle part of the other side. There is a fixed hole for the rotating shaft 11 in the middle part of the front plate 8, which is connected to the rotating shaft 11 through a bearing. The front end of the rotating shaft 11 has a flat position connected to the operating mechanism, and the rear part of the rotating shaft 11 is a spline that matches the spline groove at the front end of the moving knife insulation shaft 10. The rotating shaft 11 is made of round steel, quenched and tempered HB220~250. There are switch fixing holes at the four corners of the front plate 8, and the rear plate 9 has a hook 9.1, which is used to fix the load switch in the ring network cabinet gas box.

As shown in Figures 5 and 6, the static knife 1 is a rectangular parallelepiped and is vertically installed on the static knife insulating beam 6. The upper part is the busbar connection surface 1.1 and the lower part is the static knife surface 1.2. The busbar connection surface 1.1 is 8-10 mm thick. The static knife connection surface 1.2 is 12-14 mm thick. There is an arc extinguishing coil connection hole 1.4 at the lower part of the busbar connection surface 1.1 and a busbar connection hole 1.5 at the upper part. There are two static knife screw holes 1.3 at the rear of the static knife surface 1.2 for fixing the static knife 1 to the static knife insulating beam 6. The arc extinguishing coil connection hole 1.4 is used to install the arc extinguishing coil 2. The busbar connection hole 1.5 is used to fix the busbar of the ring network cabinet. The static knife surface 1.2 is formed by stamping to increase the strength. There is a silver-plated layer on the outside of the static knife surface 1.2, and the thickness of the silver-plated layer is 8-20 microns.

As shown in FIG7 , the arc extinguishing coil 2 comprises an arc-striking tongue 2.1, a metal ring 2.4, a plastic ring 2.5, a coil winding 2.9, an insulating layer 2.7, and a hoop 2.8. The metal ring 2.4 is fixed to the plastic ring 2.4 by a countersunk screw 2.6. The coil winding 2.9 is located between the plastic ring 2.5 and the hoop 2.8. An insulating layer 2.7 is provided between the hoop 2.8 and the metal ring 2.4. The metal ring 2.4 has an arc-striking tongue 2.1. The arc-striking tongue 2.1 has an extended end of the hoop 2.8, and the extended end has a fastening hole 2.3 and a fixing hole 2.2. The bolt passes through the fastening hole 2.3 to fasten the hoop 2.8 to the coil winding 2.9. The fixing hole 2.2 is used to connect with the static knife 1.

As shown in Figures 8 and 9, the static knife insulating beam 6 is made of insulating injection molding material and processed by a mold. The insulating material is nylon and glass fiber. There are bosses 6.1 at both ends of the static knife insulating beam, and there are inserts inside that are connected to the front plate 8 and the rear plate 9 by bolts. Triangular prisms or cylinders for process positioning can also be set at both ends of the static knife insulating beam 6 to cooperate with the process holes or grooves of the front plate 8 or the rear plate 9, the purpose of which is to improve the installation accuracy. There is an insulating support layer 6.2 on the static knife insulating beam 6 to fix the static knife 1. There are two static knife fixing holes 6.3 in the middle of the insulating support layer 6.2, and a static knife mounting groove 6.6 at the bottom for bolt fixing. There are insulating ribs 6.7 around the static knife mounting groove 6.6 to avoid the bolts from being exposed and affecting the electric field distribution. The static knife insulating beam is composed of nylon and glass fiber to form an insulating layer, which not only ensures electrical insulation, but also improves the strength and toughness of the insulating beam. The static knife insulating beam is preferably a nylon 66% + glass fiber 33% mixed material.

The moving knife insulating beam and the ground knife insulating beam have the same appearance and structure as the static knife insulating beam and can be produced in a unified manner using a mold, thereby improving the consistency and interchangeability of the insulating beams.

As shown in Figure 10, the main body of the moving knife insulating shaft 10 is in the shape of a cylinder, with a spline groove at the left end connected to the rotating shaft 11, and a rear shaft 10.3 at the right end connected to the rear plate 9. There is a moving knife square hole 10.1 on the moving knife insulating shaft 10, and below the moving knife square hole 10.1 is a moving knife groove 10.2, and there are reinforcing ribs 10.4 around the moving knife square hole 10.1. The moving knife insulating shaft 10 is also provided with an insulating cross partition 10.5, and there are grooves between the insulating cross partitions, which reduces the weight of the moving knife insulating shaft while ensuring the strength of the insulating shaft. The rotating shaft 11 can be integrally formed with the moving knife insulating shaft 10, or it can be connected separately. The rotating shaft can also be connected in a square or hexagonal manner.

The present invention adopts a static knife insulating beam, a moving knife insulating beam, and a ground knife insulating beam to connect with the front plate and the rear plate respectively by bolts to realize the assembled structure of the load switch. Compared with the existing load switch adopting the steel bracket welding mode, it reduces the mode of installing insulators on the bracket, then installing the busbar connection copper bar, and then installing the static knife copper parts, reduces the deformation of the frame caused by welding, and reduces the installation links and static knife adjustment links. The arc suppression coil eliminates the bracket that needs to be welded in the prior art, and there is no need to adjust the angle of the arc-starting tongue. The clamp fastening end is adjusted to the static knife side to optimize the electric field distribution.

The beneficial effects of the present invention are: 1. The switch adopts an assembled structure, which is simple and easy to assemble; 2. The electric field distribution is optimized, the local discharge of the product is reduced, and the life of the product is increased; 3. The insulating beam has good versatility, light weight and high strength.

Embodiment 2:

The present invention is used as a technical solution for disconnecting switches, eliminating arc extinguishing coil 2 and voltage equalizing member 3.1. Since the disconnecting switch works in conjunction with the circuit breaker and does not need to perform a load-carrying opening and closing operation, no arc is generated and the moving knife does not generate a moving electric field.

The rest is the same as in Example 1.

Embodiment 3:

The grounding copper bar 5 is cancelled, the grounding knife 4 is connected to the ground wire of the test system through a copper conductor in phase, and the grounding knife beam adopts the grounding knife insulating beam 7. This scheme is mainly used for testing the load switch test cabinet.

The rest is the same as in Example 1.

Claims (4)

1. A medium-voltage gas-insulated load switch, comprising a stationary knife (1), a moving knife (3), a ground knife (4), an arc-extinguishing coil (2), a stationary knife insulating beam (6), a moving knife insulating beam (12), a moving knife insulating shaft (10), a ground knife beam, a front plate (8), a rear plate (9), and a rotating shaft (11), characterized in that: the stationary knife insulating beam (6), the moving knife insulating beam (12), and the ground knife beam are respectively fixed to the front plate (8) and the rear plate (9) by bolts; the moving knife insulating shaft (10) is fixed to the front plate via the rotating shaft (11) and the bearing, and the rear shaft (10.3) is fixed to the rear plate via the bearing; the stationary knife (1) is vertically mounted on the stationary knife insulating beam (6), and the arc-extinguishing coil (2) is fixed The moving knife (3) is fixed at the lower part of the busbar connection surface (1.1) of the stationary knife (1); the moving knife (3) is installed in the moving knife square hole (10.1) of the moving knife insulating shaft (10); the outer end of the moving knife (3) is connected to the stationary knife (1) or the ground knife (4), and the other end is located in the moving knife groove (10.2) of the moving knife insulating shaft (10), and is connected to the moving knife support seat (3.2) through an axle pin; the moving knife support seat (3.2) is fixed on the moving knife insulating beam (12); the ground knife (4) is fixed on the ground knife beam; the upper part of the stationary knife (1) is the busbar connection surface (1.1), and the lower part is the stationary knife surface (1.2); the busbar connection surface (1.1) is 8-10 mm thick, and the stationary knife connection surface (1.2) is 1 2-14 mm; the lower part of the busbar connection surface (1.1) has an arc extinguishing connection hole (1.4) and the upper part has a busbar connection hole (1.5); the rear part of the static knife surface (1.2) has two static knife screw holes (1.3); the static knife surface (1.2) is formed by stamping; the outside of the static knife surface (1.2) has a silver plating layer, and the thickness of the silver plating layer is 8-20 microns; the arc-striking tongue (2.1) of the arc extinguishing coil (2) has an extended end of a clamp (2.8), and the extended end has a fastening hole (2.3) and a fixing hole (2.2); the bolt passes through the fastening hole (2.3) to fasten the clamp (2.8) to the coil winding (2.9); the static knife insulation beam (6) has bosses (6.1) at both ends , an insert is provided in the end face; the insulating support layer (6.2) has two static knife fixing holes (6.3) in the middle, a static knife mounting groove (6.6) is provided at the lower part, and insulating ribs (6.7) are provided around the static knife mounting groove (6.6); the main body of the movable knife insulating shaft (10) is in the shape of a cylinder, a spline groove is provided in the left end to be connected with the rotating shaft (11), and a rear shaft (10.3) is provided at the right end to be connected with the rear plate (9); a movable knife square hole (10.1) is provided on the movable knife insulating shaft (10), a movable knife groove (10.2) is provided below the movable knife square hole (10.1), and reinforcing ribs (10.4) are provided around the movable knife square hole (10.1); an insulating cross partition (10.5) is provided on the movable knife insulating shaft (10). 2. The medium-voltage gas-insulated load switch as described in claim 1 is characterized in that the insulating material of the static blade insulating beam (6) is nylon and glass fiber; and triangular prisms or cylinders for process positioning are provided at both ends of the static blade insulating beam. 3. The medium voltage gas insulated load switch as claimed in claim 1, characterized in that the insulating material of the moving blade insulating shaft (10) is nylon and glass fiber in a ratio of 2:1. 4. The medium voltage gas insulated load switch as claimed in claim 1, characterized in that: the three-phase earth switches (4) are connected together through a grounding copper busbar (5), or the three-phase earth switches are connected to the ground wire through copper conductors respectively.