C4F7N Environmentally friendly gas ring network cabinet

Abstract

The present invention relates to a C4F7N environmentally friendly gas ring main unit, comprising a gas box, the gas box is filled with a mixed gas of C4F7N and CO2, a busbar insulator, a main busbar, a load switch, a branch busbar and an outgoing line insulator are installed in the gas box, the busbar insulators are two, the two busbar insulators are respectively installed on two opposite inner walls of the gas box, the two busbar insulators are connected through the main busbar, the main busbar is connected to the load switch, the load switch is connected to a plurality of branch busbars, and each branch busbar is connected to an outgoing line insulator. The C4F7N environmentally friendly gas ring main unit is mainly matched with the insulation and breaking performance of the C4F7N and CO2 mixed gas, and the structural design and arc extinguishing grid load switch design are performed to meet the safe operation of the switchgear.

Description

Technical Field

[0001] The invention relates to the technical field of power switch equipment, and in particular to a C4F7N environmentally friendly gas ring network cabinet. Background Art

[0002] Since SF6 was designated as a greenhouse gas and its emission was restricted at the 1997 Global Warming Prevention Conference, switch cabinets that do not use SF6 gas were born. Since environmentally friendly gas ring main cabinets that are easy to expand to high voltage and large capacity have great advantages in technology and economy, the market demand for SF6-filled gas ring main cabinets is decreasing year by year. Environmentally friendly ring main cabinets that replace SF6-filled ring main cabinets will become the mainstream of the market and gradually replace SF6-filled ring main cabinets.

[0003] Environmentally friendly gas C4F7N has excellent insulation, arc extinguishing and environmental performance. Its insulation performance is more than 80% of SF6, and its arc extinguishing greenhouse effect is less than 5% of SF6. Its discharge decomposition products are non-toxic, environmentally friendly and safe, making it an ideal substitute gas for SF6.

[0004] Based on the defects of SF6 gas-filled ring main unit, the present application proposes a ring main unit which adopts a new environmentally friendly gas C4F7N as arc extinguishing and insulating medium. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a C4F7N environmentally friendly gas ring main unit, which is mainly matched with the insulation and breaking performance of the C4F7N and CO2 mixed gas, and performs structural design and arc-extinguishing grid load switch design to meet the safe operation of the switch equipment.

[0006] The present invention is achieved through the following technical scheme: a C4F7N environmentally friendly gas ring network cabinet comprises a gas box filled with a mixed gas of C4F7N and CO2; a bus insulator, a main bus, a load switch, a branch bus and an outgoing line insulator are installed in the gas box; there are two bus insulators, which are respectively installed on two opposite inner walls of the gas box; the two bus insulators are connected through a main bus, which is connected to a load switch, which is connected to a plurality of branch busbars, and each branch busbar is connected to an outgoing line insulator.

[0007] Preferably, the load switch includes a mounting seat connected to the inner wall of the gas box, and an arc extinguishing mechanism and a grounding contact seat are installed on the mounting seat; the arc extinguishing mechanism includes a supporting insulator, a static contact seat and an arc extinguishing chamber, and the static contact seat is connected to the main bus through a flexible connection; the arc extinguishing chamber includes an arc extinguishing grid frame and a plurality of arc extinguishing grids installed on the arc extinguishing grid frame; the static contact seat is a right-angle plate, one of the right-angle sides of the static contact seat is connected to the arc extinguishing grid frame, and the other right-angle side of the static contact seat is connected to the supporting insulator, and the supporting insulator is connected to the mounting seat; the grounding contact seat and the static contact seat form a three-position knife switch through a contact knife connected to the conductor, and the contact knife rotates on the conductor driven by the insulating main shaft to form a rotating conductive structure, and the conductor is connected to multiple branch busbars.

[0008] Preferably, a current blocking slot and a copper-tungsten arc contact are provided on the right-angle side connecting the stationary contact seat and the arc-extinguishing grid frame.

[0009] Preferably, the arc extinguishing grid is made of electrical pure iron.

[0010] Preferably, the arc extinguishing grid frame is connected to the right-angle side of the stationary contact seat through an elastic pin.

[0011] Preferably, the supporting insulator is connected to the right-angle side of the stationary contact seat by bolts.

[0012] The beneficial effects of the present invention are:

[0013] 1. C4F7N environmentally friendly gas ring main unit is mainly matched with the insulation and breaking performance of C4F7N and CO2 mixed gas, and the structural design and arc extinguishing grid load switch design are carried out to meet the safe operation of the switch equipment. It has the characteristics of novel structure, good reliability, flexible layout, small footprint, high modularization and low production cost.

[0014] 2. The structural design mainly focuses on the relative position of the main busbar and the arc extinguishing grid of the load switch to ensure that the current of the main busbar will not affect the arc in the arc extinguishing grid and cause breaking failure; change the overlapping position of the branch busbar, and optimize the overlapping position height by moving the overlapping position away from the gas box position, increase the insulation clearance, reduce the field strength, and improve the insulation margin. Considering the convenience of processing, the original branch busbar is changed from a round copper rod to two hard copper bars overlapped to meet the requirements of spatial reversing. The branch busbar is moved left and right to increase the insulation clearance.

[0015] 3. The breaking performance of C4F7N gas is lower than that of SF6 gas. The load switch is a special load switch developed to match the new environmentally friendly gas C4F7N. It adopts a three-position knife-type load switch and an arc extinguishing grid arc extinguishing method, that is, by adjusting the load switch structure, adding current blocking slots, adding arc contacts, and changing the arc extinguishing grid material, the breaking capacity requirements of the load switch in C4F7N gas are met.

[0016] 4. The purpose of the current blocking groove on the static contact seat is mainly to change the current flowing through the static contact seat, and to minimize the length of the current I1 to reduce the electric force F12 on the arc current I2. Increase the length of the contact knife. The original contact knife length is 100mm, and the changed contact knife length is 150mm. The contact knife length is increased by 1.5 times, and the corresponding current I3 is increased by 1.5 times. The electric force of the current I3 acting on the arc is increased by 1.5 times. In order to increase the length of the current I3, the electric force F32 on the arc current I2 is increased. Because the length of the current I3 is much greater than the length of the current I1, the electric force F32 on the arc current I2 is much greater than F12. Under the action of the electric force, the arc will move toward the arc extinguishing grid, which facilitates the arc to enter the arc extinguishing grid more smoothly and enhance the breaking capacity of the load switch.

[0017] 5. By adding a copper-tungsten arc contact to the static contact seat, the arc root does not burn the copper static contact seat when the load switch is opened, but burns the copper-tungsten arc contact with stronger anti-burning ability, so as to reduce the flying of metal charged particles and reduce the positive charged particles in the cathode area, thereby increasing the voltage drop near the cathode area, which is conducive to arc extinguishing.

[0018] 6. The arc extinguishing grid is made of electrical pure iron. Electrical pure iron with better magnetic conductivity is used instead of ordinary carbon steel to make the arc move at high speed in the slot, accelerate the arc cooling, and facilitate the arc extinguishing.

[0019] 7. By increasing the gap between the arc-extinguishing grids, the existing gap between the arc-extinguishing grids is 2mm, and the gap after the increase is 3mm. Under this gap, the insulation between the grids can be reliably guaranteed to prevent breakdown and affect the arc elongation. The arc quickly enters the arc-extinguishing grid under the action of the electric force. Due to the large spacing between the arc-extinguishing grids, the arc will be elongated inside the arc-extinguishing grid, which increases the voltage to maintain the arc and is conducive to arc extinguishing. After the arc is elongated, it can fully contact with C4F7N, taking away some heat, thereby enhancing the arc energy dissipation.

[0020] 8. The branch busbar is made of bent and overlapped copper bars, which makes the electric field more uniform and avoids the use of non-degradable organic solid materials such as epoxy resin for coating. It can meet the 50kV power frequency withstand voltage level and reach the foreign 24kV voltage level requirement.

[0021] 9. Each arc extinguishing grid is provided with multiple vents, and the vents on adjacent arc extinguishing grids are staggered to form staggered airflow channels. After the arc enters the arc extinguishing grid, a large amount of heat is generated, causing the change of the airflow field inside the arc extinguishing grid, generating airflow through the vents of the arc extinguishing grid, which blows the current and takes away a large amount of heat, accelerating the cooling of the arc and facilitating arc extinguishing.

[0022] 10. Increase the length of the contact knife. The original length was 100mm, and the current length is 150mm, to ensure reliable insulation of the break distance after breaking. When breaking, the arc can be stretched as long as possible to accelerate the cooling of the arc and increase the arc voltage to maintain the arc, which is conducive to breaking. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 This is a schematic diagram of the load switch structure of the present invention;

[0025] Figure 3 It is a front view structural schematic diagram of the arc extinguishing mechanism of the present invention;

[0026] Figure 4 yes Figure 3 Left view structural diagram;

[0027] Figure 5 It is a schematic diagram of the front view structure of the static contact seat of the present invention;

[0028] Figure 6 yes Figure 5 Left view structural diagram;

[0029] Figure 7 yes Figure 5 Schematic diagram of the structure from top view;

[0030] Figure 8 This is a schematic diagram of the current and electric force direction of the present invention;

[0031] Fig. 9 It is a schematic diagram of the arc extinguishing grid structure of the present invention;

[0032] As shown in the figure:

[0033] 1. Support insulator, 2. Static contact seat, 3. Arc extinguishing grid frame, 4. Copper tungsten arc contact, 5. Arc extinguishing grid, 6. Elastic pin, 7. Bolt, 8. Current blocking slot, 9. Grounding contact seat, 10. Mounting seat, 11. Contact knife, 12. Conductor, 13. Insulating main shaft, 14. Gas box, 15. Bus insulator, 16. Main bus, 17. Flexible connection, 18. Branch bus, 19. Outgoing line insulator. DETAILED DESCRIPTION

[0034] In order to clearly illustrate the technical features of this solution, this solution is described below through a specific implementation method.

[0035] like Figure 1As shown, the present invention includes an air box 14, in which a mixed gas of C4F7N and CO2 is filled. A bus insulator 15, a main bus 16, a load switch, a branch bus 18 and an outgoing line insulator 19 are installed in the air box 14. There are two bus insulators 15, and the two bus insulators 15 are respectively installed on two opposite inner walls of the air box 14. The two bus insulators 15 are connected by the main bus 16, and the main bus 16 is connected to the load switch. The load switch is connected to multiple branch busbars 18, and each branch busbar 18 is connected to an outgoing line insulator 19.

[0036] like Figure 2 As shown, the load switch comprises a mounting base 10 connected to the inner wall of the gas box 14, and an arc extinguishing mechanism and a grounding contact seat 9 are mounted on the mounting base 10. Figure 3 , 4 As shown, the arc extinguishing mechanism includes a supporting insulator 1, a static contact seat 2 and an arc extinguishing chamber, and the static contact seat 2 is connected to the main bus 16 through a flexible connection 17. The arc extinguishing chamber includes an arc extinguishing grid frame 3 and a plurality of arc extinguishing grids 5 installed on the arc extinguishing grid frame 3. The static contact seat 2 is a right-angle plate, one of the right-angle sides of the static contact seat 2 is connected to the arc extinguishing grid frame 3, and the other right-angle side of the static contact seat 2 is connected to the supporting insulator 1, and the supporting insulator 1 is connected to the mounting seat 10. The grounding contact seat 9 and the static contact seat 2 form a three-position knife switch through a contact knife 11 connected to the conductor 12. The contact knife 11 rotates on the conductor 12 driven by the insulating main shaft 13 to form a rotating conductive structure, and the rotating conductive structure is an existing structural form. The conductor 12 is connected to multiple branch buses 18.

[0037] like Figure 5 , 6 As shown in FIG. 7 , a current blocking slot 8 and a copper-tungsten arc contact 4 are provided on the right angle side where the stationary contact seat 2 and the arc extinguishing grid frame 3 are connected. By adding the copper-tungsten arc contact 4 to the stationary contact seat 2, when the load switch is disconnected, the arc root does not burn the copper stationary contact seat 2, but burns the copper-tungsten arc contact with stronger anti-burning ability, so as to reduce the flying of metal charged particles, reduce the positive charged particles in the cathode area, thereby increasing the voltage drop near the cathode area, which is conducive to arc extinguishing. Figure 8As shown, the function of the current blocking slot 8 is explained. The current I1 is the current flowing through the static contact seat 2, the current I2 is the arc current during the disconnection, and the current I3 is the current flowing through the contact blade 11. F12 is the electromotive force received by the arc current I2 in the magnetic field generated by the current I1, and F32 is the electromotive force received by the arc current I2 in the magnetic field generated by the current I3. The purpose of the current blocking slot 8 on the static contact seat 2 is mainly to change the current flowing through the static contact seat 2, and to reduce the length of the current I1 as much as possible to reduce the electromotive force F12 received by the arc current I2. The length of the contact blade is increased to increase the length of the current I3, thereby increasing the electromotive force F32 received by the arc current I2. Because the length of the current I3 is much greater than the length of the current I1, the electromotive force F32 received by the arc current I2 is much greater than F12. Under the action of the electromotive force, the arc will move toward the arc extinguishing grid, which facilitates the arc to enter the arc extinguishing grid more smoothly and enhances the breaking capacity of the load switch.

[0038] In this embodiment, if Fig. 9 As shown, a plurality of vents are provided on each arc extinguishing grid 5, and the vents on adjacent arc extinguishing grids 5 are staggered to form staggered airflow channels. After the arc enters the arc extinguishing grid, a large amount of heat is generated, causing the change of the airflow field inside the arc extinguishing grid, generating airflow through the vents of the arc extinguishing grid, and the airflow blows the current, taking away a large amount of heat, accelerating the cooling of the arc, and facilitating arc extinguishing.

[0039] In this embodiment, the arc extinguishing grid 5 is made of electrical pure iron. Electrical pure iron with better magnetic conductivity is selected to replace ordinary carbon steel, so that the arc moves at high speed in the slot, accelerating the arc cooling and facilitating the arc extinguishing.

[0040] In this embodiment, the arc extinguishing grid frame 3 is connected to the right-angle side of the stationary contact seat 2 through an elastic pin 6 .

[0041] In this embodiment, the supporting insulator 1 is connected to the right-angled side of the stationary contact seat 2 by means of bolts 7 .

[0042] Of course, the above description is not limited to the above examples. Technical features not described in the present invention can be achieved by or by using existing technologies, which will not be described here. The above embodiments and drawings are only used to illustrate the technical scheme of the present invention and are not limitations of the present invention. The present invention is described in detail with reference to the preferred implementation methods. Ordinary technicians in this field should understand that changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention do not depart from the purpose of the present invention, and should also fall within the scope of protection of the claims of the present invention.

Claims

1. C4F7N environmentally friendly gas ring main unit, characterized by: The invention comprises a gas box (14), in which a mixed gas of C4F7N and CO2 is filled, and a busbar insulator (15), a main busbar (16), a load switch, a branch busbar (18) and an outgoing line insulator (19) are installed in the gas box (14), wherein two busbar insulators (15) are installed on two opposite inner walls of the gas box (14), respectively, and the two busbar insulators (15) are connected through the main busbar (16), the main busbar (16) is connected to the load switch, the load switch is connected to a plurality of branch busbars (18), and each branch busbar (18) is connected to an outgoing line insulator (19); The load switch comprises a mounting seat (10) connected to the inner wall of a gas box (14), an arc extinguishing mechanism and a grounding contact seat (9) being mounted on the mounting seat (10); the arc extinguishing mechanism comprises a supporting insulator (1), a stationary contact seat (2) and an arc extinguishing chamber, the stationary contact seat (2) being connected to a main busbar (16) via a flexible connection (17); the arc extinguishing chamber comprises an arc extinguishing grid frame (3) and a plurality of arc extinguishing grid pieces (5) mounted on the arc extinguishing grid frame (3); the stationary contact seat (2) is a right-angle plate, the stationary contact seat (2) One of the right-angled sides is connected to the arc extinguishing grid frame (3), the other right-angled side of the static contact seat (2) is connected to the supporting insulator (1), and the supporting insulator (1) is connected to the mounting seat (10); the grounding contact seat (9) and the static contact seat (2) form a three-position knife switch through a contact knife (11) connected to the conductor (12), the contact knife (11) rotates on the conductor (12) driven by the insulating main shaft (13), forming a rotating conductive structure, and the conductor (12) is connected to a plurality of branch busbars (18); A current blocking groove (8) and a copper-tungsten arc contact (4) are provided on the right-angle side connecting the stationary contact seat (2) and the arc extinguishing grid frame (3); The arc extinguishing grid frame (3) is connected to the right-angle side of the stationary contact seat (2) via an elastic pin (6).

2. The C4F7N environmentally friendly gas ring main unit according to claim 1, characterized in that: The arc extinguishing grid (5) is made of electrical pure iron.

3. The C4F7N environmentally friendly gas ring main unit according to claim 1, characterized in that: The supporting insulator (1) is connected to the right-angle side of the stationary contact seat (2) via a bolt (7).

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