A nozzle structure of a GIS circuit breaker

Abstract

The present invention relates to a nozzle structure in the technical field of gas-insulated switchgear, and specifically, to a nozzle structure of a GIS circuit breaker. It includes a nozzle tube with an air inlet section at one end and an air outlet section at the other end. A throat narrower than the air inlet section and the air outlet section is provided inside the nozzle tube. The throat is an annular necking step protruding from the inner wall of the nozzle tube. A plurality of diversion channels evenly distributed in the circumferential direction are provided inside the necking step. One end of the diversion channel is communicated with the air outlet section, and the other end is communicated with the inner wall surface of the necking step, and is used for guiding the gas located at the throat out through the diversion channel. In this GIS circuit breaker nozzle structure, by providing an air suction channel and a flow discharge channel to shunt a part of the gas at the throat, on the one hand, the shunting of the air suction channel can reduce the scratching of the outer peripheral surface of the static arc contact by impurities in the mixed gas, and on the other hand, it can improve the gas flow efficiency when the gap is blocked and play a role in accelerating the separation of impurities from the gap.

Description

Technical Field

[0001] The present invention relates to a nozzle structure in the technical field of gas-insulated switchgear, and more specifically, to a nozzle structure of a GIS circuit breaker. Background Art

[0002] A gas-insulated switchgear (referred to as GIS) consists of a circuit breaker, a disconnector, an earthing switch, a current transformer, a voltage transformer, a lightning arrester, a busbar, a connecting piece, an outgoing terminal, etc. All these devices or components are enclosed in a metal earthed shell, and a certain pressure of SF6 insulating gas is filled inside, so it is also called an SF6 fully enclosed combined electrical apparatus.

[0003] Currently, the main arc extinguishing method of a high-voltage circuit breaker is the method of blowing arc with sulfur hexafluoride gas. With the opening and closing actions of the moving and static ends of the high-voltage circuit breaker, a high-voltage arc will be generated between the moving arc contact and the static arc contact. This part of the high-voltage arc will be in the nozzle of the moving end assembly, that is, in the nozzle. At this time, high-pressure gas sprayed into the nozzle from the moving end is used for blowing arc extinguishing. However, during the blowing arc extinguishing, the static arc contact and the nozzle will move axially and relatively towards each other. Especially when the static arc contact passes through the throat of the nozzle, the following problems will be faced:

[0004] First, when the outer diameter of the static arc contact is equal to or close to the inner diameter of the nozzle throat, the gap between the static arc contact and the nozzle throat is small, which affects the gas passing ability.

[0005] Second, when the outer diameter of the static arc contact is smaller than the inner diameter of the nozzle throat, although a gap for gas to pass through is generated between the static arc contact and the nozzle throat, impurities such as metal powder and ionized decomposition products generated during the blowing arc extinguishing are easily stuck in the gap, resulting in poor air flow in the nozzle throat, affecting the normal blowing arc extinguishing efficiency, and also reducing the current-carrying capacity of the high-voltage circuit breaker. Summary of the Invention

[0006] The purpose of the present invention is to provide a nozzle structure of a GIS circuit breaker, which guides the gas flow in the throat through shunting to improve the fluidity of the gas, thereby solving the problem proposed in the above background art, that is, when the static arc contact is in the throat of the nozzle, it is difficult for the gas to pass through the throat and be discharged.

[0007] To achieve the above purpose, the nozzle structure includes a nozzle tube with an intake section at one end and an outlet section at the other end. A throat narrower than the intake section and the outlet section is provided inside the nozzle tube. The throat is a ring-shaped necking step convexly provided on the inner wall of the nozzle tube. A plurality of diversion channels are circumferentially and evenly arranged inside the necking step. One end of each diversion channel is communicated with the outlet section, and the other end is communicated with the inner wall surface of the necking step, for guiding the gas located at the throat out through the diversion channels.

[0008] One end of the diversion channel connected to the necking step has a plurality of air inlets, and the plurality of air inlets are all on the inner wall surface of the necking step and are distributed along the axial direction of the nozzle. The inner diameters of the plurality of air inlets are all smaller than the inner diameter of the diversion channel.

[0009] In the above technical solution, the diversion channel connects the throat and the outlet section. In this way, when the gap between the throat and the static arc contact is blocked, the diversion channel shunts the gas in the throat, and during the shunting process, part of the gas blows the impurities forward, and the other part of the gas sucks the impurities backward, improving the efficiency of the impurities breaking away from the gap.

[0010] On this basis, the diversion channel includes a bleed channel arranged between the inner and outer walls of the nozzle. One end of the bleed channel extends into the outlet section, and the other end extends to the throat and is communicated with a plurality of suction channels arranged in the necking step. One end of the suction channel penetrates the inner wall surface of the necking step. The plurality of suction channels are distributed along the axial direction of the nozzle, and the inner diameter of the suction channel is smaller than the inner diameter of the bleed channel. When the front suction channel is opened, gas enters the suction channel through the front suction channel, so that a negative pressure is generated in the remaining suction channels, and thus the above-mentioned back suction of impurities can be realized.

[0011] In another technical solution, a return channel is arranged between the inner and outer walls of the nozzle. One end of the return channel is communicated with the outlet section, and the communication position is on the exhaust path of the bleed channel; the other end of the return channel is communicated at the connection between the throat and the outlet section.

[0012] In this technical solution, the return channel uses the negative pressure between the throat and the outlet section to suck the gas discharged through the bleed channel, and cooperates with the inertia during the flow of impurities to filter the impurities. In this way, not only the recycling of the gas in the bleed channel is realized, but also the impurities are filtered during the return process.

[0013] In another technical solution, a diversion groove for guiding the gas to rotate is arranged on the inner wall of the throat, so that the impurities in the mixed gas enter the suction channel under the action of centrifugal force. The diversion groove is a spiral structure.

[0014] In this technical solution, the spiral diversion groove can change the motion state of the gas when the gas passes through, making the gas rotate to generate centrifugal force, so as to guide the impurities to the vicinity of the suction channel through the centrifugal force, and the impurities are directly discharged through the suction channel and the bleed channel.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1. In the nozzle structure of this GIS circuit breaker, by setting the air intake channel and the flow discharge channel, a part of the gas at the throat is shunted. Compared with the prior art method of directly discharging gas through a gap, on the one hand, the shunting of the air intake channel can reduce the scratching of the outer peripheral surface of the static arc contact by impurities in the mixed gas, and on the other hand, it can improve the gas flow efficiency when the gap is blocked and play a role in accelerating the detachment of impurities from the gap.

[0017] 2. In the nozzle structure of this GIS circuit breaker, the flow discharge channel directly guides a part of the mixed gas to the gas outlet section without contacting the static arc contact, and then through the return channel, the gas discharged from the flow discharge channel is guided back again, and during the return process, the impurities in the mixed gas are filtered, reducing the impurities in the returned gas, thereby reducing the damage caused by the impact of impurities on the static arc contact.

[0018] 3. In the nozzle structure of this GIS circuit breaker, through the cooperation of the diversion groove and the air intake channel, the mixed gas generates a rotational movement when passing through the throat, forcing the impurities in the mixed gas to be thrown into the air intake channel under the action of centrifugal force, and then directly discharged through the flow discharge channel, reducing the contact between the impurities and the static arc contact, and thus reducing the damage caused by the impurities to the outer peripheral surface of the static arc contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the overall structural schematic diagram of the present invention;

[0020] Figure 2 is the schematic diagram of the air flow state in the air intake channel of the present invention Figure 1 ;

[0021] Figure 3 is of the present invention Figure 2 is the enlarged schematic diagram of the structure at point A;

[0022] Figure 4 is the schematic diagram of the air flow state in the air intake channel of the present invention Figure 2 ;

[0023] Figure 5 is the structural schematic diagram of the flow discharge port of the present invention;

[0024] Figure 6 is the structural schematic diagram of the return channel of the present invention Figure 1 ;

[0025] Figure 7 is the structural schematic diagram of the return channel of the present invention Figure 2 ;

[0026] Figure 8 is the structural schematic diagram of the diversion groove of the present invention.

[0027] The meanings of the reference numerals in the figures are as follows:

[0028] 100, nozzle; 101, intake section; 102, throat; 103, outlet section; 104, flow guiding groove; 110, discharge channel; 111, discharge port; 120, suction channel; 130, return channel; 200, static arc contact. Specific implementation mode

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] Impurities such as metal powder and ionized decomposition products mentioned above are generated in the following process. When the static arc contact 200 is still in the state of the intake section 101 of the nozzle, the arc extinguishing gas ejected from the moving contact will blow out the high-voltage arc between the moving arc contact and the static arc contact 200. At the same time, some metal powder and ionized decomposition products will be blown off from the moving arc contact and the static arc contact 200. These substances are mixed in the arc extinguishing gas to form a mixed gas. When the mixed gas enters the throat 102 from the open intake section 101, it will be pressurized, and the solid impurities mixed in the mixed gas will form a blockage in the gap between the inner wall surface of the throat 102 and the outer peripheral surface of the static arc contact 200.

[0031] Aiming at the problem that the static arc contact 200 is in the throat 102 of the nozzle, resulting in difficulty in discharging gas through the throat 102, the present invention provides a GIS circuit breaker nozzle structure, as Figure 1 shown, the nozzle structure is mainly composed of a sleeve-shaped nozzle 100. Taking the state of the nozzle 100 in Figure 1 as the standard, the left end of the nozzle 100 is the intake section 101, the right end is the outlet section 103, and a throat 102 narrower than the intake section 101 and the outlet section 103 is provided in the nozzle 100. Both the intake section 101 and the outlet section 103 are trumpet-shaped with one end thin and the other end thick. Moreover, the thin ends of the intake section 101 and the outlet section 103 are both connected to the throat 102. The throat 102 is an annular necking step protruding from the inner wall of the nozzle 100. A plurality of circumferentially distributed flow guiding channels are provided inside the necking step. One end of the flow guiding channel is communicated with the outlet section 103, and the other end is communicated with the inner wall surface of the necking step. The end of the flow guiding channel connecting the necking step has a plurality of intake ports. All the plurality of intake ports are on the inner wall surface of the necking step and are distributed along the axial direction of the nozzle 100. The inner diameter of the plurality of intake ports is smaller than the inner diameter of the flow guiding channel, and is used to lead out the gas located at the throat 102 through the flow guiding channel.

[0032] Example 1, as Figure 1As shown, the guide channel includes a leakage channel 110 arranged between the inner and outer walls of the nozzle 100, the left end of the leakage channel 110 extends to the air outlet section 103, the right end extends to the throat 102 and is connected to a plurality of suction channels 120 arranged in the necking step, one end of the suction channel 120 passes through the inner wall surface of the necking step, the plurality of suction channels 120 are distributed along the axial direction of the nozzle 100, and the inner diameter of the suction channel 120 is smaller than the inner diameter of the leakage channel 110.

[0033] Next, the principle of the nozzle structure of the present invention will be described in detail through static arc contacts 200 of different diameters.

[0034] 1. When the diameter of the static arc contact 200 is smaller than the inner diameter of the throat 102, Figure 2 and Figure 3 As shown, a gap is formed between the outer peripheral surface of the static arc contact 200 and the inner wall surface of the throat 102. When the mixed gas containing impurities such as metal powder and ionized decomposition products passes through the gap, some impurities may be stuck in the gap, thereby affecting the passage of the gas. For ease of understanding, Figure 3 The two black-filled square areas in the figure are where the impurities are located. Due to the obstruction of impurities, most of the gas can only flow into the leakage channel 110 through the first air intake channel 120 (the air intake channel 120 near the air inlet section 101). At this time, the gas entering the air intake channel 120 is limited by the inner diameter of the air intake channel 120, which causes the gas flow rate to increase sharply. Since the space of the leakage channel 110 becomes larger, the gas in the first air intake channel 120 forms a high-speed jet when it is discharged into the leakage channel 110. This high-speed jet has a suction effect and can continuously suck away the air in the leakage channel 110. The remaining two air intake channels 120 are within the range of action of the high-speed jet, so negative pressure will also be generated inside the remaining two air intake channels 120. At this time, it can be found that area a is in a positive pressure area, and the gas blows the impurities, while area b is in a negative pressure area, and the gas sucks the impurities, thereby driving the impurities out of the gap under the combined action of positive and negative pressures.

[0035] When impurities do not block the gap, part of the gas flows into the gas outlet section 103 through the gap, and the other part of the gas flows into the gas outlet section 103 through the air intake channel 120 and the discharge channel 110. Here, the air intake channel 120 and the discharge channel 110 play a role of diversion, which can also speed up the gas flow.

[0036] 2. When the diameter of the static arc contact 200 is equal to the inner diameter of the throat 102, Figure 4As shown, during the relative movement of the nozzle 100 and the static arc contact 200, the static arc contact 200 gradually disengages from the throat 102. At this time, a plurality of suction channels 120 distributed axially will be opened one by one. In this way, the gas in the intake section 101 can flow into the discharge channel 110 through the opened suction channels 120, then flow into the outlet section 103 through the discharge channel 110, and finally be discharged.

[0037] Embodiment 2: In this embodiment, one end of the discharge channel 110 is directly connected to the intake section 101. Through this design, when the static arc contact 200 is within the throat 102, the mixed gas in the gap can be further guided, reducing the scratching of the outer peripheral surface of the static arc contact 200 by impurities in the mixed gas.

[0038] Specifically, as Figure 5 shown, a discharge port 111 is connected to the left end of the discharge channel 110, and the inner diameter of the discharge port 111 is smaller than that of the discharge channel 110. And one end of the discharge port 111 penetrates the side wall of the necking step, so as to be connected to the intake section 101.

[0039] In this way, the high-pressure gas at the intake section 101 can be directly discharged through the discharge port 111. Since the inner diameter of the discharge port 111 is small, when the gas flows from the discharge port 111 into the discharge channel 110, a suction force will be generated around the connection of the discharge channel 110 and the discharge port 111. Therefore, a suction force will also be generated in the suction channel 120. At the same time, the gas in the gap is itself in a high-pressure state, which further increases the flow rate of the gas in the gap into the discharge channel 110.

[0040] That is to say, by setting the suction channel 120 and the discharge channel 110 to divert part of the gas at the throat 102, compared with the prior art of directly discharging gas through the gap, on the one hand, the diversion of the suction channel 120 can reduce the scratching of the outer peripheral surface of the static arc contact 200 by impurities in the mixed gas, and on the other hand, it can improve the gas flow efficiency when the gap is blocked and play a role in accelerating the detachment of impurities from the gap.

[0041] Embodiment 3: In this embodiment, a return channel 130 is provided between the inner and outer walls of the nozzle 100. As Figure 6 shown, the left end of the return channel 130 is connected to the outlet section 103, and the connection is on the exhaust path of the discharge channel 110. The right end of the return channel 130 is connected to the connection between the throat 102 and the outlet section 103.

[0042] During implementation, as Figure 7As shown in the figure, the left end of the return flow channel 130 is closer to the left end of the nozzle 100 than the left end of the discharge channel 110. At the same time, the left end of the return flow channel 130 and the left end of the discharge channel 110 are arranged on the same axis to ensure that the left end of the return flow channel 130 is on the exhaust path of the discharge channel 110. The right end of the return flow channel 130 only needs to penetrate the inner wall of the nozzle 100, and the penetration position is at the connection between the throat 102 and the outlet section 103.

[0043] In this way, as Figure 6 shown, the black dashed arrows in the figure represent the flow state of the mixed gas, and the white dashed arrows represent the flow state of the clean gas (gas without impurities). When the mixed gas flows from the intake section 101 to the throat 102 (i.e., region d), it is in a compressed state. When the mixed gas passes through the throat 102 and is discharged, due to the restriction of the inner diameter of the throat 102, the gas will form a high-speed jet flow inside the throat 102. When the mixed gas is ejected through the throat 102, an entrainment effect will be generated at the connection between the throat 102 and the outlet section 103 (i.e., region e), thereby forcing a negative pressure to be generated at the right end of the return flow channel 130 (i.e., region c). At this time, a suction force is generated inside the return flow channel 130. Since the left end of the return flow channel 130 is on the exhaust path of the discharge channel 110, the return flow channel 130 will suck in part of the gas discharged from the discharge channel 110. During this process, since the inertial force of the impurities is greater than the inertial force of the gas after the mixed gas is discharged from the discharge channel 110, the impurities overcome the suction force of the return flow channel 130 through their own inertial force when passing through region c. That is to say, it is difficult for the return flow channel 130 to suck in the impurities. In this way, the return flow channel 130 will only suck in gas and a small amount of impurities. The sucked-in gas is discharged through the right end of the return flow channel 130 and flows towards the static arc contact 200 along with the gas flowing inside the throat 102, thereby participating in the arc extinguishing work again.

[0044] It can be seen that the discharge channel 110 directly guides a part of the mixed gas to the outlet section 103 without contacting the static arc contact 200, and then guides the gas discharged from the discharge channel 110 back through the return flow channel 130. During the return process, the impurities in the mixed gas are filtered, reducing the impurities in the returned gas, thereby reducing the damage caused by the impurities hitting the static arc contact 200.

[0045] Embodiment 4, as Figure 8 shown, in this embodiment, a diversion groove 104 is provided on the inner wall of the throat 102, and the diversion groove 104 is a spiral structure. Through this design, the mixed gas rotates under the guidance of the spiral, and the impurities in the mixed gas will be thrown to the inner wall of the throat 102 under the action of centrifugal force and then discharged through the suction channel 120 and the discharge channel 110.

[0046] In summary, through the cooperation of the diversion groove 104 and the suction passage 120, the mixed gas generates a rotational motion when passing through the throat 102, forcing the impurities in the mixed gas to be thrown into the suction passage 120 under the action of centrifugal force, and then directly discharged through the discharge passage 110, reducing the contact between the impurities and the static arc contact 200, and thus reducing the damage caused by the impurities to the outer peripheral surface of the static arc contact 200.

[0047] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and the descriptions in the specification are only preferred examples of the present invention, and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A nozzle structure of a GIS circuit breaker, comprising a nozzle (100) with an intake section (101) at one end and an exhaust section (103) at the other end. A throat (102) narrower than the intake section (101) and the exhaust section (103) is provided inside the nozzle (100). The throat (102) is an annular necking step protruding from the inner wall of the nozzle (100), and is characterized in that: A plurality of diversion channels evenly distributed in a circumferential direction are provided inside the necking step. One end of each diversion channel communicates with the exhaust section (103), and the other end communicates with the inner wall surface of the necking step, for guiding the gas at the throat (102) out through the diversion channels.

2. The nozzle structure of the GIS circuit breaker according to claim 1, wherein: One end of the diversion channel connecting the necking step has a plurality of intake ports, and all of the plurality of intake ports are on the inner wall surface of the necking step and are distributed along the axial direction of the nozzle (100).

3. The nozzle structure of the GIS circuit breaker according to claim 2, characterized in that: The inner diameters of the plurality of intake ports are all smaller than the inner diameter of the diversion channel.

4. The nozzle structure of the GIS circuit breaker according to claim 3, wherein: The diversion channel includes a discharge channel (110) provided between the inner and outer walls of the nozzle (100). One end of the discharge channel (110) extends into the exhaust section (103), and the other end extends to the throat (102) and communicates with a plurality of suction channels (120) provided in the necking step. One end of the suction channel (120) penetrates the inner wall surface of the necking step.

5. The nozzle structure of the GIS circuit breaker according to claim 4, characterized in that: The plurality of suction channels (120) are distributed along the axial direction of the nozzle (100), and the inner diameter of the suction channel (120) is smaller than the inner diameter of the discharge channel (110).

6. The nozzle structure of the GIS circuit breaker according to claim 4, characterized in that: One end of the discharge channel (110) communicates with a discharge port (111), and one end of the discharge port (111) penetrates the side wall of the necking step to communicate with the intake section (101); The inner diameter of the discharge port (111) is smaller than the inner diameter of the discharge channel (110).

7. The nozzle structure of the GIS circuit breaker according to claim 4, characterized in that: A return channel (130) is provided between the inner and outer walls of the nozzle (100). One end of the return channel (130) communicates with the exhaust section (103), and the communication position is on the exhaust path of the discharge channel (110); The other end of the return channel (130) communicates with the connection between the throat (102) and the exhaust section (103).

8. The nozzle structure of the GIS circuit breaker according to claim 7, characterized in that: The intake end of the return channel (130) and the exhaust end of the discharge channel (110) are on the same axis.

9. The nozzle structure of the GIS circuit breaker according to claim 4, characterized in that: The inner wall of the throat (102) is provided with a diversion groove (104) for guiding the gas to rotate, so that impurities in the mixed gas enter the suction channel (120) under the action of centrifugal force.

10. The nozzle structure of the GIS circuit breaker according to claim 9, characterized in that: The diversion groove (104) is a spiral structure.

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