Gas insulated switchgear (GIS) circuit breaker nozzle structure

Abstract

The invention relates to a nozzle structure in the technical field of gas insulated switchgear, in particular to a gas insulated switchgear (GIS) circuit breaker nozzle structure. One end of the spray pipe is an air inlet section, the other end of the spray pipe is an air outlet section, a throat part narrower than the air inlet section and the air outlet section is arranged in the spray pipe, the throat part is an annular necking step convexly arranged on the inner wall of the spray pipe, a plurality of flow guide channels are circumferentially and uniformly distributed in the necking step, one end of each flow guide channel is communicated with the air outlet section, and the other end of each flow guide channel is communicated with the air outlet section. The other end of the flow guide channel is communicated with the inner wall surface of the necking step and is used for guiding out gas at the throat part through the flow guide channel. According to the GIS circuit breaker nozzle structure, partial gas at the throat part is shunted through the gas suction channel and the discharge channel, so that on one hand, the scraping of impurities in mixed gas to the peripheral surface of a static arc contact can be reduced through the shunting of the gas suction channel; and on the other hand, the gas flowing efficiency can be improved when the gaps are blocked, and the effect of accelerating separation of impurities from the gaps is achieved.

Description

Technical Field

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

[0002] Gas insulated switchgear (GIS for short) consists of circuit breakers, disconnectors, earthing switches, current transformers, voltage transformers, lightning arresters, busbars, connectors and outgoing line terminals. These devices or components are all enclosed in a metal grounded casing and filled with SF6 insulating gas at a certain pressure, so it is also called SF6 fully enclosed combination electrical appliances.

[0003] At present, the main arc extinguishing method of high-voltage circuit breakers is the arc blowing method of sulfur hexafluoride gas. As the moving and static ends of the high-voltage circuit breaker open and close, a high-voltage arc will be generated between the moving arc contact and the static arc contact, and this part of the high-voltage arc will be in the nozzle installed on the moving end, that is, in the nozzle. At this time, the high-pressure gas sprayed from the moving end into the nozzle will be used to blow the arc out. However, while blowing the arc out, the static arc contact and the nozzle will move toward each other in the axial direction. Especially when the static arc contact passes through the throat of the nozzle, it will face the following problems: 1. 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 capacity; 2. When the outer diameter of the static arc contact is smaller than the inner diameter of the nozzle throat, although a gap is created between the static arc contact and the nozzle throat for gas to pass through, impurities such as metal powder and ionized decomposition products generated during air blowing and arc extinguishing are easily stuck in the gap, resulting in poor air flow in the nozzle throat, affecting the normal air blowing and arc extinguishing efficiency, and also reducing the current carrying capacity of the high-voltage circuit breaker. Summary of the invention

[0004] The object of the present invention is to provide a GIS circuit breaker nozzle structure, which diverts and guides the gas in the throat and utilizes the diversion to improve the fluidity of the gas, thereby solving the problem raised in the above-mentioned background technology, that is, the static arc contact is in the throat of the nozzle, which makes it difficult for the gas to be discharged through the throat.

[0005] To achieve the above-mentioned purpose, the nozzle structure includes a nozzle with an air inlet section at one end and an air outlet section at the other end. The nozzle is provided with a throat narrower than the air inlet section and the air outlet section. The throat is an annular necking step convexly provided on the inner wall of the nozzle. A plurality of guide channels evenly distributed around the circumference are provided inside the necking step. One end of the guide channel is connected to the air outlet section, and the other end is connected to the inner wall surface of the necking step, so as to guide the gas located at the throat through the guide channel.

[0006] The end of the guide channel connected to the necking step has a plurality of air inlets, which are all located on the inner wall of the necking step and 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 guide channel.

[0007] In the above technical solution, the guide channel connects the throat with the air outlet section. In this way, when the gap between the throat and the static arc contact is blocked, the guide channel diverts the gas in the throat, and during the diversion process, part of the gas blows the impurities from the front, and the other part of the gas sucks the impurities from the back, thereby improving the efficiency of impurities leaving the gap.

[0008] On this basis, the guide channel includes a leakage channel arranged between the inner and outer walls of the nozzle, one end of the leakage channel extends into the air outlet section, the other end extends to the throat and is connected to a plurality of suction channels arranged in the necking step, and one end of the suction channel passes through 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 leakage channel. When the suction channel located in the front is opened, the gas enters the suction channel through the suction channel in front, so that negative pressure is generated in the remaining suction channels, thereby realizing the above-mentioned back suction of impurities.

[0009] In another technical solution, a reflow channel is provided between the inner and outer walls of the nozzle, one end of the reflow channel is connected to the air outlet section, and the connection point is located on the exhaust path of the leakage channel; the other end of the reflow channel is connected to the connection between the throat and the air outlet section.

[0010] In this technical solution, the reflux channel uses the negative pressure between the throat and the gas outlet section to inhale the gas discharged through the leakage channel, and uses the inertia of the impurities in the flow process to filter the impurities. In this way, not only the reflux of the gas in the leakage channel is realized, but also the impurities are filtered during the reflux process.

[0011] In another technical solution, the inner wall of the throat is provided with a guide groove for guiding the gas to rotate, so that impurities in the mixed gas enter the air intake channel under the action of centrifugal force. The guide groove is a spiral structure.

[0012] In this technical solution, the spiral structure of the guide groove can change the movement state of the gas when the gas passes through, causing the gas to rotate and generate centrifugal force, thereby guiding the impurities to the vicinity of the intake channel through the centrifugal force, so that the impurities can be directly discharged through the intake channel and the discharge channel.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. In the nozzle structure of the GIS circuit breaker, part of the gas at the throat is diverted by setting up an air intake channel and a discharge channel. Compared with the method of directly discharging gas through the gap in the prior art, the diversion of the air intake channel can, on the one hand, 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 flow efficiency of the gas when the gap is blocked and accelerate the escape of impurities from the gap.

[0014] 2. In the nozzle structure of the GIS circuit breaker, the discharge channel guides a part of the mixed gas directly to the gas outlet section without contacting the static arc contact, and then guides the gas discharged from the discharge channel back through the reflux channel. In the reflux process, the impurities in the mixed gas are filtered to reduce the impurities in the refluxed gas, thereby reducing the damage caused by the impurities hitting the static arc contact.

[0015] 3. In the nozzle structure of the GIS circuit breaker, the combination of the guide groove and the air intake channel causes the mixed gas to produce a rotational motion 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 discharge channel, reducing the contact between the impurities and the static arc contact, and also reducing the damage caused by the impurities to the outer peripheral surface of the static arc contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 Schematic diagram of the air flow state in the air intake channel of the present invention Figure 1 ; Figure 3 For the present invention Figure 2 A schematic diagram of the structure at A; Figure 4 Schematic diagram of the air flow state in the air intake channel of the present invention Figure 2 ; Figure 5 It is a schematic diagram of the structure of the drain port of the present invention; Figure 6 The structure of the reflux channel of the present invention is schematically shown in FIG. Figure 1 ; Figure 7 The structure of the reflux channel of the present invention is schematically shown in FIG. Figure 2 ; Figure 8 It is a schematic structural diagram of the guide groove of the present invention.

[0017] The meaning of each number in the figure is: 100. Nozzle; 101. Air inlet section; 102. Throat; 103. Air outlet section; 104. Guide groove; 110. Discharge channel; 111. Discharge port; 120. Air intake channel; 130. Return channel; 200. Static arc contact. DETAILED DESCRIPTION

[0018] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] The 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 air inlet 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, and 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. The mixed gas will be pressurized when entering the throat 102 from the open air inlet section 101, and the solid impurities contained 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.

[0020] In order to solve the problem that the static arc contact 200 is located in the throat 102 of the nozzle, making it difficult for the gas to be discharged through the throat 102, the present invention provides a nozzle structure of a GIS circuit breaker, such as Figure 1 As shown, the nozzle structure is mainly composed of a nozzle 100 in a sleeve shape. Figure 1 The state of the nozzle 100 in the figure is taken as the standard, the left end of the nozzle 100 is the air inlet section 101, the right end is the air outlet section 103, and a throat 102 narrower than the air inlet section 101 and the air outlet section 103 is provided in the nozzle 100, the air inlet section 101 and the air outlet section 103 are both trumpet-shaped with one end thin and the other end thick, and the thin ends of the air inlet section 101 and the air outlet section 103 are connected to the throat 102. The throat 102 is an annular necking step protruding from the inner wall of the nozzle 100, and a plurality of guide channels evenly distributed around the circumference are provided inside the necking step. One end of the guide channel is connected to the gas outlet section 103, and the other end is connected to the inner wall surface of the necking step. The end of the guide channel connected to the necking step has a plurality of air inlets, and the plurality of air inlets are all located on the inner wall surface of the necking step and are distributed along the axial direction of the nozzle 100. The inner diameters of the plurality of air inlets are smaller than the inner diameter of the guide channel, and are used to guide the gas located at the throat 102 out through the guide channel.

[0021] Embodiment 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.

[0022] Next, the principle of the nozzle structure of the present invention will be described in detail through static arc contacts 200 of different diameters.

[0023] 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.

[0024] 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.

[0025] 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 separates from the throat 102. At this time, the multiple suction channels 120 distributed along the axial direction will be opened one by one, so that the gas in the air inlet section 101 can flow into the leakage channel 110 through the opened suction channel 120, and then flow into the air outlet section 103 through the leakage channel 110, and finally be discharged.

[0026] Embodiment 2. In this embodiment, one end of the leakage channel 110 is directly connected to the air inlet section 101. Through this design, when the static arc contact 200 is in the throat 102, the mixed gas in the gap can be further guided to reduce the scratching of the outer peripheral surface of the static arc contact 200 by impurities in the mixed gas.

[0027] Specifically, if Figure 5 As shown, the left end of the leakage channel 110 is connected with a leakage port 111, and the inner diameter of the leakage port 111 is smaller than the inner diameter of the leakage channel 110. And one end of the leakage port 111 penetrates the side wall of the necking step, so as to be connected with the air intake section 101.

[0028] In this way, the high-pressure gas at the air inlet section 101 can be directly discharged through the leakage port 111. Since the inner diameter of the leakage port 111 is small, when the gas flows from the leakage port 111 into the leakage channel 110, suction will be generated around the connection between the leakage channel 110 and the leakage port 111, so suction will also be generated in the air intake channel 120. At the same time, the gas in the gap itself is in a high-pressure state, which further increases the flow rate of the gas in the gap entering the leakage channel 110.

[0029] That is to say, part of the gas at the throat 102 is diverted by setting up the air intake channel 120 and the discharge channel 110. Compared with the method of directly discharging the gas through the gap in the prior art, the diversion of the air intake channel 120 can, on the one hand, reduce the scratching of the outer surface of the static arc contact 200 by impurities in the mixed gas, and on the other hand, it can improve the flow efficiency of the gas when the gap is blocked and accelerate the escape of impurities from the gap.

[0030] Embodiment 3: In this embodiment, a return channel 130 is provided between the inner and outer walls of the nozzle 100. Figure 6 As shown, the left end of the return channel 130 is connected to the outlet section 103 , and the connection point is located on the exhaust path of the leakage channel 110 , and the right end of the return channel 130 is connected to the connection between the throat 102 and the outlet section 103 .

[0031] When implementing, Figure 7As shown, the left end of the return channel 130 is closer to the left end of the nozzle 100 than the left end of the leakage channel 110. At the same time, the left end of the return channel 130 and the left end of the leakage channel 110 are arranged on the same axis to achieve that the left end of the return channel 130 is on the exhaust path of the leakage channel 110. The right end of the return channel 130 only needs to penetrate the inner wall of the nozzle 100, and the penetration portion is at the connection between the throat 102 and the air outlet section 103.

[0032] In this way, if Figure 6 As shown in the figure, the black dotted arrows represent the flow state of the mixed gas, and the white dotted arrows represent the flow state of the clean gas (gas without impurities). The mixed gas is in a compressed state when it flows from the air inlet section 101 to the throat 102 (i.e., area d). When the mixed gas is discharged through the throat 102, due to the limitation of the inner diameter of the throat 102, the gas will form a high-speed jet in the throat 102. When the mixed gas is ejected through the throat 102, a suction effect will be generated at the connection between the throat 102 and the air outlet section 103 (i.e., area e), thereby forcing the right end of the reflux channel 130 (i.e., area c) to generate negative pressure. At this time, suction is generated in the reflux channel 130. Since the left end of the reflux channel 130 is located on the exhaust path of the leakage channel 110, the reflux channel 130 will inhale part of the gas discharged from the leakage channel 110. In this process, after the mixed gas is discharged from the leakage channel 110, the inertia force of the impurities is greater than the inertia force of the gas. Therefore, the impurities overcome the suction force of the reflux channel 130 through their own inertia force when passing through area c. In other words, it is difficult for the reflux channel 130 to suck in the impurities. In this way, the reflux channel 130 will only suck in gas and a small amount of impurities. The sucked gas is discharged through the right end of the reflux channel 130, and follows the gas flowing in the throat 102 to flow to the static arc contact 200, thereby participating in the arc extinguishing work again.

[0033] It can be seen that the leakage channel 110 guides a part of the mixed gas directly to the gas outlet section 103 without contacting the static arc contact 200, and then guides the gas discharged from the leakage channel 110 to flow back again through the reflux channel 130, and the impurities in the mixed gas are filtered during the reflux process, so that the impurities in the reflux gas are reduced, thereby reducing the damage caused by the impurities hitting the static arc contact 200.

[0034] Embodiment 4, as Figure 8 As shown, in this embodiment, a guide groove 104 is provided on the inner wall of the throat 102, and the guide groove 104 is a spiral structure. With this design, the mixed gas rotates under the guidance of the spiral, and the impurities in the mixed gas are 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.

[0035] In summary, through the cooperation between the guide groove 104 and the suction channel 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 channel 120 under the action of centrifugal force, and then directly discharged through the discharge channel 110, thereby reducing the contact between the impurities and the static arc contact 200, and also reducing the damage caused by the impurities to the outer peripheral surface of the static arc contact 200.

[0036] The above shows and describes 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. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A GIS circuit breaker nozzle structure, comprising a nozzle (100) having an air inlet section (101) at one end and an air outlet section (103) at the other end, wherein a throat (102) narrower than the air inlet section (101) and the air outlet section (103) is provided in the nozzle (100), wherein the throat (102) is an annular necking step convexly provided on the inner wall of the nozzle (100), and wherein: A plurality of flow guide channels evenly distributed around the circumference are provided inside the necking step, one end of the flow guide channel is connected to the gas outlet section (103), and the other end is connected to the inner wall surface of the necking step, and is used to guide the gas located at the throat (102) out through the flow guide channel.

2. The nozzle structure of GIS circuit breaker according to claim 1, characterized in that: The end of the flow guide channel connected to the necking step has a plurality of air inlets, and the plurality of air inlets are all located 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 GIS circuit breaker according to claim 2, characterized in that: The inner diameters of the plurality of air inlets are all smaller than the inner diameter of the flow guiding channel.

4. The nozzle structure of GIS circuit breaker according to claim 3, characterized in that: The flow guide channel comprises a leakage channel (110) arranged between the inner and outer walls of the nozzle (100), one end of the leakage channel (110) extends into the air outlet section (103), the other end of the leakage channel (110) extends to the throat (102) and is connected to a plurality of air intake channels (120) arranged in the necking step, and one end of the air intake channel (120) passes through the inner wall surface of the necking step.

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

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

7. The nozzle structure of GIS circuit breaker according to claim 4, characterized in that: A reflux channel (130) is provided between the inner and outer walls of the nozzle (100), one end of the reflux channel (130) is connected to the air outlet section (103), and the connection point is located on the exhaust path of the leakage channel (110); The other end of the reflux channel (130) is connected to the connection between the throat (102) and the air outlet section (103).

8. The nozzle structure of GIS circuit breaker according to claim 7, characterized in that: The air inlet end of the return channel (130) and the air outlet end of the leakage channel (110) are located on the same axis.

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

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

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