JPH04111130U - gas circuit breaker - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the generation of a low pressure region near the tip of the fixed arc contact of a puffer-type gas circuit breaker and to improve the breaking performance. [Structure] A groove portion 3d is provided in the insulating nozzle 3. When the movable arc contact 2 reaches the arc extinguishing position P2, the groove 3d
The position of the groove portion 3d is set so that the groove portion 3d is located near the tip of the fixed arc contact 1. By generating a gas flow from the groove 3d toward the boundary between the main part and the tip of the fixed arc contact 1, the gas flow near the tip of the fixed arc contact is prevented from becoming a supersonic flow, and the fixed arc contact is fixed. Prevents gas pressure from decreasing near the tip of the arc contact.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to a gas circuit breaker equipped with a puffer type arc extinguishing mechanism.

0002

[Conventional technology]

This type of gas circuit breaker has a fixed arc contact 1 and a fixed arc contact 1, as shown in FIG. Provided so that it can move in the axial direction while sharing the axis with constant arc contact 1. The movable arc contact 2 is provided concentrically on the outside of the movable arc contact. The insulating nozzle 3 is connected to the movable arc contact and is displaced together with the movable arc contact. It is equipped with a puffer mechanism 4 that blows gas onto the arc when the circuit is opened.

0003 A fixed arc contact 1 is fixed to a conductor 5 attached to an insulating container (not shown). As shown in Figure 8, the outline of the cross section is circular and the line is straight in the axial direction. It has a main portion 1a that extends in a straight line, and a tip portion 1b that has an arcuate vertical cross-sectional profile. figure In the example shown, the conductor 5 is further provided with a solid material that concentrically surrounds the fixed arc contact 1 from the outside. A fixed main contact 6 is connected.

0004 The movable arc contact 2 is slidably supported by a conductor 7 attached to an insulating container. It is attached to the movable conductor rod 8. The movable conductor rod 8 is connected via an insulated operating rod 9. The movable arc contact 2 is connected to an operating device (not shown), and the movable arc contact 2 is thrown by the operating device. It is operated to be displaced between an arc-on position and an arc-extinguishing position. Movable arc contact 2 is formed into a tubular shape, and a contact portion 2a is formed at the tip thereof. Movable Arcco The contact 2 has a number of slits that open at its tip. At the time of entry, the tip part is elastically deformed to the outer periphery of the main part 1a of the fixed arc contact 1. Contact from the outside.

[0005] The puffer mechanism 4 is integrated with the movable arc contact 2 and the insulating nozzle 3. The puffer cylinder 10 is displaced, and the cylinder 10 is fixed to the conductor 7 and fitted into the cylinder 10. when the movable arc contact 2 is displaced to the arc extinguishing position side. The volume of the puffer cylinder 10 is reduced, and the insulating nozzle 3 is removed from the cylinder 10. A high-velocity gas flow is supplied inside.

[0006] In the illustrated example, the movable main contact 12 is installed to surround the insulating nozzle 3 from the outside. The movable main contact 12 contacts the fixed main contact 6 from inside. The sea urchin is turning.

As shown in FIG. 8, the insulating nozzle 3 has an inner surface Sa that is curved so that the distance between the movable arc contact 2 and the movable arc contact 2 gradually decreases from the rear end side to the front end side. On the tip end side of the movable arc contact 2, there is a first region 3a where the inner surface Sa faces the end surface of the tip of the movable arc contact with a predetermined gap therebetween, and a first region 3a where the movable arc contact is in the arc extinguishing position. A second region 3b having an inner surface Sb that is provided so as to surround the main portion 1a of the fixed arc contact 1 at a certain time and has a tapered inner surface Sb whose diameter gradually increases toward the rear end side of the fixed arc contact. and a boundary region 3c of a predetermined length separating the first and second regions. Each of the above parts is housed in an insulating container, and SF ₆ gas is sealed in the insulating container at a predetermined pressure.

[0008] In this gas circuit breaker, at the time of closing, the movable main contact 1 2 is connected to the fixed main contact 6, and the movable arc contact 2 is connected to the fixed main contact 6. 1, respectively. In this state, conductor 5 - fixed main contact 6 - possible Drive contact 12-movable conductor bar 8-conductor 7 path, and conductor 5-fixed arc core The main circuit power is connected to the contact 1 - movable arc contact 2 - movable conductor rod 8 - conductor 7 The flow flows.

When opening the circuit breaker, the movable conductor rod 8 is moved downward in the drawing by an operating device (not shown). At this time, the movable main contact 12 first separates from the fixed main contact 6 without arcing, and then the movable arc contact 2 separates from the fixed arc contact 1 (opening). When the movable arc contact 2 separates from the fixed arc contact 1, an arc A is generated between both arc contacts. As the movable conductor moves, the volume inside the puffer cylinder 10 is reduced, so a high-speed gas flow is generated from inside the cylinder 10 toward the inside of the insulating nozzle 3, as shown by the arrow in FIG. As a result, SF ₆ gas is sprayed onto the arc A, thereby cooling the arc and extinguishing the arc at the current zero point after approximately half a cycle or approximately one cycle.

0010 In this type of gas circuit breaker, after opening (the movable arc contact is connected to the fixed arc contact) When the current waveform reaches zero point (after leaving the contact), the movable arc contact 2 is at the open position (the boundary between the main part 1a and the tip 1b of the fixed arc contact) position) so that the movable arm reaches arc extinguishing position P2, which is a predetermined distance L from P1. The opening phase of the arc contact is controlled relative to the current phase.

[0011]

[Problem that the idea aims to solve]

In conventional gas circuit breakers, after opening, the movable arc contact reaches the arc extinguishing position P2. When the taper surface of the second region of the insulating nozzle 3 and the tip of the fixed arc contact 1 The gas flow becomes supersonic in the gap between the end and the tip of the fixed arc contact 1. It has become clear that a low pressure region Q occurs near the end.

[0012]The occurrence of such a low pressure region is undesirable because it lowers the dielectric strength of the SF ₆ gas, causing re-ignition or re-ignition and failure in shutoff.

[0013] The purpose of this invention is to create a low pressure area near the tip of the fixed arc contact when disconnecting. It is an object of the present invention to provide a gas circuit breaker that prevents this from occurring and improves interrupting performance.

[0014]

[Means to solve the problem]

The present invention has a main portion having a circular cross-sectional profile and extending linearly in the axial direction; A fixed arc contact having a tip whose surface has an arcuate outline, and the fixed arc contact. It is provided so that it can move in the axial direction while sharing the axis with the arc contact. When it is turned on, it contacts the outer periphery of the main part of the fixed arc contact from the outside, and when it is turned off, it contacts the outer periphery of the main part of the fixed arc contact from the outside. is the boundary position between the main part and the tip of the fixed arc contact when the current reaches zero point. A tube whose opening phase is controlled so that the arc reaches an extinguishing position at a predetermined distance from the A movable arc contact with a shape and a movable arc contact provided concentrically outside the movable arc contact. an insulating nozzle that is displaced together with the movable arc contact, and a movable arc contact. When the movable arc contact moves to the arc extinguishing position, the insulating nozzle is inserted from the rear end of the movable arc contact. Targeting gas circuit breakers equipped with a puffer mechanism that supplies high-speed gas flow inside the Ru.

[0015] Here, the insulating nozzle runs from the rear end of the movable arc contact to the tip end. The inner surface is curved to gradually reduce the gap between it and the movable arc contact. On the tip side of the movable arc contact, the tip of the movable arc contact a first region facing the end face with a predetermined gap therebetween; and the movable arc contactor. The fixed arc contact is provided so as to surround the main part of the fixed arc contact when the contact is in the arc extinguishing position. The diameter of the fixed arc contact gradually increases toward the rear end of the fixed arc contact. a second region having a tapered inner surface separating the first and second regions; It is assumed that the boundary area has a

[0016] In the present invention, the inner surface of the second region of the insulating nozzle near the boundary region is provided with a circumferential direction. A groove section is provided that extends continuously. Then, the movable arc contact reaches the arc extinguishing position. The boundary between the main part and tip of the fixed arc contact is near the bottom of the groove. The position of the groove is set so that the

[0017]

[Effect]

The inner surface of the insulating nozzle facing near the tip of the fixed arc contact as shown above. A continuous groove is provided in the circumferential direction to prevent the movable arc contact from reaching the arc extinguishing position. When the boundary between the main part and the tip of the fixed arc contact is facing the bottom of the groove. If the gas is supplied from the puffer mechanism, it will move as shown by the arrow in Figure 1. Produces a gas flow. This is the boundary between the main part and the tip of the fixed arc contact. Expansion waves and shock waves form a fixed arc contact surface to suppress flow separation near the It separates more and lowers the gas flow rate in this area. This allows the gas flow to exceed supersonic speeds. The region where the gas flows further than the area near the boundary between the main part and the tip of the fixed arc contact move downstream. Therefore, there is a low pressure area near the tip of the fixed arc contact. It is possible to prevent the dielectric strength from decreasing and improve the breaking performance. Wear.

[0018]

【Example】

FIG. 1 shows the main parts of an embodiment of the present invention, and in the same figure, each of FIGS. 7 and 8 is shown. The same parts are given the same reference numerals. In this example, the basics of circuit breaker The structure is similar to that shown in FIG. 7, and the insulating nozzle 3 is a movable arc contactor. Increase the gap between the movable arc contact and the movable arc contact from the rear end side of the contact 2 toward the front end side. The movable arc contact has a curved inner surface Sa that gradually becomes smaller. On the tip side, it faces the end face of the tip of the movable arc contact with a predetermined gap therebetween. the first area 3a where the movable arc contact 2 is in the arc extinguishing position, and the fixed area The fixed arc contact 1 is provided so as to surround the main portion 1a of the arc contact 1. It has an inner surface Sb that is tapered so that the diameter gradually increases toward the rear end side. a second region 3b and a boundary region (throat) 3c separating the first and second regions; It is equipped with The boundary region 3c has a cylindrical surface shape with a substantially uniform inner diameter along the axial direction. It is formed.

[0019] In the present invention, the inner surface of the second region 3b of the insulating nozzle 3 near the boundary region 3c is provided with a groove 3d that extends continuously in the circumferential direction, so that the tip of the movable arc contact 2 When the arc extinguishing position P2 is reached, the main part 1a and the tip part 1b of the fixed arc contact 1 The boundary portion P1 is located near the groove portion 3d. In the example, the movable arm When the tip of fixed arc contact 2 reaches the arc extinguishing position, the main The groove is formed so that the boundary part P1 between the part 1a and the tip part 1b faces the bottom part 3d1 of the groove part 3d. The position of section 3d is set. In this embodiment, the boundary region 3c side of the groove portion 3d is also The inner surface 3d2 is an inclined surface.

[0020] Here, the width and position of the groove 3d are equal to the control range of the opening phase at the time of interruption. Set it like this. That is, let the average moving speed of the movable arc contact 2 be V, Time from the most advanced opening time in opening phase control to the current zero point at which arc extinction occurs time (travel time required for the movable arc contact to move to the arc extinguishing position P2) ) is Δt1, the time from the latest opening time to the current zero point is Δt2, and the opening position P is When the distance from 1 to the arc extinguishing position P2 is L, the following equation (1) holds true. It is preferable to set the position and width of the groove 3d so that the width of the groove 3d increases.

[0021] V・Δt2 ≦L≦V・Δt1 …(1) The relationship between the control range of the opening phase and Δt1 and Δt2 is shown in the case of half-cycle interruption. The cases of 1-cycle interruption and 1-cycle interruption are shown in Figure 2 (A) and (B), respectively. It is.

[0022] In order to confirm the effect of the groove 3d above, When the movable arc contact reaches the cutoff position, the fixed The gas flow and gas pressure conditions near the tip of the arc contact were analyzed.

[0023] The models used in the analysis are as shown in cases 1 to 4 in FIG. Each model In this case, the fixed arc contact 1 has a shape excluding the rounded tip, and is fixed. The constant arc contact 1 had an outer diameter of 25 mm and an inner diameter of 12 mm. Also movable arcco When the contact reaches the arc-extinguishing position, the insulating node is removed from the tip of fixed arc contact 1. The distance to the boundary area 3c of the nozzle is 10 mm, and the tip of the second area 3b of the insulating nozzle is The par angle was 15 degrees.

In each case shown in FIG. 3, the initial pressure in the arc extinguishing chamber before the gas starts flowing out is 5 kg/cm ² abs, the back pressure downstream of the nozzle is 5 kg/cm 2 abs, and the nozzle throat is set to 5 kg/cm ² abs. When a gas pressure twice the back pressure was applied to the tip of the fixed arc contact, the lowest gas pressure at the tip of the fixed arc contact at the time when 4 msec had passed after the gas started flowing out was as shown in FIG. From this result, in the model corresponding to the conventional example of Case 1, the minimum gas pressure at the tip of the fixed arc contact was 2.57 kg/cm ² abs, but in the models of Cases 2 to 4 with the groove 3d. , we were able to significantly increase the minimum gas pressure at the tip of a fixed arc contactor.

[0025] Figure 5 also shows that for each model in Cases 1 to 4, after the gas starts flowing out, This shows the maximum Mach number M at the tip of the fixed arc contact after 4 msec from In case 1, the gas flow at the tip of fixed arc contact 1 becomes a supersonic flow, but in other cases In the case of , the gas flow at the tip of the fixed arc contact is subsonic.

[0026] Furthermore, Figure 6 shows the gas flow velocity at each part after 4 msec and the gas flow rate for Cases 1 to 4. The figure shows the positions of expansion waves and shock waves caused by the gas flow. From this figure it is clear As is clear, in Case 1, there is a supersonic flow region and a subsonic flow region at the tip of the fixed arc contact. The boundary with the sonic flow region is located near the tip of the fixed arc contact 1, and this boundary As expansion waves occur at the interface, the pressure near the tip of fixed arc contact 1 decreases. do. In cases 2 to 4, the boundary between the supersonic flow region and the subsonic flow region is a fixed point. Expansion waves are generated because the gas flow moves downstream of the tip of contact 1. The position is moved to the downstream side of the gas flow from the tip of the fixed arc contact. follow This prevents the gas pressure from decreasing near the tip of the fixed arc contact.

[0027] In the embodiment shown in FIG. 1, the groove portion 3d is provided with an inclined surface 3d2. When an inclined surface is provided, as seen in case 3, the tip of the fixed arc contact 1 The effect of preventing a drop in gas pressure near the area can be enhanced. However, this idea It is not limited to the case where an inclined surface is provided in this way, but in Case 2 or 4. As shown, a groove having a U-shaped cross section may also be provided.

[0028]

[Effect of the idea]

As described above, according to the present invention, there is a A movable arc contact is created by providing a circumferentially continuous groove on the inner surface of the insulated nozzle. When the arc extinguishing position is reached, the boundary between the main part and the tip of the fixed arc contact becomes a groove. Because it is located near the groove, when gas is supplied from the puffer mechanism, The fixed arc contact is The gas flow velocity near the boundary between the main portion and the tip portion can be reduced. Therefore, Ga The area where the gas flow exceeds supersonic speed is further gas than near the tip of the fixed arc contact. By moving the flow downstream, a low pressure area is created near the tip of the fixed arc contact. Therefore, it is possible to improve the interrupting performance.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of essential parts of an embodiment of the present invention.

FIGS. 2A and 2B are diagrams showing the relationship between the travel time of the movable arc contact and the control range of the opening phase in the case of half-cycle interruption and one-cycle interruption, respectively.

FIG. 3 is an explanatory diagram showing the shape of a groove portion of a model used for analysis to confirm the effects of the present invention.

FIG. 4 is a graph showing the lowest gas pressure at the tip of the fixed arc contact for cases 1 to 4 in FIG. 3;

FIG. 5 is a graph showing the maximum Mach number at the tip of the fixed arc contact for cases 1 to 4 in FIG. 3;

6 is an explanatory diagram showing the generation positions of supersonic flow regions and subsonic flow regions and the generation positions of expansion waves and shock waves for cases 1 to 4 in FIG. 3; FIG.

FIG. 7 is a sectional view showing the configuration of main parts of a gas circuit breaker to which the present invention can be applied.

FIG. 8 is an explanatory diagram showing a configuration near the tip of a fixed arc contact of a conventional gas circuit breaker.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Fixed arc contact, 2... Movable arc contact, 3... Insulating nozzle, 3a... First region, 3b... Second region, 3c... Boundary region, 3d... Groove.

Claims (1)

[Scope of utility model registration request] 1. A fixed arc contact having a main portion having a circular cross-sectional profile and extending linearly in the axial direction, and a tip portion having an arcuate vertical cross-sectional profile; It is provided so that it can move in the axial direction in a shared state, and when it is turned on, it contacts the outer periphery of the main part of the fixed arc contact from the outside, and when it is turned off, when the current reaches the zero point, the main part of the fixed arc contact a tubular movable arc contact whose opening phase is controlled such that the opening phase reaches an arc extinguishing position a predetermined distance from the boundary position between the movable arc contact and the tip; An insulating nozzle that is displaced together with the movable arc contact, and a puffer mechanism that supplies a high-speed gas flow from the rear end side of the movable arc contact to the inside of the insulating nozzle when the movable arc contact is displaced to the arc extinguishing position. The insulating nozzle has an inner surface curved so as to gradually reduce a gap between the movable arc contact and the movable arc contact from the rear end side to the front end side. On the tip side of the contact, a first region facing the end face of the tip of the movable arc contact with a predetermined gap therebetween, and a main portion of the fixed arc contact when the movable arc contact is in an arc extinguishing position. A second region surrounding the fixed arc contact and having a tapered inner surface with a diameter gradually increasing toward the rear end side of the fixed arc contact is separated from the first and second regions. In the gas circuit breaker, a groove portion extending continuously in the circumferential direction is provided on an inner surface of the second region of the insulating nozzle near the boundary region, and the movable arc contact is in an arc extinguishing position. A gas circuit breaker characterized in that the position of the groove is set such that when the fixed arc contact reaches the boundary between the main part and the tip of the fixed arc contact, the boundary part is located near the groove.