Suction puffer type switch

Abstract

A suction puffer type switch that reliably and quickly extinguishes arcs and minimizes deterioration of components. [Solution] The suction puffer type switch (1) comprises a cylindrical body (10), a piston mechanism (12) configured to draw in insulating gas as the cylindrical body retracts, a fixed contact (30) that contacts the outer surface of the cylindrical body, and a fixed electrode (31). The fixed electrode is positioned with a gap (20) between it and the inner wall of the cylindrical body. Furthermore, when the cylindrical body and the fixed contact separate, a portion of the fixed electrode is inserted into the cylindrical body, and when the cylindrical body is fully retracted, it is positioned so that it is not inside the cylindrical body. A flow path is provided along the fixed electrode to guide the insulating gas (G) drawn into the open end (11) of the cylindrical body.

Description

Technical Field

[0001] The present disclosure relates to a suction buffer type switch.

Background Art

[0002] A suction buffer type switch that extinguishes an arc by the airflow of an insulating gas is known. In Patent Document 1, a suction buffer type switch is also proposed that is intended to prevent damage to a fixed contact by immediately transferring the generated arc to an arc horn provided on the inner wall of a movable contact.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, according to the study by the present disclosure inventors, in the configuration of the suction buffer type switch described in Patent Document 1, there were problems with the certainty of arc extinction. Therefore, it is desirable to realize a suction buffer type switch that can more surely and quickly extinguish an arc and also has less deterioration of members.

Means for Solving the Problems

[0005] To solve the above problems, a suction puffer switch according to one aspect of the present disclosure comprises a cylindrical body constituting a movable contact, a piston mechanism configured to draw in insulating gas from the open end of the cylindrical body through the inside of the cylindrical body as the cylindrical body retracts, a fixed contact that contacts the outer surface of the cylindrical body, and a fixed electrode electrically connected to the fixed contact and arranged coaxially with the cylindrical body so as to be inserted into the inside of the cylindrical body, wherein the fixed electrode is positioned with a gap between it and the inner wall of the cylindrical body so as not to contact the cylindrical body, and further, the fixed electrode is positioned such that a portion is inserted into the inside of the cylindrical body when the cylindrical body and the fixed contact separate, and is not inside the cylindrical body when the cylindrical body is fully retracted, and a flow path is provided along the fixed electrode to guide the insulating gas drawn into the open end of the cylindrical body. [Effects of the Invention]

[0006] According to one aspect of this disclosure, it is possible to realize a suction puffer type switch that can reliably and quickly extinguish arcs and has less deterioration of components. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic cross-sectional view of the inside of a suction puffer type switch according to one embodiment of the present disclosure. [Figure 2] Figure 1 shows the state immediately after the movable contact and fixed contact have separated. [Figure 3] Figure 2 shows the arc occurring between the movable contact and the fixed electrode. [Figure 4] These are schematic cross-sectional views and schematic diagrams of the operation of a suction puffer type switchgear related to a comparative example. [Modes for carrying out the invention]

[0008] [Embodiment 1] Hereinafter, a switch 1 (suction puffer type switch) according to one embodiment of the present disclosure will be described in detail with reference to the figures. Figure 1 is a schematic cross-sectional view of the inside of the switch 1 according to one embodiment of the present disclosure. The switch 1 is equipped with the components shown in Figure 1 inside an airtight container. The switch 1 is a suction puffer type switch that interrupts the current in a power system carrying high voltage current by blowing insulating gas onto the arc that is generated when two contacts are separated in order to interrupt the current.

[0009] The insulating gas used in this case may be dry air, carbon dioxide (CO2), sulfur fluoride (SF6), or other fluorinated gases, but in Embodiment 1, the insulating gas G is dry air. The inside of the switchgear 1 is filled with insulating gas G. The switchgear 1 comprises a cylindrical body 10, a piston mechanism 12, an electrode base 16, a fixed contact 30, a fixed electrode 31, and a shield 32.

[0010] The cylindrical body 10 is a cylindrical conductor that constitutes the movable contact. The cylindrical body 10 is movable forward and backward along its central axis. In terms of the axial direction of the cylindrical body 10, the direction in which the cylindrical body 10 moves forward is referred to as forward, and the direction in which it moves backward is referred to as backward. Moving forward is the operation of inserting the cylindrical body 10 into the fixed contact 30 described later, and moving backward is the operation of pulling the cylindrical body 10 out of the fixed contact 30. Figure 1 shows the cylindrical body 10 in its most forward position.

[0011] The cylindrical body 10 can be cylindrical in shape, for example, it may be cylindrical. The cylindrical body 10 has an open end 11 and an opening 15.

[0012] The open end 11 is located at the front of the cylindrical body 10, and the opening 15 is located inside the piston mechanism 12, which is situated at the rear of the cylindrical body 10. This allows insulating gas G to flow from the open end 11 through the opening 15 to the cylinder chamber 18 of the piston mechanism 12.

[0013] The piston mechanism 12 comprises a cylinder 13 and a piston 14. The cylinder 13 has a through hole at its front end that allows it to slide along the central axis within the cylindrical body 10. The piston 14 is fixed to the cylindrical body 10. The cylinder 13 and piston 14 define the cylinder chamber 18. The piston 14 is movable in the forward and backward direction as the cylindrical body 10 moves back and forth, thereby changing the volume of the cylinder chamber 18. The piston mechanism 12 is configured to draw in insulating gas G from the open end 11 through the inside of the cylindrical body 10 as the cylindrical body 10 retracts. For example, when the cylindrical body 10 and piston 14 move backward, the volume of the cylinder chamber 18 increases and the internal pressure decreases. This allows insulating gas G to be drawn in from the open end 11.

[0014] The electrode base 16 is a conductor that supports the components constituting the fixed contact. The electrode base 16 has ventilation holes 17 and supports the fixed contact 30, the fixed electrode 31, and the shield 32. The ventilation holes 17 are holes for the ventilation of insulating gas G. The electrode base 16 supports the fixed electrode 31 on its central axis, and the ventilation holes 17 are provided near the position where the fixed electrode 31 is supported.

[0015] The fixed contact 30 is a cylindrical or annular conductor. The fixed contact 30 is made of, for example, a metal piece and contacts the outer surface of the cylindrical body 10. The inner diameter of the fixed contact 30 is at least equal to or slightly smaller than the outer diameter of the cylindrical body 10. The axial length and position of the fixed contact 30 should be such that the cylindrical body 10 and the fixed contact 30 are in contact when the cylindrical body 10 is at its furthest forward position, and separate from the cylindrical body 10 by the time the cylindrical body 10 has fully retracted.

[0016] The ring spring 33 tightens the fixed contact 30 toward the center of the axis. As a result, the ring spring 33 fixes the fixed contact 30 to the electrode base 16 and presses the fixed contact 30 against the outer wall of the cylindrical body 10 so that it slides.

[0017] The fixed electrode 31 is electrically connected to the fixed contact 30 and is arranged coaxially with the cylinder 10 so as to be inserted into the cylinder 10. A gap 20 is provided between the fixed electrode 31 and the inner wall inside the cylinder 10 so as not to contact the cylinder 10.

[0018] The fixed electrode 31 is cylindrical. The axial length and position of the fixed electrode 31 are in a state where a part of it is inserted into the cylinder 10 from when the cylinder 10 is at the most forward position until the cylinder 10 and the fixed contact 30 are separated, and when the cylinder 10 is at the most retracted position, it is configured to be not inside the cylinder 10. The diameter of the fixed electrode 31 may be 0.2 to 0.9 times the inner diameter of the cylinder 10.

[0019] The shield 32 relaxes the electric field and prevents discharge toward the container of the switch 1 or the like. The shield 32 is arranged to surround the fixed contact 30. At this time, in the axial direction of the cylinder 10, the position of the rear end of the fixed contact 30 is in front of the position of the rear end of the shield 32.

[0020] The gap 20 may be in the range of 0.05 to 0.4 times the inner diameter of the cylinder 10.

[0021] 〔Operation of the switch 1〕 The operation of the switch 1 from when the arc A occurs until it is extinguished will be described using FIGS. 2 and 3. FIGS. 2 and 3 are both schematic diagrams when the switch 1 operates. FIG. 2 shows the state immediately after the cylinder 10 and the fixed contact 30 are separated, and FIG. 3 shows the state where the arc A is generated between the cylinder 10 and the fixed electrode 31 thereafter.

[0022] When the switch 1 begins its opening operation, the cylindrical body 10 and piston 14 retract, increasing the volume of the cylinder chamber 18 and creating negative pressure, which draws in insulating gas G from the open end 11 of the cylindrical body 10 that constitutes the movable contact. At this time, immediately after the opening operation begins, the insulating gas G flows in from the vent hole 17, flows along the fixed electrode 31, and passes through the open end 11, the gap 20, the inside of the cylindrical body 10, the opening 15, and the cylinder chamber 18 in this order. In this way, a flow path is provided along the fixed electrode 31 to guide the insulating gas G that is drawn into the open end 11 of the cylindrical body 10.

[0023] Here, the flow path provided along the fixed electrode 31 is configured to include the space between the inner wall of the electrode base 16, which is provided to surround the fixed electrode while maintaining a certain distance from the fixed electrode 31 along the central axis, and the fixed electrode 31. The space between the fixed contact 30 and the fixed electrode 31 is also part of this flow path. Furthermore, the ventilation hole 17 may also be part of this flow path.

[0024] As the cylindrical body 10 retracts further, the cylindrical body 10 and the fixed contact 30 separate. At this point, an arc A is generated between the cylindrical body 10 and the fixed contact 30, through which high-voltage current had been flowing. In addition to the flow of insulating gas G flowing in from the vent hole 17 as described above, a flow of insulating gas G is also generated through the gap 34 with the fixed contact 30 to the cylinder chamber 18.

[0025] Subsequently, the distance between the cylindrical body 10 and the fixed contact 30 increases, while the distance between the cylindrical body 10 and the fixed electrode 31, defined as the gap 20, remains constant. At a certain point, as shown in Figure 3, arc A is commutated between the cylindrical body 10 and the fixed electrode 31. That is, arc A between the cylindrical body 10 and the fixed contact 30 disappears, and arc A is generated between the cylindrical body 10 and the fixed electrode 31. Since a constant flow of insulating gas G is blown onto arc A between the cylindrical body 10 and the fixed electrode 31, arc A is in a state where it is easily extinguished.

[0026] Further retracting the cylindrical body 10 causes the fixed electrode 31 to be no longer inside the cylindrical body 10 and to separate from the cylindrical body 10. The arc A is then cooled and extinguished by the insulating gas G blown into it from the open end 11 of the cylindrical body 10.

[0027] With the above configuration, since the fixed electrode 31 is not in contact with the cylindrical body 10, wear, damage, and other reductions in mechanical rigidity are less likely to occur even after multiple opening and closing cycles. In addition, since the fixed electrode 31 faces the cylindrical body 10 with a gap in between, the arc A can be commutated between the fixed electrode 31 and the cylindrical body 10 when the cylindrical body 10 and the fixed contact 30 separate.

[0028] Furthermore, the placement of a fixed electrode 31 at the center of the open end 11 narrows the cross-sectional area of ​​the space inside the cylindrical body 10, increasing the flow velocity of the insulating gas G flowing through the gap. This allows the arc A to be extinguished more efficiently.

[0029] Furthermore, it is generally known that the lower the temperature of the insulating gas G blown onto the arc A during current interruption, the better the arc extinguishing performance. The insulating gas G flowing through the gap 34 between the separated cylinder 10 and the fixed contact 30 is heated by the arc A generated between the cylinder 10 and the fixed contact 30. In contrast, the switch 1 of the present invention is equipped with a vent hole 17, so that the insulating gas G drawn into the cylinder 10 is cooled by the insulating gas G flowing from the vent hole 17, thereby improving the arc extinguishing performance.

[0030] Furthermore, by providing a configuration in which the shield 32 covers the fixed contact 30 such that the rear end of the fixed contact 30 is located further forward than the rear end of the shield 32, the switch 1 can mitigate the electric field at the rear end of the fixed contact 30.

[0031] Furthermore, by having a gap 20 between the inner wall of the cylindrical body 10 and the outer wall of the fixed electrode 31 that is in the range of 0.05 to 0.4 times the inner diameter of the cylindrical body 10, the arc A can be extinguished more efficiently.

[0032] Furthermore, by providing the ventilation holes 17, the flow rate of the insulating gas G flowing in can be increased, allowing the arc A to be extinguished more efficiently.

[0033] [Embodiment 2] Other embodiments of the present disclosure are described below. The switch 1A (not shown) in Embodiment 2 differs from the switch 1 in Embodiment 1 in the shape of the fixed electrode 31. The fixed electrode 31A of the switch 1A is a polygonal prism.

[0034] Because the fixed electrode 31A is polygonal prism-shaped, the maximum electric field around the fixed electrode 31A is large, making it easier for an arc A to be generated between the cylindrical body 10 and the fixed electrode 31A. Therefore, it is possible to more easily commutate the arc A when the cylindrical body 10 and the fixed contact 30 separate.

[0035] [Comparison with conventional technology] The puffer-type switch described in Patent Document 1 replaces the fixed electrode 31 of the above embodiment with an arc horn that engages with a cylindrical body constituting a movable contact. Furthermore, it is said that the arc extinguishing performance is improved by the configuration such that insulating gas is rapidly drawn into the cylindrical body through the gap at the moment the cylindrical body separates from the fixed contact.

[0036] However, our investigations have revealed that in a switch with such a configuration, the arc extinguishing performance is unstable due to the relationship between the timing of the rapid suction of insulating gas into the cylindrical body and the timing of the zero point of the AC current, and there are issues with the reliability of arc extinguishing. On the other hand, the suction puffer type switch of the above embodiment does not have a configuration in which insulating gas is rapidly suctioned in before or after the timing when the cylindrical body 10 and the fixed contact 30 separate, or when the cylindrical body 10 and the fixed electrode 31 separate. Therefore, the arc extinguishing performance is stable, and arc extinguishing can be reliably performed.

[0037] Furthermore, Patent Document 1 describes a configuration in which the arc horn is fitted to close the hole in the cylindrical body. However, with such a configuration, the contact state between the arc horn and the cylindrical body fluctuates as the operation is repeated, resulting in a problem of extremely short lifespan for either the arc horn or the cylindrical body.

[0038] Furthermore, in the puffer-type switch configuration described in Patent Document 1, the tolerance for misalignment and tilt of the shaft between the movable rod and the arc horn is extremely small, making manufacturing itself difficult. In addition, there was a problem in that even slight misalignment or shaft misalignment due to the movement of the movable rod caused significant wear on the arc horn or cylindrical body.

[0039] <Operation of the comparative example> For comparison with this disclosure, a comparative example is described below. The comparative example illustrated here is an example in which an improvement was attempted to stabilize the contact between the arc horn and the cylindrical body of the puffer-type switch described in Patent Document 1. For the sake of explanation, the same reference numerals are used for components having the same function as those described in Embodiment 1, and their descriptions are not repeated.

[0040] Figure 4 shows the schematic 411 and operation 412 of switch 1C according to the comparative example. As shown in schematic 411, switch 1C differs from switch 1 in that it does not have a fixed electrode 31 and an electrode base 16, but instead has a fixed contact 31C and an electrode base 16C. The electrode base 16C differs in that it does not have a ventilation hole 17.

[0041] Furthermore, the fixed contact 31C is made of a rod-shaped conductor that has a bulge at its rear end, which is divided by a radial dividing line (slit) extending in the axial direction and biased outward. The maximum diameter of the bulge is slightly larger than the inner diameter of the cylindrical body 10. In the switch 1C according to the comparative example, only the bulge portion of the fixed contact 31C contacts the cylindrical body 10, so the tolerance for misalignment and shaft inclination is relaxed. Also, even if the switch 1C is operated repeatedly, the fixed contact 31C can reliably contact the inner wall of the cylindrical body 10 as long as the biasing force of the bulge portion is maintained.

[0042] However, when using the fixed contact 31C, the outer wall of the bulging portion of the fixed contact 31C slides against the inner wall of the cylindrical body 10, raising concerns about a decrease in the mechanical rigidity of both the fixed contact 31C and the cylindrical body 10, and also limiting the maintenance of the biasing force. Therefore, compared to the switch of the above embodiment, the switch 1C of the comparative example is still prone to wear and tear of its components.

[0043] In view of the prior art and comparative examples illustrated above, the switch 1 according to this disclosure prevents a decrease in mechanical rigidity by preventing the fixed electrode 31 from contacting the inner wall of the cylindrical body 10, and improves arc extinguishing performance by forming a narrow flow path.

[0044] 〔summary〕 A suction puffer switch according to Embodiment 1 of the present disclosure comprises a cylindrical body constituting a movable contact, a piston mechanism configured to draw in insulating gas from the open end of the cylindrical body through the inside of the cylindrical body as the cylindrical body retracts, a fixed contact that contacts the outer surface of the cylindrical body, and a fixed electrode electrically connected to the fixed contact and arranged coaxially with the cylindrical body so as to be inserted into the inside of the cylindrical body, wherein the fixed electrode is positioned with a gap between it and the inner wall of the cylindrical body so as not to contact the cylindrical body, and further positioned such that when the cylindrical body and the fixed contact separate, a portion of the fixed electrode is inserted into the inside of the cylindrical body, and when the cylindrical body is fully retracted, it is not inside the cylindrical body, and a flow path is provided along the fixed electrode to guide the insulating gas drawn into the open end of the cylindrical body.

[0045] A suction puffer type switch according to aspect 2 of the present disclosure further comprises a shield arranged to surround the fixed contact in aspect 1, wherein, with respect to the axial direction of the cylindrical body, the direction in which the cylindrical body moves forward is referred to as forward, and the direction in which it moves backward is referred to as rear, the position of the rear end of the fixed contact in the axial direction of the cylindrical body is forward of the position of the rear end of the shield.

[0046] In the suction puffer type switch according to embodiment 3 of this disclosure, the fixed electrode is cylindrical in embodiment 1 or 2.

[0047] In the suction puffer type switch according to Embodiment 4 of the present disclosure, in any one of Embodiments 1 to 3, the gap is in the range of 0.05 to 0.4 times the inner diameter of the cylindrical body.

[0048] In the suction puffer type switch according to aspect 5 of the present disclosure, in any one of aspects 1, 2, or 4, the fixed electrode is polygonal prism-shaped.

[0049] In the suction puffer type switch according to embodiment 6 of the present disclosure, in any one of embodiments 1 to 5, the insulating gas is dry air.

[0050] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure. [Explanation of symbols]

[0051] 1. Switch (Suction buff type switch) 10. Tube (movable contact) 11 Open end 12 Piston mechanism 13 Cylinders 14 pistons 15 Aperture 16 Electrode stand 17 Ventilation holes 18 Cylinder chamber 20 gap 30 Fixed Contact 31 Fixed electrode 32 Shields 33 Ring spring 34 gaps

Claims

1. The cylindrical body that constitutes the movable contact, A piston mechanism configured to draw insulating gas from the open end of the cylindrical body through the inside of the cylindrical body as the cylindrical body retracts, A fixed contact that contacts the outer surface of the cylindrical body, The system comprises a fixed electrode electrically connected to the fixed contact and arranged coaxially with the cylindrical body so as to be inserted into the cylindrical body, The fixed electrode is positioned such that it does not come into contact with the cylindrical body, with a gap provided between it and the inner wall of the cylindrical body. Furthermore, the fixed electrode is positioned such that when the cylindrical body and the fixed contact separate, a portion of it is inserted into the cylindrical body, and when the cylindrical body is fully retracted, it is not inside the cylindrical body. A suction puffer type switch, wherein a channel for guiding the insulating gas drawn into the open end of the cylindrical body is provided along the fixed electrode.

2. The fixed contact is further provided with a shield arranged to surround it. With respect to the axial direction of the cylindrical body, when the direction in which the cylindrical body moves forward is referred to as forward, and the direction in which it moves backward is referred to as backward, The suction puffer type switch according to claim 1, wherein, in the axial direction of the cylindrical body, the position of the rear end of the fixed contact is forward of the position of the rear end of the shield.

3. The suction puffer type switch according to claim 1, wherein the fixed electrode is cylindrical.

4. The suction puffer type switch according to claim 2, wherein the gap is in the range of 0.05 to 0.4 times the inner diameter of the cylindrical body.

5. The suction puffer type switch according to claim 1, wherein the fixed electrode is polygonal prism-shaped.

6. The suction puffer type switch according to any one of claims 1 to 5, wherein the insulating gas is dry air.

Images