Switch, and replacement method of switch

Abstract

To raise durability performance.SOLUTION: A switch comprises: a cylindrical case extending in a vertical direction; a plurality of power supply side bushings and a plurality of load side bushings attached to the case; a plurality of power supply side conduction members held by mutually different power supply side bushings; a plurality of load side conduction members held by mutually different load side bushings; and a plurality of connection parts accommodated inside the case to switch electric connection states between a mutually different pair of power supply side conduction members and load side conduction members, wherein the plurality of connection parts are arranged along the vertical direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a switch and a method for replacing a switch. [Background technology]

[0002] A switch is known that is installed on a support, such as a utility pole, that supports an electric wire that supplies power, and switches the primary electric wire and the secondary electric wire between an electrically connected state and an electrically disconnected state (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-192346 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described switch, the switch body has a rectangular tubular shape and includes a first connection portion for connecting the first branch line and a second connection portion for connecting the second branch line. Generally, when the switch body has a rectangular tubular shape, at least a portion of the switch body is manufactured by bending a single plate and welding together four wall portions extending vertically from the bottom. In this case, the potential of the welded portions of the switch body is lower than the potential of the unwelded portions of the switch body, making the welded portions susceptible to electrolytic corrosion. Therefore, it has been difficult to improve the durability of a switch having a rectangular tubular shape. Furthermore, each of the welded portions of the switch body is a corner with an angle of approximately 90°. Therefore, when a corrosion-resistant layer is formed on the surface of the switch body by plating, the thickness of the corrosion-resistant layer formed on the welded portions tends to be thin. Furthermore, when a coating film is formed on the surface of the corrosion-resistant layer, the thickness of the coating film formed on the welded portions tends to be thin. For these reasons, in a switch whose main body is in the shape of a rectangular tube, the welded portion is prone to corrosion, making it difficult to improve durability.

[0005] The present invention has been made in consideration of the above points, and an object of the present invention is to provide a switch that can improve durability and a method for replacing the switch. [Means for solving the problem]

[0006] (1) One aspect of the present invention is a switch comprising a cylindrical case extending in a vertical direction, a plurality of power supply side bushings and a plurality of load side bushings attached to the case, a plurality of power supply side conductive members held by the different power supply side bushings, a plurality of load side conductive members held by the different load side bushings, and a plurality of connection parts housed inside the case and switching the electrical connection state between the different pairs of power supply side conductive members and the load side conductive members, wherein the plurality of connection parts are arranged along the vertical direction.

[0007] (2) In one aspect of the present invention, in the switch described in (1) above, the plurality of power supply side bushings and the plurality of load side bushings are arranged along a vertical direction.

[0008] (3) In one aspect of the present invention, in the switch described in (1) or (2) above, the case has a cylindrical portion extending vertically and having an opening that opens vertically upward, and an upper cover portion that covers the opening, the upper cover portion being plate-shaped and extending in a direction perpendicular to the vertical direction, and the upper cover portion has a recess that is recessed vertically.

[0009] (4) In one aspect of the present invention, in the switch described in (3) above, the upper cover portion is welded to the cylindrical portion.

[0010] (5) In one aspect of the present invention, the switch according to any one of (1) to (4) above further comprises a fixing part for fixing the case to a utility pole.

[0011] (6) One aspect of the present invention is a method for replacing a switch fixed to a utility pole, the method including a replacement step of removing a first switch fixed to the utility pole from the utility pole and fixing a second switch to the utility pole, the second switch including a cylindrical case extending in a vertical direction, a plurality of power supply side conductive members, a plurality of load side conductive members, a plurality of connection parts housed inside the case and switching the electrical connection states between each pair of different power supply side conductive members and each pair of load side conductive members, and a fixing part that fixes the case to the utility pole, the replacement step including a first step of fixing the second switch to the utility pole, a second step of connecting second branch lines branched from an electric wire to each of the plurality of power supply side conductive members and the plurality of load side conductive members, a third step of removing, from the electric wire, a first branch line branched from the electric wire and connected to the first switch, and a fourth step of removing the first switch from the utility pole. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a switch capable of improving durability and a method for replacing the switch. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view showing a switch according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a switch according to an embodiment. [Figure 3] FIG. 2 is a side view showing the switch of the embodiment; [Figure 4] 1 is a first plan view of a switch according to an embodiment, seen from above; [Figure 5] FIG. 2 is a second plan view of the switch of the embodiment as seen from above. [Figure 6] 4 is a flowchart illustrating a method for replacing a switch according to an embodiment. [Figure 7] 1 is a diagram illustrating a first step of a switch replacement method according to an embodiment. FIG. [Figure 8] FIG. 10 is a diagram illustrating a second step of the switch replacement method according to the embodiment. [Figure 9] FIG. 10 is a diagram illustrating a third step of the switch replacement method according to the embodiment. [Figure 10] FIG. 10 is a diagram illustrating a fourth step of the switch replacement method according to the embodiment. [Figure 11] FIG. 10 is a perspective view showing a switch of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, a switch and a switch replacement method according to an embodiment of the present invention will be described with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiments and can be modified as desired within the scope of the technical concept of the present invention. In addition, in the following drawings, the scale and number of components may differ from the actual structure in order to make each component easier to understand.

[0015] In each drawing, the Z axis is indicated as appropriate. The Z axis is the direction in which the central axis J of the embodiment described below extends. The central axis J shown in each drawing as appropriate is a virtual axis. In the embodiment, the direction in which the Z axis extends is the vertical direction. The side in the vertical direction toward which the arrow of the Z axis points is the upper vertical side. The side opposite to the side in the vertical direction toward which the arrow of the Z axis points is the lower vertical side. In the following description, the upper vertical side may simply be referred to as the "upper side," and the lower vertical side may simply be referred to as the "lower side." Furthermore, the radial direction centered on the central axis J is simply referred to as the "radial direction." The circumferential direction centered on the central axis J is simply referred to as the "circumferential direction." The circumferential direction is indicated by arrow θ in each drawing.

[0016] Note that the terms "upper side" and "lower side" are simply names used to explain the relative positional relationship of each part, and the actual positional relationship may be a positional relationship other than the positional relationship indicated by these names.

[0017] FIG. 1 is a perspective view showing a switch 10 of this embodiment. The switch 10 of this embodiment is attached to a utility pole supporting an electric wire that supplies power to a consumer. The switch 10 can switch the electrical connection state between a power supply side electric wire and a load side electric wire between a state in which the power supply side electric wire and the load side electric wire are electrically connected and a state in which the power supply side electric wire and the load side electric wire are electrically disconnected. The switch 10 of this embodiment has a substantially cylindrical shape extending vertically about a central axis J. As shown in FIG. 2, the switch 10 includes a case 11, a bushing 20, a power supply side conductive member 25, a load side conductive member 27, and a connection portion 30. As shown in FIG. 3, the switch 10 includes a fixing portion 40.

[0018] As shown in FIG. 1, the case 11 has a cylindrical shape extending vertically about a central axis J. As shown in FIG. 2, the case 11 holds a bushing 20. The case 11 accommodates a connection portion 30 therein. The case 11 is made of metal. Examples of materials that can be used to form the case 11 include iron and stainless steel. In this embodiment, the case 11 is made of iron. Although not shown in the drawings, a corrosion-resistant layer is formed on the surface of the case 11 by plating. Examples of materials that can be used to form the corrosion-resistant layer include zinc. Although not shown in the drawings, a paint film is formed on the surface of the corrosion-resistant layer. Examples of materials that can be used to form the paint film include epoxy resin, urethane resin, and acrylic resin. The corrosion-resistant layer and the paint film each prevent the case 11 from corroding. The case 11 has a cylindrical portion 13 and an upper cover portion 17.

[0019] The cylindrical portion 13 has a cylindrical shape that extends vertically about a central axis J. The cylindrical portion 13 has an opening 13a that opens to the upper side, i.e., the vertically upward side. The cylindrical portion 13 has a side wall portion 14 and a bottom wall portion 15.

[0020] The side wall portion 14 has a cylindrical shape extending in the vertical direction around the central axis J. The side wall portion 14 surrounds the connection portion 30 from the radially outer side. The side wall portion 14 is provided with a first hole portion 14a and a second hole portion 14c. Each of the first hole portion 14a and the second hole portion 14c is a hole that penetrates the side wall portion 14 in the radial direction. When viewed in the radial direction, each of the first hole portion 14a and the second hole portion 14c is approximately circular. In this embodiment, three first hole portions 14a and three second hole portions 14c are provided in the side wall portion 14. The first hole portions 14a are provided at intervals from one another in the vertical direction. The second hole portions 14c are provided at intervals from one another in the vertical direction. Each first hole portion 14a faces a different second hole portion 14c in the radial direction. That is, the pair of first hole portion 14a and second hole portion 14c are provided at the same position in the vertical direction.

[0021] The bottom wall portion 15 has a plate shape that extends in a direction perpendicular to the vertical direction. Although not shown in the drawings, when viewed in the vertical direction, the bottom wall portion 15 has a substantially circular shape centered on the central axis line J. The radial outer edge of the bottom wall portion 15 is connected to the lower end of the side wall portion 14. Note that the bottom wall portion 15 may be a separate member from the side wall portion 14. In this case, the bottom wall portion 15 is fixed to the lower end of the side wall portion 14 by, for example, welding.

[0022] In this embodiment, the cylindrical portion 13 shown in Fig. 1 is formed by bending a single plate to form a bottom wall portion 15 and a wall portion extending vertically from the bottom wall portion 15, and then welding one circumferential end of the wall portion to the other circumferential end of the wall portion to produce a cylindrical side wall portion 14. The welded portion 13c shown in Fig. 1 is the portion where one circumferential end of the wall portion is welded to the other circumferential end of the wall portion. In this embodiment, the side wall portion 14 has only one welded portion 13c.

[0023] The top cover portion 17 is plate-shaped and extends in a direction perpendicular to the vertical direction. As shown in FIG. 1, the top cover portion 17 is substantially circular when viewed vertically. As shown in FIG. 2, the top cover portion 17 is fixed to the upper end of the side wall portion 14. In this embodiment, the top cover portion 17 is welded to the side wall portion 14. The top cover portion 17 closes the opening 13a from above, thereby sealing the interior of the case 11. Note that the welded portion 19 shown in FIG. 2 is the portion where the side wall portion 14 and the top cover portion 17 are welded. The welded portion 19 extends around the entire circumferential direction. The top cover portion 17 is provided with a recessed portion 17a. The top cover portion 17 also has a thin-walled portion 17c.

[0024] The recess 17a is a recess recessed upward from the downward-facing surface of the top cover portion 17. That is, the recess 17a is a recess recessed in the vertical direction. Although not shown, the recess 17a has a substantially circular shape when viewed vertically. When viewed vertically, the recess 17a may have other shapes, such as a rectangular shape or a triangular shape. Although not shown, in this embodiment, the top cover portion 17 is provided with four recesses 17a. The recesses 17a are provided at intervals from each other in the circumferential direction. The number of recesses 17a provided in the top cover portion 17 may be three or less, or may be five or more. The recesses 17a may also be recessed downward from the upward-facing surface of the top cover portion 17.

[0025] As shown in FIG. 2, the thin-walled portion 17c is a portion of the top cover portion 17 that overlaps with the recess 17a when viewed in the vertical direction. In this embodiment, the top cover portion 17 has four thin-walled portions 17c. Although not shown, the thin-walled portions 17c are spaced apart from one another in the circumferential direction. The thickness of each thin-walled portion 17c, i.e., the vertical dimension, is thinner than the thickness of the other portions of the top cover portion 17 other than the thin-walled portions 17c. As a result, the rigidity of each thin-walled portion 17c is lower than the rigidity of the other portions of the top cover portion 17 other than the thin-walled portions 17c. In this embodiment, the thickness of each thin-walled portion 17c is thinner than the thickness of the other portions of the case 11 other than the thin-walled portions 17c. As a result, the rigidity of each thin-walled portion 17c is lower than the rigidity of the other portions of the case 11 other than the thin-walled portions 17c. Even if recess 17a is a recess recessed downward from the upward-facing surface of top cover portion 17, the thickness of each thin portion 17c is thinner than the thickness of the portion of top cover portion 17 other than thin portion 17c.

[0026] The bushing 20 has a substantially cylindrical shape extending in the radial direction. In this embodiment, the bushing 20 is made of porcelain. The bushing 20 has insulating properties. The bushing 20 may be made of other insulating materials. In this embodiment, the switchgear 10 includes a plurality of bushings 20. The plurality of bushings 20 includes a plurality of power supply side bushings 21 and a plurality of load side bushings 23. That is, the switchgear 10 includes a plurality of power supply side bushings 21 and a plurality of load side bushings 23.

[0027] Each of the multiple power supply side bushings 21 is inserted into a different first hole portion 14a. Each power supply side bushing 21 is fixed to the case 11 by a fastening member (not shown), such as a bolt. In this way, each power supply side bushing 21 is attached to the case 11. The radially outer portion of each power supply side bushing 21 is located outside the case 11. The power supply side bushings 21 are arranged at intervals from each other in the vertical direction. A power supply side conductive member 25 is arranged inside each power supply side bushing 21. Each power supply side bushing 21 insulates the case 11 from the power supply side conductive member 25.

[0028] Each of the multiple load side bushings 23 is inserted into a different second hole portion 14c. Each load side bushing 23 is fixed to the case 11 by a fastening member (not shown), such as a bolt, to the inner surface of the second hole portion 14c. In this way, each load side bushing 23 is attached to the case 11. The radially outer portion of each load side bushing 23 is located outside the case 11. The load side bushings 23 are spaced apart from each other in the vertical direction. Each load side bushing 23 faces a different power supply side bushing 21 in the radial direction. That is, a pair of power supply side bushings 21 and load side bushing 23 are located at the same position in the vertical direction. A load side conductive member 27 is disposed inside each load side bushing 23. Each load side bushing 23 insulates the case 11 from the load side conductive member 27.

[0029] The power supply side conductive member 25 electrically connects a branch line branched from the power supply side electric wire 60a (see FIG. 7 ) to the connection portion 30. The power supply side conductive member 25 is conductive. The switch 10 includes a plurality of power supply side conductive members 25. In this embodiment, the switch 10 includes three power supply side conductive members 25. Each power supply side conductive member 25 is disposed inside a different power supply side bushing 21. Each power supply side conductive member 25 is held in a different power supply side bushing 21. Currents of different phases flow through each power supply side conductive member 25. As a result, three-phase currents flow into the switch 10. The radially inner end of each power supply side conductive member 25 protrudes radially inward from the power supply side bushing 21.

[0030] The load side conductive member 27 electrically connects a branch line branched off from the load side electric wire 60b (see FIG. 7) to the connection portion 30. The load side conductive member 27 is conductive. The switch 10 includes a plurality of load side conductive members 27. In this embodiment, the switch 10 includes three load side conductive members 27. Each load side conductive member 27 is disposed inside a different load side bushing 23. Each load side conductive member 27 is held in a different load side bushing 23. Currents of different phases flow through each load side conductive member 27. This allows the switch 10 to pass three-phase currents through the load side electric wire 60b. A radially inner end of each load side conductive member 27 protrudes radially inward from the load side bushing 23.

[0031] The connection unit 30 switches the electrical connection state between the power supply side conductive member 25 and the load side conductive member 27. More specifically, the connection unit 30 switches the electrical connection state between the power supply side conductive member 25 and the load side conductive member 27 between a first state in which the power supply side conductive member 25 and the load side conductive member 27 are electrically connected and a second state in which the electrical connection between the power supply side conductive member 25 and the load side conductive member 27 is interrupted. The connection unit 30 is housed inside the case 11. The switch 10 includes multiple connection units 30. In this embodiment, the switch 10 includes three connection units 30. Each connection unit 30 is arranged along the vertical direction. Each connection unit 30 switches the electrical connection state between a different pair of power supply side conductive members 25 and a different pair of load side conductive members 27. As shown in FIG. 4 , the connection unit 30 includes a fixed electrode 31 and a movable electrode 33.

[0032] The fixed electrode 31 is connected to the power supply side conductive member 25. A hole 31a is provided in the fixed electrode 31. The hole 31a is a hole recessed from the outer surface of the fixed electrode 31 into the inside of the fixed electrode 31.

[0033] The movable electrode 33 is connected to the load-side conductive member 27. The movable electrode 33 is rotatable around a pin 35 that passes vertically through a hole in the movable electrode 33 and a hole in the load-side conductive member 27. In this embodiment, when the movable electrode 33 rotates counterclockwise around the pin 35 as viewed from above, the tip of the movable electrode 33 enters the hole 31a and contacts the inner surface of the hole 31a. This electrically connects the fixed electrode 31 and the movable electrode 33, thereby establishing a first state in which the power-supply side conductive member 25 and the load-side conductive member 27 are electrically connected. Furthermore, as shown in FIG. 5 , when the movable electrode 33 rotates clockwise around the pin 35 as viewed from above, the tip of the movable electrode 33 moves out of the hole 31a. This disconnects the electrical connection between the fixed electrode 31 and the movable electrode 33, thereby establishing a second state in which the electrical connection between the power-supply side conductive member 25 and the load-side conductive member 27 is disconnected. As a result, the connection portion 30 switches the electrical connection state between the power supply side conductive member 25 and the load side conductive member 27. The switching of the electrical connection state between the power supply side conductive member 25 and the load side conductive member 27 may be performed manually by an operator performing maintenance on the switch 10, or may be performed by a rotating device (not shown) that automatically rotates the movable electrode 33.

[0034] As described above, in this embodiment, the connection portions 30 are disposed inside the case 11 and are disposed along the vertical direction. Also, as described above, the case 11 has a cylindrical shape extending in the vertical direction. Therefore, the radial dimension of the case 11 can be made smaller than when the connection portions 30 are disposed along the horizontal direction. This makes it possible to prevent the radial dimension of the switch 10 from increasing.

[0035] The fixing portion 40 shown in FIG. 3 fixes the case 11 to the utility pole P. In this embodiment, the switch 10 has two fixing portions 40. The number of fixing portions 40 that the switch 10 has may be one, or may be three or more. Each fixing portion 40 is arranged along the vertical direction. Each fixing portion 40 has a fixing member 41, a fastening member 42, and a gripping portion 44.

[0036] The utility pole P has a cylindrical shape extending vertically. The fixing member 41 has an arc shape extending along the outer circumferential surface of the utility pole P. One end of the fixing member 41 and the other end of the fixing member 41 are fixed by a fastening member 42 such as a bolt. In this way, the fixing member 41 is fixed to the utility pole P.

[0037] The gripping portion 44 is fixed to the outer peripheral surface of the side wall portion 14 and protrudes outside the case 11. The gripping portion 44 grips the fixing member 41 from above and below. This fixes the gripping portion 44 to the fixing member 41. Therefore, the case 11 is fixed to the utility pole P. In this embodiment, the fixing member 41 is fixed to the utility pole P itself, so the position in the vertical direction where the switchgear 10 is fixed to the utility pole P is not limited. This increases the degree of freedom in the vertical position where the switchgear 10 is fixed to the utility pole P.

[0038] Next, a switch replacement method of this embodiment will be described. The switch replacement method of this embodiment is an uninterruptible power interruption method for replacing a switch fixed to a utility pole P without stopping the supply of power to a power source side electric wire 60a (see FIG. 7). As shown in FIG. 6, the switch replacement method of this embodiment includes a replacement step S1 of removing a first switch 90 fixed to the utility pole P from the utility pole P and fixing a second switch 10a to the utility pole P. In the replacement step S1, the first switch 90 is a used switch fixed to the utility pole P. The first switch 90 may be the switch 10 of this embodiment, or may be a switch of a different form from the switch 10 of this embodiment. The second switch 10a is a switch that is newly fixed to the utility pole P in place of the first switch 90 that is removed from the utility pole P. The second switch 10a is the switch 10 of this embodiment. That is, in the replacement step S1, the used first switch 90 is replaced with the second switch 10a, which is the switch 10 of this embodiment.

[0039] The replacement process S1 includes a first process S01 of fixing the second switch 10a to the utility pole P, a second process S02 of connecting a second branch line 64 branched from the electric wire 60 to each of the plurality of power-source-side conductive members 25 and the plurality of load-side conductive members 27, a third process S03 of removing the first branch line 62 branched from the electric wire 60 and connected to the first switch 90 from the electric wire 60, and a fourth process S04 of removing the first switch 90 from the utility pole P. In the following description, the term "workers, etc." includes workers and work equipment, etc., who perform the work in each process. The work in each process may be performed by workers alone, by work equipment alone, or by both workers and work equipment.

[0040] As shown in FIG. 7 , in this embodiment, the electric wire 60 supported by the utility pole P includes three power source side electric wires 60a and three load side electric wires 60b. Each power source side electric wire 60a is a primary side electric wire. Each load side electric wire 60b is a secondary side electric wire. Currents of different phases flow through each power source side electric wire 60a. Currents of different phases flow through each load side electric wire 60b. A first branch line 62 is drawn out from the electric wire 60 and connected to a first switch 90. The first branch line 62 includes three power source side first branch lines 62a and three load side first branch lines 62c. Each power source side first branch line 62a is drawn out from a different power source side electric wire 60a and connected to a power source side conductive member held by a different power source side bushing 91 of the first switch 90. The load-side first branch lines 62c are drawn out from different load-side electric wires 60b and connected to load-side conductive members held by different load-side bushings 93 of the first switch 90.

[0041] In the first step S01, the worker or the like fixes the second circuit breaker 10a to the utility pole P. The worker or the like fixes the second circuit breaker 10a to a portion of the utility pole P that is vertically shifted from the portion to which the first circuit breaker 90 is fixed. In the present embodiment, the second circuit breaker 10a is fixed to a portion of the utility pole P that is lower than the portion to which the first circuit breaker 90 is fixed. Note that the second circuit breaker 10a may also be fixed to a portion of the utility pole P that is higher than the portion to which the first circuit breaker 90 is fixed. The worker or the like first surrounds the outer circumferential surface of the utility pole P with the fixing member 41 shown in FIG. 3 , and then fixes one end and the other end of the fixing member 41 with the fastening member 42. In this way, the fixing member 41 is fixed to the utility pole P. Next, the worker or the like fixes the gripping portion 44 to the fixing member 41. In this way, the second circuit breaker 10a is fixed to the utility pole P, as shown in FIG. 7 . When the worker or the like fixes the second switch 10a to the utility pole P, the first step S01 is completed.

[0042] In the second step S02, the worker or the like connects second branch lines 64 branched from the electric wire 60 to each of the plurality of power-side conductive members 25 and the plurality of load-side conductive members 27. As shown in FIG. 8 , the second branch lines 64 are drawn from the electric wire 60 and connected to the second switch 10a. The second branch lines 64 include three power-side second branch lines 64a and three load-side second branch lines 64c. The worker or the like draws the power-side second branch lines 64a from each power-side electric wire 60a and then connects each power-side second branch line 64a to a power-side conductive member 25 held by a different power-side bushing 21. The worker or the like draws the load-side second branch lines 64c from each load-side electric wire 60b and then connects each load-side second branch line 64c to a load-side conductive member 27 held by a different load-side bushing 23. This allows current to flow from the electric wire 60 to the second switch 10a. At this time, the current flowing through the first switch 90 via the first branch line 62 and the current flowing through the second switch 10a via the second branch line 64 flow in parallel. Therefore, an uninterruptible power supply state is maintained. When the worker connects the second branch line 64 to each of the plurality of power supply side conductive members 25 and the plurality of load side conductive members 27, the second step S02 is completed.

[0043] In the third step S03, first, the worker or the like switches the connection part (not shown) of the first switch 90 to the second state. This prevents current from flowing from the electric wire 60 to the first switch 90. Next, as shown in FIG. 9 , the worker or the like detaches the first branch line 62 connected to the first switch 90 from the electric wire 60. This breaks the electrical connection between the electric wire 60 and the first switch 90. At this time, current flows between the power supply side electric wire 60a and the load side electric wire 60b via the second branch line 64 and the second switch 10a. Therefore, an uninterruptible power supply state is maintained. When the worker or the like detaches the first branch line 62 connected to the first switch 90 from the electric wire 60, the third step S03 is completed. Note that the worker or the like may further detach the first branch line 62 from the first switch 90 in the third step S03.

[0044] In the fourth step S04, as shown in FIG. 10 , the worker or the like removes the first switch 90 from the utility pole P. When the worker or the like removes the first switch 90 from the utility pole P, the fourth step S04 is completed. When the fourth step S04 is completed, the replacement step S1 is completed. This completes the work of replacing the used first switch 90 with the second switch 10a. As described above, in the replacement step S1, current flows between the power source side electric wire 60a and the load side electric wire 60b via at least one of the first switch 90 and the second switch 10a. Therefore, in the replacement step S1 of this embodiment, the switch fixed to the utility pole P can be replaced without stopping the supply of power to the power source side electric wire 60a. Therefore, the switch replacement method of this embodiment allows the switch to be replaced without power interruption.

[0045] According to this embodiment, the switch 10 comprises a cylindrical case 11 extending in the vertical direction, a plurality of power supply side bushings 21 and a plurality of load side bushings 23 attached to the case 11, a plurality of power supply side conductive members 25 held in different power supply side bushings 21, a plurality of load side conductive members 27 held in different load side bushings 23, and a plurality of connection parts 30 housed inside the case 11 and switching the electrical connection state between different pairs of power supply side conductive members 25 and load side conductive members 27, and the plurality of connection parts 30 are arranged along the vertical direction. When the case 111 is rectangular, like the switch 110 of the comparative example shown in FIG. 11 , the cylindrical portion 113 is typically manufactured by bending a single plate to form a bottom wall 115 and four walls 114e extending vertically from the bottom wall 115, and then welding the walls 114e together to form the rectangular cylindrical side wall 114. Therefore, the rectangular cylindrical side wall 114 has four welds 113f. The potential of each weld 113f is lower than the potential of unwelded portions of the side wall 114. This makes the welds 113f susceptible to electrolytic corrosion during use of the switch 110, making it difficult to enhance the durability of the switch 110. Furthermore, if holes form in the deteriorated portions due to electrolytic corrosion, water may enter the case 111 through the holes. If water seeps into the inside of the case 111, there is a risk that a connection part (not shown) may be grounded, and that the connection parts may be short-circuited to each other. In contrast, in the present embodiment, as shown in FIG. 1 , the case 11 is cylindrical, and therefore, as described above, the number of welded portions 13c that the side wall portion 14 has is only one. Therefore, compared to the switch 110 of the comparative example, the number of welded portions 13c that the side wall portion 14 has can be reduced. This makes it possible to suppress electrolytic corrosion of the tubular portion 13 during use of the switch 10, thereby improving the durability of the switch 10. Furthermore, the tubular portion 13 of the present embodiment can suppress the formation of holes in portions deteriorated by electrolytic corrosion. Therefore, it is possible to suppress water from entering the inside of the case 11, thereby suppressing ground faults of the connection portions 30 and short-circuits between the connection portions 30.

[0046] In the switch 110 of the comparative example shown in FIG. 11, each of the four welds 113f of the side wall portion 114 is a corner portion with an angle of approximately 90° when viewed vertically. Therefore, of the corrosion-resistant layers formed on the surface of the case 111 by plating, the thickness of the corrosion-resistant layer formed at the welds 113f tends to be thin. Furthermore, of the coating films formed on the surface of the corrosion-resistant layer, the thickness of the coating layer formed at the welds 113f tends to be thin. For these reasons, the welds 113f are prone to corrosion during use of the switch 110, making it difficult to improve the durability of the switch 110. In contrast, in this embodiment, since the case 11 is cylindrical, the side wall 14 does not have any corners. This makes it easier to increase the thickness of the corrosion-resistant layer and the thickness of the coating film over the entire side wall 14. This makes it possible to suppress corrosion of the side wall 14, thereby more suitably improving the durability of the switchgear 10.

[0047] Furthermore, as described above, in this embodiment, the multiple connection parts 30 are arranged along the vertical direction. Therefore, even if a hole is formed in the case 11 during use of the switch 10 and water enters the inside of the case 11 through the hole, the lowest connection part 30 will be grounded when the water surface reaches the lowest connection part 30. Therefore, when the water surface reaches the lowest connection part 30, all of the connection parts 30 can be set to the second state in which the electrical connection between the power-source side conductive member 25 and the load side conductive member 27 is interrupted. Therefore, short-circuiting between the connection parts 30 can be prevented, and an explosion inside the case 11 can be prevented.

[0048] If the connection portions 30 are short-circuited, an explosion may occur inside the case 11. If an explosion occurs inside the case 11, the air pressure inside the case 11 will rise. As described above, since the case 11 of this embodiment is cylindrical, it is easier to equalize the air pressure applied to the inner surface of the case 11 compared to when the case 11 is rectangular tubular. This prevents a large pressure from being applied to a portion of the case 11 even if an explosion occurs inside the case 11, thereby preventing a portion of the case 11 from being destroyed and forming a hole. Therefore, even if the connection portions 30 are short-circuited and an explosion occurs inside the case 11, components such as the fixed electrode 31 housed inside the case 11 can be prevented from flying out of the case 11.

[0049] Furthermore, in the present embodiment, as described above, the plurality of connection portions 30 are arranged along the vertical direction. Therefore, as described above, it is possible to prevent the case 11 from becoming large in size in the radial direction, compared to when the plurality of connection portions 30 are arranged along the horizontal direction. That is, in the present embodiment, the case 11 is cylindrical and extends vertically, and the plurality of connection portions 30 are arranged along the vertical direction, so that it is possible to improve the durability of the switch 10 and prevent the switch 10 from becoming large in size.

[0050] According to this embodiment, the plurality of power supply side bushings 21 and the plurality of load side bushings 23 are arranged vertically. This makes it easy to arrange the power supply side bushings 21 and the load side bushings 23 close to the connection portion 30, which facilitates simplifying the configuration for electrically connecting the power supply side bushings 21 and the load side bushings 23 to the connection portion 30. This simplifies the configuration of the switch 10, thereby preventing an increase in the number of parts and manufacturing costs of the switch 10.

[0051] According to this embodiment, the case 11 has a cylindrical portion 13 that extends vertically and has an opening 13a that opens upward, and an upper cover portion 17 that covers the opening 13a. The upper cover portion 17 is plate-shaped and extends in a direction perpendicular to the vertical direction, and the upper cover portion 17 is provided with a recess 17a that is recessed in the vertical direction. If an explosion occurs inside the case 11 and the bottom wall 15 is destroyed, forming a hole in the bottom wall 15, there is a risk that the fixed electrode 31 and other components housed inside the case 11 may fall downward. In this case, there is a risk that a pedestrian passing below the switch 10 may come into contact with the components. In contrast, in this embodiment, as described above, the top cover 17 is provided with the recess 17a recessed in the vertical direction, allowing the top cover 17 to be provided with the thin-walled portion 17c with low rigidity. Therefore, if an explosion occurs inside the case 11 and the air pressure inside the case 11 increases, the thin-walled portion 17c is quickly destroyed. This allows the air pressure inside the case 11 to be quickly reduced, thereby preventing damage to portions of the case 11 other than the thin-walled portion 17c. This prevents an explosion inside the case 11 from destroying the bottom wall 15 and forming a hole in the bottom wall 15, thereby preventing components housed inside the case 11, such as the fixed electrode 31, from falling downward. This improves the safety of pedestrians and others passing under the switch 10.

[0052] According to the present embodiment, the top cover 17 is welded to the cylindrical portion 13. In a configuration in which the top cover 17 and the cylindrical portion 13 are sealed with a sealing member such as a gasket, if the sealing member deteriorates during use of the switchgear 10, the sealing performance between the top cover 17 and the cylindrical portion 13 will deteriorate. This could lead to water intrusion into the case 11. In contrast, in the present embodiment, the top cover 17 is welded to the cylindrical portion 13, and therefore the sealing performance between the top cover 17 and the cylindrical portion 13 can be prevented from deteriorating during use of the switchgear 10. This can more effectively prevent water from infiltrating into the case 11, thereby more effectively preventing the connection portion 30 from becoming a ground fault and the connection portions 30 from shorting each other.

[0053] According to this embodiment, the switch 10 includes a fixing portion 40 that fixes the case 11 to the utility pole P. Therefore, because the switch 10 can be fixed to the utility pole P itself, there is no need to provide a member such as a hanging bracket on the utility pole P to hold the switch 10 by suspending the switch 10. This makes it possible to simplify the configuration of the utility pole P. Furthermore, because the switch 10 can be fixed to the utility pole P itself, the degree of freedom in the vertical direction for the position at which the switch 10 is fixed to the utility pole P can be increased.

[0054] According to this embodiment, the method for replacing a switch is a method for replacing a switch fixed to a utility pole P, and includes a replacement step S1 of removing the first switch 90 fixed to the utility pole P from the utility pole P and fixing the second switch 10a to the utility pole P, and the second switch 10a includes a cylindrical case 11 extending in the vertical direction, a plurality of power supply side conductive members 25, a plurality of load side conductive members 27, and a plurality of switches housed inside the case 11 for switching the electrical connection state between pairs of different power supply side conductive members 25 and load side conductive members 27. and a fixing portion 40 that fixes the case 11 to the utility pole P, and the replacement process S1 includes a first step S01 of fixing the second switch 10a to the utility pole P, a second step S02 of connecting a second branch line 64 branched from the electric wire 60 to each of the plurality of power-source side conductive members 25 and the plurality of load-side conductive members 27, a third step S03 of removing, from the electric wire 60, the first branch line 62 branched from the electric wire 60 and connected to the first switch 90, and a fourth step S04 of removing the first switch 90 from the utility pole P. Therefore, as described above, in the replacement process S1, a current can flow between the power-source side electric wire 60a and the load side electric wire 60b via at least one of the first switch 90 and the second switch 10a. Therefore, in the switch replacement method of this embodiment, the used first switch 90 can be replaced with the second switch 10a without stopping the supply of power to the power source side electric wire 60a, that is, without power interruption.

[0055] Furthermore, in this embodiment, as described above, the second switch 10a, i.e., the switch to be newly fixed to the utility pole P, is the switch 10 of this embodiment. Therefore, since the case 11 of the second switch 10a to be newly fixed to the utility pole P is cylindrical, the number of welded portions 13c that the side wall portion 14 has can be reduced to only one, as described above. This makes it possible to suppress electrolytic corrosion of the cylindrical portion 13 during use of the second switch 10a, thereby improving the durability of the second switch 10a. Therefore, it is possible to suppress an increase in the frequency of replacing switches fixed to the utility pole P, and therefore it is possible to suppress an increase in maintenance costs for the power transmission system that uses the electric wire 60.

[0056] Although an embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made within the scope that does not deviate from the spirit of the present invention.

[0057] The configuration of the connection portion is not limited to this embodiment, and for example, the connection portion may have a member that electrically connects the power-supply side conductive member and the fixed electrode, or a member that electrically connects the load side conductive member and the movable electrode. Furthermore, each connection portion does not have to be arranged along the horizontal direction, and may be arranged along a direction inclined from the vertical direction to the horizontal direction.

[0058] The shape of the case is not limited to a cylindrical shape, and may be other shapes such as an elliptical cylindrical shape, a truncated cone shape, or a spherical shell shape. Even in these cases, the number of welds on the case can be reduced compared to when the case is a rectangular cylindrical shape, thereby suppressing deterioration of the case due to electrolytic corrosion. Therefore, the durability of the switch can be improved. [Explanation of symbols]

[0059] 10...switch, 10a...second switch, 11...case, 13...cylindrical portion, 13a...opening, 17...upper cover portion, 17a...recess, 21...power supply side bushing, 23...load side bushing, 25...power supply side conductive member, 27...load side conductive member, 30...connection portion, 40...fixing portion, 60...electric wire, 62...first branch line, 64...second branch line, 90...first switch, P...electric pole, S1...replacement step, S01...first step, S02...second step, S03...third step, S04...fourth step

Claims

1. a cylindrical case extending in a vertical direction; a plurality of power supply side bushings and a plurality of load side bushings attached to the case; a plurality of power supply side conductive members held by the power supply side bushings that are different from one another; a plurality of load-side conductive members held by the load-side bushings different from one another; a plurality of connection portions housed inside the case and configured to switch electrical connection states between different pairs of the power supply side conductive member and the load side conductive member; Equipped with A switch, wherein the plurality of connection portions are arranged along a vertical direction.

2. The switch according to claim 1 , wherein each of the plurality of power supply side bushings and the plurality of load side bushings is arranged along a vertical direction.

3. the case includes a cylindrical portion extending in a vertical direction and having an opening that opens upward in the vertical direction, and an upper lid portion that closes the opening, the upper cover portion is a plate-like member extending in a direction perpendicular to the vertical direction, The switch according to claim 1 or 2, wherein the upper cover portion is provided with a recess recessed in a vertical direction.

4. The switch according to claim 3 , wherein the upper cover portion is welded to the cylindrical portion.

5. The switch according to claim 1 or 2, further comprising a fixing portion for fixing the case to a utility pole.

6. A method for replacing a switch fixed to a utility pole, comprising the steps of: a replacement step of removing a first switch fixed to the utility pole from the utility pole and fixing a second switch to the utility pole; the second switch includes a cylindrical case extending in a vertical direction, a plurality of power supply side conductive members, a plurality of load side conductive members, a plurality of connection parts housed inside the case and switching electrical connection states between pairs of the power supply side conductive members and the load side conductive members that are different from each other, and a fixing part that fixes the case to a utility pole; The exchanging step includes: a first step of fixing the second switch to a utility pole; a second step of connecting second branch lines branched from the electric wire to each of the plurality of power supply side conductive members and the plurality of load side conductive members; a third step of removing a first branch line branched from the electric wire and connected to the first switch from the electric wire; a fourth step of removing the first switch from the utility pole; A method for replacing a switchgear, including:

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