Earthing switch and switchgear

Abstract

To provide an earthing switch and a switchgear that are capable of restraining occurrence of flashover when a movable electrode portion and a fixed electrode portion are connected to each other.SOLUTION: An earthing switch 8 includes a fixed electrode portion 80 and a movable electrode portion 90. The movable electrode portion 90 includes a movable electrode main body 91 and an advance / retract mechanism 50 for advancing / retracting the movable electrode main body 91 in an advance / retract direction. The fixed electrode portion 80 includes a first fixed electrode 82, a second fixed electrode 83 provided on a side which is farther away from the movable electrode portion 90 than a tip of the first fixed electrode 82, and a discharge resistor portion 85 which is electrically connected to the first fixed electrode 82. The advance / retract mechanism 50 moves the movable electrode main body 91 such that when a first state in which the first fixed electrode 82 and the movable electrode body 91 are in contact with each other transitions to a second state in which the second fixed electrode 83 and the movable electrode main body 91 are in contact with each other, a time required to transition from the first state to the second state is equal to or longer than a preset reference time.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an earthing switch and a switchgear. [Background technology]

[0002] A gas-insulated switchgear installed in a substation or the like has been disclosed that includes a circuit breaker and a grounding switch (see, for example, Patent Document 1). The circuit breaker breaks the electric path between the power receiving side (primary side) and the transformer side (secondary side) during a lightning strike or the like. The grounding switch grounds the power receiving side busbar to a ground path in order to remove any charge remaining in the power receiving side busbar after the circuit breaker breaks the electric path. The grounding switch has a fixed electrode portion connected to the power receiving side busbar and a movable electrode portion connected to the ground path and movable forward and backward relative to the fixed electrode portion. The grounding switch electrically connects the power receiving side busbar to the ground path by bringing the fixed electrode portion into contact with the movable electrode portion, thereby grounding the power receiving side busbar. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-112661 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a gas-insulated switchgear as disclosed in Patent Document 1, when the earthing switch electrically connects the movable electrode portion and the fixed electrode portion, the movable electrode portion moves from a state in which the movable electrode portion and the fixed electrode portion are separated toward the fixed electrode portion. At this time, immediately after the circuit breaker cuts off the path between the primary side and the secondary side, charges remain on the power receiving side busbar and the fixed electrode portion to which the power receiving side busbar is connected. For this reason, when the movable electrode portion and the fixed electrode portion approach each other, a flashover may occur between the movable electrode portion and the fixed electrode portion.

[0005] In view of the above circumstances, an object of the present invention is to provide an earthing switch and a switchgear capable of suppressing the occurrence of flashover when connecting a movable electrode portion and a fixed electrode portion. [Means for solving the problem]

[0006] The earthing switch according to an aspect of the present invention comprises a fixed electrode portion electrically connected to either the power receiving side or the grounding side, and a movable electrode portion electrically connected to the other of the power receiving side or the grounding side and connectable to the fixed electrode portion by moving forward and backward relative to the fixed electrode portion, the movable electrode portion comprises a movable electrode main body extending in the forward and backward direction of the movable electrode portion and electrically connected to an externally provided grounding wire, a movable electrode holding portion which holds the movable electrode main body movably in the forward and backward direction, and an advancing and retreating mechanism which moves the movable electrode main body forward and backward in the forward and backward direction relative to the movable electrode holding portion, the fixed electrode portion extending in the forward and backward direction and electrically connectable to the movable electrode main body The movable electrode mechanism includes a first fixed electrode, a second fixed electrode that is provided on a side farther away from the movable electrode portion than the tip of the first fixed electrode on the movable electrode portion side in the advance / retract direction and is electrically connectable to the movable electrode main body, and a discharge resistance portion electrically connected to the first fixed electrode.The advance / retract mechanism moves the movable electrode portion toward the fixed electrode portion along the advance / retract direction to transition from a first state in which the first fixed electrode and the movable electrode main body are in contact with each other to a second state in which the second fixed electrode and the movable electrode main body are in contact with each other, and moves the movable electrode main body toward the fixed electrode portion so that the time required to transition from the first state to the second state is equal to or longer than a predetermined reference time.

[0007] The advancing / retracting mechanism may move the movable electrode body toward the fixed electrode section at a moving speed within a preset range when transitioning from the first state to the second state. The advancing / retracting mechanism may include a biasing member that biases the movable electrode body toward the fixed electrode section along the advancing / retracting direction, and the biasing member may move the movable electrode body at a moving speed of 1.0 m / sec or more and less than 1.6 m / sec when transitioning from the first state to the second state.

[0008] The electrical resistance of the discharge resistor may be 66 Ω or more and less than 80 Ω. The movable electrode body may be formed in a cylindrical shape extending in the forward / reverse direction, the first fixed electrode may be inserted radially inside the movable electrode body and contact the inner circumferential surface of the movable electrode body, thereby being electrically connectable to the movable electrode body, and the second fixed electrode may be provided radially outwardly spaced from the first fixed electrode and electrically connectable to the movable electrode body by contacting the outer circumferential surface of the movable electrode body. The movable electrode body may have a first movable electrode that is electrically connectable to the first fixed electrode by contacting the outer circumferential surface of the first fixed electrode, and a second movable electrode that is provided radially outwardly of the first movable electrode and is electrically connectable to the second fixed electrode by contacting the inner circumferential surface of the second fixed electrode.

[0009] A switchgear according to an aspect of the present invention includes the above-described earthing switch. Effect of the Invention

[0010] The earthing switch according to the embodiment of the present invention moves the movable electrode body toward the fixed electrode section so that the time required for transition from a first state in which the first fixed electrode and the movable electrode body are in contact with each other to a second state in which the second fixed electrode and the movable electrode body are in contact with each other is equal to or longer than a reference time. In the first state, the first fixed electrode and the movable electrode body come into contact with each other, so that the charge remaining on the power receiving side flows into the discharge resistor section connected to the first fixed electrode, and discharge occurs. Thereafter, the movable electrode body is moved toward the fixed electrode section so that transition from the first state to the second state takes equal to or longer than the reference time, thereby ensuring a long discharge time in the discharge resistor section. This makes it possible to reduce the potential difference between the power receiving side and the ground side before the second fixed electrode and the movable electrode body come into contact with each other. As a result, it is possible to suppress the occurrence of a flashover when connecting the movable electrode section and the fixed electrode section.

[0011] In addition, in a configuration in which the movable electrode main body is moved toward the fixed electrode section at a moving speed within a preset range when transitioning from the first state to the second state, the time required for transition from the first state to the second state can be set to be equal to or longer than the reference time. In a configuration in which the movable electrode main body is moved at a moving speed of 1.0 m / sec or more and less than 1.6 m / sec when transitioning from the first state to the second state, the time required for transition from the first state to the second state can be set to be equal to or longer than the reference time. In a configuration in which the electrical resistance of the discharge resistor section is 66 Ω or more and less than 80 Ω, the discharge of the residual charge on the power receiving side in the discharge resistor section can be efficiently performed while suppressing the occurrence of a flashover when the first fixed electrode and the movable electrode main body approach each other.

[0012] In addition, in a configuration in which the movable electrode main body is cylindrical, the first fixed electrode contacts the inner peripheral surface of the movable electrode main body, and the second fixed electrode contacts the outer peripheral surface of the movable electrode main body, the movable electrode main body is located between the first fixed electrode and the second fixed electrode when the first fixed electrode and the second fixed electrode of the fixed electrode part are in contact with the movable electrode main body. In other words, a shield made of an insulating material is not provided between the first fixed electrode and the second fixed electrode. This allows the fixed electrode part to be made smaller and more compact. In addition, in a configuration in which the movable electrode main body has a first movable electrode that contacts the outer peripheral surface of the first fixed electrode and a second movable electrode that contacts the inner peripheral surface of the second fixed electrode, each of the first movable electrode and the second movable electrode can be configured so that the connection state with the first fixed electrode and the second fixed electrode is good.

[0013] A switchgear according to an aspect of the present invention includes the above-described earthing switch, which makes it possible to prevent the occurrence of a flashover when connecting the movable electrode portion and the fixed electrode portion. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a cross-sectional view of a switching device according to an embodiment. [Diagram 2] FIG. 2 is a plan view of a second unit of the switchgear of FIG. [Diagram 3]FIG. 2 is a cross-sectional view showing a grounding switch of a switchgear. [Figure 4] FIG. [Diagram 5] 4 is a cross-sectional view showing a state in which the movable electrode body and the fixed electrode body of the earthing switch are connected. FIG. [Figure 6] FIG. 4 is a schematic diagram showing a configuration of a reciprocating mechanism. [Figure 7] 13 is a schematic diagram showing a state in which pressure is accumulated in a biasing member of the advance / retract mechanism; FIG. [Figure 8] 13 is a schematic diagram showing a state in which the biasing force of the biasing member is released; FIG. [Figure 9] 13 is a diagram showing a first state in which the movable electrode body is in contact with the first fixed electrode. FIG. [Figure 10] 13 is a diagram showing a second state in which the movable electrode main body is in contact with the second fixed electrode. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the contents described below. In addition, in order to explain the embodiment in the drawings, some parts are enlarged or emphasized, and the scale is appropriately changed to express it, and the dimensions and shape may differ from those of the actual product. Figure 1 is a cross-sectional view of an opening and closing device 1 according to an embodiment.

[0016] A switchgear 1 according to this embodiment is installed in a substation or the like, and interrupts an electric path between a primary power receiving busbar 101 and a secondary transformer busbar (not shown) during a lightning strike or the like. As shown in Fig. 1, the switchgear 1 has a first unit 20 and a second unit 30. The first unit 20 and the second unit 30 are connected to each other.

[0017] The switchgear 1 mainly includes a housing 2, a circuit breaker 5, a disconnecting switch 7, and a grounding switch 8. The housing 2 is provided on an installation surface G such as the ground via a stand 3. The housing 2 is formed of a conductive material such as steel. The housing 2 includes a first housing 21 and a second housing 31. The first housing 21 forms an outer shell of the first unit 20. The second housing 31 forms an outer shell of the second unit 30. The first housing 21 and the second housing 31 each have a hollow structure and include chambers S1 and S2, which are sealed spaces, therein. The chamber S1 in the first housing 21 and the chamber S2 in the second housing 31 are separated by an insulating partition 23.

[0018] The first housing 21 has a housing main body 24, a bottom plate portion 25, and a top plate portion 26. The housing main body 24 is formed in a cylindrical shape that is continuous in the vertical direction. The housing main body 24 has, for example, a circular cross-sectional shape when viewed from the vertical direction, and is open at the top and bottom. The bottom plate portion 25 closes the opening at the lower end of the housing main body 24 from below. The top plate portion 26 closes the opening at the upper end of the housing main body 24 from above. The bottom plate portion 25 and the top plate portion 26 are each detachably flange-connected to the housing main body 24 by a plurality of bolts.

[0019] The housing body 24 is formed with a first opening 27 and a second opening 28. The first opening 27 and the second opening 28 each penetrate the cylindrical housing body 24 in the radial direction. The outer peripheral edge of the first opening 27 is flange-connected to the outer peripheral edge of an opening 31h formed in the second housing 31 by a plurality of bolts (not shown). The first opening 27 and the opening 31h are separated by a partition 23.

[0020] The second opening 28 is formed in the upper part of the housing body 24. When viewed from the top-bottom direction, the second opening 28 opens in a direction different from the first opening 27 in the circumferential direction around the center of the housing body 24. The second opening 28 is closed by a lid body 29. The lid body 29 is formed of a conductive material such as iron. The lid body 29 is flange-connected to the outer periphery of the second opening 28 by a plurality of bolts (not shown).

[0021] The second housing 31 has a housing main body 32, a bottom plate portion 33, and a top plate portion 34. The housing main body 32 is formed in a cylindrical shape that is continuous in the vertical direction. The housing main body 32 has, for example, a circular cross-sectional shape when viewed from the vertical direction, and is open at the top and bottom. The bottom plate portion 33 closes the opening at the lower end of the housing main body 32 from below. The top plate portion 34 closes the opening at the upper end of the housing main body 32 from above. The bottom plate portion 33 and the top plate portion 34 are each detachably flange-connected to the housing main body 32 by a plurality of bolts.

[0022] The first housing 21 and the second housing 31 are each electrically grounded to a grounding device (not shown) buried in an installation surface G such as the ground. An insulating gas is sealed in the chambers S1 and S2 of the first housing 21 and the second housing 31, respectively. For example, sulfur hexafluoride (SF6) is suitable as the insulating gas used here. The housing 2 may also have a third housing that houses a device for connecting to another switchgear, for example.

[0023] The circuit breaker 5 is accommodated in the first housing 21. The circuit breaker 5 is provided for three phases, i.e., three sets are provided. In this embodiment, each circuit breaker 5 can break an electric path between the primary side and the secondary side. One end of a secondary conductor 62 is connected to the secondary side of the circuit breaker 5 of each phase. That is, the secondary conductor 62 is also provided for three phases, i.e., three sets are provided. The other end of the secondary conductor 62 penetrates the cover 29 and is electrically connected to a secondary cable head (not shown). An end of a transformer side busbar (not shown) located outside the first housing 21 is connected to the secondary cable head (not shown). A secondary insulating mold 72 made of an insulating material is provided at the connection portion between the secondary conductor 62 and the secondary cable head (not shown). As a result, the secondary side of the circuit breaker 5 is electrically connected to the transformer side busbar (not shown) via the secondary conductor 62 and the secondary cable head (not shown).

[0024] A primary side conductor 61 is connected to the primary side of the circuit breaker 5 of each phase. The primary side conductor 61 is also provided for three phases, i.e., three sets of primary side conductors 61 are provided. The primary side conductor 61 of each phase has a primary side first conductor 61a and a primary side second conductor 61b. The primary side second conductor 61b is electrically connected to the primary side of the circuit breaker 5. The primary side second conductor 61b is led into the second housing 31 through the partition 23.

[0025] Fig. 2 is a plan view of the second unit 30 of the switchgear 1 of Fig. 1. As shown in Figs. 1 and 2, the second unit 30 houses a disconnector 7 and a grounding switch 8. The disconnector 7 and the grounding switch 8 are each provided for three phases, i.e., three sets are provided. The primary side second conductor 61b is connected to the secondary side of the disconnector 7. The primary side first conductor 61a is connected to the primary side of the disconnector 7. The primary side first conductor 61a passes through the bottom plate portion 33 and is connected to the primary side cable head 41.

[0026] The primary cable head 41 is formed in a cylindrical shape extending in the vertical direction. The primary cable head 41 is provided, for example, on the bottom plate portion 33 of the second housing 31. An end of the power receiving busbar 101 located outside the second housing 31 is connected to the primary cable head 41. There are three sets of primary cable heads 41, one for each phase. A primary insulating mold 71 made of an insulating material is provided at the connection portion between the primary conductor 61 and the primary cable head 41.

[0027] FIG. 3 is a cross-sectional view showing the earthing switch 8 of the switchgear 1. The earthing switch 8 discharges the electric charge remaining in the power receiving side busbar 101 after the circuit breaker 5 breaks the electric circuit, and then grounds the power receiving side busbar 101. The earthing switch 8 electrically connects between the power receiving side to which the power receiving side busbar 101 is electrically connected and the ground side, thereby grounding the power receiving side busbar 101. The earthing switch 8 is provided for three phases, that is, three sets. As shown in FIG. 3, the earthing switch 8 of each phase is provided between the primary side first conductor 61a and the disconnector 7 on the power receiving side, and the ground wire 99 on the ground side. The ground wire 99 penetrates the housing body 32 of the second housing 31 and is led out to the outside. An insulating material (not shown) is interposed between the ground wire 99 and the housing body 32. The ground wire 99 is connected to a grounding device (not shown) buried in the installation surface G, or the like.

[0028] FIG. 4 is an enlarged view of the earthing switch 8. As shown in FIGS. 3 and 4, the earthing switch 8 includes a fixed electrode portion 80 and a movable electrode portion 90. The fixed electrode portion 80 is electrically connected to either the power receiving side or the ground side. In this embodiment, the fixed electrode portion 80 is electrically connected to the power receiving side. The movable electrode portion 90 is electrically connected to the other of the power receiving side or the ground side. In this embodiment, the movable electrode portion 90 is electrically connected to the ground side. The movable electrode portion 90 can be connected to the fixed electrode portion 80 by moving toward or away from the fixed electrode portion 80.

[0029] The fixed electrode section 80 includes a fixed electrode body 81, a fixed electrode cover 84, and a discharge resistor section 85. The fixed electrode body 81 includes a first fixed electrode 82 and a second fixed electrode 83. The first fixed electrode 82 is made of a conductive material and is formed in a columnar shape extending in the direction of movement of the movable electrode section 90 relative to the fixed electrode section 80, that is, in the direction connecting the fixed electrode section 80 and the movable electrode section 90. The first fixed electrode 82 can be electrically connected to a movable electrode body 91 of the movable electrode section 90, which will be described later. The first fixed electrode 82 is electrically connected to the primary side first conducting wire 61a of the power receiving side and the disconnector 7 via a connecting member 88 made of a conductive material.

[0030] The second fixed electrode 83 is disposed with a gap therebetween on the radially outer side centered on the first fixed electrode 82 with respect to the first fixed electrode 82. A plurality of second fixed electrodes 83 are provided with gaps therebetween in the circumferential direction centered on the first fixed electrode 82. The plurality of second fixed electrodes 83 are cylindrical as a whole, and are disposed so as to surround the radially outer side of the first fixed electrode 82 with the first fixed electrode 82 as the center.

[0031] As shown in FIG. 4, each of the second fixed electrodes 83 is made of a conductive material and extends in the advancing / retracting direction of the movable electrode portion 90 (hereinafter simply referred to as the advancing / retracting direction). In the second fixed electrode 83, a base end portion 83b on the side away from the movable electrode portion 90 in the advancing / retracting direction is held by an electrode holding material 86. The electrode holding material 86 is directly or indirectly electrically connected to the primary-side first conductive wire 61a of the power receiving side and the disconnector 7. In the second fixed electrode 83, a tip portion 83s on the movable electrode portion 90 side in the advancing / retracting direction is located on the side away from the movable electrode portion 90 than a tip portion 82s on the movable electrode portion 90 side in the advancing / retracting direction of the first fixed electrode 82. In other words, the tip portion 82s of the first fixed electrode 82 protrudes toward the movable electrode portion 90 side in the advancing / retracting direction relative to the second fixed electrodes 83. The tip end 83s side of the second fixed electrode 83 is elastically deformable radially outward with the base end 83b as the center.

[0032] The fixed electrode cover 84 is provided so as to cover the fixed electrode main body 81 (the first fixed electrode 82 and the multiple second fixed electrodes 83) from the radial outside. The fixed electrode cover 84 is a shield made of a conductive material such as stainless steel, and is formed in a cylindrical shape extending in the forward / backward direction. The fixed electrode cover 84 has a protrusion 84t that protrudes radially inward at the tip end on the movable electrode section 90 side in the forward / backward direction.

[0033] The discharge resistor 85 is electrically connected to the first fixed electrode 82. The discharge resistor 85 has a substrate 85a and a resistor 85b. The substrate 85a is made of a conductive material and is connected to the first fixed electrode 82 via, for example, an L-shaped resistor holding member 87. A plurality of resistors 85b are mounted on the substrate 85a. In this embodiment, the discharge resistor 85 is provided with a plurality of resistors 85b so that the electrical resistance of the plurality of resistors 85b is, for example, 66Ω or more and less than 80Ω. If the electrical resistance of the discharge resistor 85 is less than 66Ω, the surge voltage of the power receiving bus 101 becomes high, which may destroy the anticorrosive layer of the cable. On the other hand, if the electrical resistance of the discharge resistor 85 is 80Ω or more, an internal flashover is likely to occur.

[0034] The movable electrode portion 90 includes a movable electrode main body 91, a movable electrode holding portion 92, and an advancing / retreating mechanism 50. The movable electrode main body 91 can be connected to the fixed electrode portion 80 by advancing / retreating relative to the fixed electrode portion 80. Under normal circumstances, the movable electrode main body 91 is spaced apart from the fixed electrode portion 80 by a preset distance. The movable electrode main body 91 is driven to advance / retreat in the advancing / retreating direction by the advancing / retreating mechanism 50, which will be described later.

[0035] The movable electrode main body 91 has a first movable electrode 93 and a second movable electrode 94. The second movable electrode 94 integrally has a second electrode base 94a and a second electrode piece 94b. The second electrode base 94a is connected to the advance / retract mechanism 50 described below. The second electrode piece 94b is formed in a cylindrical shape extending from the outer periphery of the second electrode base 94a towards the fixed electrode part 80 in the advance / retract direction.

[0036] The first movable electrode 93 is accommodated radially inward relative to the second electrode piece 94b of the second movable electrode 94. The first movable electrode 93 integrally includes a first electrode base 93a and a plurality of first electrode pieces 93b. The first electrode base 93a is fixed to a second electrode base 94a of the second movable electrode 94, which will be described later. A plurality of first electrode pieces 93b are provided at intervals in the circumferential direction centered on the first fixed electrode 82. The plurality of first electrode pieces 93b are cylindrical as a whole. Each of the first electrode pieces 93b extends from the outer periphery of the first electrode base 93a toward the fixed electrode part 80 in the forward and backward direction. The first electrode pieces 93b can be elastically deformed radially outward with the first electrode base 93a as the center.

[0037] The movable electrode holding part 92 holds the movable electrode main body 91 (first movable electrode 93 and second movable electrode 94) so ​​as to be movable in the advance / retract direction. The movable electrode holding part 92 is fixed to the housing main body 32 of the second housing 31 via a bracket (not shown). The movable electrode holding part 92 is provided so as to cover the movable electrode main body 91 from the radial outside. The movable electrode holding part 92 is a shield made of a conductive material such as aluminum, and is formed in a cylindrical shape extending in the advance / retract direction.

[0038] The movable electrode main body 91 (first movable electrode 93 and second movable electrode 94) can be advanced and retreated toward the first fixed electrode 82 and second fixed electrode 83 of the fixed electrode section 80 by an advance / retract mechanism 50 described below. The movable electrode main body 91 can be moved by the advance / retract mechanism 50 between a state in which it is accommodated in the movable electrode holding section 92 and a state in which it protrudes from the movable electrode holding section 92 toward the fixed electrode main body 81 in the advance / retract direction.

[0039] Fig. 5 is a cross-sectional view showing a state in which the movable electrode body 91 and the fixed electrode body 81 of the earthing switch 8 are connected. As shown in Fig. 4, the movable electrode body 91 is normally housed in the movable electrode holding portion 92. In this state, the movable electrode body 91 and the fixed electrode body 81 are arranged at a preset interval in the advancing / retracting direction. After the circuit breaker 5 breaks the electric circuit and the disconnector 7 separates the electric circuit, as shown in Fig. 5, when the advancing / retracting mechanism 50 advances the movable electrode body 91 toward the fixed electrode body 81, the movable electrode body 91 and the fixed electrode body 81 are connected.

[0040] In a state where the movable electrode main body 91 and the fixed electrode main body 81 are connected, the first movable electrode 93 is electrically connected to the first fixed electrode 82 by contacting the outer circumferential surface of the first fixed electrode 82. In other words, the first fixed electrode 82 can be electrically connected to the movable electrode main body 91 by being inserted radially inside the movable electrode main body 91 and contacting the inner circumferential surface of the first movable electrode 93 of the movable electrode main body 91. In addition, the second movable electrode 94 is electrically connected to the second fixed electrode 83 by contacting the inner circumferential surface of the second fixed electrode 83. In other words, the second fixed electrode 83 can be electrically connected to the movable electrode main body 91 by contacting the outer circumferential surface of the second movable electrode 94 of the movable electrode main body 91.

[0041] 6 is a schematic diagram showing the configuration of the advance / retract mechanism 50. The advance / retract mechanism 50 advances / retracts the movable electrode main body 91 in the advance / retract direction relative to the movable electrode holding part 92. The advance / retract mechanism 50 may have any configuration as long as it can advance / retract the movable electrode main body 91 within a predetermined speed range described later. In this embodiment, as shown in FIGS. 4 and 6, the advance / retract mechanism 50 mainly includes, for example, a motor 51 (see FIG. 6), a main shaft 52, a drive lever 53 (see FIG. 6), a biasing member 54 (see FIG. 6), and an advance / retract arm 55 (see FIG. 4).

[0042] As shown in FIG. 6, the motor 51 drives the main shaft 52 to rotate around its central axis. The drive lever 53 is connected to the main shaft 52. The drive lever 53 extends from the main shaft 52 radially outward of the main shaft 52. The tip of the drive lever 53 is rotatably connected to one end 54a of the biasing member 54. The biasing member 54 includes, for example, a coil spring 54s. The other end 54b of the biasing member 54 is rotatably connected to the second housing 31 (see FIG. 1) via a bracket (not shown) or the like. As shown in FIG. 4, the base end of the advance / retract arm 55 is connected to the main shaft 52. The tip of the advance / retract arm 55 is connected to the movable electrode body 91 via a connecting link 56.

[0043] 7 is a schematic diagram showing a state in which the biasing member 54 of the advancing / retreating mechanism 50 is stored with pressure. In such an advancing / retreating mechanism 50, when the movable electrode main body 91 is moved toward the fixed electrode main body 81 from a state in which the movable electrode main body 91 and the fixed electrode main body 81 are separated from each other, the motor 51 rotates the main shaft 52 in a predetermined first direction Dr1. When the main shaft 52 rotates in the first direction Dr1, as shown in FIG. 7, the coil spring 54s is compressed by the drive lever 53 that rotates integrally with the main shaft 52, and the biasing force of the coil spring 54s is stored with pressure.

[0044] FIG. 8 is a schematic diagram showing a state in which the biasing force of the biasing member 54 is released. As shown in FIG. 8, when the main shaft 52 rotates to a predetermined angle, the main shaft 52 and the motor 51 are separated by an appropriate cam mechanism or the like, and the biasing force accumulated in the coil spring 54s is released. As a result, the biasing member 54 extends and rotates the main shaft 52 together with the drive lever 53. When the main shaft 52 rotates due to the extension of the biasing member 54, the advance / retract arm 55 rotates together with the main shaft 52, and the movable electrode main body 91 advances toward the fixed electrode main body 81 along the advance / retract direction, and as shown in FIG. 5, the movable electrode main body 91 and the fixed electrode main body 81 are connected. In the state in which the movable electrode main body 91 and the fixed electrode main body 81 are connected, the movable electrode main body 91 maintains a state in which it is biased toward the fixed electrode main body 81 by the biasing force of the coil spring 54s. As a result, the movable electrode main body 91 and the fixed electrode main body 81 maintain a connected state.

[0045] When the movable electrode main body 91 is moved away from the fixed electrode main body 81 from the state in which the movable electrode main body 91 and the fixed electrode main body 81 are connected, the motor 51 rotates the main shaft 52 in the direction opposite to the first direction Dr1 in the state shown in Fig. 8. When the main shaft 52 rotates in the opposite direction, the biasing member 54 is compressed by the drive lever 53 which rotates integrally with the main shaft 52 as shown in Fig. 7, and the biasing force of the coil spring 54s is accumulated. When the main shaft 52 rotates to a predetermined angle, the main shaft 52 and the motor 51 are separated by an appropriate cam mechanism or the like, and the biasing force accumulated in the coil spring 54s is released.

[0046] As a result, the biasing member 54 extends, rotating the main shaft 52 together with the drive lever 53 in the second direction Dr2. When the main shaft 52 rotates due to the extension of the biasing member 54, the advancing / retreating arm 55 rotates together with the main shaft 52, causing the movable electrode main body 91 to retreat along the advancing / retreating direction toward a side away from the fixed electrode main body 81, and the connection between the movable electrode main body 91 and the fixed electrode main body 81 is released, as shown in Fig. 4. In the state in which the connection between the movable electrode main body 91 and the fixed electrode main body 81 is released, the biasing force of the coil spring 54s maintains the movable electrode main body 91 separated from the fixed electrode main body 81.

[0047] In this way, the movable electrode main body 91 advances and retreats toward the fixed electrode main body 81 due to the biasing force accumulated in the coil spring 54s of the biasing member 54. In other words, the moving speed of the movable electrode main body 91 when it is connected to the fixed electrode main body 81 and the moving speed of the movable electrode main body 91 when it is separated from the state where it is connected to the fixed electrode main body 81 are governed by the spring constant of the coil spring 54s.

[0048] FIG. 9 is a diagram showing a first state A1 in which the movable electrode main body 91 contacts the first fixed electrode 82. FIG. 10 is a diagram showing a second state A2 in which the movable electrode main body 91 contacts the second fixed electrode 83. When the movable electrode main body 91 advances toward the fixed electrode main body 81 along the advance / retract direction by the biasing force of the biasing member 54, the first state A1 is reached in which the first movable electrode 93 of the movable electrode main body 91 contacts the first fixed electrode 82, as shown in FIG. 9. When the movable electrode main body 91 then advances further, the second state A2 is reached in which the second movable electrode 94 contacts the second fixed electrode 83, as shown in FIG. 10. In other words, it takes a time according to the moving speed of the movable electrode main body 91 to transition from the first state A1 to the second state A2.

[0049] The advance / retract mechanism 50 moves the movable electrode main body 91 toward the fixed electrode section 80 so that the time required to transition from the first state A1 to the second state A2 is equal to or longer than a preset reference time. As a result, the first state A1 in which the first movable electrode 93 contacts the first fixed electrode 82 continues for equal to or longer than the reference time. As shown in FIG. 9, in the first state A1, since the discharge resistor section 85 is connected to the first fixed electrode 82, the charge remaining in the power receiving side busbar 101 flows into the discharge resistor section 85 and is consumed, thereby discharging. In this way, the advance / retract mechanism 50 continues the first state A1 for equal to or longer than the reference time, and then transitions to the second state A2 after sufficient discharge by the discharge resistor section 85. Here, the reference time for transitioning from the first state A1 to the second state A2 is preferably, for example, 1.5 seconds or longer.

[0050] The advance / retract mechanism 50 moves the movable electrode main body 91 toward the fixed electrode unit 80 at a moving speed within a preset range when transitioning from the first state A1 to the second state A2 so that transition from the first state A1 to the second state A2 takes more than a reference time. As described above, the moving speed of the movable electrode main body 91 is governed by the spring constant of the coil spring 54s of the biasing member 54. In this embodiment, the spring constant of the coil spring 54s of the biasing member 54, the length of the drive lever 53, the length of the advance / retract arm 55, and the like are set so that the movable electrode main body 91 is moved at a moving speed within a preset range when transitioning from the first state A1 to the second state A2.

[0051] In this embodiment, the moving speed of the movable electrode main body 91 when transitioning from the first state A1 to the second state A2 is preferably, for example, 1.0 m / sec or more and less than 1.6 m / sec. If the moving speed of the movable electrode main body 91 is 1.6 m / sec or more, the time required to transition from the first state A1 to the second state A2 becomes short, and the discharge in the discharge resistor section 85 is not sufficiently performed. Then, when the second movable electrode 94 approaches the fixed electrode main body 81, a flashover is likely to occur. Also, if the moving speed of the movable electrode main body 91 is less than 1.0 m / sec, there is a possibility that a problem will occur when the movable electrode main body 91 is separated from the fixed electrode main body 81.

[0052] In this manner, in the opening and closing device 1 according to this embodiment, the movable electrode main body 91 is moved toward the fixed electrode unit 80 so that the time required for transition from the first state A1 in which the first fixed electrode 82 and the movable electrode main body 91 are in contact to the second state A2 in which the second fixed electrode 83 and the movable electrode main body 91 are in contact is equal to or longer than a reference time. In the first state A1, the first fixed electrode 82 and the movable electrode main body 91 come into contact with each other, causing the charge remaining on the power receiving side to flow into the discharge resistor unit 85 connected to the first fixed electrode 82, and discharging occurs.

[0053] Thereafter, the movable electrode main body 91 is moved toward the fixed electrode section 80 so that it takes a reference time or more to transition from the first state A1 to the second state A2, thereby ensuring a long discharge time in the discharge resistor section 85. This makes it possible to reduce the potential difference between the power receiving side and the ground side before the second fixed electrode 83 and the movable electrode main body 91 come into contact with each other. As a result, it is possible to suppress the occurrence of a flashover when the movable electrode section 90 and the fixed electrode section 80 are connected.

[0054] In addition, in a configuration in which the movable electrode main body 91 is moved toward the fixed electrode section 80 at a moving speed within a preset range when transitioning from the first state A1 to the second state A2, the time required for transition from the first state A1 to the second state A2 can be set to be equal to or longer than the reference time. In addition, in a configuration in which the movable electrode main body 91 is moved at a moving speed of 1.0 m / sec or more and less than 1.6 m / sec when transitioning from the first state A1 to the second state A2, the time required for transition from the first state A1 to the second state A2 can be set to be equal to or longer than the reference time.

[0055] Furthermore, in a configuration in which the electrical resistance of the discharge resistor portion 85 is equal to or greater than 66 Ω and less than 80 Ω, it is possible to efficiently discharge the residual charge on the power receiving side in the discharge resistor portion 85 while suppressing the occurrence of flashover when the first fixed electrode 82 and the movable electrode main body 91 approach each other. In a configuration in which the movable electrode main body 91 is cylindrical, the first fixed electrode 82 contacts the inner circumferential surface of the movable electrode main body 91, and the second fixed electrode 83 contacts the outer circumferential surface of the movable electrode main body 91, when the first fixed electrode 82 and the second fixed electrode 83 of the fixed electrode portion 80 are in contact with the movable electrode main body 91, only the movable electrode main body 91 is located between the first fixed electrode 82 and the second fixed electrode 83.

[0056] That is, no shield made of an insulating material is provided between the first fixed electrode 82 and the second fixed electrode 83. This allows the fixed electrode section 80 to be made smaller and more compact. In addition, in a configuration in which the movable electrode main body 91 has the first movable electrode 93 in contact with the outer circumferential surface of the first fixed electrode 82 and the second movable electrode 94 in contact with the inner circumferential surface of the second fixed electrode 83, each of the first movable electrode 93 and the second movable electrode 94 can be configured so that the connection state to the first fixed electrode 82 and the second fixed electrode 83 is good, respectively.

[0057] (Modification of the embodiment) In the above embodiment, the reference time required for transition from the first state A1 to the second state A2, the moving speed range of the movable electrode main body 91, and the range of the electrical resistance of the discharge resistor portion 85 are illustrated, but these are merely examples. These can be appropriately changed according to, for example, the moving dimension of the movable electrode main body 91 when connecting to the fixed electrode main body 81, the electrical resistance of the discharge resistor portion 85, etc. [Explanation of symbols]

[0058] 1. Switchgear 8...Earthing switch 50...advance / retreat mechanism 54... Urging member 80...Fixed electrode section 82...1st fixed electrode 83...Second fixed electrode 85...Discharge resistance section 90...Movable electrode part 91...Movable electrode body 92...Movable electrode holding part 93...1st movable electrode 94...Second movable electrode 99··1·Ground wire A1: First state A2: Second state

Claims

1. A fixed electrode portion electrically connected to either one of the power receiving side and the ground side; a movable electrode portion that is electrically connected to the other of the power receiving side and the ground side and that can be connected to the fixed electrode portion by moving forward and backward relative to the fixed electrode portion, The movable electrode portion is a movable electrode body extending in a direction in which the movable electrode portion advances and retreats and electrically connected to a ground wire provided externally; a movable electrode holding portion that holds the movable electrode body so as to be movable in the forward and backward directions; a reciprocating mechanism for moving the movable electrode body forward and backward in the reciprocating direction relative to the movable electrode holding portion, The fixed electrode portion is a first fixed electrode extending in the forward / backward direction and electrically connectable to the movable electrode body; a second fixed electrode provided on a side farther from the movable electrode portion than a tip of the first fixed electrode on the movable electrode portion side in the advance / retract direction, the second fixed electrode being electrically connectable to the movable electrode main body; a discharge resistor portion electrically connected to the first fixed electrode, The advance / retract mechanism includes: when the movable electrode portion is moved toward the fixed electrode portion along the advance / retract direction to transition from a first state in which the first fixed electrode and the movable electrode main body are in contact with each other to a second state in which the second fixed electrode and the movable electrode main body are in contact with each other, the movable electrode main body is moved toward the fixed electrode portion so that a time required for transition from the first state to the second state is equal to or longer than a predetermined reference time; Earthing switch.

2. The advance / retract mechanism includes: When transitioning from the first state to the second state, the movable electrode main body is moved toward the fixed electrode portion at a moving speed within a preset range. The earthing switch according to claim 1.

3. the advancing / retracting mechanism includes a biasing member that biases the movable electrode main body toward the fixed electrode portion along the advancing / retracting direction, the biasing member moves the movable electrode main body at a moving speed of 1.0 m / sec or more and less than 1.6 m / sec when transitioning from the first state to the second state; The earthing switch according to claim 2.

4. The electrical resistance of the discharge resistor portion is 66 Ω or more and less than 80 Ω. The earthing switch according to claim 1 or 2.

5. The movable electrode body is formed in a cylindrical shape extending in the advancing and retreating direction, the first fixed electrode is inserted radially inward of the movable electrode body and contacts an inner circumferential surface of the movable electrode body, thereby being electrically connectable to the movable electrode body; the second fixed electrode is provided radially outwardly with a gap therebetween with respect to the first fixed electrode, and is electrically connectable to the movable electrode body by contacting an outer circumferential surface of the movable electrode body; The earthing switch according to claim 1 or 2.

6. The movable electrode body is a first movable electrode that is in contact with an outer peripheral surface of the first fixed electrode and is thereby electrically connectable to the first fixed electrode; a second movable electrode provided radially outward of the first movable electrode and electrically connectable to the second fixed electrode by contacting an inner circumferential surface of the second fixed electrode; The earthing switch according to claim 1 or 2.

7. A switchgear comprising the earthing switch according to claim 1 or 2.

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