Mechanical interlock device for switchgear

Abstract

To provide a mechanical interlock device for preventing a disconnector and an earthing switch from closing simultaneously.SOLUTION: A mechanical interlock device includes: a ball screw 2 that rotates when a disconnector is opened or closed; a ball screw nut 3 that is screwed with the ball screw; a nut component 4 that is fixed to the ball screw nut and moves together with the ball screw nut; a rack 21 that is connected to a first cable 12a that is connected to an earthing switch; a gear that meshes with the rack; a fork 15 with one end thereof connected to the gear and with the other end thereof formed with a groove 15a into which a sleeve 16 is inserted, the fork being configured to move the first cable up and down via the rack when the ball screw nut moves in an axial direction along with an opening or closing operation of the disconnector; a lever 8 with a substantially central portion thereof rotatably supported, with one end thereof engaged with or disengaged from the nut component along with the opening or closing operation of the earthing switch, and with the other end thereof connected to a second cable 12b connected to the earthing switch; and a compression spring 9 that is installed between the lever and a support plate 10 that supports the second cable.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a mechanical interlock device for a switchgear, and more particularly to a mechanical interlock device for a switchgear suitable for being installed between a disconnector and a grounding switch used in a gas-insulated switchgear, and configured so that when the disconnector is in a closed position, the grounding switch cannot operate, and when the grounding switch is in a closed position, the disconnector cannot operate. [Background technology]

[0002] Gas-insulated switchgear uses at least one metal-enclosed disconnector filled with gas to disconnect electrical equipment from high voltage lines to ensure safe operation and maintenance of the electrical equipment without load.

[0003] Also, from a safety point of view, in order to provide safer operation and maintenance, at least one earthing switch may be used together with the disconnector, so that capacitive or inductive currents are isolated.

[0004] Now, in order to avoid a phase to earth fault, the disconnector and the earthing switch are not allowed to be closed at the same time.

[0005] Typically, an electrical interlock device is installed between the disconnector and the earthing switch, and this electrical interlock device interlocks the disconnector and earthing switch operators by cutting off the current supply to the motors that drive the disconnector and earthing switch operators.

[0006] However, since an electrical interlock device will lose its function if there is a failure in an electrical component, in order to improve reliability, a mechanical interlock device is installed between the circuit breaker and the earthing switch.

[0007] For example, Patent Document 1 describes a switch interlock device in which an operator operates by rotating the switch operating shaft, and mechanically interlocks one switch so that when the other switch is closed or open, the other switch cannot be closed or opened, in order to reliably perform a mechanical interlock between switches separated by any distance. The operators of both switches are connected by a flexible tube containing a flexible wire, and a lock pin is driven in conjunction with the operation of one switch, preventing the shutter of the other switch from being opened, thereby mechanically interlocking both operators.

[0008] Furthermore, Patent Document 2 describes an interlock device for switches in which the opening and closing operations of a first switch, a second switch, and a third switch are transmitted to each other via an interlock wire to the other switches, in order to obtain an interlock device between multiple switches required in multiple power receiving and distribution circuits, etc., and when the second switch is closed, the actuator of the first switch moves to a first position, and when both the second and third switches are closed, the actuator of the first switch moves to a second position, and when the actuator of the first switch moves to the second position, an interlock device for switches is provided with a locking mechanism that restricts the closing operation of the first switch. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 60-167220 [Patent Document 2] Japanese Patent Application Publication No. 7-193923 Summary of the Invention [Problem to be solved by the invention]

[0010] Incidentally, in a mechanical interlock device, the operating part is designed to block the shaft or lever in the main operating part of the switching device, resulting in a very large blocking force, and the blocking part is designed to block the part that moves together with the movable contact of the switching device.

[0011] For this reason, if there is always a gap between the blocking parts, in the blocked state, when an attempt is made to close the switchgear by a motor or manual operation, the movement of the movable contact of the switchgear may become small and the dielectric distance may decrease, which may affect the dielectric performance of the switchgear.

[0012] In addition, when the disconnector and the earthing switch are installed at different positions far away from each other due to the layout of the gas-insulated switchgear substation, it is very difficult to connect to the mechanical interlock device installed between the disconnector and the earthing switch, and even if the connection can be made, the connection structure will be complicated, which may increase the cost and reduce the reliability.

[0013] However, the above-mentioned Patent Documents 1 and 2 do not disclose any solutions to solve such problems.

[0014] The present invention has been made in consideration of the above-mentioned points, and an object of the present invention is to provide a mechanical interlock device for switchgear that can reliably prevent the disconnector and earthing switch from being closed simultaneously without affecting the switch functions of the disconnector and earthing switch, even if a mechanical interlock device is installed between the disconnector and earthing switch. [Means for solving the problem]

[0015] In order to achieve the above object, the mechanical interlock device of the switchgear of the present invention is installed between a disconnector and a grounding switch and mechanically interlocks the opening and closing operations of the disconnector and the grounding switch, and includes a ball screw connected to an operating shaft of the disconnector and rotating as the disconnector is opened and closed, a ball screw nut hinged to the ball screw and moving in the axial direction of the ball screw as the ball screw rotates, a nut part fixed to the ball screw nut, having a sleeve and moving together with the ball screw nut, a rack connected to a first cable connected to the grounding switch and having an uneven portion formed on a part of the rack, a gear that meshes with the concave-convex portion of the gear; one end connected to the gear and the other end formed with a groove into which the sleeve is inserted, and when the ball screw nut moves axially in conjunction with the opening and closing operation of the disconnector, the sleeve moves within the groove in conjunction with the movement, thereby rotating the gear and moving the first cable up and down via the rack; a lever supported so as to be freely rotatable approximately at the center, one end of which engages or disengages with the nut part in conjunction with the opening and closing operation of the earthing switch and the other end of which is connected to a second cable connected to the earthing switch; and a spring installed between the lever and a support plate that supports the second cable. Effect of the Invention

[0016] According to the present invention, even if a mechanical interlock device is installed between the disconnector and the earthing switch, it is possible to reliably prevent the disconnector and the earthing switch from being closed simultaneously without affecting the switch functions of the disconnector and the earthing switch. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a front view showing a first embodiment of a mechanical interlock device for a switching device according to the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along the line AA′ in FIG. [Diagram 3]2 is a cross-sectional view of the gear box and its surroundings with the cover removed from the gear box in the state shown in FIG. 1, showing the vicinity of a first cable. [Figure 4] FIG. 2 is a cross-sectional view taken along the line BB′ in FIG. [Figure 5(a)] FIG. 2 is a front view showing a state in which a disconnector is open in the switchgear mechanical interlock device according to the first embodiment of the present invention. [Figure 5(b)] FIG. 2 is a front view showing a state in which a disconnector is closed in the switchgear mechanical interlock device according to the first embodiment of the present invention. [Figure 6(a)] FIG. 2 is a front view showing a state in which a grounding switch is open in the switchgear mechanical interlock device according to the first embodiment of the present invention. [Figure 6(b)] 1 is a front view showing a state in which a grounding switch is closed in a switchgear mechanical interlock device according to a first embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, a mechanical interlock device for a switchgear according to the present invention will be described based on the illustrated embodiments. In each drawing, the same reference numerals are used for the same components. EXAMPLES

[0019] 1, 2, 3 and 4 show a first embodiment of a mechanical interlock device 100 for a switchgear according to the present invention.

[0020] FIG. 1 is a front view showing a first embodiment of a mechanical interlock device 100 for switching equipment of the present invention, FIG. 2 is a cross-sectional view taken along line AA' in FIG. 1, FIG. 3 is a cross-sectional view of the area around gear box 17 with cover 14 removed from gear box 17 in the state shown in FIG. 1, showing the area near first cable 12a, and FIG. 4 is a cross-sectional view taken along line BB' in FIG. 1.

[0021] In the mechanical interlock device 100 of the switching device of this embodiment shown in the figure, a circuit breaker (not shown) has an operating shaft 1 of the circuit breaker connected to a ball screw 2 that constitutes the mechanical interlock device 100, and a grounding switch (not shown) is connected to a first cable 12a and a second cable 12b.

[0022] The mechanical interlock device 100 is installed between the disconnector and the earthing switch, and mechanically interlocks the opening and closing operations of the disconnector and the earthing switch.

[0023] The specific details will be explained below.

[0024] The mechanical interlock device 100 of this embodiment shown in FIGS. 1, 2, 3, and 4 is connected to the operating shaft 1 of the circuit breaker and includes a ball screw 2 that rotates as the circuit breaker opens and closes (both ends of the ball screw 2 are rotatably supported by ball bearings), a ball screw nut 3 that is screwed onto the ball screw 2 (threaded) and moves in the axial direction of the ball screw 2 as the ball screw 2 rotates, a nut component 4 that is fixed to the ball screw nut 3, has a sleeve 16, and moves together with the ball screw nut 3 (the sleeve 16 is loaded in the nut component 4), a rack 21 that is connected to the first cable 12a connected to the earthing switch and has uneven portions 21a formed in part thereof, a gear 18 that has uneven portions 18a meshing with the uneven portions 21a of the rack 21 and is rotatably supported by a ball bearing, a fork 15 that has one end connected to the gear 18 and a U-shaped groove 15a formed at the other end into which the sleeve 16 is inserted, and when the ball screw nut 3 moves axially as the circuit breaker is opened and closed, the sleeve 16 moves in the U-shaped groove 15a axially, thereby rotating the gear 18, and the uneven portions 18a of the gear 18 and the uneven portions 21a of the rack 21 mesh to move the first cable 12a up and down, a lever 8 that has its approximate center portion rotatably supported by a bolt 7 on the housing 11, engages or disengages (details will be described later) with the nut component 4 and the ball screw nut 3 at one end as the earthing switch opens and closes, and is connected to the second cable 12b connected to the earthing switch at the other end, and a compression spring 9 installed along the second cable 12b between the lever 8 and the support plate 10 that supports the second cable 12b.

[0025] Also, as shown in FIG. 3, the connection between the first cable 12a and the rack 21 is made by screwing the core wire 12a1 of the first cable 12a into the end portion 21b of the rack 21, and the connection between the second cable 12b and the lever 8 is made by inserting the core wire of the second cable 12b into a through hole (not shown) provided at the end portion 8a of the lever 8.

[0026] Further, a long groove 21c is formed in the longitudinal direction on the side opposite to the side on which the uneven portion 21a of the rack 21 is formed, and a guide screw 23 for preventing the rack 21 from rotating is attached to this long groove 21c.

[0027] Furthermore, a guide rod 5 is installed in parallel with the ball screw 2, and the nut part 4 can move in the axial direction together with the ball screw nut 3 by being guided by this guide rod 5, so that the stability of the movement can be maintained.

[0028] A cover plate 6 fixed to a housing 11 is installed on one end (right side in FIG. 1) of the ball screw 2 and the guide rod 5, and the ball screw 2 and one end (right side in FIG. 1) of the guide rod 5 are supported by this cover plate 6. Both ends of the ball screw 2 are rotatably supported by ball bearings (not shown).

[0029] In addition, a plastic sleeve 25 is interposed between the lever 8 and the bolt 7, and a plastic washer 26 is interposed between the lever 8 and the housing 11 near the bolt 7, thereby reducing friction and wear between the lever 8 and the bolt 7 and between the lever 8 and the housing 11.

[0030] In addition, the fork 15 is fixed to the housing 11 by a plate 19.

[0031] The first cable 12a and the second cable 12b are fixed to the wall 11a of the housing 11, respectively.

[0032] Specifically, the first cable 12a and the second cable 12b are covered with a first cable sleeve 13a and a second cable sleeve 13b which are fixed to the wall 11a of the housing 11 with screws 22 and 28, and the first cable sleeve 13a is fixed to the first cable 12a with two nuts 20a, 20b, and the second cable sleeve 13b is fixed to the second cable 12b with two nuts 27a (not shown in the figure) and 27b (see Figure 1).

[0033] The above-mentioned components constituting the mechanical interlock device 100 of the switchgear of this embodiment are installed inside the housing 11.

[0034] Next, the interlock in the mechanical interlock device 100 of the switchgear of this embodiment will be described with reference to Figs. 5(a), 5(b), 6(a) and 6(b).

[0035] As shown in Figures 5(a) and 5(b), when the operating shaft 1 of the disconnector is operated from the open state, the ball screw 2 rotates and the ball screw nut 3 and the nut part 4 move in the axial direction. As a result, the sleeve 16 of the nut part 4 moves within the groove 15a having a U-shaped cross section, bringing the disconnector into a closed state (the state of Figure 5(b)). In this state, the gear 18 connected to the fork 15 on the opposite side to the side on which the U-shaped cross section groove 15a is formed rotates, and the uneven portion 18a of this gear 18 meshes with the uneven portion 21a of the rack 21, moving the rack 21 downward in Figures 5(a) and 5(b). As a result, the first cable 12a connected to the rack 21 moves downward, and the earthing switch becomes in the open state (the state of Figure 6(a)).

[0036] Furthermore, when the earthing switch is switched from the open state (the state in FIG. 6(a)) to the closed state (the state in FIG. 6(b)), the end of the second cable 12b moves downward and rotates the lever 8 clockwise, whereby the compression spring 9 is compressed between the lever 8 and the support plate 10 (the state in FIG. 6(b)), and the end of the lever 8 opposite to the side connected to the second cable 12b engages with the ball screw nut 3 and the nut part 4, blocking the operation of the disconnector (the state in FIG. 6(b)).

[0037] The operation of this disconnector is blocked by forming a stepped portion 31 when the ball screw nut 3 and the nut part 4 are hinged together, and the end 8a of the lever 8 opposite the side connected to the second cable 12b is formed with a stepped portion 31 that engages with the stepped portion 30 of the ball screw nut 3 and the nut part 4, and this stepped portion 30 engages with the stepped portion 31 to block the operation of the disconnector.

[0038] On the other hand, when the earthing switch is switched from a closed state (the state in Figure 6(b)) to an open state (the state in Figure 6(a)), the end of the second cable 12b moves upward and the compression of the compression spring 9 is released (the state in Figure 6(a)), and the lever 8 rotates counterclockwise, and as a result, the engagement between the stepped portion 30 and the stepped portion 31 is released and the block on the operation of the disconnector is released (the state in Figure 6(a)).

[0039] According to this embodiment, even if a mechanical interlock device is installed between the disconnector and the earthing switch, it is possible to reliably prevent both from being closed simultaneously without affecting the switch functions of the disconnector and the earthing switch.

[0040] The present invention is not limited to the above-mentioned embodiment, but includes various modifications. For example, the above-mentioned embodiment has been described in detail to easily explain the present invention, and is not necessarily limited to those including all of the configurations described. It is also possible to add a part of the configuration of one embodiment to the configuration of another embodiment. It is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0041] 1...operating shaft of disconnector, 2...ball screw, 3...ball screw nut, 4...nut part, 5...guide rod, 6...cover plate, 7...bolt, 8...lever, 8a...end of lever, 9...compression spring, 10...support plate, 11...casing, 11a...wall of casing, 12a...first cable, 12a1...core wire of first cable, 12b...second cable, 13a...sleeve for first cable, 13b...sleeve for second cable, 14...cover, 15...fork, 15a...groove with U-shaped cross section, 16, 25...sleeve, 17...gearbox, 18...gear, 18a...gear concave / convex portion, 19...plate, 20a, 20b, 27a, 27b...nut, 21...rack, 21a...rack concave / convex portion, 21b...end of rack, 21c...long groove formed in rack, 22, 28...screw, 23...guide screw, 26...washer, 30...step portion, 31...staircase portion, 100...mechanical interlock device.

Claims

1. A mechanical interlock device for a switchgear that is installed between a disconnector and a grounding switch and mechanically interlocks the opening and closing operations of the disconnector and the grounding switch, a ball screw connected to an operating shaft of the disconnector and rotating in response to opening and closing of the disconnector; a ball screw nut hinged to the ball screw and moving in the axial direction of the ball screw in response to the rotation of the ball screw; a nut part fixed to the ball screw nut, having a sleeve and moving together with the ball screw nut; a rack connected to a first cable connected to the earthing switch and having a concave-convex portion formed on one part; a gear that meshes with the concave-convex portion of the rack; a fork that rotates the gear by moving the sleeve within the groove as the ball screw nut moves axially during operation, thereby moving the first cable up and down via the rack; a lever that is supported rotatably at approximately the center, has one end that engages or disengages with the nut component as the earthing switch is opened or closed, and has the other end connected to a second cable that is connected to the earthing switch; and a spring that is installed between the lever and a support plate that supports the second cable.

2. The mechanical interlock device for a switching device according to claim 1, a first cable connected to the rack and a second cable connected to the rack being moved downward, the first cable being connected to the rack being moved downward, and the earthing switch being brought into an open state.

3. The mechanical interlock device for a switching device according to claim 2, When the earthing switch is switched from an open state to a closed state, the end of the second cable moves downward to rotate the lever clockwise, whereby the spring is compressed between the lever and the support plate, and the end of the lever opposite to the side connected to the second cable engages with the ball screw nut and the nut component, thereby blocking operation of the disconnector.

4. The mechanical interlock device for a switching device according to claim 3, a step portion formed on an end of the lever opposite to the end connected to the second cable, the step portion being adapted to engage with the step portions of the ball screw nut and the nut part, and the step portion engaging with the step portion blocks operation of the disconnector.

5. The mechanical interlock device for a switching device according to claim 4, When the earthing switch is switched from a closed state to an open state, the end of the second cable moves upward and the compression of the spring is released, causing the lever to rotate counterclockwise, thereby disengaging the stepped portion from the stepped portion and releasing the block on operation of the disconnector.

6. The mechanical interlock device for a switching device according to claim 5, 2. A mechanical interlock device for a switchgear, comprising: a first interlocking member for interlocking said first and second openings and closing said first and second openings;

7. The mechanical interlock device for a switching device according to claim 6, a first cable being connected to the rack by screwing a core wire of the first cable into an end of the rack, and a second cable being connected to the lever by inserting a core wire of the second cable into a through hole provided at the end of the lever.

8. The mechanical interlock device for a switching device according to claim 7, A mechanical interlock device for an opening and closing device, characterized in that a long groove is formed in the longitudinal direction of the rack on the side opposite to the side on which the uneven portion is formed, and a guide screw for preventing rotation of the rack is attached to the long groove.

9. The mechanical interlock device for a switching device according to claim 8, 13. A mechanical interlock device for an opening and closing device, comprising: a guide rod disposed in parallel with the ball screw; and a nut component that moves in the axial direction while being guided by the guide rod.

10. The mechanical interlock device for an opening and closing device according to claim 9, 13. A mechanical interlock device for a switchgear, comprising: a first interlocking portion for interlocking a switchgear;

11. The mechanical interlock device for a switching device according to claim 10, A mechanical interlock device for an opening and closing device, characterized in that a cover plate fixed to the housing is installed on the ball screw and one end of the guide rod, and the ball screw and one end of the guide rod are supported by the cover plate.

12. The mechanical interlock device for a switching device according to claim 11, A mechanical interlock device for an opening and closing device, characterized in that a plastic sleeve is interposed between the lever and a bolt that fixes the lever to the housing, and a plastic washer is interposed between the lever and the housing near the bolt.

13. A mechanical interlock device for a switching device according to claim 12, 13. A mechanical interlock device for a switching device, comprising: a fork, the fork being fixed to the housing by a plate;

14. A mechanical interlock device for a switching device according to claim 13, 13. A mechanical interlock device for a switching device, comprising: a first cable and a second cable, each of which is fixed to the housing.

15. A mechanical interlock device for a switching device according to claim 14, A mechanical interlock device for a switching device, characterized in that the first cable and the second cable are covered by a first cable sleeve and a second cable sleeve fixed to the housing, and the first cable sleeve is fixed to the first cable, and the second cable sleeve is fixed to the second cable, respectively.

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