DOOR AND EARTHING SWITCH

FIELD OF THE INVENTION

[0001] The invention relates to the technical field of electric power products, particularly relates to an interlock device to be applied among a cable door, a rear door and an earthing switch on an air insulated switchgear. The device is particularly suitable for a high voltage switchgear with a ST1 -UG earthing switch.

BACKGROUND OF THE INVENTION

[0002] The purpose of the future five-protection interlock of a switchgear is to fundamentally avoid dangers and misoperations that may result in serious problems, so as to more effectively protect the safety of operators and the switchgear. To ensure the safety and convenient operation, an interlock, preferably a mechanical interlock, is required among different components of a metal-enclosed switchgear and controlgear.

[0003] Mechanical interlock is only available between the cable door and the earthing switch in the conventional metal-enclosed air insulated switchgear and controlgear, and the interlock functions are as follows: the cable door can only be opened when the earthing switch is switched on; the cable door cannot be opened when the earthing switch is switched off. When the earthing switch is switched on, as shown in Figure 1 , an operation shaft 111 is rotated to drive a pressure piece 114 sleeved on the operation shaft 111 to rotate, a pressure shaft 115 is driven to move downwards to push a push rod 120 to move downwards, a rotation piece 122 is rotated to drive a tongue piece 118 to move leftwards, and the tongue piece 118 cannot be inserted into a lower slide piece 116 capable of moving up and down, so that the cable door 117 can be opened; when the earthing switch is switched off, as shown in Figure 2, the operation shaft 111 is rotated to drive the pressure piece 114 sleeved on the operation shaft 111 to rotate, the pressure shaft 115 on the pressure piece 114 is driven to move away from the push rod 120,the push rod 120 moves upwards under the action of a spring 123, the rotation piece 122 is rotated to drive the tongue piece 118 to move rightwards, the tongue piece 118 is inserted into the lower slide piece 116 capable of moving up and down, and an ejector piece 119 stops the lower slide piece 116 from moving upwards through the tongue piece 118, so that the cable door 117 cannot be opened.

[0004] Another interlock function of the mechanical interlock between the cable door and the earthing switch in the prior art is as follows: the earthing switch can only be operated when the cable door is closed; the earthing switch cannot be operated when the cable door is opened. As shown in Figure 3, when the cable door is closed, an unlock piece 112 pushes the rotation piece 121 to rotate in the direction shown in Figure 3, an unlock pin 113 is pulled out, and an earthing switch operating handle can be inserted, so that the earthing switch can be operated. As shown in Figure 4, when the cable door is opened, the unlock piece 112 departs, the rotation piece 121 and the unlock pin 113 are restored to the original positions, and the earthing switch operating handle cannot be inserted, so the earthing switch cannot be operated.

[0005] As mentioned above, the mechanical interlock is only available between the cable door and the earthing switch in the conventional air insulated switchgear. There is no mechanical interlock aiming at inter-control among the rear door, the cable door and the earthing switch. In the conventional air insulated switchgear, the earthing switch can be operated by opening the rear door and the closing the cable door, so that both the operator and the switchgear are vulnerable to safety hazards. To better ensure the safety, the mechanical interlock between the rear door and the earthing switch is particularly important.

SUMMARY OF THE INVENTION

[0006] To solve the problem that the absence of mechanical interlock between the rear door and the earthing switch in the conventional air insulated switchgear leads to safety hazards, the present invention provides a reliable mechanical interlock device, which ensures that the cable door and the rear door of the switchgear cannot be opened when the earthing switch is switched off, so that the operator can be prevented from entering a live interval by mistake. Moreover, the mechanical interlock device can ensure that the earthing switch can only be operated when the cable door and the rear door of the switchgear are both closed, so that the personal safety of the operator can be ensured.

[0007] According to one aspect of the invention, a mechanical interlock device among a cable door, a rear door and an earthing switch is provided. The mechanical interlock device comprises a rear door locking device for locking the rear door of an air insulated switchgear, a rear shaft space-providing component for providing a space-providing space to a rear outer shaft, an intermediate force transfer device for transferring the acting force of rear door closure to an unlock pin, and an unlock pin control device for controlling the locking and unlocking of the unlock pin.

[0008] According to a preferred embodiment of the present invention, the rear door locking device of the mechanical interlock device comprises a rear door lock hook positioned on the rear outer shaft and a rear door lock groove positioned on the rear door, the rear door lock hook and the rear door lock groove can interact to lock the rear door.

[0009] According to a preferred embodiment of the present invention, the rear shaft space-providing component of the mechanical interlock device is a C-shaped component which is used for providing space to the rear outer shaft when the earthing switch is switched off. The rear shaft space-providing component can also be a C-shaped component.

[0010] According to a preferred embodiment of the present invention, the intermediate force transfer device of the mechanical interlock device comprises the rear outer shaft and a rear inner shaft, the rear outer shaft is so installed and arranged that the rear outer shaft can rotate with an operation shaft, a pin is fixed on the rear inner shaft and used for limiting or permitting the insertion of the operation shaft.

[0011] According to the preferred embodiment, the rear outer shaft is so installed and arranged that the rear outer shaft can rotate with the operation shaft, that is, when the operation shaft is rotated, the rear outer shaft rotates to drive the rear door lock hook on the rear outer shaft to be clamped into the rear door lock groove so as to lock the rear door.

[0012] According to a preferred embodiment of the present invention, the unlock pin control device comprises the unlock pin and a rotation piece, the rotation piece is fixedly connected with the unlock pin and can drive the unlock pin to move between an earthing switch locking position and an earthing switch unlocking position.

[0013] According to a preferred embodiment of the present invention, the intermediate force transfer device further comprises a spring for restoring the rear inner shaft.

[0014] The intermediate force transfer device further comprises a pressure piece positioned on the operation shaft. The pressure piece is used for controlling whether to lock the cable door through a cable door interlock device.

[0015] According to the preferred embodiment, the cable door interlock device comprises a moving pressure shaft, a push rod, a rotation piece and a tongue piece, the moving pressure shaft is in close contact with the push rod and can move downwards to push the push rod to move downwards, one end of the push rod is rotationally and axially connected with one end of the rotation piece, and the other end of the rotation piece is rotationally and axially connected with the tongue piece.

[0016] According to another aspect of the present invention, a gas insulated switchgear is provided. The gas insulated switchgear comprises any one of the preceding lock device among the cable door, the rear door and the earthing switch.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The embodiments of the invention that are presented in the sense of examples and their advantages are explained in greater detail below with reference to the accompanying drawings, in which:

[0018] Figure 1 depicts the interlock between the cable door and the earthing switch in the conventional air insulated switchgear when the earthing switch is switched on;

[0019] Figure 2 depicts the interlock between the cable door and the earthing switch in the conventional air insulated switchgear when the earthing switch is switched off;

[0020] Figure 3 depicts the position of the unlock pin in the conventional air insulated switchgear when the cable door is closed; [0021] Figure 4 depicts the position of the unlock pin in the conventional air insulated switchgear when the cable door is opened;

[0022] Figure 5 depicts the general structure of the mechanical interlock device of the present invention among the cable door, the rear door and the earthing switch of the conventional air insulated switchgear;

[0023] Figure 6 depicts the structural details of the mechanical interlock device of the present invention;

[0024] Figure 7 depicts the rear door locking device of the mechanical interlock device of the present invention when the earthing switch is switched on;

[0025] Figure 8 depicts the rear door locking device of the mechanical interlock device of the present invention when the earthing switch is switched off;

[0026] Figure 9 depicts the rear shaft space-providing component of the mechanical interlock device of the present invention when the earthing switch is switched off;

[0027] Figure 10 depicts the rear shaft space-providing component of the mechanical interlock device of the present invention when the earthing switch is switched on;

[0028] Figure 11 depicts how the intermediate force transfer device of the mechanical interlock device of the present invention transfers an acting force to the operation shaft;

[0029] Figure 12 depicts how the intermediate force transfer device of the mechanical interlock device of the present invention transfers an acting force to the rear door;

[0030] Figure 13 depicts the position of the unlock pin of the present invention when the earthing switch is inoperable;

[0031] Figure 14 depicts the position of the unlock pin of the present invention when the earthing switch is operable;

[0032] Figure 15 is a structure diagram of the unlock pin control device of the mechanical interlock device of the present invention;

[0033] Figure 16 depicts the rear door locking device of the mechanical interlock device of the present invention when the rear door is opened;

[0034] Figure 17 depicts the intermediate force transfer device of the mechanical interlock device of the present invention when the rear door is opened;

[0035] Figure 18 depicts the unlock pin mechanism of the mechanical interlock device of the present invention when the rear door is opened.

DETAILED DESCRIPTION OF EMBODIMENTS

[0036] Hereinafter, the principle and spirit of the present invention will be described with reference to the illustrative embodiments. It should be understood, all these embodiments are given merely for the skilled in the art to better understand and further practice the present invention, but not for limiting the scope of the present invention.

[0037] To solve the problem that the absence of mechanical interlock between the rear door and the earthing switch in the conventional air insulated switchgear leads to safety hazards, the invention provides a reliable mechanical interlock device, which ensures that the cable door and the rear door of the switchgear cannot be opened when the earthing switch is switched off, so that the operator can be prevented from entering a live interval by mistake. Moreover, the mechanical interlock device can ensure that the earthing switch can only be operated when the cable door and the rear door of the switchgear are both closed, so that the personal safety of the operator can be ensured.

[0038] Figures 5 and Figure 6 depict the structure of the mechanical interlock device used among the cable door, the rear door and the earthing switch of the conventional air insulated switchgear, wherein Figure 5 depicts the general structure and Figure 6 depicts the structural specifics. As shown in Figure 5, the interlock device of the invention includes four main parts, wherein, part I is the rear door locking device 21 , part II is the rear shaft space-providing component 22, part III is the intermediate force transfer device 23, and part IV is the unlock pin control device 24. As shown in Figure 6, the rear door locking device 21 is aimed at locking the rear door of the air insulated switchgear; the rear shaft space-providing component 22 is aimed at providing a space-providing space for the rear outer shaft 211 ; the intermediate force transfer device 23 is aimed at transferring the closing action and force of the rear door to the unlock pin 113, and providing a restoration force to the rear inner shaft 212; and the unlock pin control device is aimed at controlling the locking and unlocking of the unlock pin 113.

[0039] The following is a detailed description of the status and working principle of each part of the best embodiment of the invention.

[0040] The rear door locking device 21 comprises the rear door lock hook 216 on the rear outer shaft 211 and the rear door lock groove 213 on the rear door. The rear door lock hook 216 and the rear door lock groove 213 can interact to lock the rear door. When the rear door lock hook 216 is clamped into the rear door lock groove 213, the rear door is locked and cannot be opened; when the rear door lock hook 216 is separated from the rear door lock groove 213, the rear door can be opened.

[0041] The rear door locking device 21 has two statuses. As shown in Figure 7, when the earthing switch is switched on, the rear door lock hook 216 is separated from the rear door lock groove 213, so that the rear door can be opened. The rear inner shaft 212 also has two positions, that is, a pressure piece 214 push position and a spring 235 restoration position. As shown in Figure 8, when the earthing switch is switched off, the rear door lock hook 216 is clamped into the rear door lock groove 213, so the rear door cannot be opened.

[0042] The rear shaft space-providing component 22 has two statuses. As shown in Figure 9, when the earthing switch is switched off, the C-shaped component 221 provides a space-providing space to the rear outer shaft 211 to avoid interference; and Figure 10 shows the status of the rear shaft space-providing component when the earthing switch is switched on.

[0043] The intermediate force transfer device 23 comprises the rear outer shaft 211 and the rear inner shaft 212, wherein, when the operation shaft 111 is rotated, the rear outer shaft 211 can rotate through the sleeve 232 to enable the rear door lock hook 216 on the rear outer shaft to be clamped into the rear door lock groove 213, so the rear door is locked. The pin 231 is fixed on the rear inner shaft 212, and the rear inner shaft 212 is aimed at transferring the opening action of the rear door to enable the pin 231 to be positioned in the earthing switch locking position P1 , thereby limiting the insertion of the operation shaft, that is, stopping the earthing switch from being operated. When the rear door is opened, as shown in Figure 13, the push block 233 drives the rod 234 fixedly connected therewith, the rod 234 drives the slide block 241 fixedly connected therewith, the slide block 241 pushes the rotation piece 245 to rotate, and the unlock pin 113 is further driven to be positioned in the earthing switch locking position P1 to prevent the insertion of the operation shaft 111 , thereby preventing the earthing switch from being operated.

[0044] The intermediate force transfer device 23 has the following two purposes: firstly, as shown in Figure 11 , when operating the earthing switch, the operation shaft 111 controls the on/off of the earthing switch through the sleeve 232, and the intermediate force transfer device 23 transfers the operating force of the operation shaft 111 to the rear outer shaft 211 which rotates to drive the rear door lock hook 216 thereon to be clamped into the rear door lock groove 213, so the rear door is locked; secondly, as shown in Figure 12, the intermediate force transfer device 23 transfers the closing force of the rear door to the unlock pin 113 through the rear inner shaft 212, the pin 231 , the slide block 233 and the rod 234 in sequence. Moreover, the rear inner shaft 212 can be restored to the original position under the action of the spring 235.

[0045] According to the best embodiment of the invention, the intermediate force transfer device 23 further comprises the pressure piece 114 on the operation shaft 111 , and the pressure piece 114 controls the locking or unlocking of the cable door 117 through the cable door interlock device 10. The cable door interlock device 10 comprises the moving pressure shaft 115, the push rod 120, the rotation piece 122 and the tongue piece 118; the moving pressure shaft 115 is in close contact with the push rod 120 and moves downwards to push the push rod 120 to move downwards; and one end of the push rod 120 is rotationally and axially connected with one end of the rotation piece 122, and the other end of the rotation piece 122 is rotationally and axially connected with the tongue piece 118, so that the movement of the push rod 120 is transferred to the tongue piece 118 to control the lower slide piece 116 capable of moving up and down to control the locking or unlocking of the cable door 117.

[0046] The unlock pin control device 24 comprises the unlock pin 113 and the rotation piece 245, the rotation piece 245 is fixedly connected with the unlock pin 113 and can drive the unlock pin 113 to move between the earthing switch locking position P1 and the earthing switch unlocking position P2. As shown in Figure 13, the earthing switch operating handle cannot be inserted, so the earthing switch cannot be operated. As shown in Figure 14, the earthing switch operating handle can be inserted, so the earthing switch can be operated. As shown in Figures 13-14, the position of the unlock pin 113 is determined as the unlock piece 112 of the cable door and the rear door force transferred to the slide block 241 jointly control the rotation piece 245 whether to pull out the unlock pin 113.

[0047] Following presents a detailed description of the working principles of the invention based on the attached figures, and how to realize the following two scenarios: the rear door and the cable door can only be opened when the earthing switch is switched on; and the rear door and the cable door cannot be opened when the earthing switch is switched off, so as to prevent the operator from entering the live interval by mistake. The earthing switch can only be operated when the rear door and the cable door are closed, and the earthing switch cannot be operated when either the rear door or the cable door is opened, so as to ensure the personal safety of the operator.

[0048] Firstly, the rear door and the cable door can only be opened when the earthing switch is switched on, and cannot be opened when the earthing switch is switched off.

[0049] As shown in Figure 2 and in view of the description of the background technology, when the earthing switch is switched on, the cable door can be opened. As shown in Figure 7, when the earthing switch is switched on, the rear outer shaft 211 cannot lock the rear door locking groove 213 riveted to the rear door 215, so the rear door 215 can be opened. As shown in Figure 3 and in view of the description of the background technology, when the earthing switch is switched off, the cable door 117 cannot be opened. As shown in Figure 8, when the earthing switch is switched off, the rear outer shaft 212 can lock the rear door lock groove 213 riveted to the rear door 215, so the rear door 215 cannot be opened.

[0050] Secondly, the earthing switch can only be operated when the rear door and the cable door are both closed, and cannot be operated when either the rear door or the cable door is opened.

[0051] As shown in Figure 14, when the cable door is closed, the unlock piece 112 is in the position as shown in the figure. As shown in Figure 12, when the rear door is closed, the rear inner shaft 212 is pushed to move in the direction of the arrow in Figure 12, the pin 231 fixedly connected with the rear inner shaft 212 is driven and pushes the push block 233 to move, and the push block 233 drives the rod 234 fixedly connected therewith. As shown in Figure 15, the rod 234 drives the slide block 241 fixedly connected therewith to move towards the unlock piece 112, the slide block 241 is fixed on the slide block bracket 243, and the slide block 241 pushes the rotation piece 245 to rotate, thereby pulling out the unlock pin 113. When the unlock pin 113 stays in the earthing switch unlocking position P2 as shown in Figure 14, the earthing switch operating handle can be inserted, and the earthing switch can be operated.

[0052] When the rear door is opened, the unlock pin return spring 244 provides power to the slide block bracket 243 and the slide block 241 fixed thereon.

[0053] As shown in Figure 13, when the cable door is not closed, the unlock piece 112 is not in the unlocking position, the slide block 241 cannot push the rotation piece 245 to rotate, and the unlock pin 113 stays in the earthing switch locking position P1 as shown in Figure 13, so the earthing switch operating handle cannot be inserted, and the earthing switch cannot be operated. As shown in Figure 16 and Figure17, when the rear door is not closed, the push block 233 is under the restoring force of the spring 235, the intermediate force transfer device is restored to the position as shown in Figure 17, the rear inner shaft 212 is restored to the position as shown in Figure 16, and the rod 234 is driven by the push block 233 to move in the direction of the arrow in Figure 17. The slide block 241 is also pulled by the rod 234 back to the position shown in Figure 18, the slide block 241 moves away from the rotation piece 245, and the unlock pin 113 is restored to the earthing switch locking position P1 as shown in Figure 13, so that the earthing switch operating handle cannot be inserted, and the earthing switch cannot be operated.

[0054] According to another aspect of the present invention, a gas insulated switchgear is provided. The gas insulated switchgear comprises an above described lock device among the cable door, the rear door and the earthing switch.

[0055] Advantages :

Through the reliable mechanical interlock device, the invention ensures not only that the cable door and the rear door of the switchgear cannot be opened when the earthing switch is switched off, but also that the earthing switch can only be operated when both the cable door and the rear door are closed. The invention achieves the mechanical interlock among the rear door, the cable door and the earthing switch, and greatly improves the safety performance of the air insulated switchgear.

[0056] Though the present invention has been described on the basis of some preferred embodiments, those skilled in the art should appreciate that those embodiments should by no means limit the scope of the present invention. There are many variations and modifications to the embodiments. For example, the C-shaped component 221 of the rear shaft space-providing component 22 can be replaced with a C-shaped component.

[0057] Without departing from the spirit and concept of the present invention, any variations and modifications to the embodiments should be within the apprehension of those with ordinary knowledge and skills in the art, and therefore fall in the scope of the present invention which is defined by the accompanied claims.