WO2016061720A1

WO2016061720A1 - Switchgear

Info

Publication number: WO2016061720A1
Application number: PCT/CN2014/085346
Authority: WO
Inventors: Xin Zhang; Zhian Wang; Wenfu ZHENG; Xuedong QIU
Original assignee: Abb Technology Ltd
Priority date: 2014-10-24
Filing date: 2014-10-24
Publication date: 2016-04-28
Also published as: CN106575859B; CN106575859A

Abstract

A switchgear comprises a bypass busbar (101B); at least one main busbar (101A); a disconnector (104A); and a circuit breaker (102A) connected with the at least one main busbar (101A). The disconnector (104A) comprises a blade (1045) which can be driven to three positions, i. e., a first position (P1) for connecting with an outcoming of the circuit breaker (102A), a second position (P2) for connecting with an outcoming of the bypass busbar (101B), and a third position (P0) for disconnection. The bypass busbar (101B), the at least one main busbar (101A), the circuit breaker (102A), and the disconnector (104A) are all arranged within a single panel. Moreover, the blade (1045) is driven by an operation mechanism (106) including a four-bar linkage driving means (1040). The three-position disconnector (104A) is implemented by means of four-bar linkage driving means (1040) and thus all functionalities for a feeder can be achieved within one single panel, which provides a great deal of cost and space savings.

Description

SWITCHGEAR

FIELD OF THE INVENTION

[0001] Embodiments of the present disclosure generally relate to a field of electric power feeding and particularly relates to a switchgear and a feeder unit comprising the switchgear, especially for a railway power supplying.

BACKGROUND OF THE INVENTION

[0002] By far, switchgears are widely used to provide control, protection and isolation of electrical equipment in many fields, for example in railway application. A switchgear may de-energize the electrical equipment to allow operations to be done so as to, for example, clear faults downstream. The switchgear typically includes a circuit breaker, a disconnector, an operation mechanism, a current transformer, and etc., to control, protect and isolate the electrical equipment.

[0003] In the railway application, switchgears will be arranged along a railway line and designed to adapt to requirements of the application. In railway market, especially in Chinese railway market, a feeder unit usually has two feeders, one of which is designed for providing power for an up line, and the other of which is designed for a down line. Moreover, each feeder includes two outcomings, i.e., a feeder outcoming for providing power through, for example, a bypass outcoming for bypassing the failed line and powering the up or down line using a backup line. Each of the outcomings has a separate disconnector respectively.

[0004] Only for a purpose of illustration, Fig. 1 schematically illustrates a single line diagram of a feeder unit 100 in the prior art. As illustrated in Fig.l, from the bus bar 101, there are three branches, i.e. a left branch, a middle branch and the right branch. The left branch is configured to provide power for the up line and includes a circuit breaker 102 A, a current transformer 103 A, and disconnector 104A; the right branch is configured to provide power for the down line and includes a circuit breaker 102B, a current transformer 103B and disconnector 104B; the middle branch is designed as a backup branch for providing power for the up or down line upon a failure of the left or right branch and includes a circuit breaker 102C, current transformer 103C, a disconnector 104C-1 for connecting to the feeder end 105U for the up line and a disconnector 104C-2 for connecting to the feeder end 105D for the down line.

[0005] Currently, the existing switchgear available in the market is usually equipped with a 2-posistion disconnector to realize functionalities of the above-described feeder unit. In such a case, two switchgears are required for one feeder since each feeder should be capable of connecting to both the bypass outcoming and the feeder outcoming, which means two disconnectors are required. Fig.2 illustrates an example design of an existing switchgear, wherein a disconnector 104A for the up line feeder together with the circuit breaker 102A and the current transfomier 103 A are arranged within a panel 100A and another disconnector 104A-2 for connecting to the bypass outcoming is arranged within a separate disconnector panel 100B.

[0006] In the existing switchgear, in the panel 100B, only a single disconnector 104A-2 is a used component, which means a great deal of space waste and high cost. Besides, with respect to the existing design, it requires a complex interlock system between the two disconnectors so as to avoid them to serve at the same time.

[0007] In view of this, there is a need to provide a new design for the switchgear.

SUMMARY OF THE INVENTION

[0008] To this end, the present disclosure provides a new solution for a switchgear so as to solve or at least partially mitigate at least a part of problems in the prior art.

[0009] According to a first aspect of the present disclosure, there is provided a switchgear. The switchgear comprises a bypass busbar; at least one main busbar; a disconnector; and a circuit breaker connected with the at least one main busbar. The disconnector comprises a blade which can be driven to a first position for connecting with an outcoming of the circuit breaker, a second position for connecting with an outcoming of the bypass busbar, and a third position for disconnection. The bypass busbar, the at least one main busbar, the circuit breaker, and the disconnector are all arranged within a single panel.

[0010] In an embodiment of the present disclosure, the blade may be driven by an operation mechanism including four-bar linkage driving means.

[0011] In an embodiment of the present disclosure, the four-bar linkage driving means may be in one extreme position when the blade is located in the first position and may be in the other extreme position when the blade is located in the second position.

[0012] In another embodiment of the present disclosure, the operation mechanism may further comprise a first gear that can be operated by an operator using an operation rod and a second gear engaging with the first gear and having a shaft rigidly connected with an end of the four-bar linkage driving means, the other end of the four-bar linkage driving means being rotatably connected to the blade.

[0013] In a further embodiment of the present disclosure, the four-bar linkage driving means may comprise a crank connected to the shaft of the second gear, a swing arm rotatably connected to the blade and a lever connected therebetween.

[0014] In a yet embodiment of the present disclosure, the lever may include three segments connected in a zigzag shape, the crank and one of the three segments near to the crank may be formed of metal material and the other two of the three segments and the swing arm may be made of insulating material.

[0015] In a still embodiment of the present disclosure, the operation mechanism may be provided with two operation holes, both of the two operations holes may be exposed to an operator when the disconnector is located at the third position while different ones of the two operation holes may be exposed during changing between the first position and the third position and during changing between the second position and the third position.

[0016] In a still further embodiment of the present disclosure, the switchgear may comprise a low voltage compartment for low voltage devices; a disconnector compartment for the disconnector and the bypass busbar; a circuit breaker compartment for the circuit breaker and a current transformer; and a busbar compartment for the at least one main busbar. The low voltage compartment, the disconnector compartment, the circuit breaker compartment and the busbar compartment may be partially separated by metal plates.

[0017] In a yet further embodiment of the present disclosure, the circuit breaker may be arranged on a truck which can slide along a rail so that it can be at least partially drawn out from the switchgear.

[0018] In another embodiment of the present disclosure, the switchgear may comprise a vertical shutter for the at least one main busbar, which includes a vertical door and a rotation shaft at one of its sides, wherein the rotation shaft may be connected to the truck via a pushing rod so that moving of the truck can drive the rotation shaft to rotate so as to open or close the vertical door.

[0019] In a further embodiment of the present disclosure, the vertical shutter may further comprise a driving rod rigidly connected with the rotation shaft and pivotably connected with the vertical door; and a rail parallel to the top or bottom of the vertical door when the vertical door is closed and connected to the top or bottom of the vertical door via a slider.

[0020] In a still further embodiment of the present disclosure, the switchgear may comprise a horizontal shutter for the main busbar, which includes a horizontal door and a driving rod, wherein the driving rod may be slidably connected to the horizontal door at one end and rigidly connected with the rotation shaft at the other end so that a rotation of the rotation shaft could drive the driving rod to open or close the horizontal door.

[0021] In a yet further embodiment of the present disclosure, the switchgear may comprise a bypass busbar shutter driven by the operation mechanism, wherein the bypass busbar shutter may be opened when the disconnector is located in the second position and closed when the disconnector is located in either of the first position and the third position.

[0022] In a still further embodiment of the present disclosure, the bypass busbar shutter may comprise two fixed side doors and two movable central doors, the two movable central doors may be respectively connected to a first four-bar linkage driving unit and a second four-bar linkage driving unit which are symmetric to each other and driven by the operation mechanism.

[0023] In another embodiment of the present disclosure, each of the first four-bar linkage driving unit and the second four-bar linkage driving unit may comprise a crank, a lever, a vertical swing ami and a horizontal swing arm connected in turn, and the crank may be connected to the shaft of the second gear of the operation mechanism and the horizontal swing arm may be connected to one of the two movable central doors and can slide in a rail parallel to the top or bottom of the two fixed side doors.

[0024] In a further embodiment of the present disclosure, the crank may be provided with a protrusion on a part of its outer circumference and connected to the shaft of the second gear of the operation mechanism through a connection ring provided with a slot provided on a part of its inner circumference, the protrusion and the slot may be designed so that the connection ring rotates in an idle stroke when the disconnector is operated between the first position and the third position while the connection ring can drive the crank when the disconnector is operated between the second position and the third position.

[0025] In a still further embodiment of the present disclosure, the connection ring further may comprise a reset element for resetting the crank to the state in which the disconnector is located at the third position, when the disconnector is operated from the second position to the third position.

[0026] According to a second aspect of the present disclosure, there is also provided a feeder unit comprising a switchgear according to any of embodiments in the first aspect.

[0027] In embodiments of the present disclosure, a three-position disconnector , which can be driven to three operation positions, is implemented by means of four-bar linkage driving means and thus all functionalities for a feeder can be achieved within one single panel, which provides a great deal of cost and space savings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other features of the present disclosure will become more apparent through detailed explanation on the embodiments as illustrated in the description with reference to the accompanying drawings, throughout which like reference numbers represent same or similar components and wherein:

[0029] Fig. 1 schematically illustrates a circuit diagram of a feeder unit for railway power supplying in the prior art;

[0030] Fig. 2 schematically illustrates an example switchgear design for a feeder unit in the prior art;

[0031] Figs. 3A and 3B schematically illustrate diagrams of an example switchgear for a feeder unit according to an embodiment of the present disclosure;

[0032] Figs. 4A to 4C schematically illustrate operation positions of an example switchgear for a feeder unit according to an embodiment of the present disclosure;

[0033] Figs. 5A and 5B schematically illustrate diagrams of a three-position disconnector for an example switchgear when it is operates at a disconnection position according to an embodiment of the present disclosure;

[0034] Figs. 6A and 6B schematically illustrate diagrams of a three-position disconnector for an example switchgear when it operates in bypass busbar connection position according to an embodiment of the present disclosure;

[0035] Figs. 7 A and 7B schematically illustrate diagrams of a three-position disconnector for an example switchgear when it operates at main busbar connection position according to an embodiment of the present disclosure;

[0036] Figs. 8A and 8B schematically illustrate diagrams of shutters for the bypass busbar according to an embodiment of the present disclosure;

[0037] Figs. 9A to 9D schematically illustrate diagrams of operations of a bypass busbar shutter and connection relationship between a crank and the connection ring according to an embodiment of the present disclosure;

[0038] Figs. 10A and 10B schematically illustrate diagrams of a shutter for the main busbar shutter according to an embodiment of the present disclosure; and

[0039] Figs. 11 A to 11C schematically illustrate diagrams of operations of a shutter for the vertical shutter according to an embodiment of the present disclosure.

[0040] Figs. 12A to 12C schematically illustrate diagrams of operations of horizontal and vertical shutters according to an embodiment of the present disclosure;

[0041] Figs. 13 A to 13D schematically illustrate diagrams of connection relationship and interactive operations between a driving rod and a pushing rod for the vertical shutter according to an embodiment of the present disclosure;

[0042] Figs. 14A to 14D schematically illustrate diagrams of connection relationship between the vertical shutter and the horizontal shutter and operations of the vertical shutter according to an embodiment of the present disclosure;

DETAILED DESCRIPTION OF EMBODIMENTS

[0043] Hereinafter, a switchgear and a feeder unit comprising the switchgear will be described in details through embodiments with reference to the accompanying drawings. It should be appreciated that these embodiments are presented only to enable those skilled in the art to better understand and implement the present disclosure, not intended to limit the scope of the present disclosure in any manner. [0044] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the/said [element, device, component, means, step, etc.]" are to be interpreted openly as refemng to at least one instance of said element, device, component, means, unit, step, etc., without excluding a plurality of such devices, components, means, units, steps, etc., unless explicitly stated otherwise. Besides, the indefinite article "a/an" as used herein does not exclude a plurality of such steps, units, modules, devices, and objects, and etc.

[0045] For a better understanding of the present disclosure, the following description will be made to embodiments of the present disclosure by taking a switchgear for the railway application as an example; however, the skilled in the art can be appreciated that the switchgear may also be used in any other suitable applications.

[0046] Next, reference will be made to Figs. 3A to 3B to describe the basic idea of the present disclosure. Reference is first made to Fig. 3A, which illustrates a principle diagram of an example switchgear for a feeder unit according to an embodiment of the present disclosure. As illustrated in Fig. 3 A, in the switchgear, in addition to the bus bar 101, the current transformer 103 A and the circuit breaker 102A, there is further included a three-position disconnector 104A instead of a traditional two-position disconnector. The three-position disconnector 104A can be driven to three positions, i.e., a main busbar connection position, a disconnection position and a bypass busbar connection. Because of the three-position disconnector 104A, all these components required for the up line feeder could be assembled within a single panel 100A. For the down line, it could employ similar switchgear, which will not be elaborated for a purpose of simplification.

[0047] Fig. 3B schematically illustrates a sectional diagram of an example switchgear according to an embodiment of the present disclosure. From Fig. 3B, it is clear that the switchgear includes four compartments 1110, 1120, 1130 and 1140 which are at least partially separated by metal plates. The compartment 1110 is a low- voltage (LV) compartment for containing low-voltage devices such as electric meters, relay, etc.; the compartment 1120 is a disconnector (Dis.) compartment containing the disconnector 104A and also the bypass busbar 101B; the compartment 1130 is a circuit breaker (CB) compartment containing the circuit breaker 102 A, for example vacuum circuit breaker, and the current transformer 103 A; and the compartment 1140 is a busbar (BB) compartment containing the main busbars 101 A. The three-position disconnector 104A is located in the Dis. compartment 1140 and may be operated at three positions P0, PI and P2, which is clearly illustrated in Fig. 3B. The position P0 is a disconnection position at which the disconnector 104A is not connected to either of the main bus bars 101A or the bypass/ backup busbar 101B and at this time, repair and maintenance operations may be done by an engineer or technician. The position PI is a main busbar connection position at which the disconnector 104A connects the main busbar 101 A to the feeder 105U so that the power is supplied from the main busbar 101 A. The position P2 is a bypass outcoming connection position at which the disconnector 104A connects the bypass busbar 101B to the feeder 105U so that power is supplied from the bypass busbar 101B.

[0048] In embodiments of the present disclosure, the three-position disconnector 104A may be driven by an operation mechanism 106 which includes a first gear 1061 and a second gear 1062 and a four-bar linkage driving means 1040. The four-bar linkage driving means 1040 is attached to the blade of the disconnector 104A at one end and connected to the second gear 1062 of the operation mechanism 106 on the other end, as illustrated in Figs. 4A to 4C. The operator may operate the operation mechanism 106 by means of an operating rod to change the disconnector 104A from position P0 illustrated in Fig. 4A to position PI illustrated in 4B. When the disconnector is operated at position PI, the power will supplied from the main busbar 101 A to the feeder 105U via the circuit breaker 102A, the current transformer 103 A, and the disconnector 104A, as illustrated in Fig. 4B. Upon of a failure in the main busbars 101 A, the power cannot be supplied therefrom, and the operator may use the operating rod to operate the operation mechanism 106 such that the disconnector 104A may be changed from position P0 to position P2, as illustrated in Fig. 4C. At position P2, the power will be supplied from the bypass busbar 101B to the feeder 105U, as illustrated in Fig. 4C. Hereinafter, detailed operation will be made to the structure and operations of the three-position disconnector 104 A with reference to Figs. 5 A to 7B.

[0049] As illustrated in Figs. 5A and 5B, an operating rod 1041 is provided for using by an operator to operate the operation mechanism 106. In an operation panel 1042, there are provided two slots 1045L and 1045R through which the operating rod can be inserted into operation holes arranged in the operation mechanism 106. The operation mechanism 106 includes two gears 1061 and 1062 engaged with each other and components for supporting and mounting them on the housing of the switchgear. In the first gear 1061 , which is near to the operation panel 1042, there are provided two holes into which the operating rod can be inserted. The second gear 1062 is located further away from the operation panel 1042 than the first gear 1061 and rigidly connected with the four-bar linkage driving mechanism 1040 at its shaft. At the disconnection position P0, two holes will be exposed through operation slots 1045L, 1045R so that the operator can select either one of them to connect the blade 1045 with the main busbar 101 A or bypass busbar 101B, while during changing between the first position and the third position, only one hole for operating the disconnector to switch between the main busbar connection position and the disconnection position is exposed while during changing between the second and the third position, a different one is exposed to the operator. In other words, after the operator selects one hole and begins to operate and he/she cannot make a change unless the disconnector is returned to the disconnection position P0. In such a way, it can avoid the false operation due to carelessness of the operation.

[0050] The four-bar linkage driving mechanism 1040 includes crank 1044A, lever 1044B, and the swing arm 1044C. The crank 1044A is attached with, at one end, the shaft of the gear 1062 of the operation mechanism 106 and rotate together with the shaft. At the other end, the crank 1044A is rotatably connected to one end of the lever 1044B. The lever 1044B as illustrated in Figs. 5 A and 5B is in a zigzag shape. In other words, the lever 1044B includes three segments and the three segments are connected and secured with each other to form a zigzag, which means they cannot move relative to each other. With such a design, it may accommodate the inner space of the switchgear and implement the single panel switchgear without enlarging the size of the switchgear. The other end of the lever 1044B is connected with the swing arm 1044C which is further attached with the blade 1045 of the disconnector 104A, especially the middle part of the blade 1045. The blade 1045 is connected rotatably at one end and the other end can be operated to connect with either of the bypass busbar 101B or the main busbars 101 A, or be located in the disconnection position.

[0051] As illustrated in Figs. 5A and 5B, in the disconnection position, the operation rod 1041 can be inserted into a hole arranged in the first gear 1061 through either the left slot 1045L or the right slot 1045R, depending on which position the operator desires to connect the blade to, the main busbars 101 A or the bypass busbar 101B. At this point, two holes arranged in the gear 1061 will be exposed through two slots 1045L and 1045R and the operator can select one of them to operate the operation mechanism.

[0052] If the left slot 1045L is selected as illustrated in Fig. 5 A, the operator may insert the operation rod into the hole exposed at the top of the slot 1045L and pull down the operation rod to operate the operation mechanism 106 in a counterclockwise direction. Thus the gear 1061 will rotate in the counterclockwise direction and the gear 1062 engaged with the gear 1062 will rotate in a contrary direction, i.e., in a clockwise direction. As a result, the crank attached with the shaft of the gear 1062 also rotates in a clockwise direction and the lever will move towards the direction far away from the operation panel 1042. With the force of the lever, the blade will be pushed by the swing arm 1044C to rotate in a clockwise direction, and finally the four-bar linkage driving mechanism 1040 reaches its one extreme position and connected with the bypass busbar 101B, as illustrated in Fig. 6A and 6B. Herein, an extreme position means a position where the crank and the lever are collinear. At the extreme position, it is easy to connect with the busbar, because it is possible to exert a large force by the application of a small force to overcome a thrust force of the current.

[0053] In embodiments of the present disclosure, the crank 1044A and the first segment of the level 1044B, which is nearest to the crank 1044A, are made of metal materials while the other two segments and the swing arm are made of insulating material. When the blade is connected with the busbar 101B, it is live and thus insulation should be provided; on the other hand, the four-bar linkage driving mechanism 1040 cannot be a completely rigid component, otherwise, it might be broken at the extreme position. Thus, such a design could provide required rigidity, insulation and flexibility.

[0054] Besides, if the operator hopes to return the blade of the disconnector 104A return from the bypass connection position P2 to the disconnection position P0, he/she can pull up the operation rod 1041 back its original position to operate the operation mechanism 106 in the clockwise direction. [0055] If at the state as illustrated in Figs. 5A and 5B, the right slot 1045R is selected, the operation rod 1041 will be first inserted into the hole exposed at the bottom of the slot 1045R and the operator may pull up the operation rod 1041 to operate the operation mechanism 106 in a clockwise direction. Thus, the gear 1061 will rotate in the clockwise direction and the gear 1062 engaged with the gear 1062 will rotate in a contrary direction, i.e., in a counterclockwise direction. As a result, the crank attached with the shaft of the gear 1062 also rotates in a counterclockwise direction and the lever 1044B will move towards the operation panel 1042. With the pulling force of the lever 1044B, the blade 1045 will be pulled by the swing arm 1044C to rotate in a counterclockwise and finally connected with the main busbar 101 A, as illustrated in Fig. 7A and 7B. Similarly, at the state as illustrated in Figs. 7A, 7B, the four-bar linkage driving mechanism 106 is in its the other extreme position, which enables the operator to switch the disconnector onto the main busbar 101 A easily. In addition, the blade of the disconnector 104A can return from the main busbar connection position PI to the disconnection position P0 by pulling down the operation rod back to its original position.

[0056] According to an embodiment of the present disclosure, when the disconnector is switched from the main busbar connection position or the bypass busbar connection position to the disconnection position, the crank 1044A will rotate about 90 degree while the blade rotate about 50 degree and vice versa. However, it should be appreciated it is only for a purpose of illustration and another suitable degrees can be used depending on specific designs.

[0057] Since there is provided a three-position disconnector in embodiment of the present disclosure without requiring two disconnectors, all necessary components required for a feeder for e.g., a up line or a down line, can be enclosed in only a single panel, which means both a compact electronic equipment and a great deal of space and cost savings.

[0058] As mentioned hereinabove, the switchgear 100 is divided into four compartments, namely, LV compartment, CB compartment, BB compartment and Dis. Compartment, but this switchgear 100 could not be considered as electric equipment meeting the LSC2B standard. According to requirements of the LSC2B, if a user wants to get access to the CB compartment or the Dis. compartment, the other switchgears should be still at work without any impact, which means both the main busbar and the bypass busbar should be isolated at the time. However, according to the current design, if the user has an access to the Dis. compartment or the CB compartment, the main busbar outcoming and bypass busbar outcoming are likely still live because other panels might be supplied from the live busbars. Therefore, to meet the requirement of LSC2B-PM, it requires providing protection means for the main busbars and the bypass busbar so that the user is kept isolated from the live busbars when the user gets access to the CB compartment or the Dis. compartment. Therefore, in embodiments of the present disclosure, there is further provided a new arrangement of shutters. Next, description will be first made the shutters for the BB compartment with reference to Figs. 8 A to 12D.

[0059] As schematically illustrated in 8 A, there is provided a shutter 110 for the bypass busbar 101B to meet the requirements of the LSC2B. As illustrated, in the Dis. Compartment 1120, a shutter 110 is arranged so that it is opened when the blade of the disconnector 104A is switching onto the bypass busbar from the disconnection position and closed when the disconnection is in other positions.

[0060] Fig. 8B schematically illustrates the shutter 110 for the bypass busbar according to an embodiment of the present disclosure. As illustrated, the shutter 110 includes two fixed side plates 1101 A, 1101B and two movable central plates 1101C and 1101D, and symmetric four-bar linkage driving units 1102 A, 1102B and reset rings 1103 A, 1103B. The symmetric four-bar linkage driving units 1102A, 1102B respectively includes cranks 11021A 11021B, lever 11022A, 11022B, vertical swing arms 11023A, 11023B and horizontal swing arms 11024A, 10224B. The crank 11021 A, the lever 11022 A, the vertical swing arm 11023 A and the horizontal swing arm 11024A are in turn connected, thereby forming a first four-bar linkage driving unit. The crank 1102 IB, the lever 11022B, the vertical swing arm 11023B and the horizontal swing arm 11024B are connected in a similar way to form a second four-bar linkage driving unit. The first and second four-bar driving units 1102A, 1102B are symmetric and form a symmetric four-bar linkage driving mechanism. The cranks 11021 A, 1102 IB are connected with the shaft of gear 1062 in the operation mechanism 106, for example through connection ring 1103 A, 1103B so that, when the disconnector is operated by means of operation rod, the cranks 11021 A, 1102 IB will rotate together with the shaft of the gear 1062. Other ends of the cranks 11021 A, 1102 IB is connected to the levers 11022A, 11022B, which in turn connected to the vertical swing anus 11023 A, 11023B. Ends of the vertical swing arms 11023A, 11023B, which are near the connection point with the levers 11022A, 11022B, are pivoted at a fix point of the housing of the switchgear. The horizontal swing arms 11024A, 11024B are connected to the movable plates 1105 A, 1105B respectively at respective ends different from ends connected to the vertical swing arms 11023A, 11023B and these ends can slide in rails parallel to the top or bottom of the fixed side doors 1101 A, 1101B so that the movable plates can move sideward or inward to open and close the shutter 110.

[0061] Fig. 9A illustrates a shutter 110 for the bypass busbar according to an embodiment of the present disclosure when it is opened. When the shutter 110 is opened, the cranks 11021 A, 1102 IB are rotated by 90 degree in a clockwise direction and thus bring the levers 11022A, 11022B and the vertical swing armsl l023A, 11023B to move toward the direction far away from the doors. In such a way, ends of horizontal swing amis 11024 A, 11024B connected to the vertical swing arms 11023 A, 11023B will also move toward the direction far away from the doors and thus the other ends of horizontal swing arms 11024A, 11024B connected to the movable central doors 1101 C, 1101D will be rotated by 90 degree and move sideward. In such way, it can drive the movable central doors 1101 C, HOlD to move sideward and overlap with the fixes side doors 1101 A, 100 IB respectively.

[0062] Figs. 9B to 9D illustrate details of the connection between the connection ring 1103A and the crank 11021A. As illustrated in Fig. 9B, the crank 11021 A is connected with a connection ring 1103 A and it has a protrusion 11025 A at the end connected with the connection ring 1103 A. The connection ring 1103 A is in a rigid connection with the shaft of gear 1062 at one end (not shown) and at the other end it is sleeved on the crank 11021 A. In the connection ring 1103 A, there is arranged a corresponding slot 11031 A for the protrusion 11025 A to fit in, so that the rotation of the shaft of the gear 1062 could drive the crank 11021 A to rotate. Optionally, the slot 11031A is designed much wider than the protrusion 11025A to provide an idle stroke so that the rotation of the driving shaft due to the operation of connecting the disconnector onto the main busbar will not cause the crank to rotate. It can be understood that when the disconnector is located at the main busbar connection position or the disconnection position, the disconnector will have no connection with the bypass busbar and thus at these situations, the shutter for the bypass busbar should be closed. Thus, in such a case, the shaft of the gear 1062 should not drive the shutter to open. However, the connection ringl l03A is connected rigidly to the shaft of gear 1062 and rotates together therewith, thus an idle stroke may be provided to the connection ring 1103 A so that during the operations between the main busbar connection position and the disconnection position, the connection ring 1103 A rotates by a distance corresponding to the idle stroke and will not drive the crank to rotate.

[0063] Description will be made in detail with reference to Figs. 9B to 9D, which illustrate the crank 11021 A and the connection ring 1103 A when the disconnector is located at the main busbar connection position, the disconnection position, the bypass busbar connection position respectively.

[0064] First, from Figs. 9B to 9C, it is clear that when the connection ring 1103 A is rotated with the rotation the shaft of gear 1062 in a clockwise direction from the state as illustrated in Fig. 9B, or in a counterclockwise direction from the state as illustrated in Fig. 9C, it only rotates in an idle stroke and will not drive the crank 11021 A to rotate due to the design of the slot 11031 A and the protrusion 11025 A. While at the disconnection position, if the operator continues to operate the operation mechanism to connect the disconnector 104A onto the bypass busbar, the shaft of the gear 1062 and thus the connection ring 1103 A will rotate in a clockwise direction. Due to the fact that the idle stroke is ended, and the further rotation of the connection ring 1103 A will drive the crank 11021 A to rotate and thus the crank 11021 A will rotate by 90 degree in the clockwise direction together with the rotation of the connection ring 1103 A.

[0065] When the operator operates the operation mechanism to change the disconnector from the bypass connection position to the disconnection position, the shaft of the gear 1062 and thus the connection ring 1103 A will rotate in a counterclockwise direction. In this case, due to the idle stroke, the rotation movement of the connection ring 1103 A cannot drive the crank 11021 A. If the connection ring 1103 A continues to rotate and achieve the state as illustrated in Fig. 9B, the shutter will be closed. Thus, optionally, in the connection ring 1103 A, there may be provided a reset element such as torsional spring, which will cause the crank 11021 A to go back to the state as illustrated in Fig. 8C.

[0066] By providing such a shutter 110, it is possible to protect the user from injury by the bypass busbar when the user has an access to the Dis. Compartment and at the same time the normal operations of the disconnectors can be done.

[0067] Besides, as illustrated in Fig. 10A, there is also provide a shutter mechanism for the main busbar which comprises a horizontal shutter 130 and a vertical shutter 120. As illustrated, the circuit breaker 102A and the current transformer 103 A may be arranged on a truck 107 which has a base plate and a plurality of wheels so that it can move along rails. When the truck 107 with the circuit breaker 102 A and the current transformer 103 A arranged thereon is located within the switchgear, the vertical shutter 120 and the horizontal shutter 130 will be opened so that normal operations can be done; when the truck 107 is drawn out from the switchgear, the vertical shutter 120 and the horizontal shutter 130 will be closed to prevent the operator from touching the main busbars 101 A.

[0068] Fig. 10B schematically illustrated a top view of the horizontal and vertical shutters for the main busbars according to an embodiment of the present disclosure. As illustrated in Fig. 10B, the vertical shutter 120 comprises a vertical door 121, which is connected to the rotation shaft 123 through a first driving rod 124 and the rotation shaft 123 may be driven by a pushing rod 122 which is attached onto the base plate of the truck 107. At the same time, the vertical door 121 is also connected at the middle part of the top to a rail 126 through slider (not shown). In addition, the horizontal shutter 130 comprises a horizontal door 131 and a second driving rod 125, the second driving rod 125 is rigidly connected to the rotation shaft 123 at one end, and at the other end, the second driving rod 125 is connected to a rail arranged at the bottom of the horizontal doorl31 through a slider (not illustrated because of being covered).

[0069] Figs. 11A to 11C schematically illustrate operations of the vertical shutter 120. As illustrated in Fig. 11 A, the vertical door 121 is in a closing state. When the truck 107 is pushed into the switchgear, the pushing rod 122 will move toward inside of the switchgear and drive the rotation shaft 123 to rotate in the counterclockwise direction, due to the fact that the first driving rod 124 is rigidly connected or secured to the rotation shaft 123 at one end, the first driving rod 124 also rotates in the counterclockwise direction. The other end of the first driving rod 124 are pivotally connected the vertical door 121 and thus the rotation of the first driving rod 124 will drive the vertical door 121 to rotate in clockwise direction and begin to open as illustrated in Fig. 1 I B. With further movement of the first driving rod 124, the slider 127 in the rail 126 will move toward the rotation shaft 123 and the vertical door continues to rotate in a clockwise direction and, as a result, the vertical door 121 is opened completely as illustrated in Fig. 11C. When the rotation shaft 123 is driven by the pushing rod to rotate in a contrary direction (i.e. in a clock direction), the vertical door 121 will rotate in a counterclockwise direction and be closed in a contrary order as illustrated in Figs. 11 A to 11 C.

[0070] As mentioned hereinabove, the horizontal door 131 is also connected with the rotation shaft 123 through the second driving rod 125. With the rotation of the rotation shaft 123 in the counterclockwise direction, the second driving rod 125 will also rotate in the counterclockwise direction and push the horizontal shutter to move backward so as to expose the main busbars under the horizontal door 131 as illustrated in Figs. 12A to 12C.

[0071] Figs. 13A to 13D illustrate interactive operations between the rotation shaft 123 and the pushing rod 122 for the vertical shutter 120 according to an embodiment of the present disclosure. As illustrated in Fig. 13A to 13D, the pushing rod 122 is secured onto the truck 107 at one end so that it could move together with the truck and at the other end it is connected to the rotation shaft 123. It is clear that on the rotation shaft 123, there is provided an element 1231 which can rotate together with the rotation shaft 123. The element 1231 has a small post 1232 which protrudes from the body of the element 1231 in a direction of the axis of the rotation shaft 123. Correspondingly, the pushing rod 122 has a driving slot arranged therein, into which the small post 1232 may be inserted. The slot looks like a tobacco pipe or have and "L" shape, as seen from the above. That is to say, in addition to a straight line slot 1221 , it further includes an addition sidewise slot 1222 at the end near to the rotation shaft 123. The pushing rod 122 is connected to the rotation shaft 123 by limiting movement of the small post 1232 only in the slot 1221 ,1222. When the vertical door 121 is closed, the small post 1232 will be located in the addition sidewise slot 1221 as illustrated in Fig. 13A. When the truck 107 moves inward, the small post 1232 will be driven by the pushing rod 122, which cause the counterclockwise rotation of the rotation shaft 123 as illustrated in Figs. 13B and 13C. When the vertical shutter 121 is completely opened, the small post 1222 comes out from the addition sidewise slot 1222 of the pushing rod 122 and if the pushing rod 122 keeps moving inward together with the truck 107, the small post 1232 will not interfere with the movement of the pushing rod 122 because the slot 1221 will allow the pushing rod 111 to move inward without any obstruction from the small post 1232. When the truck 107 is drawn out from the housing of the switchgear, similar operations occur but in an order contrary to those illustrated in Figs. 13A to 13D.

[0072] Figs. 14A to 14D schematically illustrate bottom views of connection relationship between the vertical shutter 120 and the horizontal shutter 130 and operations of the horizontal shutter 120 according to an embodiment of the present disclosure. As illustrated in Fig. 14 A, the horizontal door 131 is supported by at least one side rail 132 and can slide back and forth along the at least one side rail 132. In addition, there is also provided another rail 133 which is substantially perpendicular to the side rail 132. The second driving rod 125 is connected to the rail 131 at the end 125A and can move along the rail 133. The other end 125B of the second driving rod 125 is secured to the rotation shaft 123 so that it can rotate together therewith.

[0073] When the horizontal door 131 is closed as illustrated in Fig. 14B, the horizontal door 131 nearly abuts the back surface of the vertical door 121 and the second driving rod 125 is substantially parallel to the rail 133 and located adjacent to the rotation shaft 123. If the rotation shaft 123 begins to rotate in a counterclockwise direction, the second driving rod 132 is also rotated in the counterclockwise direction and pushes the horizontal door 131 away from the rotation shaft 123, as illustrated in Fig. 14C. At the same time, the end 125A of the second driving rod 125 moves from its original location towards the side of the horizontal door near the rotation shaft 123. Finally, the second driving rod 125 will be perpendicular to the rail 133 and the horizontal door is opened completely, as illustrated in Fig. 14D.

[0074] With embodiments of the present disclosure, the vertical shutter 120 and the horizontal shutter 130 could move with the movement of the truck 107 and are opened when the truck is located inside of the switchgear and closed when the truck 107 is drawn out from the switchgear. In such a way, it could prevent the operator from touching the live main busbars when the user has an access to the CB compartment.

[0075] Additionally, in the present disclosure, there is also provided a feeder unit which comprises at least one switchgear as described herein.

[0076] Hereinbefore, the switchgear as provided in the present disclosure is described in detail with reference to exemplary embodiments of the present disclosure, however, it should be appreciated that these exemplary embodiments are only illustrated for illustration purpose. Various modifications, adaptations to the foregoing exemplary embodiments of this disclosure may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. For example, in the above-described embodiments of the present disclosure, the driving of blade is achieved by an operation mechanism including a four-bar linkage driving means; however, it is only described for a purpose of illustration and other driving methods such as hydraulic pressure driving are also possible. In addition, it may provide one main busbar or three or more busbars but it's not limited to only two busbars. It is also possible to provide only operation hole in the first gear 1061a of the operation mechanism 106 instead of two operation holes, although two operation holes are preferable. Reset means as provided in connection ring 1103 A, 1103B is optional and it is also possible provide a connection ring without such a reset means. The rail 126 for the vertical shutter 120 may also be arranged under the vertical door 121 instead of over the vertical door 121. The shutter 110 for the bypass busbar may be implemented in any other manner, for example, comprising two symmetric vertical shutters each like the vertical shutter 120. Besides, hereinabove, the switchgear is described with reference to the railway application; however, it can be applied in any other applications which have similar requirements. It can also be appreciated that any and all modifications will still fall within the scope of the non-limiting and exemplary embodiments of this disclosure. Furthermore, other embodiments of the disclosures set forth herein will come to mind to one skilled in the art to which these embodiments of the disclosure pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings.

[0077] Therefore, it is to be understood that the embodiments of the disclosure are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are used herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

WHAT IS CLAIMED IS:

1. A switchgear comprising:

a bypass busbar (101B);

at 1 east one main busbar ( 101 A) ;

a disconnector (104A); and

a circuit breaker (102 A) connected with the at least one main busbar;

wherein the disconnector (104A) comprises a blade (1045) which can be driven to a first position (PI) for connecting with an outcoming of the circuit breaker, a second position (P2) for connecting with an outcoming of the bypass busbar, and a third position (P0) for disconnection,

wherein the bypass busbar (10 IB), the at least one main busbar (101 A), the circuit breaker (102A), and the disconnector (104A) are arranged within a single panel.

2. The switchgear of Claim 1, wherein the blade (1045) is driven by an operation mechanism (106) including four-bar linkage driving means (1040).

3. The switchgear of Claim 2, wherein the four-bar linkage driving means (1040) is in one extreme position when the blade (1045) is located in the first position (PI) and is in the other extreme position when the blade (1045) is located in the second position (P2).

4. The switchgear of Claim 2 or 3, wherein the operation mechanism (106) further comprises a first gear (1061) that can be operated by an operator using an operation rod (1041) and a second gear (1062) engaging with the first gear (1061) and having a shaft rigidly connected with an end of the four-bar linkage driving means (1040), the other end of the four-bar linkage driving means (1040) being rotatably connected to the blade (1045).

5. The switchgear of any of Claim 4, wherein the four-bar linkage driving means

(106) comprises a crank (1044A) connected to the shaft of the second gear (1062), a swing arm (1044C) rotatably connected to the blade (1045) and a lever (1044B) connected therebetween.

6. The switchgear of Claim 5, wherein the lever 1044B includes three segments connected in a zigzag shape, the crank (1044A) and one of the three segments near to the crank (1044A) are formed of metal material and the other two of the three segments and the swing arm (1044B) are made of insulating material.

7. The switchgear of any of Claims 1 to 6, wherein the operation mechanism (106) is provided with two operation holes (1045L, 1045R), both of the two operations holes (1045L, 1045R) are exposed to an operator when the disconnector (104A) is located at the third position (P0) while different ones of the two operation holes (1045L, 1045R) are exposed during changing between the first position (PI) and the third position (P0) and during changing between the second position (P2) and the third position (P0).

8. The switchgear of any of Claims 1 to 7, comprising:

a low voltage compartment (1110) for low voltage devices;

a disconnector compartment (1120) for the disconnector (104A) and the bypass busbar (101 B);

a circuit breaker compartment (1130) for the circuit breaker (102 A) and a current transformer (103 A); and

a busbar compartment (1140) for the at least one main busbar (101 A),

wherein the low voltage compartment (1110), the disconnector compartment (1120), the circuit breaker compartment (1130) and the busbar compartment (1140) are partially separated by metal plates.

9. The switchgear of any of Claims 1 to 8, wherein the circuit breaker (102A) is arranged on a truck (107) which can slide along a rail so that it can be at least partially drawn out from the switchgear.

10. The switchgear of Claim 9, further comprising a vertical shutter (120) for the at least one main busbar (101 A), which includes a vertical door (121) and a rotation shaft (123) at one of its sides, wherein the rotation shaft (123) is connected to the truck (107) via a pushing rod (122) so that moving of the truck (107) can drive the rotation shaft (123) to rotate so as to open or close the vertical door (121).

11. The switchgear of Claims 9 or 10, wherein the vertical shutter (120) further comprises:

a driving rod (124) rigidly connected with the rotation shaft (123) and pivotably connected with the vertical door (121); and

a rail parallel to the top or bottom of the vertical door (121) when the vertical door (121) is closed and connected to the top or bottom of the vertical door (121) via a slider (127).

12. The switchgear of any of Claims 9 to 11, further comprising a horizontal shutter (130) for the main busbar (101 A), which includes a horizontal door (131) and a driving rod (125), wherein the driving rod (125) is slidably connected to the horizontal door (131) at one end and rigidly connected with the rotation shaft (123) at the other end so that a rotation of the rotation shaft (123) could drive the driving rod (125) to open or close the horizontal door (131).

13. The switchgear of any of Claims 1 to 12, further comprising a bypass busbar shutter (120) driven by the operation mechanism (106), wherein the bypass busbar shutter (120) is opened when the disconnector (104 A) is located in the second position (P2) and closed when the disconnector is located in either of the first position (PI) and the third position (P0).

14. The switchgear of Claim 13, wherein the bypass busbar shutter (120) comprises two fixed side doors (1101A, 1101B) and two movable central doors (1101C, 1101D), the two movable central doors (1101C, 1101D) are respectively connected to a first four-bar linkage driving unit (1102A) and a second four-bar linkage driving unit (1102B) which are symmetric to each other and driven by the operation mechanism (106).

15. The switchgear of Claim 14, wherein each of the first four-bar linkage driving unit (1102A) and the second four-bar linkage driving unit (1102B) comprises a crank (11021A, 11021B), a lever(11022A, 11022B) a vertical swing arm (11023A, 11023B) and a horizontal swing arm (11024A, 11024B) connected in turn, and the crank (11021 A, 1102 IB) is connected to the shaft of the second gear (1062) of the operation mechanism (106) and the horizontal swing arm (11024A, 11024B) is connected to one of the two movable central doors (1101 C, 1101 D) and can slide in a rail parallel to the top or bottom of the two fixed side doors (1101 A, 1101B).

16. The switchgear of Claim 15, wherein the crank (11021 A, 1102 IB) is provided with a protrusion (11025 A, 11025B) on a part of its outer circumference and connected to the shaft of the second gear (1062) of the operation mechanism (106) through a connection ring (1103A, 1103B) provided with a slot (11031A, 11031B) provided on a part of its inner circumference, the protrusion (11025 A, 11025B) and the slot (11031 A, 11031B) are designed so that the connection ring (1103A, 1103B) rotates in an idle stroke when the disconnector (104 A) is operated between the first position (PI) and the third position (P0) while the connection ring (1103A, 1103B) can drive the crank (11021 A, 1102 IB) when the disconnector (104A) is operated between the second position (P2) and the third position (P0).

17. The switchgear of Claim 16, wherein the connection ring (1031 A) further comprises a reset element for resetting the crank (11021 A, 11021B)to the state in which the disconnector (104A) is located at the third position (P0), when the disconnector (104A) is operated from the second position (P2) to the third position (P0).