Patent Publication Number: US-9406458-B2

Title: Switching device and related power distribution system

Description:
RELATED APPLICATION 
     This application claims priority under 35 U.S.C. §119 to European Patent Application No. 11171073.7 filed in Europe on Jun. 22, 2011, the entire content of which is hereby incorporated by reference in its entirety. 
     FIELD 
     The present disclosure relates to a switching device for an electric circuit, such as a low voltage or a medium voltage electric circuit, having an improved locking functionality. 
     BACKGROUND INFORMATION 
     As known, switching devices used in low voltage and medium voltage electric circuits, such as circuit breakers, disconnectors and contactors, are devices designed to allow the correct operation of specific parts of the electric circuits in which they are installed, and of the associated electric loads. 
     In the context of the present disclosure the term “low voltage” is referred to applications with operating voltages up to 1000V AC/1500V DC, and the term “medium voltage” is referred to applications in the range from 1 kV up to some tens of kV, e.g. 50 kV. 
     Known switching devices can include a case housing one or more electric poles, each one including at least one movable contact and a corresponding fixed contact. 
     A driving mechanism causes the movement of the movable contacts between a first closed position in which they are coupled to the corresponding fixed contacts and a second open position in which they are spaced away from the corresponding fixed contacts. 
     The operation of the driving mechanism on the movable contacts can be carried out through a main shaft which is operatively connected to the movable contacts; a kinematic chain of the driving mechanism causes the desired movement of the main shaft for opening or closing the switching device. 
     The driving mechanism may be manually actuated by an operator for causing the opening or the closure of the switching device, or the driving mechanism may be actuated by one or more protection devices, in the event that electrical faults or failures occur and the opening of the switching device is therefore required, for example when a short circuit or an electric overload occurs. 
     Further, the driving mechanism may be actuated for causing the opening or the closure of the switching device by one or more accessories, such as for example motor operated equipment (MOE) or coil actuators. 
     Various types of locking devices are known which are operatively connected to one or more parts of the kinematic chain so as to indirectly act, through such kinematic chain, on the rotating shaft to lock the movable contacts in their open position, therefore preventing re-closure of the locked open switching device. As a result, an operator may operate in a safe way on one or more parts of the electric circuit in which the switching device is installed. 
     Further, known locking devices are configured only for visually signaling their actuation and therefore the locked status of the open switching device, for example thorough the positioning of one or more of their components. Only operators close to the switching device may visually check such locked status. 
     Such a condition can be disadvantageous, for example, when the switching device is located in a non-easy accessible location, or many switching devices are located at different distant locations in the electric circuit in which they are installed. For example, in a wind power generation plant, switching devices are installed at the base or on the top of wind towers. 
     Therefore, although known solutions perform in a rather satisfying way, there is still a need for further improvements. 
     SUMMARY 
     An exemplary switching device for an electric circuit is disclosed, comprising: at least one contact movable between a closed position in which it is coupled to a corresponding fixed contact and an open position in which it is spaced away from said corresponding fixed contact; and a main shaft suitable for rotating about an axis and operatively connected to said at least one movable contact so as to cause with its rotation the movement of said at least one movable contact between the open and closed positions, wherein at least one locking device which has one or more parts coupled to and which is configured for directly acting on said main rotating shaft and locking said at least one movable contact in the open position. 
     An exemplary power distribution system is disclosed, comprising: at least one circuit breaker; and at least one of a monitor and control station at a remote location from the at least one circuit breakers, wherein the at least one circuit breaker comprises: at least one contact movable between a closed position, wherein the at least one contact is coupled to a corresponding fixed contact and an open position in which it is spaced away from said corresponding fixed contact; and a main shaft for rotating about an axis and operatively connected to said at least one movable contact so as the main shaft rotates said at least one movable contact moves between the open and closed positions; wherein at least one locking device which has one or more parts coupled thereto and which is configured for directly acting on said main rotating shaft and locking said at least one movable contact in the open position, and wherein each of the locking devices of the at least one circuit breaker is connected to at least one of the remote monitor and the remote control station so as to transmit thereto one or more electrical signals which are indicative of at least one of a rest configuration, an operative configuration, and an under actuation condition of the locking device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further characteristics and advantages of the claimed embodiments will be more apparent from the description of exemplary, but non-exclusive, embodiments of the switching device according to the present disclosure, illustrated in the accompanying drawings, wherein: 
         FIG. 1  shows a switching device with a locking device coupled to one of its flanks in accordance with an exemplary embodiment of the present disclosure; 
         FIG. 2  is an exploded view showing the components of the locking device of  FIG. 1  in accordance with an exemplary embodiment of the present disclosure; 
         FIG. 3  shows the coupling between one element of a locking device with a corresponding portion of the main rotating shaft of an associated switching device in accordance with an exemplary embodiment of the present disclosure; 
         FIG. 4  is a perspective view of some parts of a locking device in a rest configuration in accordance with an exemplary embodiment of the present disclosure; 
         FIG. 5  is a perspective view of the locking device shown in  FIG. 4 , when such locking device is under actuation in accordance with an exemplary embodiment of the present disclosure; 
         FIG. 6  shows a detailed view of the locking device in  FIG. 1  in accordance with an exemplary embodiment of the present disclosure; 
         FIG. 7  is a perspective view of some parts of a locking device corresponding to a closed status of the associated switching device in accordance with an exemplary embodiment of the present disclosure; 
         FIG. 8  is a perspective view of the locking device shown in  FIG. 7 , corresponding to an open status of the associated switching device in accordance with an exemplary embodiment of the present disclosure; 
         FIG. 9  is a block diagram schematically representing a switching device in accordance with an exemplary embodiment of the present disclosure; and 
         FIG. 10  is a block diagram schematically representing a power distribution system equipped with a plurality of switching devices in accordance with an exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments of the present disclosure are directed to a switching device for an electric circuit, including at least one contact movable between a closed position in which it is coupled to a corresponding fixed contact and an open position in which it is spaced away from said corresponding fixed contact. A main shaft suitable for rotating about an axis and operatively connected to said at least one movable contact so as to cause with its rotation the movement of said at least one movable contact between the open and closed positions. 
     The switching device includes at least one locking device which has one or more parts coupled to and which is configured for directly acting on the main rotating shaft and locking said at least one movable contact in the open position. 
     In the present disclosure, exemplary switching devices are described by making reference to embodiments as an open air circuit breaker (ACB); such as embodiments are to be understood only as illustrative and non limiting examples since the principles and technical solutions introduced in the following description can be applied to other types of circuit breakers, such as for example molded case circuit breakers (MCCBs), or to other types of switching devices, such as for example disconnectors or contactors. 
     It the present disclosure, identical or similar components, either from a structural and/or functional point of view, have the same reference numerals, regardless of whether they are shown in different embodiments of the present disclosure; it should also be noted that in order to clearly and concisely describe exemplary embodiments of the present disclosure, the drawings may not necessarily be to scale and certain features of the wherein may be shown in schematic form. 
       FIG. 1  shows a switching device with a locking device coupled to one of its flanks in accordance with an exemplary embodiment of the present disclosure.  FIG. 1  illustrates an exemplary non-limiting embodiment of a circuit breaker and of a related locking device, globally indicated throughout the following description by reference numbers  1  and  100 , respectively. 
     As shown in  FIG. 1 , an exemplary non limiting embodiment of an open air circuit breaker  1  includes a case housing three electric poles  2 , or phases  2 ; the exemplary principles and technical solutions that will be introduced in the following description are intended to be applicable also to a circuit breaker  1  with a number of phases  2  different from the illustrated one, such as for example a monophase circuit breaker  1 , or a circuit breaker  1  with two or four phases  2 . 
     Each phase  2  of the circuit breaker  1  includes at least one movable contact  3  and a corresponding fixed contact  4  (which are schematically depicted in the block diagram of  FIG. 9 ). The movable contacts  3  are actuated by an associated driving mechanism  10  of the circuit breaker  1  (schematically depicted in the block diagram of  FIG. 9 ) so as to move between a first position, or closed position, in which they are coupled to the corresponding fixed contacts  4  (closed or “ON” circuit breaker  1 ), and a second position, or open position, in which they are spaced away from the corresponding fixed contacts  4 , so as to interrupt the current flowing into the phases  2  (open or “OFF” circuit breaker  1 ). 
       FIG. 2  is an exploded view showing the components of the locking device of  FIG. 1  in accordance with an exemplary embodiment of the present disclosure. The driving mechanism  10  is of a known type, and therefore only its elements useful for the understanding of the following description are herein shortly disclosed. As shown in  FIG. 2 , the driving mechanism  10  includes a main rotating shaft  11  whose ends are operatively coupled to the flanks  5  of the circuit breaker  1 , so as the rotating shaft  11  is able to rotate about a rotation axis  20 . The rotating shaft  11  is operatively connected to the movable contacts  3  so as to cause with its rotation about the axis  20  the movement of such contacts  3  from the closed position to the open position (opening operation of the circuit breaker  1 ) or from the open position to the closed position (closure of the circuit breaker  1 ). For example, the rotating shaft  11  can be operatively connected to the movable contacts  3  by means of contact-holding members; alternatively, the contacts  3  may by directly mounted in corresponding seats defined on the rotating shaft  11 , so as to configure with the rotating shaft  11  itself a movable equipment. 
     The driving mechanism  10  includes (e.g., comprises) a kinematic chain which is operatively connected to the rotating shaft  11  and which is suitable for transmitting the force for causing the rotation of the rotating shaft  11  about the axis  20 , when it is actuated. 
     For example, one or more protection devices of the circuit breaker  1 , such as one or more relays, are suitable for causing the actuation of the kinematic chain to drive the rotation of the shaft  11  in order to open the circuit breaker  1 , upon the occurrence of electric faults or failures. 
     The kinematic chain may also be manually actuated by an operator; for example, an opening button  12  (“O” or “OFF”) and a closure button  13  (“I” or “ON”) are accessible to the operator on the front mask  6  of the circuit breaker  1  depicted in  FIGS. 1-2 , and are operatively associated to the kinematic chain to cause the opening and the closure of the circuit breaker  1 , respectively, when they are pushed. 
     Further, the circuit breaker  1  may include one or more accessories  30 ,  31 , or actuators  30 ,  31 , which are operatively connected to the driving mechanism  10  and are suitable for causing with their intervention the closure and/or the opening of the circuit breaker  1 . 
     In an exemplary embodiment, the closure actuators  30  can be configured for being driven to act on one or more corresponding parts of the driving mechanism  10  causing the rotation of the rotating shaft  11  about the axis  20  with the consequent movement of the movable contacts  3  from the open position to the closed position. Non-limiting examples of closure actuators  30  suitable for being used to close the circuit breaker  1  are a motor operated equipment (MOE) or a shunt closing relay. 
     The opening actuators  31  are configured for being driven to act on one or more corresponding parts of the driving mechanism  10  causing the rotation of the rotating shaft  11  about the axis  20  with the consequent movement of the movable contacts  3  from the closed position to the open position. 
     For example, the circuit breaker  1  schematically depicted in  FIG. 9  includes at least: a motor operated equipment  30  (hereinafter indicated as “MOE  30 ”) which is suitable for causing the opening or the closure of the circuit breaker  1 ; and an opening coil actuator  31 , for example, an undervoltage release actuator  31  (hereinafter indicated as “UVR  31 ”) which is an actuator configured for intervening on the corresponding parts of the driving mechanism  10  to cause the opening of the circuit breaker  1  when the power supplied to it falls below a predetermined threshold of intervention. 
     Both the MOE  30  and the UVR  31  are actuating accessories that are well known in the art, and therefore they are not described in more detail therein. 
     The exemplary locking device  100  according to the present disclosure has one or more parts coupled to the rotating shaft  11  and is configured for directly acting on such rotating shaft  11  and locking the movable contacts  3  in the open position. 
     In practice, the locking device  100  locks the open circuit breaker  1  and prevents the closure thereof which may be attempted for example by a manual operation or by one or more closure actuators, such as the MOE  30 . As a result, the safety of the operators operating on the electric circuit parts disconnected from the power line through the opening of the circuit breaker  1  is guaranteed. 
     In an exemplary embodiment of the present disclosure, the locking device  100  can be configured for being actuated between a rest configuration in which the rotating shaft  11  is free to rotate (and therefore the movable contacts  3  are free to move) and an operative configuration in which it directly acts on the rotating shaft  11  and locks the movable contact  3  in the open position. 
     According to the exemplary embodiments of  FIGS. 1-8 , the locking device  100  includes a first movable element  101 , preferably made of metallic material, such as for example a metal sheet, which is coupled to the rotating shaft  11  so as to be movable between a first position corresponding to the closed position of the movable contacts  3  (closed circuit breaker  1 ), and a second position corresponding to the open position of the movable contacts  3  (open circuit breaker  1 ). For example, as shown in the exemplary embodiments of  FIGS. 1-8 , the first movable element  101  is coupled to an end  15  of the rotating shaft  11 , which is accessible from the outside of the case of the circuit breaker  1  through an opening  16  defined in the corresponding flank  5  of the circuit breaker  1 . 
     The locking device  100  further includes blocking means  102  configured for operatively interacting with the first movable element  101  in the second position, so as to block the first movable element  101  in the second position and to lock the movable contacts  3  in the open position. 
     In practice, the blocking means  102  are coupled in a removable way to the first movable element  101  and constrains the first movable element  101  itself to a fixed support, which may be constituted by one or more parts of the locking device  100  and/or by one or more parts of the circuit breaker  1 , such as the case of the circuit breaker  1 . The constrained first movable element  101  constrains in turn the rotating shaft  11  and the movable contacts  3  in the open position. 
     As shown in the exemplary embodiments of  FIGS. 2, 3, 7, and 8  the first movable element  101  includes a lever  101  (shown by dashed lines in  FIGS. 7 and 8 ) with at least a first arm  103 , a second arm  104 , and a fulcrum portion  105 ; a pin  106  leans forward transversally from the fulcrum portion  105  and includes a protrusion  18  defined at its end. 
       FIG. 3  shows the coupling between one element of a locking device with a corresponding portion of the main rotating shaft of an associated switching device in accordance with an exemplary embodiment of the present disclosure. As shown in detail in  FIG. 3 , the lever  101  is mechanically coupled to the end  15  of the rotating shaft  11 , which is accessible through the opening  16  defined in the corresponding flank  5  of the circuit breaker  1  (see  FIG. 2 ). For example, the end  15  of the rotating shaft  11  includes a slot  17  defined for mating the protrusion  18  of the pin  106 ; a fixing screw  107  is inserted in corresponding holes  19  and  20  defined through the end  15  and through the pin  106 , respectively, so as to fix the lever  101  to the rotating shaft  11 . 
     Therefore, the lever  101  is fastened with the rotating shaft  11 , meaning that the rotating shaft  11  and the coupled lever  101  are free to rotate about the axis  20 , when the lever  11  is not blocked by the blocking means  102  (locking device  100  in the rest configuration); the rotation of the rotating shaft  11  and the coupled lever  101  about the axis  20  is instead blocked when the lever  101  is blocked by the blocking means  102  (locking device  100  in the operative configuration). 
     The locking device  100  according to the exemplary illustrated embodiments includes a mounting plate  109 , for example made of metallic material, such as for example metal sheet, which is coupled, (e.g., fixed), to the flank  5  of the circuit breaker  1 , from which the end  15  of the rotating shaft  11  is accessible through the opening  16  (see  FIG. 2 ). 
     The mounting plate  109  includes first and second opposite faces  110 ,  112 , wherein the second face  112  faces the corresponding flank  5  of the circuit breaker  1 . The lever  101  is mounted in a movable way on the first surface  110 . An opening  111  can be defined across the mounting plate  109 , between the first and second faces  110 ,  112 , and allows the insertion therethrough of the pin  106  for coupling the lever  101  with the end  15  of the rotating shaft  11 . 
     The exemplary locking device  100  according to the present disclosure includes a second movable element  120 , made of metallic material, such as for example metal sheet, which is movable between a rest position and an actuated position, when actuated by an operator. 
     The second movable element  120  is configured to prevent the blocking of the first movable element  101  by the blocking means  102  when it is in the rest position, and to enable the blocking of the first movable element  101  by the blocking means  102  when it is in the actuated position. 
     Hence, the displacement of the movable element  120  from the rest position to the pulled position causes the actuation of the locking device  100  for moving, or changing, between the rest configuration and the operative configuration in which the blocking means  102  are coupled to the first movable element  101 . 
     For example, at least a first through hole  150  and a second through hole  151  are defined across the first movable element  101  and across the second movable element  120 , respectively, wherein the first and second movable elements  101 ,  120  are configured so as the first and second through holes  150 ,  151  are aligned each other for the removable insertion therethrough of at least a portion of the blocking means  102  when the first movable element  101  is in the second position and the second movable element  120  is in the actuated position. 
       FIG. 4  is a perspective view of some parts of a locking device in a rest configuration in accordance with an exemplary embodiment of the present disclosure.  FIG. 5  is a perspective view of the locking device shown in  FIG. 4 , when such locking device is under actuation in accordance with an exemplary embodiment of the present disclosure. As shown in  FIG. 4 , the second movable element  120  can be configured for sliding between the rest position and the actuated position. As shown in  FIG. 5 , the second movable element  120  can be configured for sliding between the rest position and the pulled position (see for example  FIG. 5  or  FIGS. 7 and 8 ). The sliding element  120  is mounted in a movable way on the second surface  112  of the mounting plate  109 , so as the mounting plate  109  is interposed between the sliding element  120  and the lever  101 ; the sliding element  120  includes for example two slots  121  defined at two opposite ends  135  of such sliding element  120  and having their edge surfaces which slid during the movement of the sliding element  120  onto a corresponding fixed pin  113  leaning forward from the second face  112  of the mounting plate  109 . 
       FIG. 7  is a perspective view of some parts of a locking device corresponding to a closed status of the associated switching device in accordance with an exemplary embodiment of the present disclosure. As shown in  FIG. 7 , the locking device  100  includes at least a biasing spring  130  having a first end  170  hooked to the mounting plate  109  and an opposed second end  171  hooked to the sliding element  120 , so as to cause the return of the sliding element  120  from the pulled to the rest position. 
       FIG. 8  is a perspective view of the locking device shown in  FIG. 7 , corresponding to an open status of the associated switching device in accordance with an exemplary embodiment of the present disclosure. According to the exemplary embodiments disclosed herein, the first through hole  150  is defined across the second arm  104  of the lever  101 , and the second through hole  151  is defined across the sliding element  120 . For example, as shown in  FIG. 8 , the first through hole  150  can be defined across the second arm  104  so as to be aligned with the second through hole  152  of the sliding element  120  in the pulled position when the lever  101  is in the second position corresponding to the open circuit breaker  1  (see for example  FIG. 8 ). 
     The first arm  103  of the lever  101  includes a covering portion  131  which is suitable for covering the second through hole  151  of the sliding element  120  in the pulled position when the lever  101  is in the first position corresponding to the closed circuit breaker  1  (see for example  FIG. 7 ). 
     Further, a third through hole  152  is defined across the mounting plate  109 , between the first and second faces  110 ,  112 , in such a way to be aligned with the first and second through holes  150 ,  151 , when the lever  101  is in the second position and the sliding element  120  is in the pulled position. 
     When the circuit breaker  1  is open and the sliding element  120  has been pulled by an operator, at least a portion of the blocking means  102  can be inserted in a removable way through the overall hole defined by the series of the aligned first, second and third through holes  150 ,  151 ,  152 . For example, a padlock  108  may be coupled to above mentioned overall hole so as the lever  101  in the second position is constrained to the structure of the locking device  100 , such as to the mounting plate  109 , which in turn is fixed to the case of the circuit breaker  1 ; an attempt of re-closure of the circuit breaker  1  fails because the rotating shaft  11  is fastened to the constrained lever  101 . 
     In the exemplary embodiment illustrated in  FIG. 1 , the blocking means  102  advantageously includes a crimp-configured portion  160  having an end inserted through the overall hole defined by the aligned through holes  150 ,  151 ,  152 ; the portion  160  further includes a plurality of opening  161  each coupled to a corresponding padlock  108 . The padlocks  108  lock the crimp-configured portion  160  inserted into the aligned through holes  150 ,  151 ,  152 , blocking the lever  101  in the second position and locking the open circuit breaker  1 . 
     The keys associated to the padlocks  108  can be assigned each to a corresponding operator, and the open circuit breaker  1  can be unlocked by removing the blocking means  102  from the corresponding aligned through holes  150 ,  151 ,  152  only by means of the intervention of all the operators, therefore increasing the security of the electric circuit in which the circuit breaker  1  is installed. 
     According to the exemplary embodiments of the present disclosure, the sliding element  120  may have a shaped portion  122  which, when the sliding element  120  is in the rest position, is suitable for covering the portion  131  of the first arm  103  when the lever  101  is in the first position or for covering the first through hole  150  of the second arm  104  when the lever  101  is in the second position. 
     The shaped portion  122  includes for example a first section  123  and a second section  124  connected transversally by a third section  125 ; when the sliding element  120  is in the rest position, the third section  125  covers a corresponding portion of the edge of the mounting plate  109  which links the first and second faces  110 ,  112 . Hence, the first section  122  and the second section  124  face to the first face  110  and the second face  112 , respectively, when the sliding element  120  is in the rest position (see for example  FIGS. 4 and 6 ). At least a portion of the second section  124  can cover the covering portion  131  of the lever  101  in the first position, or the first through hole  150  of the lever  101  in the second position. 
     The exemplary locking device  100  according to the present disclosure, which includes a cover  500 , made for example of metallic material, which covers one or more parts of at least the first movable element  101 . 
     In the embodiment illustrated for example in  FIG. 1 , the cover  500  is coupled to the mounting plate  109  so as to cover the parts of the lever  101  (in the first position or in the second position) which are not covered by the above described shaped portion  122  of the sliding elements  120  in the rest position. Therefore, the lever  101 , for example where its fulcrum portion  105  is coupled to the end  15  of the rotating shaft  11 , is not directly accessible by an operator from the outside of the locking device  100 , thus guaranteeing an improved safety. 
     The exemplary locking device  100  according to the present disclosure may be configured for outputting one or more electrical signals S 1 , S 2  which are indicative of at least one of the rest configuration, the operative configuration, and an under actuation condition of the locking device  100  itself, e.g., the locking device  100  is moving, or changing, between such rest and operative configurations. 
     According to the exemplary embodiments of the present disclosure, as shown in  FIGS. 4, 5, and 7-9 , the locking device  100  includes one or more signaling devices  200 ,  201  each configured for receiving a first electrical signal S 1 , S 2  provided from the outside of the locking device  100 , for example an electrical signal S 1 , S 2  sent from a monitor and/or control location  300  for the circuit breaker  1  (see  FIG. 9 ). Such signaling devices  200 ,  201  are configured for outputting the received first electrical S 1 , S 2  when they are operated. 
     Preferably, the signaling devices  200 ,  201  are configured for operatively interacting with one or more parts of the locking device  100  so as to be operated by such one or more parts when the locking device  100  is under actuation and/or is in the operative configuration. 
     According to the exemplary embodiments disclosed herein with reference to  FIGS. 4, 5, 7, and 8 , the signaling devices  200 ,  201  are configured for operatively interacting with the second movable element  120  of the locking device  100  so as to start being operated by such second movable element  120  during its movement from the rest position to the actuated position (locking device  100  under actuation condition), and to be kept operated while the second movable element  120  is locked in the operated position by the blocking means  102  (locking device  100  in the operative configuration). 
     Alternatively, the signaling devices  200 ,  201  may be configured for operatively interacting with one or more parts of the locking device  100 , preferably the second movable element  120 , so as to be operated by such one or more parts only when the received locking device  100  is under actuation or only when the locking device  100  is in the rest configuration. 
     According to an exemplary embodiment, the signaling devices  200 ,  201  may be configured for not outputting any electrical signal when they are not operated for outputting the first electrical signal S 1 , S 2 , therefore acting as simple “one way” switches. 
     According to another exemplary embodiment, at least one of the signaling devices  200 ,  201  of the locking device  100  may be further configured for receiving in input a second electrical signal S 3 , S 4  which is provided from the outside of the locking device  100  and which is different with respect to the first electrical signal S 1 , S 2 ; such signaling device  200 ,  201  is configured for outputting the second electrical signal S 3 , S 4  when it is not operated for outputting the received first electrical signal S 1 , S 2 . Therefore, the signaling device  200 ,  201  according to second embodiment is configured for acting as a “two way” switch which outputs the first received electrical signal S 1 , S 2  or the second received electrical signal S 3 , S 4 , so as to electrically signaling the actuation condition and/or the operative configuration of the locking device  100 , and also the rest configuration of such locking device  100 . 
     The exemplary locking device  100  according to the present disclosure may be operatively connected to one or more of the closure actuators  30  of the circuit breaker  1 , so as to automatically disable such one or more closure actuators  30 ,  31  by means of at least one outputted electrical signal S 1  which is indicative of the under actuation condition and/or the operative configuration of the locking device  100 . For example, for each closure actuator  30  a corresponding signaling device  200  is provided in the locking device  100 ; such signaling device  200  is operatively connected to the corresponding closure actuator  30  to automatically disable it by means of the outputted first electrical signal S 1  which is indicative of the under actuation condition and/or the operative configuration of the locking device  100 . 
     As a result, re-closure attempts of the locked open circuit breaker  1  by the closure actuators  30  are prevented, which may cause damages of one or more parts of the circuit breaker  1  and/or the locking device  100  and/or the closure actuators  30  itself. 
     An operator may forget to check the open or closed status of the circuit breaker  1  before actuating the locking device  100 ; therefore the operator may dangerously try to lock the movable contacts  3  through the locking device  100  when the circuit breaker  1  is closed. Advantageously, the exemplary locking device  100  according to the present disclosure may be operatively connected to one or more opening actuators  31  of the circuit breaker  1 , to automatically cause the intervention of such opening actuators  31  for opening of the circuit breaker  1 . The intervention of the opening actuators  31  is caused by at least one electrical signal S 2  outputted by the locking device  100  and indicative of the under actuation condition and/or the operative configuration of the locking device  100  itself. For example, for each opening actuator  31  a corresponding signaling device  201  is provide in the locking device  100 ; such signaling device  201  is operatively connected to the corresponding opening actuator  31  to automatically cause the intervention of the opening actuator  31  for opening the circuit breaker  1  by means of the outputted first electrical signal S 2  which is indicative of the under actuation condition and/or the operative configuration of the locking device  100 . 
     As a result, the opening of the circuit breaker  1  during the actuation of the locking device  100  is guaranteed, therefore improving the safety of the operators. 
     In the exemplary embodiments illustrated in  FIGS. 4 and 5 and 7-9 , the locking device  100  includes a first signaling device  200  (or first micro-switch  200 ) and a second signaling device  201  (or second micro-switch  201 ) which are mounted on the second face  112  of the mounting plate  109 . 
       FIG. 9  is a block diagram schematically representing a switching device in accordance with an exemplary embodiment of the present disclosure. As shown schematically in  FIG. 9 , the first signaling device  200  and the second signaling device  201  receive in input the electrical signal S 1  and the electrical signal S 2 , respectively, through respective cables or wires  400 . For example, the electrical signals S 1  and S 2  are sent to the corresponding first and second signaling devices  200 ,  201  from the schematically illustrated monitor and/or control location  300 . 
     Each of the first and second signaling devices  200 ,  201  includes a lever  202  which causes the outputting of the respective electrical signal S 1  or S 2  received in input, when they are actuated. 
     In the exemplary embodiment of  FIGS. 7 and 8  the first and second signaling devices  200 ,  201  are “one way” switches which do not output any electrical signal when their lever  202  are not actuated; in the exemplary embodiment of  FIGS. 4 and 5  the first and second signaling devices  200 ,  201  are “two way” switches which output the electrical signal S 3  and the electrical signal S 4 , respectively, when the levers  202  are not actuated; as schematically shown in  FIG. 9 , the first and second signaling devices  200 ,  201  receive in input the respective electrical signals S 3  and S 4  from the monitor and/or control location  300  through cables  401 . 
     The sliding element  120  of the locking device  100  includes portions  140  shaped for starting to actuate the levers  202  of the first and second signaling devices  100 ,  101  during the movement of the sliding element  120  from the rest to the pulled position, and for keeping the levers  202  actuated when the sliding element  120  is in the pulled position and the blocking means  102  are coupled to the first movable element  101  of the locking device  100  to lock the open circuit breaker  1 . The shaped portions  140  start to actuate the corresponding levers  202  of the first and second signaling devices  200 ,  201  after a short delay time calculated from the starting of the sliding element  120  movement, which for example, can be within a range of 1 ms and 20 ms, and in an exemplary embodiment less than 10 ms. 
     The electrical signals S 1  and S 2  (and the electrical signals S 3 , S 4  if present) outputted by the first and second signaling devices  200 ,  201  are transmitted to the outside of the locking device  100  through cables  402 . As schematically shown in  FIG. 9 , the first and second signaling devices  200 ,  201  are for example connected to the monitor and/or control location  300 , which can be in a location  300  remote with respect to the circuit breaker  1 , so as to transmit the outputted signals S 1 , S 2  (and the outputted signals S 3 , S 4 ) to such a location  300  for monitoring and/or controlling by remote the actuation of the locking device  100  and/or the locked or unlocked status of the circuit breaker  1 . 
     Further, the first and second signaling devices  200 ,  201  can be connected to one or more electronic devices and/or accessories of the circuit breaker  1 , so as to transmit the electrical signals S 1  and S 2  to such electronic devices and/or accessories. In the exemplary embodiment of  FIG. 9  the first signaling device  200  is operatively connected to the MOE  30  of the circuit breaker  1  so as to disable such MOE  30  by means of the outputted electrical signal S 1 , and the second signaling device  201  is operatively connected to the UVR  31  of the circuit breaker  1  so as to cause the fall of the power supplied to the UVR  31  below the predetermined threshold of intervention by means of the outputted electrical signal S 2 . 
     For example, the first and second electrical signals S 1 , S 2  disable the power supply provided to the MOE  30  and to the UVR  31 , respectively, by interrupting the power delivery in the power supply circuits associated to the MOE  30  and to the UVR  31 . In an exemplary embodiment, the first and second signals S 1 , S 2  can switch off one or more electronic switches, such as for example MOS transistors, provided in the power supply circuit of the MOE  30  and of the UVR  31 , respectively. 
     Alternatively to the exemplary embodiments shown, the locking device  100  may include a number of signaling devices  200 ,  201  which is different from the illustrated one; for example, the locking device  100  of  FIG. 9  may include only the first signaling device  200  (or the second signaling device  201 ) whose outputted electrical signal S 1  (or S 2 ) is used for disabling the MOE  31  and for causing at the same time the intervention of the UVR  31 . 
     The exemplary operation of the locking device  100  according to the present disclosure is described in the following description by making reference to the exemplary embodiments illustrated in  FIGS. 1-9 . 
     Starting from the situation in which the circuit breaker  1  is closed, the movable contacts  3  are coupled to the corresponding fixed contacts  4  and the lever  101  is in the first position, illustrated for example in  FIG. 7 . The locking device  100  is in its rest configuration and therefore the rotating shaft  11  is free to rotate about the axis of rotation  20  when actuated by the kinematic chain of the driving mechanism  10  to open the circuit breaker  1 . 
     While the locking device  100  is in the rest configuration, the sliding element  120  remains in the rest position and the first and second signaling devices  200 ,  201  of  FIGS. 7 and 8  do not output any electrical signal, while the first and second signaling devices  200 ,  201  of  FIGS. 4 and 5  output the electrical signal S 3  and the electrical signal S 4 , respectively, which are indicative of the rest configuration of the locking device  100  itself and which are transmitted to the outside of the locking device  100  through the cables  402 , preferably to the remote monitor and/or control location  300  (see  FIG. 9 ). 
     An operator can attempt to lock the circuit breaker  1  through the actuation of the locking device  100  by gripping the shaped portion  122  and pulling the sliding element  120  from the rest position to the pulled position (see for example  FIG. 5  or  FIG. 7 ), in which the second through hole  151  of the sliding element  120  is aligned with the third through hole  152  of the mounting plate  109 . 
     After a short delay time (e.g. less than 10 ms) from the starting of the movement of the sliding element  120 , the portions  140  of the sliding element  120  itself start actuating the levers  202  of the first and second signaling devices  200 ,  201  which consequently start outputting the first electrical signal S 1  and the second electrical signal S 2 , respectively, which are indicative of at least the actuation of locking device  100  and are transmitted to the outside of the locking device  100  itself through the cables  402 , preferably at least to the monitor and/or control remote location  300  (see  FIG. 9 ). 
     Before the actuation of the locking device  100  the circuit breaker  1  may have been already open, for example due to the intervention of the protection devices of the circuit breaker  1  itself against an electric fault or failure, or due to the manual intervention of the operator pushing the button  12  (“OFF”, “O ”). In such situation, the rotating shaft  11  has rotated about the axis  20  to move the contacts  3  from the closed to the open position and to move the coupled lever  101  from the first position (see  FIG. 7 ) to the second position (see  FIG. 8 ). The first through hole  150  of the second arm  104  of the lever  101  is aligned with the third through hole  152  of the mounting plate  109  and with the second through hole  151  of the sliding element  120  when it is in the pulled position. 
     The actuation of the locking device  100  may dangerously start when the circuit breaker  1  is still closed. According to the exemplary embodiment of  FIG. 9 , the electrical signal S 2  outputted by the second signaling device  201  is transmitted to the power supply circuit of the UVR  31  to interrupt the supply path and causing the fall of the supplied voltage below the intervention threshold. Therefore, the closed circuit breaker  1  is open by the intervention of the UVR  31 , after a short delay time (e.g. less than 10 ms) from the starting of the movement of the pulled sliding element  120 . The outputting of the electrical signal S 2  guarantees a prompt opening of the circuit breaker  1  and improves the safety of the operators. 
     When the circuit breaker  1  is open and the sliding element  120  is in the pulled position, the operator can insert the blocking means  102  (such as a padlock  108  or the crimp-configured portion  160  illustrated in  FIG. 1 ) through the overall through hole defined by the aligned through holes  150 ,  151  and  152 . In this way the locking device  100  is in its operative configuration in which the lever  101  and the coupled rotating shaft  11  are constrained by the blocking means  102  to the mounting plate  109 , and therefore to the case of the circuit breaker  1 . Hence, the circuit breaker  1  is locked, preventing any re-closure attempt of the circuit breaker  1  itself by means of manually actuation (pushing the button  13 , “ON” or “I”) or by means of one or more closure actuators  30  of the circuit breaker  1 . While the locking device  100  is kept in its operative configuration by the blocking means  102 , the levers  202  of the first and second signaling devices  200 ,  201  are kept operated by the corresponding portions  140  of the sliding element  120 , so as the respective electrical signals S 1 , S 2  are continuously outputted for signaling such operative configuration of the locking device  100 . 
     The electrical signal S 2  may not be correctly outputted or transmitted to the UVR  31 ; further, alternatively to the embodiment illustrated in  FIG. 9 , neither the first signaling device  200  nor the second signaling devices  201  may be connected to the UVR  31 . Anyway, in such conditions the covering portion  131  of the first arm  103  of the lever  101  in the first position covers the third through hole  152  of the mounting plate  109  and the second through hole  152  of the sliding element  120  in the pulled position. In this way is prevented the coupling of the blocking means  102  to the lever  101  through the insertion in the aligned through holes  150 ,  151 ,  152 . Therefore, the locking of the closed circuit breaker  1  is prevented, which would avoid the open of the circuit breaker  1  at the occurrence of electric faults or failures. 
     According to the exemplary embodiment shown in  FIG. 9 , the electrical signal S 1  outputted by the first signaling device  200  is transmitted to the power supply circuit of the MOE  30  to interrupt the supply path and causing the disabling of the MOE  30 . Therefore, while the lever  202  of the first signaling device  200  is operated for outputting the electrical signal S 1  the MOE  30  is prevented to attempt the re-closure of the open locked circuit breaker  1 , which may cause damages of one or more parts of the circuit breaker  1  and/or the locking device  100  and/or the MOE  30  itself. 
     When the blocking means  102  are removed from the aligned through holes  150 ,  151 ,  152 , the sliding element  120  is recalled from the pulled to the rest position by the biasing spring  130 , so as the locking device  100  returns in its rest configuration wherein the lever  101  and the coupled rotating shaft  11  are free again to rotate about the axis  20 , allowing the re-closure of the switching device  1 . 
     The levers  202  of the first and second signaling devices  200 ,  201  stop to be actuated by the corresponding portions  140  a short time before (e.g. less than 10 ms) the sliding element  120  reaches the rest position. As a consequence, the outputting of the respective electrical signals S 1 , S 2  is stopped and therefore the power supply path of the MOE  30  and the UVR are automatically restored so as the MOE  30  is re-enabled for causing the closure and/or the aperture of the circuit breaker  1 , and the UVR is re-enabled for causing the opening of the circuit breaker  1 . 
     Such results can be achieved based on a solution which in principle makes the circuit breaker  1  according to the present disclosure easy to be used in connection with a power distribution system and/or a wind power generation plant. 
       FIG. 10  is a block diagram schematically representing a power distribution system equipped with a plurality of switching devices in accordance with an exemplary embodiment of the present disclosure. As shown in  FIG. 10 , a power distribution system  600  can include one or more circuit breakers  1  each having at least one locking device  100 . The power distribution system  600  includes at least a monitor and/or control location  300 , or station  300 , which is placed remote with respect to the one or more circuit breakers  1 , wherein each of the locking devices  100  of the circuit breakers  1  is connected to the remote monitor and/or control station  300  so as to transmit thereto one or more electrical signals S 1 , S 2  which are indicative of at least one of the rest configuration, the operative configuration, and an under actuation condition of the locking device  100 , e.g., the locking device  100  is moving between such rest and operative configurations. 
     Further exemplary embodiments of the present disclosure encompasses a wind power generation plant including the power distribution system or at least one circuit breaker  1 . 
     In practice, it has been seen how the switching device  1  according to the present disclosure allows achieving the intended object offering some improvements over known solutions. 
     For example, the locking device  100  according to the present disclosure can be configured for directly acting on the rotating shaft  11  and locking the open circuit breaker  1 , through one or more of its parts coupled to such rotating shaft  11  (e.g. the lever  11  coupled to the accessible end  15  of the rotating shaft  11 ). 
     Therefore, the locking device  100  guarantees a high reliability of the locking operation of the circuit breaker  1 , because it directly acts on the rotating shaft  11 , without the intervention or other mechanical parts, such as one or more components of the kinematic chain for driving the rotating shaft  11 . 
     Further, the locking device  100  according to the exemplary embodiments shown in the cited figures is able to generate electrical information relative to the actuation of the locking device and/or to the locked status and/or the unlocked status of the circuit breaker  1 . 
     Such electrical information is suitable for being transmitted and used for monitoring and/or controlling even remotely. This effect is can be advantageous when the circuit breaker  1  and the related locking device  100  are placed in non easy accessible locations or in different and distant locations inside the power distribution system  600 . For example, the power distribution system  600  may be provided in a wind power generation plant, wherein one or more circuit breakers  1  are placed at the wind towers. 
     The monitoring and/or controlling by remote of the locked and/or unlocked status of the circuit breaker  1  is provided in a simple and economic way by means of the locking device  100  according to the present disclosure, and improves the functionalities of the power distribution system  600  and the employment of the operators in such a system  600 . 
     Further, the electrical signals S 1 , S 2  outputted by the locking device  100  may be advantageously used for automatically disabling the closure actuators  30  and/or for causing the intervention of the opening actuators  31  for opening the circuit breaker  1 . 
     Moreover, all parts/components can be replaced with other technically equivalent elements; in practice, the type of materials, and the dimensions, can be any according to needs and to the state of the art. 
     For example, the lever  101  can be replaced by an element coupled to the rotating shaft  11  and mounted in a movable way on the mounting plate  109  so as to rotate between a first position and a second position; the cover  500  coupled to the mounting plate  109  may be suitable for covering the lever  101  and also the overall mounting plate  109 . 
     Further the lever  101  and/or the sliding element  120  and/or the cover  500  may be made of plastic materials, such as for example polyester. 
     Thus, it will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the invention is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.