Patent Publication Number: US-2023154712-A1

Title: Power device monitoring system

Description:
FIELD 
     The present disclosure relates to a monitoring system of a power device, and more particularly, to a monitoring system of a power device capable of continuously detecting an exact position of a circuit breaker body moving in a cradle. 
     DESCRIPTION OF RELATED ART 
     In general, a power device refers to any device that may receive and transmit power and convert the power. 
       FIG.  1    is a perspective view showing a conventional power device. 
     Referring to  FIG.  1   , the conventional power device includes a cradle terminal  110  connected to a power line connected to an external power source or a load. Further, the power device includes a cradle  100  fixed to a switchboard, a circuit breaker body  200  mechanically and electrically connected to or disconnected from the terminal  110  of the cradle  100 , and a girder  300  and a truck  400  to bring the circuit breaker body  200  to a contact or disconnection position in which the body is mechanically and electrically connected to or disconnected from the terminal  110  of the cradle  100 . 
     In this regard, the contact position means a position in which the circuit breaker body  200  approaches the cradle terminal  110  at the maximum level and electrically contacts the terminal  110 . 
     Further, the disconnection position means a position in which the circuit breaker body  200  is spaced from the cradle terminal  110  by the maximum spacing and thus is electrically disconnected from the cradle terminal  110 . 
     Further, a test position means a position corresponding to a process in which the body is being displaced from the contact position to the disconnection position or from the disconnection position to the contact position. 
     Further,  FIG.  2    and  FIG.  3    are perspective views showing the girder  300  and the truck  400  according to the disconnection position and the contact position in  FIG.  1   , respectively. 
     Further,  FIG.  4    shows cross-sectional views of the girder  300  and the truck  400  according to disconnection, test, and contact positions in the conventional power device, respectively. 
     Referring to  FIGS.  2  to  4   , in the conventional power device, the girder  300  includes a pair of handle bars  310  formed on a front face thereof, support ribs  320  respectively formed at both opposing sides thereof, and a spindle  330  having one end rotatably coupled to a center of the front face thereof, and a switch actuation bar  340  formed on one side of the spindle  330 . 
     Further, the truck  400  includes a plurality of wheels  410  formed at each of both opposing sides thereof and a plurality of micro switches  420  actuated by the switch actuation bar  340 . As the spindle  330  rotates, a spacing between the truck  400  and the girder  300  is adjusted as shown in  FIGS.  2  and  3   . 
     That is, as the spindle  330  rotates clockwise or counterclockwise, the spacing between the truck  400  and the cradle terminal  110  is adjusted. 
     Further, the switch actuation bar  340  includes an elongate groove  341  formed to correspond to a movement range of the truck  400 , a rear end inclined portion  342  formed at one end of the groove  341 , and a top planar portion  343  constituting a top face except for the groove  341  and the rear end inclined portion  342 . 
     Further, the micro switch  420  includes first to third micro switches  421 ,  422 , and  423 . 
     In more detail, the first micro switch  421  includes a first contact lever  421   a  formed on a bottom thereof so as to contact the switch actuation bar  340 , and is closest to the girder  300 . 
     Further, the second micro switch  422  includes a second contact lever  422   a  formed on a bottom thereof so as to contact the switch actuation bar  340 , and is adjacent to a rear end of the first micro switch  421 . 
     Further, the third micro switch  423  includes a third contact lever  423   a  formed on a bottom thereof so as to contact the switch actuation bar  340 , and is adjacent to a rear end of the truck  400 . 
     A method for detecting a relative position between the terminal  110  of the cradle  100  and the circuit breaker body  200  using the truck  300  in this conventional power device is as follows. 
     Referring to (a) of  FIG.  4   , the spacing between the truck  400  and the girder  300  becomes minimum at the disconnection position of the conventional power device. 
     Accordingly, the distance between the circuit breaker body  200  and the cradle terminal  110  becomes maximum. 
     Further, the first contact lever  421   a  is in contact with the top planar portion  343 , while each of the second contact lever  422   a  and the third contact lever  423   a  is in contact with the groove  341 . 
     Further, referring to (b) of  FIG.  4   , at the test position of the conventional power device, as the spacing between the girder  300  and the truck  400  increases, each of the first contact lever  421   a  and the second contact lever  422   a  comes into contact with the groove  341 . 
     Further, the third contact lever  423   a  passes by the rear end inclined portion  342  and then comes into contact with the top planar portion  343 . 
     Further, referring to (c) of  FIG.  4   , at the contact position of the conventional power device, the spacing between the truck  400  and the girder  300  becomes maximum. 
     Accordingly, the circuit breaker body  200  is in contact with and thus electrically connected to the cradle terminal  110 . 
     At this time, the first contact lever  421   a  comes into contact with the groove  341 , and the second contact lever  422   a  passes by the rear end inclined portion  342  and comes into contact with the top planar portion  343 . 
     As described above, in the prior art, the spacing the truck  400  and the girder  300  is adjusted in a state in which the switch actuation bar  340  is coupled to the girder  300 . Thus, the position of the circuit breaker body  200  is detected based on whether the plurality of micro switches  420  fixedly installed on the truck  400  are in contact with the switch actuation bar  340 . 
     Accordingly, in the prior art, the position of the circuit breaker body  200  may be detected at each of the disconnection, test, and contact positions of the power device. However, a varying distance between the circuit breaker body  200  and the cradle terminal  110  cannot be detected. 
     DISCLOSURE 
     Technical Purposes 
     A purpose of the present disclosure is to provide a monitoring system of a power device which is capable of linearly detecting a position of a circuit breaker body over an entirety of a movement range using a relatively simple structure. 
     Purposes according to the present disclosure are not limited to the above-mentioned purpose. Other purposes and advantages according to the present disclosure that are not mentioned may be understood based on following descriptions, and may be more clearly understood based on embodiments according to the present disclosure. 
     Further, it will be easily understood that the purposes and advantages according to the present disclosure may be realized using means shown in the claims and combinations thereof. 
     Technical Solutions 
     In order to achieve the purpose, the present disclosure, the present disclosure provides a monitoring system of a power device comprising: a cradle having a cradle terminal disposed on a rear side thereof; a circuit breaker configured to mechanically and electrically contact or be disconnected from the cradle terminal; at least one position detecting means mounted inside the circuit breaker so as to detect a position of a circuit breaker body in real time; and a display for outputting movement characteristics of the circuit breaker body detected by the position detecting means. 
     More specifically, the movement characteristics of the circuit breaker body output from the display may include at least one of a movement distance of the circuit breaker body, a remaining distance thereof to a contact or disconnection position, a movement speed thereof, change in the movement speed thereof, a contact amount between the circuit breaker body and the cradle terminal, or an expected time duration for which the circuit breaker body has been inserted. 
     Further, the position detecting means may include: a position bar including at least one position detected area portion extending in a corresponding manner to a movement range of the circuit breaker body, wherein one end of the position bar is coupled to a girder fixedly installed on a front face of the cradle, and the other end of the position bar acts as a free end facing the rear side of the cradle; a sensor module installed inside a truck, wherein the circuit breaker body is loaded on the truck, and the position bar is inserted into the truck, wherein the truck is configured to reciprocate from the girder to the cradle terminal and inside the cradle, wherein the sensor module includes at least one sensor facing the position detected area portion; and a controller configured to receive movement characteristics of the position detected area portion detected by the sensor module, and to detect the movement characteristics of the circuit breaker body based on the received movement characteristics of the position detected area portion. 
     Alternatively, the position detecting means may include: a position detected area portion formed on at least one of both opposing side faces of the circuit breaker body; a sensor module including at least one sensor facing the position detected area portion so as to detect a displaced position of the position detected area portion and thus detect a position of the circuit breaker body, based on the detect displaced position, wherein the sensor module is fixed to at least one of both opposing inner faces of the cradle; and a controller configured to receive movement characteristics of the position detected area portion detected by the sensor module, and to detect the movement characteristics of the circuit breaker body based on the received movement characteristics of the position detected area portion. 
     More preferably, the controller may be configured to: when a contact amount between the circuit breaker body and the cradle terminal exceeds a preset allowable range of the contact amount while the circuit breaker body is at a contact position, generate a notification alarm, and output the generated notification alarm to the display. 
     Further, the controller may be configured to: when at least two values of a movement characteristic of the same type of among the movement characteristics of the position detected area portion detected by the sensor module are detected, compare the at least two values with each other; and when a difference between the at least two values exceeds a preset error tolerance, generate a notification alert, and output the generated notification alert to the display. 
     More preferably, the sensor module may include at least one of a non-contact type sensor or a contact type sensor. 
     Further, the position detected area portion may include at least one of: a position sticker having a shade varying in a movement direction of the truck; a plurality of position protrusions, wherein at least one of a number, a shape, or a position thereof varies in the movement direction of the truck; or a position inclined portion having one face inclined downwardly or upwardly in the truck movement direction. 
     More preferably, the sensor module may further include a contact type sensor configured to contact the position inclined portion and to detect a varying height of the position inclined portion and to detect the position of the circuit breaker body based on the detected varying height. 
     Technical Effects 
     The monitoring system of the power device according to the present disclosure is capable of linearly detecting a position of a circuit breaker body over an entirety of a movement range, thereby achieving an advantage of being able to identify an accurate position of the circuit breaker body in real time. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective view showing a conventional power device. 
         FIG.  2    is a perspective view showing a girder and a truck according to a disconnection position in the conventional power device. 
         FIG.  3    is a perspective view showing the girder and the truck according to a contact position in the conventional power device. 
         FIG.  4    is a cross-sectional view showing the girder and the truck according to each of the disconnection, test, and contact positions in the conventional power device. 
         FIG.  5    is a perspective view showing a configuration of a monitoring system of a power device according to an embodiment of the present disclosure. 
         FIG.  6    is a perspective view showing a state in which a circuit breaker body is disconnected from a cradle in the monitoring system of the power device according to an embodiment of the present disclosure. 
         FIG.  7    is a perspective view showing a girder and a truck at a disconnection position in the monitoring system of the power device according to an embodiment of the present disclosure. 
         FIG.  8    is a perspective view showing a girder and a truck at a contact position in the monitoring system of the power device according to an embodiment of the present disclosure. 
         FIG.  9    is a perspective view showing a position bar in the monitoring system of the power device according to an embodiment of the present disclosure, respectively. 
         FIG.  10    is a perspective view showing each of a top face and a bottom face of a sensor module in a monitoring system of a power device according to an embodiment of the present disclosure. 
         FIG.  11    is a side cross-sectional view at a disconnection position in the monitoring system of the power device according to an embodiment of the present disclosure. 
         FIG.  12    is a side cross-sectional view at a contact position in the monitoring system of the power device according to an embodiment of the present disclosure. 
         FIG.  13    is a perspective view showing a position detected area portion in the monitoring system of the power device according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTIONS 
     The above objects, features and advantages will be described in detail later with reference to the accompanying drawings. Accordingly, a person with ordinary knowledge in the technical field to which the present disclosure belongs will be able to easily implement the technical idea of the present disclosure. In describing the present disclosure, when it is determined that a detailed description of a known component related to the present disclosure may unnecessarily obscure gist the present disclosure, the detailed description is omitted. Hereinafter, a preferred embodiment according to the present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar elements. 
     In addition, it will also be understood that when a first element or layer is referred to as being present “on” or “beneath” a second element or layer, the first element may be disposed directly on or beneath the second element or may be disposed indirectly on or beneath the second element with a third element or layer being disposed between the first and second elements or layers. 
     It will be understood that when an element or layer is referred to as being “connected to”, or “coupled to” another element or layer, it may be directly on, connected to, or coupled to the other element or layer, or one or more intervening elements or layers may be present. 
     As used herein, the singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     It will be further understood that the terms “comprises”, “comprising”, “includes”, and “including” when used in this specification, specify the presence of the stated features, integers, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, operations, elements, components, and/or portions thereof. 
     As used herein, the term “A and/or B” includes any and all combinations of one or more of A and B unless otherwise specified. When referring to “C to D”, this means C inclusive to D inclusive unless otherwise specified. 
     Hereinafter, a monitoring system of a power device according to some embodiments of the present disclosure will be described. 
     The same reference numerals are allocated to the same components of the monitoring system of the power device according to the present disclosure as those of the conventional power device. 
       FIG.  5    is a perspective view showing a configuration of a monitoring system of a power device according to an embodiment of the present disclosure. 
     Further,  FIG.  6    is a perspective view illustrating a state in which the circuit breaker body is disconnected from the cradle in the monitoring system of the power device according to an embodiment of the present disclosure. 
     Referring to  FIG.  5    and  FIG.  6   , the monitoring system of the power device according to the present disclosure includes the cradle  100  having the cradle terminal  110 , the girder  300  fixed to the cradle  100 , the truck  400  which is movable so that a spacing between the girder  300  and the truck  400  may be adjusted, and the circuit breaker body  200  loaded on the truck  400  so as to contact or be disconnected from the cradle terminal  110 . 
     Further, in the monitoring system of the power device according to the present disclosure, the circuit breaker includes the circuit breaker body  200 , the girder  300  and the truck  400 . 
     Further, the monitoring system of the power device according to the present disclosure includes at least one position detected area portion  500  and  500 ′ extending in a corresponding manner to a movement range of the truck  400  and formed on the circuit breaker body  200  or the girder  300 , at least one sensor module  600  and  600 ′ that is fixedly installed on the cradle  100  or the truck  400  so as to detect movement characteristics of the position detected area portion  500  and  500 ′ in real time, a controller  800  configured to receive the movement characteristics of the position detected area portion  500  and  500 ′ sensed by the sensor module  600  and  600 ′ and to detect movement characteristics of the circuit breaker body  200  based on the received movement characteristics, and a display  900  for outputting the movement characteristics of the circuit breaker body  200  detected by the controller  800 . 
     In this case, various wired/wireless communication networks may be applied to connection between the sensor module  600  and  600 ′ and the controller  800  and connection between the controller  800  and the display  900 . 
     Further, the display  900  may be embodied as an administrator&#39;s portable terminal. 
     In one example, in the monitoring system of the power device according to the present disclosure, the disconnection position means a position in which the circuit breaker body  200  is spaced from the cradle terminal  110  by the maximum spacing and thus is electrically disconnected from the cradle terminal  110 . 
     That is, the disconnection position refers to a state in which a spacing between the girder  300  and the truck  400  is minimized 
     Further, in the monitoring system of the power device according to the present disclosure, the contact position means a position in which the circuit breaker body  200  approaches the cradle terminal  110  at the maximum level and electrically contacts the terminal  110 . 
     That is, the contact position refers to a state in which the spacing between the girder  300  and the truck  400  is maximized, and a terminal formed on the circuit breaker body  200  is coupled to the cradle terminal  110 . 
     Further, in the monitoring system of the power device according to the present disclosure, an operation position means a state in which the spacing between the girder  300  and the truck  400  is adjusted in a process in which the body is being displaced from the contact position to the disconnection position or from the disconnection position to the contact position. 
     The girder  300  includes a pair of handle bars  310  formed on a front face thereof, support ribs  320  respectively formed at both opposing sides thereof, and a spindle  330  having one end rotatably coupled to a center of the front face thereof. 
     More specifically, the handle bar  310  may refer to a part gripped by an operator when the girder  300  and the truck  400  are mounted to or disconnected from the cradle  100  and be formed in various shapes. 
     Further, the girder  300  is fixed to the cradle  100  while each of the support ribs  320  is inserted into and fixed to each of both opposing sides of the cradle  100 . 
     Further, the spindle  330  is coupled to the truck  400  such that one end of the spindle is coupled to a central portion of the girder  300  and the other end thereof faces the cradle terminal  110 . 
     Thus, when the spindle  300  rotates clockwise or counterclockwise, the spacing between the girder  300  and the truck  400  is adjusted. 
     Further, the rotation of the spindle  330  may be achieved by an operator inserting a handle to a hole formed in a front face of the girder and manually rotating the handle, or may be automatically achieved by a driving motor. 
     In one example, the movement characteristics of the circuit breaker body  200  output from the display  900  may include at least one of a movement distance of the circuit breaker body  200 , a remaining distance thereof to the contact or disconnection position, a movement speed thereof, change in the movement speed thereof, and a contact amount between the circuit breaker body  200  and the cradle terminal  110 . 
     More preferably, the movement characteristics of the circuit breaker body  200  output from the display  900  may be output in a form of a graph or a figure including a numerical value so that an administrator may easily identify the same. 
     Further, when the circuit breaker body  200  is in the contact position, the controller  800  may generate a notification alert when the contact amount between the circuit breaker body  200  and the cradle terminal  110  exceeds a preset allowable range of the contact amount, and may output the generated notification alert to the display  900 . 
     In one example, sizes of the circuit breaker body  200  and the cradle  100  may vary based on applications thereof. Thus, when the sizes of the circuit breaker body  200  and the cradle  100  and specifications of the cradle terminal  110  are input to the controller  800 , the controller  800  may be configured to automatically extract the contact amount between the circuit breaker body  200  and the cradle terminal  110  based on a distance between the circuit breaker body  200  and the cradle  100 . 
     Accordingly, the monitoring system of the power device according to the present disclosure may minimize heat generation, device damage, safety accidents, etc. caused by incorrect coupling between the circuit breaker body  200  and the cradle terminal  110 . 
     Further, at least two values of the same type of the movement characteristic among the movement characteristics of the position detected area portion  500  detected by the sensor module  600  may be detected. In this case, when a difference between the detected values exceeds a preset error tolerance, the controller  800  may generate a notification alert and output the same to the display  900 . 
     More specifically, the controller  800  may compare movement characteristics respectively sensed by a plurality of sensor modules  600  respectively facing a plurality of position detected area portions  500  with each other. When the movement characteristics are different from each other based on the comparing result, the controller  800  may output the notification alert to the display  900 , such that the administrator may be guided to inspect the position detecting means including the position area sensor  500  and the sensor module  600  and an entirety of the power device. 
     Accordingly, the monitoring system of the power device according to the present disclosure may identify an error in the movement characteristics of the circuit breaker body  200  caused by an error in the position detecting means, a defect in the sensor module  600  or a transfer failure of the truck  400  in a short time. 
     In one example,  FIG.  7    and  FIG.  8    are perspective views showing a girder and a truck at a disconnection position and a contact position in a monitoring system of a power device according to an embodiment of the present disclosure, respectively. 
     Further,  FIG.  9    is a perspective view showing a position bar in a monitoring system of a power device according to an embodiment of the present disclosure.  FIG.  10    is a perspective view showing each of a top face and a bottom face of a sensor module in a monitoring system of a power device according to an embodiment of the present disclosure, 
     Referring to  FIG.  7    to  FIG.  10   , in the monitoring system of the power device according to the present disclosure, the position detected area portion  500  may be formed on a position bar  350  having one end coupled to the girder  300  and the other end acting as a free end facing the cradle terminal  110 . The sensor module  600  may be fixedly coupled to one side of the truck  400  so as to detect movement characteristics of the position detected area portion  500 . 
     More specifically, the position bar  350  may extend in parallel to the spindle  330  such that one end of the position bar  350  is coupled to the girder  300 , and the other end thereof acts as the free end. 
     Further, the sensor module  600  may include at least one of a non-contact type sensor  610  disposed to face the position detected area portion  500  and a contact type sensor  620  disposed to contact the position detected area portion  500 . 
     In this case, the non-contact type sensor  610  may be embodied as an optical sensor and may be configured to detect a shade, a distance, a shape, etc. of a predefined area of the position detected area portion  500 . 
     Further, as shown in (b) of  FIG.  10   , the contact type sensor  620  may be embodied as an FPCB (Flexible Printed Circuit Board) or an elastic member extending toward the position bar  350  and thus contacting the position bar  350 . 
     In one example, the position detected area portion  500  may extend along the movement range of the truck  400  as described above. More preferably, as shown in (a) of  FIG.  9   , the position detected area portion  500  may be embodied as a position sticker  510  having a shade varying depending on a position, such as a gradation sticker. 
     In this regard, the position sticker  510  may have a polygon shape such as a triangle having an area size varying in the movement direction of the circuit breaker body  200 , as shown in (b) of  FIG.  9   . 
     In one example, the position detected area portion  351  may be formed as a position inclined portion  520  as shown in (c) of  FIG.  9   . The position inclined portion  520  may be formed to protrude upwardly beyond the top face of the position bar  350 . Alternatively, the position inclined portion  520  may be formed to be recessed downwardly beyond the top face of the position bar  350 . 
     In this regard, a gradation tape whose a shade varies as described above may be attached to a top face of the position inclined portion  520 . 
     In one example, the position detected area portion  500  may include a plurality of position protrusions  530  arranged and spaced from each other by a predefined spacing as shown in (d) of  FIG.  9   . 
     More preferably, the numbers, shapes, positions of the position protrusions  530  may vary in the movement direction of the truck  400  so that the position of the circuit breaker body  200  may be detected by the sensor module  600 . 
     Further, the position detected area portion  500  may include a combination of the position protrusions  530  and the position tape  510 . 
     In one example, in the monitoring system of the power device according to the present disclosure, the truck  400  may include a plurality of position bar guides  430  adjacent to or in contact with both opposing side faces of the position bar  350 . 
     Further, as shown in  FIG.  6   , the position bar guide  430  is preferably provided with a brush-type cleaner  700  capable of removing dust or foreign substances deposited on the position detected area portion  500 . 
     Accordingly, the monitoring system of the power device according to the present disclosure may minimize a detection error of the sensor module  600  due to the foreign material deposited on the position detected area portion  500 . 
     Further, the contact type sensor  620  may contact the position inclined portion  520  and may detect a varying height of the position inclined portion  520  and thus detect the position of the circuit breaker body  200  based on the varying height. 
     In one example,  FIG.  11    and  FIG.  12    are side cross-sectional views at the disconnection position and the contact position in the monitoring system of the power device according to an embodiment of the present disclosure, respectively. 
     Further,  FIG.  13    is a side view illustrating a position detected area portion in a monitoring system of a power device according to an embodiment of the present disclosure. 
     Referring to  FIG.  11    to  FIG.  13   , in the monitoring system of the power device according to the present disclosure, the position detected area portion  500 ′ may be formed on a side face of the circuit breaker body  200 , and the sensor module  600 ′ may be fixedly coupled to an inner side face of the cradle  100  so as to detect the movement characteristics of the position detected area portion  500 ′. 
     In this regard, as shown in (a) of  FIG.  13   , the position detected area portion  500 ′ may be embodied as a position sticker  510 ′ having a shade varying depending on a position, such as a gradation sticker. 
     Alternatively, the position detected area portion  500 ′ may have a polygon shape such as a triangle having an area size varying in the movement direction of the circuit breaker body  200 , as shown in (b) of  FIG.  13   . 
     Alternatively, the position detected area portion  500 ′ may be formed as a position inclined portion  520 ′ as shown in (c) of  FIG.  13   . The position inclined portion  520 ′ may be formed to protrude upwardly beyond the side face of the circuit breaker body  200 . Alternatively, the position inclined portion  520 ′ may be formed to be recessed downwardly beyond the side face of the circuit breaker body  200 . 
     In this regard, a gradation tape whose a shade varies as described above may be attached to a top face of the position inclined portion  520 ′. 
     In one example, the position detected area portion  500 ′ may include a plurality of position protrusions  530 ′ arranged and spaced from each other by a predefined spacing as shown in (d) of  FIG.  13   . 
     More preferably, the numbers, shapes, positions of the position protrusions  530 ′ may vary in the movement direction of the truck  400  so that the position of the circuit breaker body  200  may be detected by the sensor module  600 . 
     Further, the position detected area portion  500 ′ may include a combination of the position protrusions  530 ′ and the position tape  510 ′. 
     In one example, in the monitoring system of the power device according to the present disclosure, the position detected area portion  500 ′ may be formed on the inner side face of the cradle  100 , and the sensor module  600 ′ may be formed on the side face of the circuit breaker body  200 . 
     However, it is more preferable that the sensor module  600 ′ is disposed on the inner side face of the cradle  100  as described above such that connection, control, and inspection of the sensor module  600 ′ is facilitated. 
     In this regard, when the sensor provided in the sensor module  600 ′ is embodied as an optical sensor including wireless communication means, the position detected area portion  500 ′ may be formed on an inner side face of the cradle  100 , and the sensor module  600 ′ may be disposed on the side face of the breaker body  200 , according to a design specification. 
     More specifically, the cradle terminal  110  which the circuit breaker body  200  electrically and mechanically contacts may include terminals of three-phases (R, S, T). In this case, when contacts between the circuit breaker body  200  and these terminals  110  fail to occur concurrently, damage to the power device and power accident may occur. 
     Therefore, when the cradle terminal  110  which the circuit breaker body  200  electrically and mechanically contacts may include terminals of three-phases (R, S, T), the power device for continuously detecting extended and retracted positions according to the present disclosure may be configured such that the position detected area portion  500 ′ is formed on each of both opposing side faces of the circuit breaker body  200  and accordingly, the sensor module  600 ′ is formed on each of both opposing inner side faces of the cradle  100  so that contacts or disconnections between the circuit breaker body  200  and these terminals  110  occur concurrently. 
     Further, when the positions of the circuit breaker body  200  respectively detected by the two sensor modules  600 ′ fail to coincide with each other, the display  900  may output a notification alert. 
     Accordingly, in the monitoring system of the power device according to the present disclosure, the circuit breaker body  200  may contact or may be disconnected from the cradle terminal  110  to prevent device damage and power accidents. 
     In one example, the sensor module  600 ′ may include at least one of a non-contact type sensor  610 ′ disposed to face the position detected area portion  500 ′ and a contact type sensor  620 ′ of a roller type contacting the position detected area portion  500 ′, as shown in  FIG.  6   . 
     Further, a brush or roller type cleaner  700 ′ may be disposed in front or rear of the sensor module  600 ′ so as to remove dust or foreign substances adhering to a surface of the position detected area portion  500 ′. 
     In one example, the cleaner  700  is more preferably installed in front of the sensor module  600 . 
     When the cleaner  700  is adjacent to the cradle terminal  110 , arc may occur such that the cleaner  700  may be damaged or an electrical problem may occur. Thus, the cleaner  700  may be spaced from the cradle terminal  110  by a maximum spacing. 
     The present disclosure has been described above with reference to the illustrated drawings. However, the present disclosure is not limited to the embodiments and drawings disclosed in the present specification. It is obvious that various modifications may be made by those skilled in the art within the scope of the technical idea of the present disclosure. In addition, although effects according to the configurations of the present disclosure are not explicitly described while describing the embodiments of the present disclosure, it is natural that the predictable effects from the configurations should also be appreciated.