Patent Publication Number: US-2022239073-A1

Title: Interlock structure of bypass transfer switching device

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korean Patent Application No. 10-2021-0012494, filed Jan. 28, 2021, the entire contents of which is incorporated herein for all purposes by this reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present disclosure relates generally to an interlock structure of a bypass transfer switching device and, more particularly, to an interlock structure of a bypass transfer switching device capable of performing physical prevention of manual switching on an automatic transfer switch when supply power is bypassed, and capable of allowing the automatic transfer switch to be input into a switchboard when power input directions of a bypass switch and the automatic transfer switch match with each other. 
     Description of the Related Art 
     In general, a large building or a factory receives a normal supply from a source of a power supply such as Korea Electric Power Corporation. When an abnormality like a power outage occurs in the normal supply, the above facilities generate an alternative supply using a power generator provided inside. In a large building or the factory, an automatic transfer switching device including an automatic transfer switch (ATS) is provided to supply electric power to a load side by connecting the normal supply to the load side in normal times and to supply emergency electric power to the load side by connecting the alternative supply to the load side when an abnormality occurs in a source of the normal supply. The automatic transfer switching device consists of automatic transfer switches connected to each other in parallel. When an error occurs in one of the automatic transfer switches, the automatic transfer switching device performs switching to supply a power supply through another automatic transfer switch arranged in parallel. Accordingly, the automatic transfer switching device is provided as a bypass transfer switching device so that maintenance, testing, etc. of an automatic transfer switch with an error may be efficiently performed. 
     As shown in  FIG. 1 , the bypass transfer switching device has an automatic transfer switch  10  and a bypass switch  20  in a switchboard  30 . As shown in  FIG. 2 , at an fixed terminal portion of each switch  10 ,  20 , a normal supply terminal  10 - 1 ,  20 - 1  provided to supply the normal supply and an alternative supply terminal  10 - 2 ,  20 - 2  provided to supply the alternative supply, and a load terminal  10 - 3 ,  20 - 3  provided to supply a power supply to the load supply are wired in parallel connection, so that a moving terminal  10 - 4 ,  20 - 4  provided at the switch  10 ,  20  performs switching to the power supply terminal  10 - 1 ,  10 - 2 ,  20 - 1 , and  20 - 2 . As shown in  FIG. 1 , a lever input portion  10   a  is provided at a front surface of the automatic transfer switch  10  and administrator inputs a lever to the lever input portion  10   a , thereby manually switching a power supply of the automatic transfer switch  10 . Meanwhile, when maintenance, repair, or testing of the automatic transfer switch  10  is required, the bypass transfer switching device performs switching so that a power supply is supplied without a cut-off to the load side through the bypass switch  20 . Therefore, maintenance, repair, or testing of the automatic transfer switch  10  may be efficiently performed. 
     However, the conventional bypass transfer switching device described above has following problems. 
     First, when the administrator switches the bypass switch  20  into the normal supply or the alternative supply in order to perform maintenance, repair, testing, etc. of the automatic transfer switch, without recognizing that the bypass switch  20  is switched, the administrator or an operator may input the lever into the lever input portion  10   a  to manually switch a power supply of the automatic transfer switch  10 , so there is a problem causing a fire accident in addition to a damage of an apparatus such as a power supply apparatus, etc. The bypass transfer switching device does not have a problem when an input power supply of the bypass switch  20  and an input power supply of the automatic transfer switch match with each other. However, when the operator performs manual switching of the automatic transfer switch through the lever input portion  10   a  from carelessness in the state in which the input power supply of the bypass switch  20  and the input power supply of the automatic transfer switch do not match with each other, there may be a problem causing a large accident. 
     Second, in a process that the administrator draws the automatic transfer switch  10  from the switchboard in a state in which a power supply is bypassed using the bypass switch  20  and performs testing or maintenance of the automatic transfer switch  10  and then returns the automatic transfer switch  10  to the switchboard, when an input power supply of the bypass switch  20  and an input power supply of the automatic transfer switch  10  do not match with each other, the bypass transfer switching device may have a problem of causing the above-described accidents. The administrator performs testing or maintenance while drawing the automatic transfer switch  10  from the switchboard  30  and then inputting the normal supply or the alternative supply to the automatic transfer switch  10 . When the operator returns the automatic transfer switch  10  into the switchboard  30  after completion of a series of operations, mismatch between the input power supply of the automatic transfer switch  10  and the input power supply of the bypass switch  20  may lead to an accident such as a damage of an apparatus and a fire accident. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present disclosure has been made keeping in mind the above problems occurring in the related art, and the present disclosure is intended to provide an interlock structure of a bypass transfer switching device, wherein when supply power is bypassed through a bypass switch, a lever input portion of an automatic transfer switch is automatically closed to fundamentally prevent manual switching of the automatic transfer switch. 
     In order to achieve the above object, according to one aspect of the present disclosure, there is provided an interlock structure of a bypass transfer switching device. The interlock structure of the bypass transfer switching device includes: an automatic transfer switch having a lever input portion of a through hole shape for manual switching of a normal supply and an alternative supply; a bypass switch configured to bypass electric power of the normal supply or the alternative supply supplied to a load side through the automatic transfer switch, the bypass switch including a bypass lever capable of manually switching a bypass circuit; and an interlock device configured to automatically close the lever input portion when the bypass lever is operated, wherein the interlock device includes: a main bar shaft-coupled to the bypass lever and configured to raise and lower the automatic transfer switch by a turning operation of the bypass lever; an elevation member configured to be raised and lowered in a height direction of the automatic transfer switch while being in conjunction with raising and lowering movement of the main bar, and having an inclined surface formed toward the lever input portion; and an opening and closing plate configured to open and close the lever input portion while being moved toward the lever input portion or returned to an initial location thereof along the inclined surface of the elevation member by a raising and lowering operation of the elevation member. 
     The interlock structure of the bypass transfer switching device according to the present disclosure is configured to automatically close the lever input portion of the automatic transfer switch when supply power is bypassed through the bypass switch. Therefore, it is possible to fundamentally prevent an operator from manually switching power supplies of the automatic transfer switch. Accordingly, the present disclosure has an effect that a damage to an apparatus at a load side or a fire accident due to mismatch between an input power supply of the bypass switch and an input power supply of the automatic transfer switch does not occur during repair and testing of the automatic transfer switch. 
     Furthermore, the interlock structure of the present disclosure is configured such that, when supply power is bypassed through the bypass switch, the automatic transfer switch may input into a switchboard only when a power input direction of the automatic transfer switch drawn from the switchboard and a power input direction of the bypass switch match with each other. Accordingly, damage to an apparatus and an accident due to mismatch between the input power of the bypass switch and the input power of the automatic transfer switch can be prevented. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objectives, features, and other advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a view showing a bypass transfer switching device. 
         FIG. 2  is a view showing a circuit structure of the bypass transfer switching device. 
         FIG. 3  is a view showing an installed state of an interlock structure of the bypass transfer switching device according to an exemplary embodiment of the present disclosure. 
         FIG. 4  is a front perspective view showing the interlock structure of the bypass transfer switching device according to the exemplary embodiment of the present disclosure. 
         FIG. 5  is a rear perspective view showing the interlock structure of the bypass transfer switching device according to the exemplary embodiment of the present disclosure. 
         FIGS. 6A and 6B  are a side view and a front view showing the interlock structure of the bypass transfer switching device with an automatic transfer switch in an operated state according to the exemplary embodiment of the present disclosure. 
         FIGS. 7A and 7B  are a side view and a front view showing the interlock structure of the bypass transfer switching device according to the exemplary embodiment of the present disclosure in a state in which power is bypassed to a normal supply through a bypass switch. 
         FIGS. 8A and 8B  are a side view and a front view showing the bypass transfer switching device of the interlock structure according to the exemplary embodiment of the present disclosure in a state in which power is bypassed to an alternative supply through the bypass switch. 
         FIG. 9  is a view showing a state in which a power supply of the automatic transfer switch drawn from a switchboard is input to the alternative supply while a power supply is bypassed to the normal supply through the bypass switch. 
         FIG. 10  is a view showing a state in which a power supply of the automatic transfer switch drawn from the switchboard is input to the normal supply while power is bypassed to the alternative supply through the bypass switch. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     It should be noted that the terms and words used in the specification and the claims should not be construed as being limited to ordinary meanings or dictionary definitions. Meanwhile, the embodiments described in the specification and the configurations illustrated in the drawings are merely examples and do not exhaustively present the technical spirit of the present disclosure. 
     Hereinbelow, an interlock structure of the bypass transfer switching device (hereinbelow, the interlock structure of the bypass transfer switching device refers to ‘the interlock structure’) according to an exemplary embodiment of the present disclosure will be described with reference to  FIGS. 3 to 10 . 
     With the bypass transfer switching device in which an automatic transfer switch  10  and a bypass switch  20  are connected to each other in parallel, the interlock structure includes an interlock device capable of closing a lever input portion  10   a  formed in the automatic transfer switch  10 , as shown in  FIGS. 3 and 4 . The bypass switch  20  includes a bypass lever  21  capable of switching an input direction of the bypass switch  20 , the bypass lever  21  is provided to be turned upward and downward in a switchboard  30 , as shown in  FIGS. 6A, 7A, and 8A . For example, when the bypass lever  21  is turned upward in the switchboard  30 , a normal supply is bypassed to the bypass switch  20 , and when the bypass lever  21  is turned downward in the switchboard  30 , an alternative supply is bypassed to the bypass switch. 
     As shown in  FIG. 4 , the interlock device includes a main bar  100 , an elevation member  200 , an opening and closing plate  300 , an interlock means  400 , and the guide means  500 . 
     The main bar  100  is configured to transmit a turning operation of the bypass lever  21  to the opening and closing plate  300 , and is provided between the bypass lever  21  and the interlock means  400 , which will be described later. The main bar  100  is provided in a direction perpendicular to the bypass lever  21 . The main bar  100  is shaft-coupled to the bypass lever  21 , and when the bypass lever  21  is turned normally and reversely, the main bar  100  is raised and lowered in a height direction of the switchboard  30  at a side portion in the switchboard  30 . 
     The elevation member  200  is raised and lower by a raising and lowering operation of the main bar  100 , and serves to push or pull the opening and closing plate  300 . The elevation member  200  is raised and lowered by the interlock means  400 , which will be described later. As shown in  FIGS. 4 and 5 , the elevation member  200  has a panel shape bent along a side portion and a front surface of the automatic transfer switch  10 . An elevation hole  210  is provided at a first side of the elevation member  200  corresponding to the side surface of the switchboard  30  to be coupled to the guide means  500  so that the raising and lowering operation of the elevation member  200  is efficiently performed. The elevation hole  210  allows rollers of the guide means  500 , which will be described later, to be rotatable while being inserted in the elevation hole, so the elevation member  200  may be efficiently raised and lowered. The longitudinal elevation hole  210  is formed in a height direction of the elevation member  200  and preferably includes a plurality of elevation holes. An inclined surface  220  is formed on a second side of the elevation member  200  corresponding to a front surface of the switchboard  30 . The inclined surface  220  is formed toward the lever input portion  10   a  of the automatic transfer switch  10  and is formed at an angle that is symmetric in a vertical direction with a center portion of the elevation member  200  as the center. The inclined surface  220  is formed such that upper and lower widths thereof are gradually increased toward the lever input portion  10   a  with the center portion of the second side of the elevation member  200  as the center. The inclined surface  220  may be divided into an upper inclined surface  221  and a lower inclined surface  222  with the center portion of the elevation member  200  as the center. 
     The opening and closing plate  300  is configured to effectively close the lever input portion  10   a  by the turning operation of the bypass lever  21 . The opening and closing plate  300  is located in rear of a front panel of the automatic transfer switch  10  and is configured to be reciprocatively moved toward the lever input portion  10   a . It is safe to form the opening and closing plate  300  in a shape capable of closing the lever input portion  10   a , and a guide bar  310  is provided at a first side of the opening and closing plate  300  as shown in  FIG. 5 . The guide bar  310  is configured such that the opening and closing plate  300  may be operated in conjunction with the raising and lowering operation of the elevation member  200 , and the guide bar  310  is formed by protruding outward from the opening and closing plate  300 . The guide bar  310  is located at the center portion of the elevation member  200  where the inclined surface  220  of the elevation member  200  begins, and the guide bar  310  may be moved along the inclined surface  220  when the elevation member  200  is raised and lowered. The opening and closing plate  300  has springs  320  so that the reciprocating movement of the opening and closing plate  300  is efficiently performed, as shown in  FIG. 6B . The opening and closing plate  300  has rollers  330  to allow the opening and closing plate  300  to reciprocate smoothly, as shown in  FIG. 4 . 
     The interlock means  400  serves to transmit the raising and lowering operation of the main bar  100  to the elevation member  200  and may be located between the main bar  100  and the elevation member  200 . As shown in  FIG. 4 , the interlock means  400  includes an interruption member  410 , a first link  420 , and a second link  430 . The interruption member  410  has a longitudinal groove  411  protruding outward from the main bar  100  and being open toward the front of the switchboard  30 . A first end of the first link  420  is located in the longitudinal groove  411 , and the longitudinal groove  411  is configured such that turning operation of the first link  420  according to the raising and lowering movement of the interruption member  410  is efficiently performed without interruption. The first link  420  is shaft-coupled to a portion inside the automatic transfer switch  10  and is configured to be turned in a height direction of the main bar  100 , i.e. a raising and lowering direction of the main bar  100  by the raising and lowering operation of the interruption member  410 . The first end of the first link  420  is located in the longitudinal groove  411  of the interruption member  410  as described above, and more precisely, an interruption protrusion  421  protrudes outward on the first end of the first link  420 . The interruption protrusion  421  is located in the longitudinal groove  411  to allow the movement of the interruption member  410  to be transmitted to the first link  420  through the interruption protrusion  421 . The second link  430  is operated in conjunction with the movement of the first link  420  and is provided between the first link  420  and the elevation member  200 . A first end of the second link  430  is shaft-coupled to a second end of the first link  420 , and a second end of the second link  430  is shaft-coupled to the elevation member  200 . With the above-described structure, when the first link  420  is turned on a shaft, the second link  430  performs the operation of pushing downward or pulling upward the elevation member  200 . 
     The guide means  500  serves to guide the elevation member  200  and the opening and closing plate  300 , so that the elevation member  200  efficiently performs the raising and lowering operation and the opening and closing plate  300  efficiently performs the reciprocating movement. In other words, the guide means  500  serves to guide a raising and lowering path of the elevation member  200  and a movement path of the opening and closing plate  300 . As shown in  FIGS. 4 and 5 , the guide means  500  is formed in a shape bent along a side portion and the front surface of the automatic transfer switch  10 . The guide means  500  has rollers  510  at a first side thereof, and the rollers  510  is provided to be rolled along the elevation hole  210  of the elevation member  200 . In other words, when the elevation member  200  is raised and lowered, the rollers  510  of the guide means  500  is rolled along the elevation hole  210 , whereby the elevation member  200  may be efficiently raised and lowered. The guide means  500  has guide holes  520  at a second side thereof. The guide holes  520  is configured to allow the rollers  330  provided at the opening and closing plate  300  to be rolled, thereby allowing the opening and closing plate  300  to be efficiently moved during the reciprocating movement thereof. 
     Hereinbelow, the operation of the interlock structure having the above-described structure will be described. 
       FIGS. 6A and 6B  are a side view and a front view showing an operating state the automatic transfer switch  10  in a state in which power is normally supplied. As shown in the drawings, the bypass lever  21  is in a state in which the bypass lever  21  is not connected to any power supply of the bypass switch  20 . The lever input portion  10   a  is in an open state so that manual switching of the automatic transfer switch  10  may be performed. When the automatic transfer switch  10  in the above-described open state of the lever input portion  10   a  needs maintenance, testing, etc., an operator bypasses a power supply, which is supplied through the automatic transfer switch  10 , through the bypass switch  20 . 
     For example, as shown in  FIG. 7A , the operator turns the bypass lever  21  upward to bypass the normal supply from the automatic transfer switch  10  to the bypass switch  20 . The main bar  100  is raised to the upper portion of the switchboard  30  with the interruption member  410 , as the bypass lever  21  is turned upward. The interruption protrusion  421  of the first link  420  is located in the longitudinal groove  411  of the interruption member  410 , thereby allowing the first link  420  to be turned upward in conjunction with the interruption member  410 . When the first link  420  is turned as described above, a first end of the first link  420  is raised and a second end thereof is lowered, as shown in  FIGS. 6A and 7A . When the second end of the first link  420  is lowered, the elevation member  200  is lowered to a lower portion of the switchboard  30 , and lowering movement of the elevation member  200  may be supply performed as the rollers  510  are rolled along the elevation hole  210 . 
     When the elevation member  200  is lowered, the guide bar  310  of the opening and closing plate  300  is moved by being guided along the upper inclined surface  221  of the elevation member  200 . The opening and closing plate  300  is moved by a distance in which the guide bar  310  is moved along the upper inclined surface  221 , as shown in  FIGS. 6A and 7B . In other words, the opening and closing plate  300  is moved rightward along the guide holes  520  of the guide means  500  while extending the springs  320 , thereby closing the lever input portion  10   a . Accordingly, according to the present disclosure, when the bypass lever  21  bypasses a power supply of the automatic transfer switch  10 , the opening and closing plate  300  automatically closes the lever input portion  10   a  while being operated in conjunction with the operation of the bypass lever  21 , so that the manual switching for the automatic transfer switch  10  is completely blocked. Then, the operator performs a series of operations on the automatic transfer switch  10 , and when the operations are completed, the operator returns the bypass lever  21  to an initial location thereof, as shown in  FIG. 6A . 
     Meanwhile, the operator turns the bypass lever  21  downward as shown in  FIGS. 8A , so that the alternative supply may be bypassed from the automatic transfer switch  10  to the bypass switch  20 . The main bar  100  is lowered with the interruption member  410  to the lower portion of the switchboard  30 . The first link  420  is turned to raise the second end thereof by the downward movement of the interruption member  410  as shown in  FIGS. 6A and 8A . When the second end of the first link  420  is raised, the elevation member  200  is raised toward the upper portion of the switchboard  30 . When the elevation member  200  is raised, the guide bar  310  of the opening and closing plate  300  is moved by being guided along the lower inclined surface  222  of the elevation member  200 . The opening and closing plate  300  is moved as a distance in which the guide bar  310  is moved along the lower inclined surface  222  to close the lever input portion  10   a  as shown in  FIGS. 6B and 8B . 
     As known in the operation of the interlock device, in the present disclosure, regardless of whether the bypass lever  21  bypasses the normal supply or bypasses the alternative supply, when supply power is bypassed, the opening and closing plate  300  is automatically moved to close the lever input portion  10   a . When a power supply of the automatic transfer switch  10  is bypassed, the present disclosure is configured to close the lever input portion  10   a  unconditionally, whereby it is possible to completely prevent the operator from manually switching the automatic transfer switch  10  inadvertently. 
     Meanwhile, according to the present disclosure, in a process in which the automatic transfer switch  10  is drawn from the switchboard  30  and undergoes repair or testing after the power supply of the automatic transfer switch  10  is bypassed, when an input power supply of the automatic transfer switch  10  and an input power supply of the bypass switch  20  are different from each other, it is possible to prevent the automatic transfer switch  10  from being returned to the switchboard  30 . As described above, the technical feature of the present disclosure is also provided to prevent equipment damages and accidents caused by difference between the input power supply of the automatic transfer switch  10  and the input power supply of the bypass switch  20 . 
     Therefore, as shown in  FIG. 4 , the automatic transfer switch  10  of the present disclosure includes a normal supply rotary shaft  12  and an alternative supply rotary shaft  22  for inputting of the normal supply and the alternative supply. The normal supply rotary shaft  12  and the alternative supply rotary shaft  22  are arranged in a height direction from each other. A cam link  13 ,  23  is provided at an end of each of the normal supply rotary shaft  12  and the alternative supply rotary shaft  22 , and the cam link  13 ,  23  is operated in conjunction with the rotation of each rotary shaft  12 ,  22 . A cam link  13  of the normal supply rotary shaft  12  and a cam link  23  of the alternative supply rotary shaft  22  are arranged while being in a symmetrical state from each other and, more particularly, eccentric portions thereof face each other. The cam link  13 ,  23  has a restraining protrusion  14 ,  24  formed by protruding outward. The restraining protrusion  14 ,  24  is formed by protruding from the cam link  13 ,  23  toward the main bar  100 , and may be provided to be interrupted with each of the stoppers. 
     The main bar  100  has stoppers  110  in a height direction of the main bar  100 . The stoppers  110  are configured to interrupt with the restraining protrusions  14  and  24  and a plurality of stoppers  110  is provided in the main bar  100 . In detail, two stoppers  110  are provided at the main bar  100 , and an interval between the stoppers  110  corresponds to a gap between the restraining protrusions  14  and  24  arranged between the normal supply rotary shaft  12  and the alternative supply rotary shaft  22 , and the stoppers  110  the stoppers  110  is configured to interrupt with the restraining protrusions  14  and  24  provided at the normal supply rotary shaft  12  and the alternative supply rotary shaft  22  when the main bar  100  is raised and lowered by the turning operation of the bypass lever  21 . 
     Hereinbelow, the operation in which the automatic transfer switch  10  of the bypass transfer switching device that includes the stoppers  110  and the restraining protrusions  14  and  24  enters and exits from the switchboard  30  will be described. 
       FIG. 6A  is a view showing a state in which the automatic transfer switch  10  is normally operated. The restraining protrusions  14  and  24  of the normal supply rotary shaft  12  and the alternative supply rotary shaft  22  are located between the stoppers  110 , so that the input of the automatic transfer switch  10  into the switchboard  30  is free. The operator draws the automatic transfer switch  10  from the switchboard  30  while bypassing the normal supply, as shown in  FIG. 9 , and then performs a series of operations. For example, the operator draws the automatic transfer switch  10  from the switchboard  30  and then performs various operations while changing an input power supply of the automatic transfer switch  10 . However, a main circuit is in a connected state through the bypass switch  20 , so even when the automatic transfer switch  10  is drawn from the switchboard  30 , power supply may be performed without problems. Then, when a series of operations on the automatic transfer switch  10  is completed, the operator returns the automatic transfer switch  10  to the switchboard. As shown in  FIG. 9 , the bypass lever  21  is turned upward to bypass the normal supply, and an input direction of a power supply of the automatic transfer switch  10  is arranged such that the alternative supply rotary shaft  22  is rotated to allow the cam link  23  faces the alternative supply. Accordingly, the restraining protrusion  24  provided at the alternative supply rotary shaft  22  is interrupted by a lower stopper  110  of the main bar  100 . Accordingly, the automatic transfer switch  10  drawn from the switchboard  30  is not input into the switchboard  30  unless the operator rotates the alternative supply rotary shaft  22  rotated in the input direction of the alternative supply in an opening direction. 
     As shown in  FIG. 10 , in a case in which the normal supply rotary shaft  12  of the automatic transfer switch  10  is rotated for input of the normal supply while the bypass lever  21  is turned downward to bypass the alternative supply, the restraining protrusion  14  of the normal supply rotary shaft  12  is interrupted by an upper stopper  110  of the main bar  100  to prevent the automatic transfer switch from being input into the switchboard  30  unless the operator rotates the normal supply rotary shaft  12  rotated in an input direction of the normal supply in an opening direction. 
     As described above, the interlock structure of the bypass transfer switching device according to the present disclosure is configured such that, when the supply power is bypassed, the lever input portion of the automatic transfer switch is automatically closed regardless of the bypassed power supply. When a power supply of the automatic transfer switch drawn from the switchboard and the bypassed power supply do not match with each other, the interlock structure of the bypass transfer switching device according to the present disclosure is configured to prevent the automatic transfer switch from being input into the switchboard. Accordingly, the present disclosure is configured to prevent device damages and safety accidents such as an electric shock to the operator when supply power is bypassed for performing repair, maintenance, testing, etc. on the automatic transfer switch. 
     Although a preferred embodiment of the present disclosure has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.