Abstract:
A system and method for resetting a tripped circuit breaker are provided. The system includes a monitoring mechanism for monitoring a state of at least one electrical circuit breaker and for generating at least one monitoring signal indicative of the state of the at least one electrical circuit breaker; an actuating mechanism for actuating the at least one electrical circuit breaker in a plurality of positions; and a controller for receiving the at least one monitoring signal and for generating and transmitting at least one control signal to the actuating mechanism for resetting the at least one circuit breaker. The breaker reset system is self-contained and dimensioned as an add-on component to previously installed circuit breaker enclosure or as an integrated component of a circuit breaker enclosure. Additionally, the system allows for manual over-ride of the reset function.

Description:
PRIORITY  
       [0001]     The present application is a U.S. patent application claiming priority from U.S. Provisional Application No. 60/484,936 entitled “BREAKER RESET SYSTEM” filed in the United States Patent and Trademark Office on Jul. 3, 2003, the contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates generally to systems and methods for resetting electrical breakers, and more particularly, to systems and methods for resetting electrical breakers without user intervention.  
         [0004]     2. Description of the Prior Art  
         [0005]     Electrical wiring found in homes and industry typically includes multiple circuits each protected by a circuit breaker. The circuit breaker&#39;s primary function is to provide protection against fire or electrocution resulting from a short or other wiring problem in the circuit. Additionally, circuit breakers provide a means for temporarily removing power from a circuit so that it may be safely worked on by an electrician or technician.  
         [0006]     Circuit breakers may trip for any of a number of reasons, ranging from excessive load, e.g., too many appliances in operation at the same time, to dangerous electrical problems such as a short circuit. Usually, simply resetting the breaker is all that is required when the fault is caused by appliance load or random power spikes. However, faults caused by electrical wiring problems need to have the cause diagnosed and corrected before resetting the breaker.  
         [0007]     Generally, circuit breakers are positioned in out-of-the-way and sometimes not easily accessible areas of homes and commercial buildings, thus, when a circuit breaker trips due to a wiring problem or needs to be opened so that an electrician can safely work on the circuit, it can be a time consuming task to locate the circuit breaker and manually place the breaker into the desired operational mode (e.g., open or closed) for lockout/tagout.  
         [0008]     One application where an automatic breaker reset solution is most useful is in the Railroad Signal Industry. In this industry, the electrical equipment, e.g., lights, signals, movable barricades, etc., are often place in remote locations; often quite distant from one another and from any monitoring station. Circuit breaker boxes are generally scattered throughout the rail network and thus for minor circuit trips it would be highly inconvenient to require technicians to manually reset the tripped breaker. Therefore, an automatic breaker reset system would increase convenience, and reduce costs and equipment downtime by requiring technicians to respond only to severe or reoccurring circuit trips.  
         [0009]     Automatic breaker reset systems are commercially available, however these systems can only be used with specially designed circuit breakers and are generally quite costly to install. Such systems are not feasible for installation in homes or as an add-on to an existing circuit breaker system.  
       SUMMARY OF THE INVENTION  
       [0010]     A breaker reset system and method thereof are provided, which detect a tripped circuit breaker and subsequently perform a reset procedure on the circuit breaker without user intervention.  
         [0011]     An embodiment of the present disclosure provides a breaker reset system for detecting a tripped circuit breaker and subsequently resetting the circuit breaker. The breaker reset system includes a controller, e.g., a programmable logic controller (PLC), for executing instructions for detecting and resetting a tripped circuit breaker. Additionally, a line voltage control relay and a load voltage control relay are provided, which are positioned, respectively, on the line-side and load-side of the circuit breaker and in electrical communication with the controller. The control relays are configured for monitoring the voltages on their respective sides of the circuit breaker and relaying voltage status to the controller.  
         [0012]     The system analyzes the voltage status and determines if the circuit breaker has tripped. If a trip has resulted, the controller controls an actuator assembly having a motor and screw assembly. The actuator assembly is in mechanical communication with the circuit breaker&#39;s handle. The actuator assembly is configured to actuate the handle to a RESET position followed by actuating the handle to a SET position and finally returning said handle to a default position. A plurality of position sensors provides positioning information of the actuator assembly to the controller.  
         [0013]     An aspect of the present disclosure provides for a breaker reset system, which provides monitoring of a breaker&#39;s operational status, and reset of a tripped breaker, while still allowing the breaker to be opened when desired, for example, during lockout/tagout.  
         [0014]     An additional aspect of the present disclosure provides for an automated breaker reset system, which is controllable and programmable remotely.  
         [0015]     A further aspect of the present disclosure provides for an automated breaker reset system, which is adapted to be installable onto standard, commercially available circuit breakers. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     These and other features, aspects, and advantages of the present disclosure will become better understood with regard to the following description, appended claims, and accompanying drawings wherein:  
         [0017]      FIG. 1  is a schematic view of an embodiment of a self-contained breaker reset system in accordance with the present disclosure;  
         [0018]      FIG. 2  is a schematic view of the embodiment of  FIG. 1  in the RESET position configuration;  
         [0019]      FIG. 3  is a schematic view of an embodiment of  FIG. 1  in the SET position configuration; and  
         [0020]      FIG. 4  is a flowchart of the steps executed by an embodiment of the present disclosure.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]     With reference to  FIG. 1 , there is shown a schematic view of a breaker reset system  100  according to the present disclosure. The various components of the system  100  are identified in  FIG. 1 . Generally, the system  100  includes a monitoring mechanism, e.g., relays  108  and  110 , for monitoring an electrical property of a load cable  107  and a line cable  109 , respectively, a resetting mechanism  140  for resetting the circuit breaker  106  after a trip has been detected, and a controller  130  for receiving and interpreting the electrical property information from the monitoring relays  108  and  110  and controlling the resetting mechanism  140  based on the electrical property information via a control signal.  
         [0022]     The resetting mechanism  140  includes a linear drive motor  101  coupled to an interface block  104  for actuating a lever  105  of the circuit breaker  106  to reset the breaker. The linear drive motor  101  is capable of operating in two modes, a forward and a reverse mode. In the forward mode, a screw axle  102  is rotated in a clockwise direction; and in the reverse mode, the screw axle  102  is rotated in a counter-clockwise direction. The screw axle  102  is joined to an actuator assembly  103  for driving the removable interface block  104 . The interface block  104  is dimensioned to surround the lever  105  of the circuit breaker  106 . The removability of the interface block  104  allows for user-override of the system  100  so that a particular circuit breaker can be manually tripped or prevented from being tripped, for example, during lockout/tagout.  
         [0023]     The resetting mechanism  140 , additionally, includes several position sensors  120 ,  122  and  124 . The position sensors  120 ,  122  and  124  detect the position of the actuator assembly  103 , e.g., default  122 , RESET  124  or SET  120 , and relays the position data to the controller  130 , preferably, a Programmable Logic Controller (PLC). The position sensors may include a pressure switch, a magnet and contact, an LED and photodetector, etc. The controller  130  also receives voltage status data via cabling  111  from a line-voltage control relay  110  positioned to monitor the voltage present on the incoming (e.g., line-side) electrical cable  109  and a load-voltage control relay  108  positioned to monitor the voltage present on the outgoing (e.g., load-side) electrical cable  107 .  
         [0024]     The controller  130  is programmed with executable instructions, which utilize the status data received to determine if the circuit breaker  106  has been tripped. Upon failure of the circuit breaker, the load-voltage will drop significantly and load-current will approach zero-amps. This causes monitoring relay  108  to de-energize. When conditions are such that monitoring relay  110  (line-voltage) is energized and monitoring relay  108  (load-voltage) is de-energized, the controller  130  will confirm a tripped circuit breaker condition. These conditions will cause the system  100  to respond by initiating a Reset Cycle as will be described below in relation to  FIG. 2-4 .  
         [0025]     Once the controller  130  determines that a trip fault has occurred, the controller  130  issues commands via control cabling  112  directing the linear drive motor  101  to move the actuator assembly first to a RESET position (see  FIG. 2 ), then to a SET position (see  FIG. 3 ) and finally to the lever&#39;s  105  default position, as will be described in detail below. The position sensors  120 ,  122  and  124  provide feedback to the controller  130 , indicating whether the actuator assembly  103  has moved to the directed position. Once the controller  130  receives feedback from the position sensors  120 ,  122  and  124  indicating successful actuator assembly  103  movement to the directed position, the controller  130  issues the next command directing the actuator assembly  103  to move to the next position, and so on until the circuit breaker has been properly reset.  
         [0026]     While most faults occur due to transient power spikes and require simply resetting the tripped circuit breaker  106 , some faults, however, are caused by damaged or faulty wiring. Faults caused by damaged or faulty wiring will cause the circuit breaker  106  to repeatedly trip. In such a situation, the controller  130  is programmed to track repeated faults and upon reaching a threshold number of faults in a predetermined period of time, the controller  130  will cease attempts to reset the circuit breaker  106 . The controller  130  may be further configured to issue a notification alerting a technician of a possibly serious wiring problem if the threshold number of faults has been exceeded. The notification may take the form of an indicator light, an alarm or both.  
         [0027]     Additionally, a communication module  132  may be incorporated to provide notification over a wireless data connection, e.g., IEEE 802.11/a/b/g, Bluetooth, or mobile telephony (GSM, CDMA, etc.), or a hard-wired connection. Wireless notification over mobile phone systems is especially useful in cases where the breaker reset system  100  is installed at a remote, off-site location as may occur when the breaker reset system is used in railroad applications.  
         [0028]     Ideally, the breaker reset system  100 , is powered by the voltage of the line-side cable  109 . However, an additional uninterruptible backup power source may be present for situations where power is lost from the line-side (e.g., blackout, etc.). Such a backup power source can be a battery that is rechargeable from the line-side voltage or it may be an electric generator disposed for providing power to the system during power loss. Additionally, solar energy may be used for recharging the battery.  
         [0029]      FIG. 4  illustrates a flow chart of a preferred method of operating the breaker reset system  100  of the present disclosure. At step  401 , the breaker reset system  100  begins operation, initializing the controller  130 . The status of the controller  130  is checked in step  402 . Step  402  is performed until the controller  130  is enabled and operational at which point, the PLC  130  proceeds to step  403  and checks for line voltage via relay  110 , followed by a check for load voltage via relay  108  in step  404 . If line voltage is not detected then the process returns to step  402  and continues as previously described. If load voltage is not detected, step  406  is initiated, wherein the system is evaluated to determine if a fault has occurred, e.g., if a predetermined number of trips have occurred within a predetermined period of time. In the event of a fault, the method proceeds to step  407  and pauses until an operator clears the fault manually. If a fault is not diagnosed, the method continues to step  409  to reset the tripped breaker as described below.  
         [0030]     In the event that both monitoring relays  108 ,  110  become de-energized, the system  100  will determine that a major power failure has occurred and that a reset cycle is not necessary. In event of a major power failure during a reset cycle, the system  100  will wait for line-power to return before attempting any further cycle actions.  
         [0031]     If both line and load voltages are detected in steps  403  and  404 , the method allows a user to selectively perform step  405 , where a cycle test, e.g., diagnostic test, is performed. The cycle test performs the steps  409  to  413  as if an actual trip of the circuit breaker  106  had been detected. Step  405  may also be performed automatically as part of system initialization or a periodic system check.  
         [0032]     Proceeding on to step  409 , when it is detected that the circuit breaker  106  has tripped, e.g. line voltage is detected but load voltage is not as in step  404 , the controller  130  directs the resetting mechanism  140  to drive the actuator assembly  103 , moving the circuit breaker lever  105  to the RESET position (see  FIG. 2 ). In step  410 , the actuator assembly  103  is confirmed to be in the RESET position via position sensor  124 . In step  411 , the controller  130  energizes the actuator assembly  103  once again, moving the circuit breaker lever  105  to the SET position (see  FIG. 3 ). In step  412 , the actuator assembly  103  is confirmed to be in the SET position via position sensor  120 . Finally, in step  413 , the actuator assembly  103  is allowed to return to a default position.  
         [0033]     A system and method for resetting an electrical circuit breaker has been described. It is to be appreciated that the system and method may be employed with individual or double circuit breakers. Furthermore, since the system does not require a specially-configured circuit breaker, the system may easily be retrofitted into existing circuit breaker enclosure and may be integrated into the enclosure cover or door.  
         [0034]     The described embodiments of the present disclosure are intended to be illustrative rather than restrictive, and are not intended to represent every embodiment of the present disclosure. Various modifications and variations can be made without departing from the spirit or scope of the disclosure as set forth in the following claims both literally and in equivalents recognized in law.