Electronic status reporting circuit breaker

Abstract

A circuit breaker includes a control circuit capable of generating and transmitting a test pulse through its attached circuit and any connected load while its contacts are open, with the breaker in the OFF, or TRIPPED, state, to determine if detrimental anomalies exist, such as a short circuit. In certain configurations, the control circuit can measure and store a circuit's parameters for a properly operating load when the breaker is in the OFF state, and subsequently with the breaker in the OFF, or TRIPPED, state, compare the stored parameters to determine if an alarm condition exists and thereby initiate appropriate alerts and actions. In an alternate configuration, the breaker can be commanded to the OFF position by the load sending a signal through the power connection, with the breaker then being able to store the load's reason for shut-down and report such information to a remote location.

Claims

1. A circuit breaker comprising: a line connection; a load connection; a first and a second contact moveable with respect to each other and corresponding to a closed state and an open state; an overcurrent protection circuit coupled between said line connection and said load connection, where when a measured current passing through the circuit breaker exceeds an overcurrent threshold, said overcurrent circuit determines that a fault condition is present and moves the contacts from the closed state to the open state; a memory mechanism to enable a memory save function; a control circuit coupled to said load connection, wherein said load connection receives a load parameter signal from the control circuit while the contacts are in an open state and a load is connected to said load connection, said control circuit having a storage with a signal value saved thereon; wherein the signal value is determined by setting the contacts to the open state, activating the memory mechanism when the load is connected to said load connection to transmit the load parameter signal to the load connection and measure baseline electrical signal parameters of the transmitted load parameter signal, and saving the measured baseline electrical signal parameters reflecting normal operating parameters of the load as the signal value in said storage; wherein when the overcurrent protection circuit has moved the contacts to the open state, said control circuit transmits a test signal to said load connection while the load is connected thereto and measures the test signal; and wherein said control circuit compares the measured test signal to the saved signal value that reflects the normal operating parameters of the connected load and, if the measured test signal exceeds a threshold value of deviation from the signal value, said control circuit maintains the contacts in the open state.

2. The circuit breaker according to claim 1 wherein if the measured test signal exceeds the discrepancy threshold value, said control circuit further generates an alarm that is transmitted via a network connection.

3. The circuit breaker according to claim 2 further comprising a remote monitoring device coupled to said circuit breaker via the network connection, wherein said control circuit transmits a status signal to said remote monitoring device and if a status signal is not sent to said remote monitoring device after a threshold period of time, said remote monitoring device generates an alarm related to said circuit breaker.

4. The circuit breaker according to claim 2 further comprising a remote monitoring device coupled to said circuit breaker via the network connection, wherein said control circuit measures the electrical characteristics of the test signal to generate measured test signal data and transmits the measured test signal data to said remote monitoring device.

5. The circuit breaker according to claim 1 wherein said circuit breaker generates an alarm condition based on the comparison of the measured test signal to the signal value in said storage.

6. The circuit breaker according to claim 5 wherein said circuit breaker prevents resetting of said contacts for as long as the alarm condition exists.

7. The circuit breaker according to claim 5 wherein said circuit breaker allows said contacts to be reset when it is determined that the alarm condition no longer exists.

8. The circuit breaker according to claim 5 wherein the alarm condition is transmitted to a remote monitoring device.

9. The circuit breaker according to claim 1 wherein if the measured test signal does not exceed the discrepancy threshold value, said control circuit generates a notification that is transmitted via a network connection.

10. The circuit breaker according to claim 1 further comprising: a housing enclosing said first and second contacts, said overcurrent protection circuit and said control circuit; and a handle coupled to said housing, said handle moveable between an on position, an off position and a tripped position.

11. The circuit breaker according to claim 1 wherein said control circuit is positioned on a Printed Circuit Board (PCB).

12. The circuit breaker according to claim 1 wherein said test signal is transmitted periodically.

13. A circuit breaker comprising: a line connection; a load connection coupled to a self-monitoring load, the load monitoring itself and generating a trouble signal if the load determines that current operating parameters of the load fall outside a range of safe operating parameters; a first and a second contact moveable with respect to each other and corresponding to a closed state and an open state; an overcurrent protection circuit coupled between said line connection and said load connection, where when a measured current passing through the circuit breaker exceeds an overcurrent threshold, said overcurrent circuit determines that a fault condition is present and moves the contacts to the open state; and a control circuit that receives the trouble signal from the load when the load determines that current operating parameters fall outside the range of safe operating parameters, said trouble signal being independent from the measured current; wherein when the trouble signal is received by said control circuit, said control circuit moves said contacts to the open state.

14. The circuit breaker according to claim 13 wherein the trouble signal is transmitted from said load to said circuit breaker via power cabling connecting said load to said load connection.

15. The circuit breaker according to claim 13 wherein the trouble signal is transmitted from said load to said circuit breaker via an Ethernet connection extending between said load and said circuit breaker.

16. The circuit breaker according to claim 13 further comprising: a remote monitoring device coupled to said circuit breaker via a network connection; wherein an alarm is generated when the trouble signal is received by said circuit breaker and the alarm is transmitted to said remote monitoring device.

17. The circuit breaker according to claim 13 wherein said control circuit is coupled to said load connection, said control circuit having a storage with a signal value saved thereon; wherein when the contacts are in the open state, said control circuit transmits a test signal to said load connection and measures the test signal; wherein said control circuit compares the measured test signal to the signal value in said storage and if the measured test signal exceeds a discrepancy threshold value, said control circuit maintains the contacts in the open state.

18. The circuit breaker according to claim 17 wherein if the measured test signal exceeds the discrepancy threshold value, said control circuit further generates an alarm that is transmitted via a network connection.

19. The circuit breaker according to claim 18 further comprising a remote monitoring device coupled to said circuit breaker via the network connection, wherein said control circuit transmits a status signal to said remote monitoring device and if a status signal is not sent to said remote monitoring device after a threshold period of time, said remote monitoring device generates an alarm related to said circuit breaker.

20. The circuit breaker according to claim 18 further comprising a remote monitoring device coupled to said circuit breaker via the network connection, wherein said control circuit measures the electrical characteristics of the test signal to generate measured test signal data and transmits the measured test signal data to said remote monitoring device.

21. The circuit breaker according to claim 18 further comprising: a remote monitoring device coupled to said circuit breaker via the network connection; and a memory mechanism to enable a memory save function; and wherein the signal value is determined by setting the contacts to the open state, activating the memory mechanism to transmit a load parameter signal to the load and to measure baseline electrical signal parameters of the transmitted load parameter signal, and saving the measured baseline electrical signal parameters as the signal value in said storage.

22. The circuit breaker according to claim 21 wherein said circuit breaker generates an alarm condition based on the comparison of the measured test signal to the signal value in said storage.

23. The circuit breaker according to claim 22 wherein said circuit breaker prevents resetting of said contacts for as long as the alarm condition exists.

24. The circuit breaker according to claim 22 wherein said circuit breaker allows said contacts to be reset when it is determined that the alarm condition no longer exists.

25. The circuit breaker according to claim 22 wherein the alarm condition is transmitted to said remote monitoring device.

26. The circuit breaker according to claim 18 wherein if the measured test signal does not exceed the discrepancy threshold value, said control circuit generates a notification that is transmitted via a network connection.

27. The circuit breaker according to claim 18 further comprising: a housing enclosing said first and second contacts, said overcurrent protection circuit and said control circuit; and a handle coupled to said housing, said handle moveable between an on position, an off position and a tripped position.

28. The circuit breaker according to claim 18 wherein said control circuit is positioned on a Printed Circuit Board (PCB).

29. The circuit breaker according to claim 18 wherein said test signal is transmitted periodically.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an illustration of a circuit breaker according to one aspect of the invention.

(2) FIG. 2 is a block diagram of multiple circuit breakers according to FIG. 1

(3) FIG. 3 is a schematic diagram of the circuit breaker according to FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

(4) Referring now to the drawings, wherein like reference numerals designate corresponding structure throughout the views.

(5) FIG. 1 depicts a circuit breaker 100 having a housing 102 with a handle 104. The circuit breaker could be any type of circuit breaker including, but not limited to having a line connection 106 that comprises a stab circuit breaker that includes two tines that connect to an electrical service bus bar in an electrical panel and a screw type connector comprising load connection 108 to be attached to a load 110 (FIG. 2); or line connection 106 could comprise a screw type connection for attaching to an electrical service bus bar in an electrical panel. There are numerous configurations that are possible and the above are just provided as two examples.

(6) An overcurrent protection circuit 112 is provided that receives incoming power from line connection 106. Overcurrent protection circuit 112 is provided to measure the current 113 passing through the circuit breaker such that, if the measured current 113 exceeds an overcurrent threshold amount 119, the overcurrent protection circuit 112 actuates a linkage 114 that functions to open the contacts 116 setting them in the tripped position preventing the delivery of electricity to the load 110. As is generally known in the art, the contacts 116 generally comprise a moveable contact and a stationary contact, where the position of the handle will determine the positioning of the moveable contact with respect to the stationary contact. For example, in the on position, the linkage 114 will function to close the contacts. In the off position, the linkage 114 will function to fully open the contacts 116; and in the tripped position, the linkage 114 will function to open the contacts 116. To reset the circuit breaker 100 when in the tripped position, a user will typically move the handle 104 to the off position, and then to the on position.

(7) Also illustrated in FIG. 1 is control circuit 118 that is provided with a storage 120. Control circuit 118 is provided with electronics for generating and measuring signal characteristics of the load circuit 122 and the load 110. For example, control circuit 118 is coupled to load circuit 122 via connection 124, which is used to inject a signal into load circuit 122, and may, in certain configurations, be used to receive a trouble signal from the load 110.

(8) Also illustrated in FIG. 1 is data connection 126, which is connected to control circuit 118. Data connection 126 is provided for transmission and reception of data and control signals.

(9) Referring to FIG. 2, a block diagram of circuit breaker 100, 100, 100 is provided showing various circuit breakers attached to a source of power (such as power provided on a bus bar of a panel board) and labeled Line in FIG. 2. The circuit breaker 100 is connected to load 110 via load circuit 122. Additionally, in one configuration the circuit breaker 100 may also be connected to load 110 via data connection 126. It is further contemplated that data connection 126 may configured as an Ethernet connection and connected in a daisy chain configuration, extending to a remote monitoring device 128.

(10) Turning back to FIG. 1, a memory mechanism 130 is provided on the upper surface of the housing 102 of circuit breaker 100. In one configuration, the memory mechanism 130 may be provided as a button that may be depressed. Alternatively, the memory mechanism 130 does not have to be physically located on circuit breaker 100, but could comprise functional software that is actuated remotely by a computer. The function and operation of memory mechanism 130 will be discussed further in conjunction with FIGS. 2 and 3.

(11) Referring now to FIG. 3, a schematic diagram is illustrated. In operation, the circuit is enabled when the circuit breaker 100 is in the open position and disabled when circuit breaker is in the closed position. It should be noted that the circuit shown in FIG. 3 is partially maintained within control circuit 118.

(12) The circuit shown in FIG. 3 is provided, in one configuration, to test for a short circuit condition between all lines (Line to Neutral; Line to Line). A test pulse is active near the AC zero crossing range reference to neutral or to each pull down lines.

(13) During a Line to Line test, the circuit pulls one of the lines low through the totem pole driver; and sends the test pulse through another line. The comparator (LINE_DETECT & NEUT_REF) monitors the sense voltage to check for a short circuit. The information gathered and potentially saved in memory 120 includes: the program test pulse width, the number of the test pulses needed, and the test pulses string duration.

(14) If a short is detected, the circuit will latch off (sw) the solenoid and send a fault alarm. It is contemplated that, in one configuration, the circuit can continuously monitor the line condition and can automatically unlatch the SW when it is determined that the short no longer exists.

(15) Capacitors (C_iso) are positioned as AC isolation elements when circuit breaker closed to supply the power to the load. The double capacitor isolation option is double fault protection

(16) Theory of Operation:

(17) When the circuit breaker is off or the contacts are in an open position (whether because of being tripped or turned to off) a capacitive coupled (C_iso) pulse from a voltage source (Microprocessor and Totem Pole Drives) with a series resistance (sense network) is applied across the load and the load voltage drop is detected (sense network resistors to microprocessor inputs). The capacitive coupling supplies isolation between the pulse source and load at low frequencies while providing a high frequency path for the leading edge of the test pulse. In operation, a short may be detected as a low voltage drop at the leading edge of the pulse. Pairs of lines may be tested in sequence to cover all possible short circuit paths. However, this short circuit detection system will be inactive when the breaker is on or the contacts are in the closed position. If a short is detected when the circuit breaker is in the OFF or TRIPPED position, the circuit breaker is blocked, or prevented from being turned ON, or closed and an alert or indication is provided to a user indicating the status.

(18) The series resistance of the pulse source is set to be comparable to the expected maximum loads to that of the measureable voltage drop seen with nominal loads, while a short produces very little voltage drop. The detection of the short is made at the beginning or leading edge of the pulse. If, at this time, there is less than a set voltage drop across the load, a determination that a short exists is made.

(19) If the load is inductive with a low DC resistance (e.g., a motor at start up) the inductance will present a high enough impedance to the pulse that the voltage drop will be near the value of the pulse voltage level at the start of the pulse even though the DC resistance is low.

(20) Purely capacitive loads without significant series resistance will appear as short circuits. However, large capacitive loads will also have enough series resistance and/or inductance to prevent a false short detection.

(21) The UL standards most likely will not support the capacitive coupling to the de-energized load if the smart system is powered directly from the line, so an isolated AC/DC power supply (low power) will be needed to power the system. Alternatively, the series combination of two safety rated capacitors as shown for C_iso may provide the required performance to achieve compliance.

(22) The zero crossing (phase detect) network is incorporated as needed to support the timing of the short detection pulses.

(23) While FIG. 3 illustrates a three phase circuit, it is contemplated that a single phase circuit could effectively be used in a similar manner as described above.

(24) Turning back to FIG. 2, it is contemplated that remote monitoring device 128 can send a status signal to circuit breaker 100 to ensure that the device is active and functional. If, after a threshold period of time 125 or a threshold number of tries, remote monitoring device 128 does not receive a confirmation from circuit breaker 100, then remote monitoring device 128 generates and alarm related to said circuit breaker 100 indicating that the device is inactive or offline.

(25) In one configuration, control circuit 118 is configured to generate a test signal 115 to be transmitted to load 110 and to measure the electrical characteristics of the test signal 115. The control circuit then generates measured test signal data 117, which is then saved in storage 120 and/or transmitted to remote monitoring device 128.

(26) For circuit breakers 100 that hardwired loads (e.g., loads that are not unpluggable and therefore fixed), memory mechanism 130 may be used to take a measurement of the load 110 that can be saved in storage 120. Functionally, the circuit breaker 100 is set to the off position and then the memory mechanism 130 may be activated (either as a button on the housing or as software from a remote location). When activated, a load parameter signal is transmitted to load 110 and control circuit 118 measures electrical signal parameters of the transmitted load parameter signal. This will create a baseline of normal operating parameters that will be saved in storage 120. If the circuit breaker is set to off or is tripped, the control circuit can then send a test pulse to load 110, which is measured and compared against the saved data 121 to determine if a fault is present. Deviation from the saved data can provide further information as to what or the type of fault that may exist. This deviation information or discrepancy data can be transmitted to a remote location so that a technician can have gathered data to examine even before arriving on site.

(27) In one configuration, the circuit breaker 100 can generate and alarm condition based on the measured test signal deviation. It is contemplated that the circuit breaker 100 could prevent resetting of the contacts while the alarm condition exists. Likewise, once it is determined that the alarm condition no longer exists, the circuit breaker may allow the contacts to be reset. This alarm condition could further be transmitted to remote monitoring device 128.

(28) It is further contemplated that the test signal can be transmitted to the load 110 as previously described herein, however, if the measured signal does not exceed a discrepancy threshold value 123 (i.e., no short exists, or no significant deviation from a previously measured value exists), the control circuit 118 may generate a notification that the load circuit 122 and/or load 110 is normal and functional. The notification may further be transmitted to remote monitoring device 128.

(29) Although the invention has been described with reference to a particular arrangement of parts, features and the like, these are not intended to exhaust all possible arrangements or features, and indeed many other modifications and variations will be ascertainable to those of skill in the art.