Ground fault interruption system for HVAC equipment

Abstract

Apparatus and methods for interrupting power of a branch circuit and a connected load are provided. The apparatus comprises: a first ground fault (GF) sensor for monitoring a first leakage current on a line conductor and a ground conductor of a branch, which ignores a leakage current on the ground conductor; and a second GF sensor for monitoring a second leakage current on the line conductor from the load, taking into account the leakage current on the ground conductor. The processor detects the GF on the branch circuit based on the first leakage current monitored by the first GF sensor; detecting a ground fault at the load due to the excess leakage current based on the second leakage current and an allowable / acceptable amount of leakage current of the load; and if the GF on the branch circuit or at the load is detected, controlling the power interruption of the branch circuit.

Description

Technical Field

[0001] The present disclosure relates generally to ground fault detection and protection and, more particularly, to systems and methods for providing ground fault detection and protection for heating, ventilation, and air conditioning (HVAC) equipment and other equipment that has significant allowable / acceptable leakage current under normal operation. Background Art

[0002] Modern HVAC equipment may utilize variable speed drives and electronically controlled motors to achieve the highest possible efficiency. A disadvantage of these systems is the increased electrical noise generated by the high frequency switching. The filtering equipment added to mitigate the switching noise increases the current flowing through the ground conductor, including a combination of line frequency and high frequency currents. The current returning through the ground conductor is detected by the GFCI circuit breaker as a ground fault, which may cause the GFCI protection to trip. Due to the normal leakage current associated with this type of equipment, the standards for this type of equipment allow for leakage currents higher than the current at which the GFCI must trip. Therefore, modern HVAC equipment is not compatible with Class A GFCI protection.

[0003] A new and improved system-based ground fault detection and protection method is needed that allows for adequate levels of ground conductor leakage current from HVAC equipment or other similar types of equipment while providing protection from "runaway" or other physiological conditions for the branch circuit conductors supplying the equipment. Summary of the invention

[0004] According to one embodiment, there is provided a device for interrupting power to a branch circuit supplying power to a load, the circuit comprising at least a line conductor and a ground conductor different from the line conductor. The device comprises: a first ground fault sensor for monitoring the amount of a first leakage current on the line conductor and the ground conductor, the amount of the first leakage current ignoring the leakage current on the ground conductor; and a second ground fault sensor for monitoring the amount of a second leakage current from the load on the line conductor, the amount of the second leakage current taking into account the leakage current on the ground conductor. The device also comprises a processor configured to: detect a ground fault on the branch circuit based on the amount of the first leakage current monitored by the first ground fault sensor; detect a ground fault at the load due to excessive leakage current based on the amount of the second leakage current and the amount of allowable / acceptable leakage current of the load under normal operation; and control interruption of power supply to the branch circuit if a ground fault on the branch circuit or at the load is detected.

[0005] In various embodiments, the processor can be configured to detect a ground fault on the circuit if the amount of a first leakage current exceeds a first threshold based on a breakaway current threshold or other physiological condition. The processor can be configured to detect excessive leakage current at the load if a second leakage current of the load exceeds a second threshold based on a maximum or upper limit of an allowable / acceptable leakage current for the load. The load can include HVAC equipment, and the first current threshold can be in a first range of about 4 mA to about 6 mA, and the second current threshold can be in a second range of about 15 mA to about 20 mA, where the maximum or upper limit of the allowable / acceptable leakage current can be 15 mA.

[0006] In various embodiments, the load may include HVAC equipment or other outdoor electrical equipment having an allowable / acceptable leakage current under normal operation that is greater than the branch circuit's get-away (or 6mA) current level or a current level based on other physiological conditions.

[0007] In various embodiments, the device may further include a set of electrical contacts through which power is supplied to the branch circuit, wherein the processor is configured to enable or interrupt power supply to the branch circuit via a switch or trip mechanism.

[0008] In various embodiments, the device may also include a communication device or a local output device. The processor may also be configured to output a report or notification to a remote computer device or system or to a local output device via the communication device. The report or notification may be related to the monitored power, status and / or diagnosis related to powering a branch circuit or load. In addition, if the second leakage current is within a third threshold, repair or maintenance is performed on the load or device associated therewith, and the third threshold includes a predetermined current range or value before the second threshold, and the third threshold is used to detect that the second leakage current is approaching an excessive or abnormal level. The third current threshold may include a third range between about 10mA and about 15mA or a value within the third range.‎

[0009] In various embodiments, the processor may also be configured to: monitor a pilot signal on a pilot signal line connected to a pilot control circuit within a housing of the load. The control pilot circuit may have an electrical component having a predefined load curve connected between the pilot signal line and the ground conductor. The processor may also be configured to use the monitored pilot signal to detect the impedance of the load curve of the control pilot circuit between the pilot signal line and the ground conductor; if the detected impedance of the load curve is different from the acceptable impedance range of the predefined load curve, the ground conductor is detected to be open, disconnected, or improperly connected; and if the ground conductor is open, disconnected, or improperly connected, the interruption of power supply to the branch circuit is controlled. In some embodiments, the electrical component of the control pilot circuit may include a resistor and a diode connected in series. In addition, in some embodiments, the apparatus may also include a communication device or a local output device. The processor is also configured to output a notification to a remote computer device or system or to a local output device via a communication device, indicating that the ground conductor is open, disconnected, or improperly connected.

[0010] In various embodiments, the line conductor may include at least two line conductors. For example, the line conductor may be a non-grounded conductor, a grounded conductor, or a combination thereof. The device may further include an arc fault protection subsystem, an overcurrent protection subsystem, and / or a short circuit subsystem.

[0011] In various embodiments, the device can be a miniature circuit breaker or an MCB. The device can further include: at least two line-side voltage terminals for plugging into a load center; at least two load current-carrying conductor terminals for branch circuit line connections; at least one maintenance entrance-side grounding conductor line connection; and at least one branch circuit-side grounding conductor line connection.

[0012] According to an embodiment, a method for interrupting power to a branch circuit that supplies power to a load is provided. The circuit includes at least a line conductor and a grounding conductor different from the line conductor. For example, the line conductor may include a power supply conductor, such as two or more ungrounded conductors, or a grounding conductor together with one or more ungrounded conductors. The method includes: monitoring the amount of a first leakage current on the line conductor and the grounding conductor via a first ground fault sensor, the amount of the first leakage current ignoring the leakage current on the grounding conductor; monitoring the amount of a second leakage current of the load on the line conductor via a second ground fault sensor, the amount of the second leakage current taking into account the leakage current on the grounding conductor; detecting a ground fault on the branch circuit via a processor based on the amount of the first leakage current monitored by the first ground fault sensor; detecting a ground fault at the load due to excessive leakage current via a processor based on the amount of the second leakage current and the amount of allowable / acceptable leakage current of the load under normal operation; and controlling the interruption of power supply to the branch circuit via a processor if a ground fault on the branch circuit or at the load is detected. In some embodiments, the load may have an allowable / acceptable leakage current that is greater than a threshold of ground fault protection of the branch circuit under normal operation. ‎

[0013] According to yet another embodiment, a device for interrupting power to a branch circuit that supplies power to a load is provided. The circuit includes at least two line conductors and a ground conductor different from the at least two line conductors. For example, the line conductors may include power supply conductors, such as two or more ungrounded conductors, or one ground conductor together with one or more ungrounded conductors. The device includes at least one ground fault sensor, which includes: a first ground fault sensor for monitoring the amount of a first leakage current on at least two line conductors and the ground conductor, the amount of the first leakage current ignoring the leakage current on the ground conductor, and / or a second ground fault sensor for monitoring the amount of a second leakage current of the load on at least two line conductors, the amount of the second leakage current taking into account the leakage current on the ground conductor, the device also includes a processor configured to: detect at least one type of ground fault, the processor is configured to detect a ground fault on the branch circuit based on the amount of the first leakage current monitored by the first ground fault sensor, and / or detect a ground fault at the load due to excessive leakage current based on the amount of the second leakage current and the amount of allowable / acceptable leakage current of the load under normal operation; and if at least one type of ground fault is detected, control the interruption of power supply to the branch circuit. Loads include HVAC or other electrical equipment that, under normal operation, has an allowable / acceptable leakage current greater than the threshold of the branch circuit's ground fault protection.

[0014] In various embodiments, the at least one ground fault sensor may include first and second ground fault sensors. The processor may be configured to detect a ground fault on the branch circuit based on an amount of a first leakage current monitored by the first ground fault sensor, and to detect a ground fault at the load due to an excessive leakage current based on an amount of the second leakage current and an amount of allowable / acceptable leakage current of the load under normal operation.

[0015] In various embodiments, the processor may also be configured to: monitor a pilot signal on a pilot signal line connected to a pilot control circuit within a housing of a load, the control pilot circuit having an electrical component with a predefined load curve connected between the pilot signal line and a ground conductor; use the monitored pilot signal to detect the impedance of the load curve of the control pilot circuit between the pilot signal line and the ground conductor; detect that the ground conductor is open, broken, or improperly connected if the detected impedance of the load curve is different from an acceptable impedance range of the predefined load curve; and control the interruption of power supply to the branch circuit if the ground conductor is open, broken, or improperly connected.

[0016] According to another embodiment, a method for interrupting power to a branch circuit that supplies power to a load is provided. The circuit includes at least two line conductors and a ground conductor that is different from the at least two line conductors. For example, the line conductors may include power conductors, such as two or more ungrounded conductors, or one ground conductor together with one or more ungrounded conductors. The method includes: monitoring at least one type of leakage current, the monitoring including: monitoring the amount of a first leakage current on at least two line conductors and the ground conductor via a first ground fault sensor, the amount of the first leakage current ignoring the leakage current on the ground conductor, and / or monitoring the amount of a second leakage current of the load on at least two line conductors via a second ground fault sensor, the amount of the second leakage current taking into account the leakage current on the ground conductor. The method also includes detecting at least one type of ground fault via a processor, the detection including: detecting a ground fault on the branch circuit based on the amount of the first leakage current monitored by the first ground fault sensor, and / or detecting a ground fault at the load due to excessive leakage current based on the amount of the second leakage current and the amount of allowable / acceptable leakage current of the load under normal operation. The method also includes controlling the interruption of power to the branch circuit via a processor if at least one type of ground fault is detected. Loads include HVAC or other electrical equipment that, under normal operation, has an allowable / acceptable leakage current that is greater than the threshold for ground fault protection of the branch circuit.

[0017] In various embodiments, monitoring may include: monitoring an amount of a first leakage current on at least two line conductors and a ground conductor via a first ground fault sensor, and monitoring an amount of a second leakage current of a load on at least two line conductors via a second ground fault sensor. Detection may also include: detecting a ground fault on a branch circuit based on the amount of the first leakage current monitored by the first ground fault sensor, and detecting a ground fault at a load due to excessive leakage current based on the amount of the second leakage current and an amount of allowable / acceptable leakage current of the load under normal operation.

[0018] In various embodiments, the method may also include: monitoring a pilot signal on a pilot signal line, the pilot signal line being connected to a pilot control circuit within a housing of a load, the control pilot circuit having an electrical component having a predefined load curve connected between the pilot signal line and a ground conductor; using the monitored pilot signal to detect the impedance of the load curve of the control pilot circuit between the pilot signal line and the ground conductor; if the detected impedance of the load curve is different from an acceptable impedance range of the predefined load curve, detecting via a processor that the ground conductor is open, broken, or improperly connected; and if the ground conductor is open, broken, or improperly connected, controlling the interruption of power supply to the branch circuit. ‎

[0019] It will be appreciated that there are numerous features, advantages and aspects associated with the disclosed invention as will be apparent from the following discussion and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The foregoing features of the present disclosure, as well as the present disclosure itself, may be more fully understood from the following detailed description of the accompanying drawings, in which:

[0021] Figure 1 An example of a ground fault detection and protection device (or system) for use with an electrical system including HVAC equipment according to a first embodiment of the present disclosure is shown;

[0022] Figure 2 The first embodiment of the present disclosure is shown. Figure 1 An example scenario of a ground fault detection and protection device (or system) of the present invention, wherein a ground fault occurs on a first line conductor of a branch circuit of an electrical system;

[0023] Figure 3 The first embodiment of the present disclosure is shown. Figure 1 An example scenario of a ground fault detection and protection device (or system) of the present invention, wherein a ground fault occurs on a second line conductor of a branch circuit of an electrical system;

[0024] Figure 4 The first embodiment of the present disclosure is shown. Figure 1An example scenario of a ground fault detection and protection device (or system) wherein the leakage current from the load is at a normal level on the electrical system;

[0025] Figure 5 The first embodiment of the present disclosure is shown. Figure 1 An example scenario of a ground fault detection and protection device (or system) wherein leakage current from a load is at an excessive abnormal level on an electrical system;

[0026] Figure 6 The first embodiment of the present disclosure is shown. Figure 1 An example scenario of a ground fault detection and protection device (or system) in which an open circuit or a disconnection of a ground conductor occurs on an electrical system;

[0027] Figure 7 The first embodiment of the present disclosure is shown. Figure 1 An example scenario of a ground fault detection and protection device (or system) wherein the leakage current is at a warning or reporting level, which precedes an abnormal level, for which a maintenance notification is implemented;

[0028] Fig. 8A A flow chart illustrating an example process for detecting and protecting against different types of ground faults on an electrical system according to an embodiment of the present disclosure;

[0029] Figure 8B A flow chart illustrating an example process for detecting and protecting against different types of faults and conditions on an electrical system according to an embodiment of the present disclosure;

[0030] Fig. 9 An example of a ground fault detection and protection device (or system) for use with an electrical system having HVAC equipment according to a second embodiment of the present disclosure is shown;

[0031] Fig.10 An example of a ground fault detection and protection device (or system) for use with an electrical system having HVAC equipment according to a third embodiment of the present disclosure is shown;

[0032] Fig.11 An example of a ground fault detection and protection device (or system) for use with an electrical system having equipment other than HVAC equipment according to a fourth embodiment of the present disclosure is shown;

[0033] Fig.12 An example of a ground fault detection and protection device (or system) for use with an electrical system having HVAC equipment according to a fifth embodiment of the present disclosure is shown;

[0034] Fig.13An example of a ground fault detection and protection device (or system) for use with an electrical system having HVAC equipment according to a sixth embodiment of the present disclosure is shown;

[0035] Fig.14 A diagram showing different example configurations for different scenarios of a ground fault detection and protection device (or system) according to various embodiments of the present disclosure; and

[0036] Fig.15 Example components of a computer device or system according to embodiments of the present disclosure are shown. DETAILED DESCRIPTION

[0037] The features and other details of the concepts, systems and techniques for which protection is sought herein will now be described in greater detail. It should be understood that any specific embodiments described herein are shown by way of illustration, rather than as limitations on the disclosure and concepts described herein. The features of the subject matter described herein may be employed in various embodiments without departing from the scope of the concepts for which protection is sought.

[0038] According to one embodiment, a system and method for ground fault detection and protection of an electrical system is provided, which may supply power to a load such as HVAC equipment through a branch circuit. The load may be located in an outdoor environment. The system and method may be implemented by a ground fault interrupting device or system (or other circuit protection device), such as a circuit breaker (e.g., a miniature circuit breaker or MCB), which may be located at a load center of a building, such as a house, residence, or other structure. The system and method may allow for an appropriate level of leakage current inside the HVAC equipment while providing shock protection at a "get out" level.

[0039] For example, in the system and method, the wiring of the branch circuit (also referred to as "branch circuit wiring") can be monitored and protected by using a first ground fault sensor that ignores leakage current returning from the load through the ground conductor. The first ground fault sensor can detect any ground current flowing outside the system, such as from the line conductor to the ground ground or from the line conductor to other grounded equipment, which can be detected at a breakaway level (e.g., 6 mA) or a current level based on other physiological conditions. The line conductor can include a power supply conductor, such as two or more ungrounded conductors, or a ground conductor together with one or more ungrounded conductors. In various embodiments, the breakaway level (or a threshold value related thereto) can be in the range of 4-6 mA. The system and method can also employ a separate second ground fault sensor to monitor for excessive leakage current from the HVAC equipment, such as leakage current that exceeds an allowable, acceptable, or normal leakage current under normal operation of the equipment. The second ground fault sensor can take into account the leakage current returning through the ground conductor. In the event of a ground fault detected on the branch circuit, or due to excessive leakage current from the load, power to the branch circuit and the load can be interrupted to de-energize the circuit and the load.

[0040] The system and method can allow, for example, up to 15 mA of line frequency leakage current to flow to ground within the HVAC equipment, which can allow the equipment to operate within a normal leakage current range, such as an allowable or acceptable (allowable / acceptable) leakage current range under normal operation of the equipment. The increased leakage current at the equipment can be safely returned through the ground conductor. The allowable / acceptable leakage current can depend on the type of load or its equipment, the application, and other factors that may affect the leakage current from the load.

[0041] The system and method may also provide a ground monitor (also referred to as a "ground monitor system") that can continuously check that the ground conductor is properly installed, e.g., properly connected. In some embodiments, the ground monitor may only allow the branch circuit that supplies power to the device to be energized as long as the ground conductor is properly connected to the device. The ground conductor may ensure that a safe voltage on the device housing remains within an allowable leakage current range. Alternatively, in some embodiments, the ground monitor may also be configured to periodically check the ground conductor in response to a user command or a remote control (RC) command from a remote computer system, or according to a desired schedule.

[0042] The systems and methods may also include power monitoring, status, or diagnostic functionality that may provide information about the status of a detection and protection system (e.g., a circuit breaker or other circuit protection device) to a user or a central monitoring / management computer system, which in turn may notify a user or other facility. This information may be provided remotely via a communications device (or system) of the detection and protection system and / or locally via a user interface on a circuit breaker. The status or diagnostic information may provide a notification or report to a user when excessive (or abnormal) leakage current occurs, such as when an HVAC leakage current exceeds an expected threshold range or value, but is still below a level at which a device will trip to interrupt power to a branch circuit and load.

[0043] The systems and methods of the present disclosure may provide various technical benefits and / or advantages. For example, the systems and methods may resolve or address existing compatibility issues between HVAC equipment (or equipment with similar leakage current issues) and GFCI protection that have prevented widespread adoption of GFCI protection for outdoor equipment. The systems and methods of the present disclosure may also allow HVAC equipment to operate without tripping ground fault protection while maintaining a level of shock protection for branch circuit conductors.

[0044] In various embodiments, in the system and method, the ground fault interrupt system for HVAC equipment can be a circuit breaker. The circuit breaker can include at least two levels of ground fault protection. For the first level, a first ground fault sensor (or sensing circuit) can be provided for detecting a "get rid of" level ground fault current, such as a current level generally considered to be in the range of 4-6mA, or based on other physiological conditions. The first ground fault sensor ignores leakage current returned through the ground conductor and is intended to provide "get rid of" or other physiological or type ground fault protection for the branch circuit conductor. For the second level, a second ground fault sensor (or sensing circuit) can be provided for detecting a higher level of ground fault current in the range of 15 to 20mA. The second ground fault sensor does not ignore leakage current returned through the ground conductor and is intended to guard against excessive leakage current from the HVAC equipment.

[0045] In various embodiments, the circuit breaker may include a set of electrical contacts that may be opened to disconnect / interrupt line voltage from a branch circuit (and closed to connect / allow line voltage to a branch circuit) so as to de-energize the circuit and connected loads. The set of electrical contacts may be opened in response to detecting a ground fault using a first ground fault sensor or a second ground fault sensor. The circuit breaker may also include a ground monitor (e.g., a pilot monitor / pilot controller) to detect or verify the presence of a properly connected ground conductor between the circuit breaker and the HVAC equipment. The same electrical contacts as described above or a different set of electrical contacts may be opened in the event that a ground fault is detected or verified due to an improperly connected ground conductor, such as an open circuit, a break, or other improper connection of a ground conductor.

[0046] In various embodiments, the circuit breaker may also implement arc fault protection, overcurrent protection, and / or short circuit protection, for example, through its subsystems.

[0047] In various embodiments, the circuit breaker may include two or more line-side voltage terminals in the form of lugs or devices for plugging into a load center. The circuit breaker may also include two or more load current-carrying conductor terminals for branch circuit line connections. The circuit breaker may also include a maintenance entrance-side grounding conductor line connection, a branch circuit-side grounding conductor line connection, and a ground monitor pilot signal line connection.

[0048] In various embodiments, a ground fault interrupt device (or system) for HVAC equipment may include a pilot signal conductor connected between a circuit breaker pilot wire connection and the HVAC equipment. A pilot control circuit (also referred to as a pilot control wire termination circuit) may be located within the HVAC equipment housing. The pilot control circuit may include a resistor and a diode or other combination of electronic components that present a unique load characteristic to the ground monitoring pilot signal. One side of the pilot wire termination of the pilot control circuit may be connected to the pilot wire from the circuit breaker pilot wire connection. A second side of the pilot wire termination may be bonded to the ground chassis of the HVAC equipment.

[0049] In various embodiments, the ground monitor may be designed to detect an acceptably low impedance in the ground conductor to verify a properly installed ground conductor. The ground monitor may be designed to have a sufficiently low ground conductor impedance threshold so that a ground fault in the equipment will be interrupted by a thermal or short circuit response of the circuit breaker without the need for additional ground fault protection and without the presence of hazardous voltages on the HVAC equipment enclosure.

[0050] In various embodiments, the branch circuit wiring between the circuit breaker and the HVAC equipment may include a minimum of at least two line conductors (e.g., load current carrying or line conductors), a ground conductor, and a ground monitor pilot signal conductor (e.g., a pilot signal line). The circuit breaker may include a communication device (e.g., a wireless / wired transmitter / TX and a receiver / RX) for providing power monitoring, status, and diagnostic information (or data) to a user device or other monitoring / management computer system. In some embodiments, the communication of status and diagnostics may include a communication status of a repair (or maintenance) notification, such as a notification that repair of the HVAC equipment needs to be performed in the event that an HVAC leakage current is detected approaching an excessive or abnormal threshold range or value of leakage current (e.g., >10mA but less than 15mA). The power monitoring, status, and diagnostic information may also be output locally on the circuit breaker in the form of a user interface, such as a display and / or other visual indicator.

[0051] These and other example features of the systems and methods are described in detail below with reference to the figures.

[0052] Figure 1 An example system environment 10 of a ground fault detection and protection system according to a first embodiment of the present disclosure is shown, such as a ground fault interrupting device 100 for use with an electrical system including HVAC (heating, ventilation, air conditioning) equipment. Figure 1 As shown, the system environment 10 includes a branch circuit that provides power from a power source 20 to a load, such as an AC unit 50 of an HVAC device, through a power outlet 30. A ground fault interrupting device 100 is connected between the power source 20 and the branch circuit to provide ground fault protection to the AC unit 50 and the branch circuit wiring connected between the device 100 and the AC unit 50. In this example, the branch circuit wiring includes two line conductors, such as L1 and L2, and a ground conductor. In this example, the HVAC device (such as the AC unit 50) is located outside the residence, and the ground fault interrupting device 100 is a circuit breaker that is located at a load center at the residence.

[0053] The power source 20 provides 120VAC (volts alternating current) to neutral (240VAC L1 to L2) on each line conductor L1 and L2, and its neutral is connected / bonded to a ground electrode to provide a ground conductor. As shown, the line conductors L1 and L2 and the ground conductor are connected to the device 100 (e.g., a circuit breaker) via the device's connections / terminals. The line conductors L1 and L2 and the ground conductor of the device 100 are connected downstream to corresponding conductors of branch circuit wiring, which in turn is connected to a load, such as the AC unit 50 and its components.

[0054] AC unit 50 is an HVAC device that includes various electrical and mechanical components housed in a housing. In this example, AC unit 50 includes components such as an AC inverter unit 52 that is connected to line conductors L1 and L2 and provides power to compressor 54. As discussed herein, HVAC equipment may have leakage current under normal operation. This allowable / acceptable leakage current (e.g., 15mA to 20mA) may exceed the "get rid of" leakage current (e.g., 4mA to 6mA) of the branch circuit wiring and its conductors (e.g., L1, L2, etc.). In this example, leakage current from the HVAC device (e.g., AC unit 50) can be redirected from the HVAC device and its housing along a return path via a ground conductor to provide protection against potential electrical hazards from such leakage current.

[0055] The AC unit 50 may also include a pilot control circuit 150 to help monitor ground conductor connections (e.g., correct connections or incorrect connections, such as open circuits, broken circuits, or other incorrect connections of ground conductors). The pilot control circuit 150 may include electrical components or combinations thereof, which may be selected based on their unique impedance characteristics. In this example, the electrical components may include resistors and diodes connected in series and have a known predefined load curve. The terminal electrical component is connected between the pilot signal line and the ground conductor, both of which are connected between the device 100 and the AC unit 50. When the ground conductor is incorrectly connected, the detection impedance of the load curve seen between the pilot signal line and the ground conductor changes from the acceptable range of the predefined load curve of the electrical component. In this way, a ground monitor may be provided, for example, in the device 100 to monitor the pilot signal and detect a ground fault caused by an incorrect connection of the ground conductor based on the monitored pilot signal.

[0056] The ground fault interrupting device 100 may include a controller 110, a memory 120, a communication device 130, an input / output (I / O) device 140, and a plurality of sensors / monitors for monitoring energy-related signals on wiring (e.g., branch circuit wiring and pilot signal lines). In this example, the device 100 may be a circuit breaker, which may include a set of electrical contacts 102 for a first line conductor L1 and a set of electrical contacts 104 for a second line conductor L2, and may also include other conventional components of a circuit breaker, such as: a power interruption system (e.g., a trip mechanism, a solid-state switch, etc.), for opening two sets of electrical contacts to interrupt or cut off the flow of power to the branch circuit and the load (such as the AC unit 50), a handle or lever for resetting or turning on / off the circuit breaker, a test function (e.g., a one-touch test button or function), a line-side electrical connector / connection, a load-side electrical connector / connection, a housing / casing, and other conventional circuit breaker components.

[0057] The sensors / monitors of the device 100 may include a first ground fault sensor (GFS-1), a second ground fault sensor (GFS-2), and a control pilot monitor (e.g., a ground monitor) connected to the pilot signal line and the ground conductor. The first ground fault sensor is configured to monitor (e.g., monitor, sense, measure, etc.) the amount of a first leakage current on the line conductors L1, L2 and the ground conductor. The monitored first leakage current ignores the leakage current on the ground conductor, which is offset by the first ground fault sensor, for example, because both the return path on the ground conductor and the output path on the line conductor are received and monitored by the ground fault sensor. If the leakage current exceeds a first threshold range or value, for example, the leakage current exceeds a "breakaway" current level such as 4-6 mA or a current level based on other physiological conditions, the first leakage current is monitored to detect a ground fault on the branch circuit wiring (e.g., a ground fault between the line conductor L1 or L2 and the ground ground). In this example, the first threshold may be a typical breakaway level, such as 5 mA, and the first ground fault sensor GFS-1 may be referred to as GFID5. In various embodiments, the first threshold may be a current threshold in the range of 4-6 mA, depending on load device specifications, applications, and / or other factors that may affect ground fault detection in an electrical system environment.

[0058] The second ground fault sensor (or GFS-2) is configured to monitor the amount of a second leakage current on the line conductors L1, L2. The second leakage current takes into account the leakage current on the ground conductor. In this way, the second ground fault sensor can be used to monitor the amount of leakage current from the load (e.g., AC unit 50) on the ground conductor. If the leakage current exceeds a second threshold range or value (e.g., the leakage current exceeds a level associated with an allowable / acceptable or normal leakage current level), the second ground fault sensor can be used to monitor when such leakage current from the load is excessive or abnormal. The second ground fault sensor can also be used to detect when such second leakage current is approaching or almost at an excessive or abnormal level using a third threshold value that is less than the second threshold value. In this example, the second threshold value can be 15 to 20 mA, and the first ground fault sensor GFS-2 can be referred to as GFID20. The third threshold range of 10 to 15 mA or a value within the range can be used to detect leakage currents approaching or near excessive / abnormal levels for notification and other purposes. In various embodiments, the second threshold value can be based at least on the increase in branch circuit wiring and the allowable / acceptable leakage current level of the load.

[0059] Pilot Control Monitor (in Figure 1The pilot control circuit 150 (referred to as a “control pilot” monitor in the illustration) is configured to use the pilot signal to monitor the load impedance between the pilot signal line and the ground conductor in order to detect any unacceptable changes in impedance compared to a predefined load curve or acceptable range thereof for the electrical components of the pilot control circuit 150 at the AC unit 50. In this manner, an improper connection of the ground conductor (e.g., an open, broken, or improperly connected ground conductor) may be detected if the monitored impedance is outside of an acceptable impedance range or value for the predetermined load curve.

[0060] The sensors / monitors may include other sensors for measuring energy-related signals (e.g., current, voltage, power, etc.) on conductors (e.g., L1 and L2) or branch circuit wiring. These other sensors may be used to perform additional monitoring and diagnostics, including detecting other types of conditions related to the electrical system, device 100, branch circuits, and / or loads (e.g., arc fault conditions, overcurrent conditions, short circuit conditions, normal / abnormal operating conditions, power quality events, etc.).

[0061] The memory 120 may store various information, including programs, modules, codes, and other data, for facilitating the control and operation of the device 100, its components, and various functions and operations, including ground fault detection and protection and other functions and operations described herein. As shown, the memory 120 may store programs, modules, and / or codes to enable the processor 110 to perform various detection, protection, and status / diagnostic notification methods and processes, including, for example, ground fault detection (GFD), arc fault detection (AFD), and detection of other types of faults or conditions on the device 100, branch wiring, and loads based on information monitored from sensors / monitors. Other data may include storage of status, diagnostic, and other information to be reported to a user or remote monitoring / management computer system, parameters associated with condition detection (e.g., threshold ranges, levels, or values ​​associated with various types of fault detection described herein, predefined load / impedance curves for pilot monitoring, etc.), device / component operating parameters and settings, and other data described herein.

[0062] The communication device 130 may include wireless and wired transmitters and receivers (TX / RX), such as RF transmitters / receivers, which may enable communications with other remote devices and systems using appropriate wireless / wired communication protocols.

[0063] Input / output (I / O) devices 140 may include input devices, such as user interfaces, including: graphical user interfaces (GUIs), handles, buttons, switches, dials, touch screens, microphones, and / or other input devices that may be used in conventional circuit breakers or circuit protection devices. Input / output devices 140 may also include output devices, such as displays, speakers, LEDs, handle positions, other visual indicators, and / or other output devices that may be used in conventional circuit breakers or circuit protection devices.

[0064] The controller 110 may include a processor and other electronic components, and may be configured to control and manage the operation of various components of the device 100, as well as various functions and operations of the device 100, including those described herein. The functions and operations may include, for example: various fault detection / protection processes, algorithms and methods, such as different types of ground fault detection (GFD) and protection, arc fault detection (AFD) and protection, and detection of other conditions on the device 100, branch wiring circuits and loads, and any other detection and protection described herein; monitoring, storing and outputting / transmitting (e.g., outputting, notifying, reporting, transmitting, etc.) the status, diagnostics and other information of the electrical system, the device 100, the branch wiring and the loads; controlling the power supply to the branch wiring and the loads, such as controlling the interruption / cutting off and connection / connection of the power supply to the branch wiring and the loads; controlling and executing the conventional functions and operations of the circuit breaker, and / or other functions and operations described herein.

[0065] In various embodiments, the controller 110 or its processor may be configured to: detect a ground fault on a branch circuit based on the amount of a first leakage current monitored by a first ground fault sensor; detect a ground fault at a load due to an excessive leakage current based on the amount of a second leakage current and the allowable / acceptable amount of leakage current of the load under normal operation; and control interruption of power to the branch circuit (e.g., de-energizing the circuit and connected loads) if a ground fault on a branch circuit or at a load is detected. The first leakage current may be compared to a first threshold to detect a ground fault on a branch circuit (e.g., a ground fault from L1 or L2 to ground). The first threshold may be related to a breakaway current level or other physiologically based current level of the branch circuit. The second leakage current may be compared to a second threshold to detect a ground fault due to an excessive or abnormal leakage current from the load. The second threshold may be related to an allowable, acceptable, or normal leakage current level of a load or its device (e.g., AC unit 50), and may also take into account breakaway current or other physiological conditions when the first and second ground fault sensors cooperate to detect different types of ground fault currents on the electrical system.

[0066] In various embodiments, the controller 110 or its processor may be configured to output a report or notification to a remote computer device or system via a communication device or to a local output device. The report or notification may be related to a status and / or diagnosis related to power supply to a branch circuit or load, or other monitored energy-related characteristics, operations, or components of the electrical system. If a second leakage current associated with the load approaches an excessive or abnormal level, such as associated with a third threshold (e.g., a predefined current range or value before the second threshold), the report or notification may include a status notification to perform repair or maintenance on the load or equipment associated therewith.

[0067] In various embodiments, the controller 110 or its processor may also be configured to monitor the pilot signal on the pilot signal line using a pilot monitor (or circuit thereof). The pilot monitor (or sensor) is connected to a pilot control circuit, which is located within the housing of the load (e.g., AC unit 50). As previously described, the control pilot circuit in the load housing may have an electrical component with a predefined load curve connected between the pilot signal line and the ground conductor. The controller 110 may use the monitored pilot signal to detect the impedance of the load curve of the control pilot circuit between the pilot signal line and the ground conductor; if the detected impedance of the load curve is different from the acceptable range of the impedance of the predefined load curve, detect that the ground conductor is open, broken, or improperly connected; and if the ground conductor is open, broken, or improperly connected, control the interruption of power to the branch circuit (e.g., de-energizing the circuit and the connected load).

[0068] In various embodiments, the ground fault interrupt device 100 may also be configured to provide detection and protection for other types of faults and conditions, such as short circuit fault detection (SCFD) and protection, and / or over current fault detection (OCFD) and protection. The SCFD and OCFD and their protection may be provided as or through separate electromechanical functions / components, such as using conventional SC and OC electromechanical functions / components. Alternatively, such detection and protection functions may be provided through or in cooperation with the controller 110 and the memory 120, which may store executable code or programs for implementing such detection / protection processes, algorithms, or methods.

[0069] The different scenarios of the system environment 10 are described Figure 1 Various exemplary operating modes of the ground fault interrupting device 100 will be referred to below. Figure 2 , 3 , 4, 5, 6 and 7 for discussion.

[0070] Figure 2 The first embodiment of the present disclosure is shown. Figure 1An exemplary scenario of the ground fault interrupting device 100 is shown in FIG. 1 , where a ground fault occurs on a first line conductor L1 of a branch circuit of an electrical system.

[0071] In this scenario, there is a ground fault 200 between the line conductor L1 and the earth ground, with a fault current path 210. The leakage current on the line conductors L1, L2 exceeds a breakaway level, which in this example is 5 mA or more. As previously described, the first ground fault sensor GFS-1 leakage current monitors the leakage current on the line conductors L1, L2 and ignores the leakage current on the ground conductor (e.g., the leakage current on the ground conductor is eliminated in the monitoring operation of the sensor GFS-1). The sensor GFS-1 detects the leakage current on the line conductor (e.g., L1) at or above 5 mA along the fault current path 210. The controller 110 detects the occurrence of the ground fault 200 on the line conductor because the leakage current monitored by the sensor GFS-1 is at or exceeds a first threshold associated with the breakaway current level, e.g., the monitored leakage current is equal to or greater than the 5 mA breakaway level. In response to ground fault detection, the controller 110 controls the electrical contacts 102, 104 to open, which in turn interrupts the supply of power from the power source 20 to the branch circuit and load (eg, AC unit 50) and de-energizes the circuit and connected load.

[0072] Figure 3 The first embodiment of the present disclosure is shown. Figure 1 An exemplary scenario of the ground fault interrupting device 100 is shown in FIG. 1 , wherein a ground fault occurs on a second line conductor L2 of a branch circuit of an electrical system.

[0073] In this scenario, a ground fault 300 exists between the line conductor L2 and the earth ground, with a fault current path 310. The leakage current on the line conductors L1, L2 exceeds a breakaway level, in this example 5 mA or more. As previously described, the first ground fault sensor GFS-1 monitors the leakage current on the line conductors L1, L2 and ignores the leakage current through the ground conductor (e.g., the leakage current on the ground conductor is eliminated in the monitoring operation of the sensor GFS-1). The sensor GFS-1 detects the leakage current on the line conductor (e.g., L2) at or above 5 mA along the fault current path 310. The controller 110 detects the occurrence of the ground fault 300 on the line conductor because the leakage current monitored by the sensor GFS-1 is at or exceeds a first threshold value associated with a breakaway current level, e.g., the monitored leakage current is equal to or greater than the 5 mA breakaway level. In response to the ground fault detection, the controller 110 controls the electrical contacts 102, 104 to open, which in turn interrupts the power supply from the power source 20 to the branch circuit and the load (e.g., the AC unit 50), and de-energizes the circuit and the connected load.

[0074] Figure 4The first embodiment of the present disclosure is shown. Figure 1 An example scenario of a ground fault interrupting device 100 in which leakage current from a load on a ground conductor is at an allowable, acceptable, or normal level on the electrical system.

[0075] In this case, there is leakage current flowing from the load (e.g., AC unit 50) along the leakage current path 410 including the ground conductor and the line conductor L1. The leakage current is below a detection level associated with an allowable or acceptable leakage current of the load, such as a second threshold. As previously described, the first ground fault sensor GFS-1 ignores the leakage current from the ground conductor along the leakage current path 410 (e.g., in the monitoring operation of the sensor GFS-1, the leakage current on the ground conductor is eliminated). However, the second ground fault sensor GFS-2 detects the leakage current from the ground conductor, which is below 15 mA to 20 mA in this example, which is the second threshold. Therefore, based on the leakage current monitored by the sensor GFS-2, the controller 110 does not detect a ground fault caused by an excessive or abnormal level of leakage current from the load because the monitored leakage current on the ground conductor is below the second threshold. In this example, the second threshold may be 15 mA to 20 mA, or a variation thereof.

[0076] Figure 5 The first embodiment of the present disclosure is shown. Figure 1 An example scenario of a ground fault interrupting device 100 is described in which leakage current from a load on a ground conductor is at an excessive or abnormal level on an electrical system.

[0077] In this case, there is a leakage current flowing from the load (e.g., AC unit 50) along the leakage current path 510 including the ground conductor and the line conductor L1. The leakage current is above a detection level associated with an allowable or acceptable leakage current of the load, such as a second threshold value (e.g., 15 mA to 20 mA). As previously described, the first ground fault sensor GFS-1 ignores the leakage current from the ground conductor along the leakage current path 510 (e.g., in the monitoring operation of the sensor GFS-1, the leakage current on the ground conductor is eliminated). However, the second ground fault sensor GFS-2 detects a leakage current from the ground conductor, which is above a second threshold value, such as 20 mA, in this example. The second threshold value may be an allowable / acceptable leakage current level, such as 15 mA to 20 mA, or a variation thereof. Therefore, the controller 110 detects a ground fault caused by an excessive or abnormal level of leakage current from the load based on the leakage current monitored by the sensor GFS-2 because the monitored leakage current is above the second threshold value (e.g., >20 mA). In response to ground fault detection, the controller 110 controls the electrical contacts 102, 104 to open, which in turn interrupts the supply of power from the power source 20 to the branch circuit and load (eg, AC unit 50) and de-energizes the circuit and connected load.

[0078] Figure 6 The first embodiment of the present disclosure is shown. Figure 1 An example scenario of a ground fault interrupting device 100 in which an open circuit or break 600 of a ground conductor occurs on an electrical system.

[0079] In this situation, there is an improper connection of the grounding conductor, such as an open circuit or a break 600 of the grounding conductor. The ground monitor (control pilot monitor) can monitor the pilot signal on the pilot signal line to monitor the impedance of the load curve of the terminal electrical components of the pilot circuit 150 between the pilot signal line and the grounding conductor. In this case, as a result of the improper connection of the grounding connector (such as an open circuit or a break 600 on the grounding conductor of the pilot signal circuit), the monitored pilot signal reflects the change of impedance from the acceptable range of the predefined load curve. Therefore, the controller 110 detects a ground fault caused by the improper connection of the grounding conductor or the open pilot signal circuit. In response to the ground fault detection, the controller 110 controls the electrical contacts 102, 104 to open, which in turn interrupts the power supply from the power supply 20 to the branch circuit and the load (such as the AC unit 50), and de-energizes the circuit and the connected load. ‎

[0080] Figure 7 The first embodiment of the present disclosure is shown. Figure 1In an example situation of a ground fault interrupt device 100, the leakage current from the load on the ground conductor is close to or near an excessive or abnormal level, but has not exceeded the level (e.g., slightly below the level). In this case, a maintenance notification can be provided to the user or remote monitoring / management computer system.

[0081] For example, in this case, there is a leakage current flowing from the load (e.g., AC unit 50) along the leakage current path 710 including the ground conductor and the line conductor L1. The leakage current is within a detection level associated with an allowable or acceptable leakage current of the load, such as below a second threshold (e.g., 20 mA); however, the leakage current is approaching an excessive or abnormal level reflected by a third threshold (e.g., a range of 10 to 15 mA). As previously described, the first ground fault sensor GFS-1 ignores the leakage current from the ground conductor along the leakage current path 710 (e.g., in the monitoring operation of the sensor GFS-1, the leakage current on the ground conductor is eliminated). However, the second ground fault sensor GFS-2 detects a leakage current from the ground conductor, which in this example is within the third threshold (e.g., 10 mA to 15 mA), but below the second threshold, such as 20 mA. The second threshold may be an allowable / acceptable leakage current level, such as 15 mA to 20 mA or a variation thereof. Thus, the controller 110 detects a leakage current from the load on the ground conductor within the third threshold (but below the second threshold), indicating that the leakage current is approaching or near an excessive or abnormal level, and some action may need to be taken. In response to detecting the leakage current within the third threshold, the controller 110 may output a status notification, such as a maintenance notification, on a user interface of the device 100 via the I / O 140, or to a user / user device or a remote monitoring / management computer system via the communication device 130. The maintenance notification may be a request for repair or maintenance of the equipment at the load (e.g., the AC unit 50).

[0082] Fig. 8A A flow chart showing an example process for detecting and protecting against different types of ground faults on an electrical system according to an embodiment of the present disclosure is shown. For purposes of example explanation, reference will be made to Figure 1 The process 800 is described with reference to a ground fault interrupting device 100 (eg, 100 ), such as in the form of a circuit breaker, and its components, such as a controller (eg, 110 ) and sensors / monitors, etc.

[0083] The process begins at block 802 where the circuit breaker monitors a first leakage current (or a first type thereof) on a line conductor and a ground conductor using a first ground fault sensor (eg, GFS-1). The first ground fault sensor is configured to ignore leakage current on the ground conductor from the load.

[0084] At block 804, the circuit breaker monitors a second leakage current (or a second type thereof) on the line conductor using a second ground fault sensor (eg, GFS-2). The second ground fault sensor is configured to account for leakage current on the ground conductor from the load.

[0085] At block 806, the circuit breaker monitors a pilot signal on a pilot signal line using a ground (or pilot) monitor or circuit thereof.

[0086] At block 810, the circuit breaker determines whether the monitored first leakage current satisfies (e.g., is greater than or equal to, etc.) a first threshold TH1, which is associated with a runaway current level or other physiologically based current level of the branch circuit or its wiring. If so, the circuit breaker detects the occurrence of a ground fault on the branch circuit wiring (e.g., a ground fault between a line conductor and an earth ground). In response to the ground fault detection, the circuit breaker interrupts the supply of power (e.g., power, current, voltage, etc.) to the branch circuit and the load, thereby de-energizing the circuit and the connected load at block 812. At block 812, the circuit breaker may also output a status notification, such as a ground fault (GF) alarm or its type, such as locally output through a user interface (e.g., via I / O 140) or output to a user / user device or a remote monitoring / management computer system (e.g., via communication device 130).

[0087] Otherwise, if the first leakage current is below the first threshold at block 810, process 800 proceeds to block 820, where the circuit breaker determines whether the monitored second leakage current meets (e.g., is greater than or equal to, etc.) a second threshold, which is associated with an allowable / acceptable (or excessive / abnormal) leakage current on the ground conductor from the load. If so, the circuit breaker detects that a ground fault has occurred due to the excessive / abnormal leakage current from the load. In response to the ground fault detection, the circuit breaker interrupts the supply (e.g., power, current, voltage, etc.) to the branch circuit and the load, thereby de-energizing the circuit and the connected load at block 822. At block 822, the circuit breaker may also output a status notification, such as a ground fault (GF) alarm or its type, such as locally output through a user interface (e.g., via I / O 140) or output to a user / user device or a remote monitoring / management computer system (e.g., via communication device 130).

[0088] Returning to block 820, if the second leakage current is below the second threshold TH2, the process 800 proceeds to block 830, in which the circuit breaker determines whether the monitored second leakage current meets (e.g., is greater than or equal to, etc.) a third threshold. The third threshold is associated with an indication that the second leakage current is close to or near an excessive / abnormal level but has not yet reached this level (e.g., the second TH2), and some action may need to be taken. If the second leakage current meets the third threshold TH3 (and is below the second threshold TH2), the circuit breaker detects that the second leakage current from the load is close to an excessive / abnormal level. In response to this detection, at block 832, the circuit breaker outputs a status notification, such as a maintenance notification. The maintenance notification can be output locally through a user interface (e.g., via I / O 140), or output to a user / user device or a remote monitoring / management computer system (e.g., via communication device 130). Thereafter, the process 800 can return to block 802 to continue the process.

[0089] Returning to block 830, if the second leakage current is below the third threshold (TH3) at block 830, process 800 proceeds to block 840, where the circuit breaker uses the monitored pilot signal to determine whether the load impedance between the pilot signal line and the ground conductor has changed from an acceptable range of the predefined load curve. If so, the circuit breaker detects the occurrence of a ground fault due to an improper connection of the ground conductor (e.g., an open circuit, a broken circuit, or other improper connection of the ground conductor, or an open pilot signal circuit). In response to the ground fault detection, the circuit breaker interrupts the supply of power (e.g., power, current, voltage, etc.) to the branch circuit and the load, thereby de-energizing the circuit and the connected load at block 842. At block 842, the circuit breaker may also output a status notification, such as a ground fault (GF) alarm or its type, such as locally output through a user interface (e.g., via I / O 140) or output to a user / user device or a remote monitoring / management computer system. Otherwise, if the impedance of the load is within an acceptable range of the predefined load curve, process 800 returns to block 802 to continue the process.

[0090] Although process 800 describes an example of three types of ground fault (GF) detection performed by the process, according to various embodiments, a circuit breaker or other protection device as described herein may be configured to perform any combination of different types of GF detection and protection as described in process 800.

[0091] Figure 8B A flow chart of an example process 850 for detecting and protecting against different types of faults and conditions on an electrical system according to an embodiment of the present disclosure is shown. For purposes of example explanation, reference will be made to Figure 1The process 850 is described with respect to a ground-fault interrupting device 100 (eg, 100 ), for example in the form of a circuit breaker, and its components, such as a controller (eg, 110 ) and sensors / monitors, etc.

[0092] The process begins at block 852, where the circuit breaker may monitor various energy-related (ER) signals and other signals associated with the protected branch circuit using a plurality of sensors / monitors including current sensors, voltage sensors, pilot monitors (or sensors), etc. The monitored signals may include energy-related signals such as current, voltage, power, etc. on each line conductor, all line conductors, and all line conductors and ground conductors; and other signals such as pilot signals.

[0093] At block 860, the circuit breaker may perform ground fault detection and protection by analyzing the monitored energy-related signals, as described herein. In response to ground fault detection, the circuit breaker interrupts the supply of power (e.g., power, current, voltage, etc.) to the branch circuit and the load, thereby de-energizing the circuit and the connected load at block 862. At block 862, the circuit breaker may also output a status notification, such as a ground fault (GF) alarm or its type, such as locally through a user interface (e.g., via I / O 140) or to a user / user device or a remote monitoring / management computer system.

[0094] If no ground fault is detected at block 860, the circuit breaker may perform arc fault detection and protection of the branch circuit by analyzing the monitored energy-related signals at block 870. In response to arc fault detection, the circuit breaker interrupts the supply of power (e.g., power, current, voltage, etc.) to the branch circuit and the load, thereby de-energizing the circuit and the connected load at block 872. At block 872, the circuit breaker may also output a status notification, such as an arc fault (AF) alarm or its type, such as locally through a user interface (e.g., via I / O 140) or to a user / user device or a remote monitoring / management computer system.

[0095] If no arc fault is detected at block 870, the circuit breaker may perform short circuit fault detection and protection of the branch circuit by analyzing the monitored energy-related signals at block 880. In response to the short circuit fault detection, the circuit breaker interrupts the supply of power (e.g., power, current, voltage, etc.) to the branch circuit and the load, thereby de-energizing the circuit and the connected load at block 882. At block 882, the circuit breaker may also output a status notification such as a short circuit (SC) fault alarm or its type, such as locally output through a user interface (e.g., via I / O 140) or output to a user / user device or a remote monitoring / management computer system.

[0096] If a short circuit fault is not detected at block 880, the circuit breaker may perform overcurrent fault detection and protection of the branch circuit and the load by analyzing the monitored energy-related signals at block 890. In response to overcurrent fault detection, the circuit breaker interrupts the supply of power (e.g., power, current, voltage, etc.) to the branch circuit and the load, thereby de-energizing the circuit and the connected load at block 892. At block 892, the circuit breaker may also output a status notification such as an overcurrent (OC fault alarm or type thereof), such as locally output through a user interface (e.g., via I / O 140) or output to a user / user device or a remote monitoring / management computer system).

[0097] If no overcurrent fault is detected at block 890, the circuit breaker may store and output (e.g., in real time) monitored, derived, and determined states and diagnostics of the electrical system, circuit breakers, branch circuits, and loads at block 898. Such information may be output locally through a user interface (e.g., via I / O 140), or to a user / user device or remote monitoring / management computer system for further analysis or action. Thereafter, process 850 may return to block 852 to continue the process.

[0098] Process 850 describes examples of different types of faults or conditions (e.g., GF, AF, SCF, OCF, etc.) that may be detected and protected by a circuit breaker or circuit protection device for protected branch circuits and loads. It should be understood that a circuit breaker or protection device as described herein may be configured to perform any combination of ground fault detection and protection types and in combination with any combination of other fault and / or condition detection and protection as described above. In addition, AF detection, OC fault detection, and SC fault detection may be performed using conventional detection processes or algorithms that may be used, for example, in conventional circuit breakers or circuit protection devices.

[0099] Fig. 9 An example system environment 10A of a ground fault detection and protection system according to a second embodiment of the present disclosure is shown, for example, a ground fault interruption device 100A for an electrical system including HVAC (heating, ventilation, air conditioning) equipment. Fig. 9 , the components and functions of the device 100A are similar to those of Figure 1 The same or similar example of the device 100 of 100A, except that the device 100A does not include the first ground fault sensor GFS-1. In this second embodiment, the device 100A can use the second ground fault sensor GFS-2 to detect a ground fault due to excessive / abnormal leakage current from the load on the ground conductor, and use a pilot or a ground monitor (control pilot) to detect a ground fault due to an improper connection of the ground conductor. In various embodiments, the allowable / acceptable leakage current range of the load can be 15mA to 20mA.

[0100] Fig.10 An example system environment 10B of a ground fault detection and protection system according to a third embodiment of the present disclosure is shown, such as a ground fault interrupting device 100B for use with an electrical system including HVAC (heating, ventilation, air conditioning) equipment. Fig.10 , the components and functions of the device 100B are similar to those of Figure 1 The same or similar example of the device 100 of 100B, except that the device 100B does not include the second ground fault sensor GFS-2. In this third embodiment, the device 100B can use the first ground fault sensor GFS-1 to detect a ground fault on the branch circuit or its wiring (e.g., a ground fault between the line conductor L1 or L2 and the ground ground), and use a pilot or a ground monitor (control pilot) to detect an improper connection of the ground conductor. In various embodiments, the branch circuit's breakaway level can be in the range of 4 mA to 6 mA.

[0101] Fig.11 An example system environment 10C of a ground fault detection and protection system according to a fourth embodiment of the present disclosure is shown, for example, a ground fault interruption device 100C for use with an electrical system including HVAC (heating, ventilation, air conditioning) equipment. Fig.11 , the components and functions of the device 100C are similar to those of Figure 1 The same or similar example of the apparatus 100 of FIG. 100B, except that the apparatus 100C does not include the second ground fault sensor GFS-2 and the pilot or ground monitor. In this fourth embodiment, the apparatus 100B can use the first ground fault sensor GFS-1 to detect a ground fault on a branch circuit or its wiring (e.g., a ground fault between a line conductor L1 or L2 and an earth ground). In various embodiments, the branch circuit's breakaway level can be in the range of 4 mA to 6 mA.

[0102] Fig.12 An example system environment 10D of a ground fault detection and protection system according to a fifth embodiment of the present disclosure is shown, such as a ground fault interrupting device 100C for use with an electrical system including electrical equipment other than HVAC equipment. Fig.12 , the components and functions of the device 100D are similar to those of Figure 1 The example device 100 is the same or similar to the example device 100, except that the device 100C is used to provide protection to connected loads other than HVAC equipment. In various embodiments, the load or its equipment may have an allowable, acceptable or normal leakage current level that is higher or greater than the branch circuit's runaway current level.

[0103] Fig.13An example system environment 10E of a ground fault detection and protection system according to a sixth embodiment of the present disclosure is shown, for example, a ground fault interruption device 100E for use with an electrical system including HVAC (heating, ventilation, air conditioning) equipment. Fig.13 , the components and functions of the device 100E are similar to those of Figure 1 The device 100E is the same or similar to the example device 100 of , except that the device 100E does not include a pilot or ground monitor. In this fourth embodiment, the device 100B can use a first ground fault sensor GFS-1 to detect a ground fault on a branch circuit or its wiring (e.g., a ground fault between a line conductor L1 or L2 and an earth ground). The device 100E can also use a second ground fault sensor GFS-2 to detect a ground fault due to an excessive / abnormal leakage current from a load on a ground conductor. In various embodiments, the branch circuit's escape level can be in the range of 4 mA to 6 mA, and the allowable / acceptable range of the leakage current of the load can be 15 mA to 20 mA.

[0104] Fig.14 A chart 1400 in tabular form is shown, which provides for the purpose of comparing example configurations, including detection levels or values ​​for different ground fault detection and protection scenarios. These scenarios include scenarios for devices implementing the current UL 943 safety standard for GFCI, and scenarios for ground fault interrupting devices 100, 100A, 100B, 100C, 100D, and 100E for the first, second, third, fourth, and fifth embodiments of the present disclosure, respectively.

[0105] For example, each scenario shows the relevant configuration of the ground fault interrupting device, such as the GF detection level of L1-GC, L2-GC, L1-E, L2-E, where GC is the ground conductor, E is the ground, L1 is the ungrounded conductor line 1, and L2 is the ungrounded conductor line 2. The configuration can also include the detection level related to the appliance metal frame to the ground ground (appliance metal frame-E), such as whether a ground monitor is provided and the leakage allowed by the appliance. As shown in the diagram 1400, in the absence of a ground monitor, the allowable leakage current from the appliance metal frame to the ground can nominally be equal to the allowable leakage current to the ground L1 / L2. With the ground monitor, the leakage current from the metal frame to the ground is close to zero because the ground monitor can ensure that the impedance from the frame to the ground is very low, which is due to monitoring the ground conductor and ensuring that the ground conductor impedance is low.

[0106] It should be understood that the various configurations, including values, on chart 1400 are provided by way of example only.

[0107] Fig.15Example components of a computer device (or system) 1500 according to an embodiment of the present disclosure are shown. Computer device 1500 may be a controller / processor-implemented fault interrupt device (e.g., ground fault interrupt device, circuit breaker, etc.), a local or remote computer device or system (e.g., user device, central monitoring computer system, etc.), or other controller / processor-based devices or systems described herein.

[0108] Device 1500 may include memory 1510, processor 1520, communication device 1530, clock 1540, input / output device 1550, which may be communicatively connected. In this example, the various components may be communicatively connected via bus 1570. Clock 1540 may be used to time stamp data or events with time values ​​and synchronize operations within the device and with remote devices or systems. Communication device 1530 may include a transmitter and a receiver for wireless communication and / or wired communication with other remote devices or networks.

[0109] The memory 1510 may store computer executable code, programs, software, or instructions that, when executed by the processor, control the operation of the device 1500, including the various processes / algorithms described herein. The memory 1510 may also store other data used by the device 1500 or its components to perform the operations described herein. The other data may include, but is not limited to, threshold (or level) values ​​or ranges, diagnostic information, status information, alarm information, and other information described herein.

[0110] Processor 1520 , in interaction with other components of the computer device, is configured to control or implement various operations and functions described herein, including control of components of computer device 1500 and quality analysis of network installations.

[0111] Input / output devices 1550 may include one or more input devices, and one or more output devices. Input devices may include handles, buttons, keyboards, keypads, touch panels or screens, microphones, cameras, or other known user input devices for computer devices or systems, including controller / processor-based circuit protection devices, such as fault interrupting devices, miniature circuit breakers, and other devices or systems described herein. Output devices may include display screens, speakers, printers, intelligent output devices, LEDs, handle positions, or other known output devices in or used with computer devices or systems, including controller / processor-based circuit protection devices, such as fault interrupting devices, miniature circuit breakers, and other devices or systems described herein.

[0112] Sensor 1560 may include one or more sensors for monitoring energy-related signals on conductors (e.g., line conductors, ground conductors, pilot signal lines, etc.), including those described herein. Sensor 1560 may include current sensors, voltage sensors, power sensors, ground fault sensors for measuring conductors (e.g., different combinations of line conductors and / or ground conductors (including neutral ground, etc.), pilot signal sensors, or other types of sensors (including sensors described herein) for sensing energy-related signals to diagnose the electrical system including its circuits and loads.

[0113] Depending on the application, the computer device 1500 may or may not include the following: Fig.15 The various components shown in the examples may be examples of, or additional components may be included.

[0114] It should be understood that the embodiments disclosed herein may be configured as a system, method, or a combination thereof. Therefore, the embodiments of the present disclosure may include various devices, including hardware, software, firmware, or any combination thereof.

[0115] It should also be understood that the example embodiments disclosed and taught herein are susceptible to many and various modifications and alternative forms. Therefore, the use of singular terms, such as but not limited to "one", etc., is not intended to limit the number of items. In addition, the naming conventions of various components, functions, features, thresholds and other elements used herein are provided as examples and may be given different names or labels. The use of the term "or" is not limited to an exclusive "or" and can also mean "and / or".

[0116] It should be understood that the development of practical, real business applications incorporating aspects of the disclosed embodiments will require many implementation-specific decisions to achieve the developer's ultimate goals for the business embodiments. Such implementation-specific decisions may include, and may not be limited to, compliance with system-related, business-related, government-related, and other constraints, which may vary with the specific implementation, location, and time. While the developer's efforts may be complex and time-consuming in an absolute sense, such efforts are still routine tasks for those skilled in the art who benefit from this disclosure.

[0117] Using the description provided herein, the example embodiments may be implemented as a machine, process, or article of manufacture by using standard programming and / or engineering techniques to produce programming software, firmware, hardware, or any combination thereof.

[0118] Any resulting program with a computer-readable program code may be included on one or more tangible or non-transitory computer-usable media, such as a resident memory device, a smart card or other removable memory device, or a transmission device, thereby forming a computer program product or article of manufacture according to an embodiment. Likewise, the terms "article of manufacture" and "computer program product" as used herein are intended to include a computer program that is permanently or temporarily present on any computer-usable or storage medium or in any transmission medium that transmits such a program.

[0119] The processor, controller or processing unit described herein may be a processing system, which may include one or more processors, such as a CPU, a controller, an ASIC or other processing unit or circuit, which controls or performs the operation of the device or system described herein. The memory / storage device may include, but is not limited to, a disk, a solid-state drive, an optical disk, a removable storage device such as a smart card, a SIM, a WIM, a semiconductor memory such as RAM, ROM, PROMS, etc. The transmission medium or network may include, but is not limited to, transmission via wired communication, wireless communication (e.g., radio frequency (RF) communication, Bluetooth®, Wi-Fi, Li-Fi, etc.), the Internet, an intranet, a telephone / modem-based network communication, a hardwired / cable communication network, a satellite communication, and other fixed or mobile network systems / communication links.

[0120] The flow charts and block diagrams in the accompanying drawings illustrate the possible architectures, functions and / or operations of various embodiments of the present disclosure. In this regard, each frame in the flow chart or block diagram may represent a module, a code segment or a portion, which includes one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions annotated in the frame may not appear in the order annotated in the figure. For example, the two frames shown in succession can actually be performed substantially simultaneously, or these frames can sometimes be performed in reverse order, depending on the functions involved. It will also be noted that each frame in the block diagram and / or flow chart illustration and the frame combination in the block diagram and / or flow chart illustration can be implemented by a system based on dedicated hardware or a combination of dedicated hardware and computer instructions that performs a specified function or action.

[0121] It should be understood that the concepts, systems, circuits, and techniques sought to be protected herein are not limited to use in the example applications (e.g., industrial applications) described herein, but may be used in substantially any application where it is desired to receive decision support for each step in an automated manner. Although specific embodiments and applications of the present disclosure have been shown and described, it should be understood that the embodiments of the present disclosure are not limited to the precise construction and composition disclosed herein, and that various modifications, changes, and variations are apparent from the foregoing description without departing from the spirit and scope of the present disclosure as defined in the appended claims.

[0122] Having described preferred embodiments for illustrating various concepts, structures, and techniques that are the subject of this patent, it will now be apparent to those skilled in the art that other embodiments that combine these concepts, structures, and techniques may be used. In addition, the elements of the different embodiments described herein may be combined to form other embodiments not specifically described above.

[0123] Accordingly, it is intended that the scope of this patent should not be limited to the described embodiments, but should be limited only by the spirit and scope of the appended claims.

Claims

1. A device for interrupting power to a branch circuit supplying power to a load, the circuit comprising at least a line conductor and a ground conductor different from the line conductor, the device comprising: a first ground fault sensor for monitoring an amount of a first leakage current on the line conductor and the ground conductor, the amount of the first leakage current ignoring the leakage current on the ground conductor; a second ground fault sensor for monitoring an amount of a second leakage current from the load on the line conductor, the amount of the second leakage current taking into account the leakage current on the ground conductor; as well as Processor, which is configured as: detecting a ground fault on the branch circuit based on an amount of a first leakage current monitored by a first ground fault sensor; detecting a ground fault at the load due to an excessive leakage current based on the amount of the second leakage current and an amount of allowable / acceptable leakage current of the load under normal operation; and If a ground fault is detected on a branch circuit or at a load, interruption of power to the branch circuit is controlled.

2. The device according to claim 1, wherein: The processor is configured to detect a ground fault on the circuit if an amount of the first leakage current exceeds a first threshold based on a breakaway current threshold or other physiological condition.

3. The device according to claim 2, wherein: The processor is configured to detect excessive leakage current at the load if a second leakage current of the load exceeds a second threshold value based on a maximum or upper limit of an allowable / acceptable leakage current of the load.

4. The device according to claim 3, wherein: The load includes HVAC equipment, the first current threshold is within a first range of about 4 mA to about 6 mA, and the second current threshold is within a second range of about 15 mA to about 20 mA, wherein the maximum or upper limit of the allowable / acceptable leakage current is 15 mA.

5. The device according to claim 1, wherein: The loads include HVAC equipment or other outdoor electrical equipment having an allowable / acceptable leakage current under normal operation that is greater than the branch circuit's runaway current level or a current level based on other physiological conditions.

6. The apparatus of claim 1 further comprising a set of electrical contacts through which power is supplied to the branch circuit, wherein: The processor is configured to enable or interrupt power to the branch circuit via a switch or trip mechanism.

7. The apparatus according to claim 1, further comprising a communication device or a local output device, in, The processor is further configured to output reports or notifications related to monitored power, status and / or diagnostics related to power supplied to the branch circuit or load to a remote computer device or system via a communication device or to a local output device.

8. The device according to claim 7, wherein: The report or notification includes a status notification, and if the second leakage current is within a third threshold, repair or maintenance is performed on the load or equipment related thereto, the third threshold including a predetermined current range or value before the second threshold, and the third threshold is used to detect that the second leakage current is approaching an excessive or abnormal level.

9. The device according to claim 8, wherein: The third current threshold includes a third range between about 10 mA and about 15 mA or a value within the third range.

10. The device according to claim 1, wherein: The processor is further configured to: monitoring a pilot signal on a pilot signal line connected to a pilot control circuit within a housing of the load, the control pilot circuit having an electrical component having a predefined load curve connected between the pilot signal line and a ground conductor; using the monitored pilot signal to detect an impedance of a load curve of a control pilot circuit between a pilot signal line and a ground conductor; detecting an open, broken, or improperly connected ground conductor if the sensed impedance of the load profile is different than an acceptable impedance range for a predefined load profile; and Controls interruption of power to a branch circuit if the grounding conductor is open, broken, or improperly connected.

11. The device according to claim 10, wherein: The electrical components of the control pilot circuit include a resistor and a diode connected in series.

12. The apparatus according to claim 10, further comprising a communication device or a local output device, in, The processor is further configured to output a notification to a remote computer device or system via a communication device or to a local output device, the notification indicating that the ground conductor is open, broken, or improperly connected.

13. The device according to claim 1, wherein: The line conductors include at least two line conductors including ungrounded conductors, grounded conductors, or a combination thereof.

14. The apparatus according to claim 1, further comprising: Arc fault protection subsystem, overcurrent protection subsystem and / or short circuit subsystem.

15. The device according to claim 1, wherein: The device is a miniature circuit breaker or MCB.

16. The apparatus according to claim 15, further comprising: at least two line-side voltage terminals for insertion into a load center; at least two load current carrying conductor terminals for branch circuit line connection; At least one service entrance-side grounding conductor wire connection; as well as At least one branch circuit side ground conductor wire is connected.

17. A method of interrupting power to a branch circuit supplying power to a load, the circuit comprising at least a line conductor and a ground conductor distinct from the line conductor, the method comprising: monitoring, via a first ground fault sensor, an amount of a first leakage current on the line conductor and the ground conductor, the amount of the first leakage current ignoring the leakage current on the ground conductor; monitoring, via a second ground fault sensor, an amount of a second leakage current of a load on the line conductor, the amount of the second leakage current taking into account a leakage current on the ground conductor; detecting, via the processor, a ground fault on the branch circuit based on an amount of a first leakage current monitored by a first ground fault sensor; detecting, via the processor, a ground fault at the load due to excessive leakage current based on the amount of the second leakage current and an amount of allowable / acceptable leakage current of the load under normal operation; as well as If a ground fault on a branch circuit or at a load is detected, interruption of power to the branch circuit is controlled via a processor.

18. The method according to claim 17, wherein: The load has an allowable / acceptable leakage current under normal operation that is greater than a threshold for ground fault protection of the branch circuit.

19. A device for interrupting power to a branch circuit supplying power to a load, the circuit comprising at least two line conductors and a ground conductor distinct from the at least two line conductors, the device comprising: at least one ground fault sensor comprising: a first ground fault sensor for monitoring an amount of a first leakage current on at least two line conductors and a ground conductor, the amount of the first leakage current ignoring a leakage current on the ground conductor, and / or a second ground fault sensor for monitoring an amount of a second leakage current of a load on at least two line conductors, the amount of the second leakage current taking into account a leakage current on the ground conductor; Processor, which is configured as: detecting at least one type of ground fault, the processor being configured to detect a ground fault on the branch circuit based on an amount of a first leakage current monitored by a first ground fault sensor, and / or to detect a ground fault at the load due to excessive leakage current based on an amount of a second leakage current and an amount of allowable / acceptable leakage current of the load under normal operation; and Controls the interruption of power supply to the branch circuit if at least one type of ground fault is detected, Where the load includes HVAC or other electrical equipment that has an allowable / acceptable leakage current under normal operation that is greater than the threshold of the branch circuit's ground fault protection.

20. The device according to claim 19, wherein said at least one ground fault sensor comprises said first and second ground fault sensors, The processor is configured to detect a ground fault on the branch circuit based on an amount of a first leakage current monitored by a first ground fault sensor, and to detect a ground fault at the load due to an excessive leakage current based on an amount of the second leakage current and an amount of an allowable / acceptable leakage current of the load under normal operation.

21. The device according to claim 19, wherein The processor is further configured to: monitoring a pilot signal on a pilot signal line connected to a pilot control circuit within a housing of the load, the control pilot circuit having an electrical component having a predefined load curve connected between the pilot signal line and a ground conductor; using the monitored pilot signal to detect an impedance of a load curve of a control pilot circuit between a pilot signal line and a ground conductor; detecting an open, broken, or improperly connected ground conductor if the sensed impedance of the load profile is different than an acceptable impedance range for a predefined load profile; and Controls interruption of power to a branch circuit if the grounding conductor is open, broken, or improperly connected.

22. A method of interrupting power to a branch circuit supplying power to a load, the circuit comprising at least two line conductors and a ground conductor distinct from the at least two line conductors, the method comprising: Monitoring at least one type of leakage current, the monitoring comprising: monitoring, via a first ground fault sensor, an amount of a first leakage current on at least two line conductors and a ground conductor, the amount of the first leakage current ignoring a leakage current on the ground conductor, and / or monitoring, via a second ground fault sensor, an amount of a second leakage current of a load on at least two line conductors, the amount of the second leakage current taking into account a leakage current on the ground conductor; detecting, via a processor, at least one type of ground fault, the detecting comprising: detecting a ground fault on the branch circuit based on an amount of a first leakage current monitored by a first ground fault sensor, and / or detecting a ground fault at the load due to an excessive leakage current based on the amount of the second leakage current and an amount of allowable / acceptable leakage current of the load under normal operation; and If at least one type of ground fault is detected, interruption of power supply to the branch circuit is controlled via a processor, Where the load includes HVAC or other electrical equipment that has an allowable / acceptable leakage current under normal operation that is greater than the threshold of the branch circuit's ground fault protection.

23. The method according to claim 22, wherein: The monitoring includes: monitoring an amount of a first leakage current on the at least two line conductors and the ground conductor via a first ground fault sensor, and monitoring an amount of a second leakage current of a load on at least two line conductors via a second ground fault sensor; and The detection includes: detecting a ground fault on the branch circuit based on an amount of a first leakage current monitored by a first ground fault sensor, and Based on the amount of the second leakage current and the amount of allowable / acceptable leakage current of the load under normal operation, a ground fault at the load due to excessive leakage current is detected.

24. The method according to claim 23, further comprising: monitoring a pilot signal on a pilot signal line connected to a pilot control circuit within a housing of the load, the control pilot circuit having an electrical component having a predefined load curve connected between the pilot signal line and a ground conductor; using the monitored pilot signal to detect an impedance of a load curve of a control pilot circuit between a pilot signal line and a ground conductor; detecting, via the processor, that the ground conductor is open, broken, or improperly connected if the detected impedance of the load profile is different than an acceptable impedance range for a predefined load profile; and Controls interruption of power to a branch circuit if the grounding conductor is open, broken, or improperly connected.

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