Method and apparatus for intelligent centralized arc fault detection in system

Abstract

A method and system for facilitating arc fault detection on an electrical system is provided. In the method and system, a first device may measure or obtain measurements of a high-frequency signal on a circuit monitored by a first sensor on an electrical system, which measurements are used to determine a high-frequency characteristic. The branch device may measure or obtain measurements of the low frequency signal on an associated branch circuit monitored by the second sensor, which measurements are used to determine a low frequency characteristic on the branch circuit. The branch circuit monitored by the second sensor is located downstream of the circuit monitored by the first sensor. The first device or the branch device uses the high-frequency and low-frequency features to detect the occurrence of an arc fault on the branch circuit.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to co - pending U.S. Non - Provisional Patent Application Serial No. 18 / 376,904, filed on October 5, 2023, which claims priority to U.S. Provisional Patent Application Serial No. 63 / 431,439, filed on December 9, 2022. The entire disclosure of the above - mentioned existing U.S. patent applications is hereby incorporated by reference in its entirety and considered part of this application. Technical Field

[0003] The present invention generally relates to fault detection, and more particularly, to centralized arc fault detection in an electrical system. Background Art

[0004] Existing AFCI devices (e.g., circuit breakers, disconnects, or wiring devices) are stand - alone devices for AF (arc fault) detection. Such devices can provide independent protection for each branch, allowing the load center to provide all or part of the protection in a home. Over the years, the cost of the devices has been increasing because of the need to equip AF sensors, AFE (active front - end) components, and require stronger processing capabilities to implement multiple signal - processing functions. As a result, the devices require more power and are more costly to manufacture.

[0005] As the complexity of remotely controlling such devices increases, each branch may also include some communication devices with a main processing unit that can control which loads and / or branches are energized or de - energized. These mechanical components further increase the cost and complexity of the devices. Summary of the Invention

[0006] According to an embodiment, a method and system are provided to facilitate arc fault detection in an electrical system. The method and system include: providing high - frequency characteristics determined from a high - frequency signal on a circuit monitored by a first sensor of the electrical system, the high - frequency signal being measured or obtained by a first device configured to communicate with a first remote device, the first remote device including a branch device on a branch circuit downstream of the monitored circuit. The method and system also include providing low - frequency characteristics determined from a low - frequency signal on the branch circuit monitored by a second sensor, the low - frequency signal being measured or obtained by the branch device. The method and system also include detecting the occurrence of an arc fault on the branch circuit based on the high - frequency characteristics and the low - frequency characteristics. In various embodiments, in the method and system, the operation of providing high - frequency characteristics, the operation of providing low - frequency characteristics, and the operation of detecting the occurrence of an arc fault are performed by the first device (e.g., a main or central unit or device) or the branch device. In some embodiments, the first device may determine the high - frequency characteristics of each phase or power line of the electrical system.

[0007] In various embodiments, the first device may be located inside or outside the distribution board. The branch device may include a circuit breaker, a relay, a switching device, a wiring device, a lighting switch or control device, or an electrical device connected to the associated branch circuit.

[0008] In various embodiments, the method and system may further include transmitting an energy measurement between the first device and a branch device associated with the branch circuit. The energy measurement may include one of the high-frequency characteristics of the monitored circuit or information from which the high-frequency characteristics can be derived, or the low-frequency characteristics of the branch circuit or information from which the low-frequency characteristics can be derived. The first device or the branch device may detect the occurrence of an arc fault on the branch circuit based on the high-frequency and low-frequency characteristics of the branch circuit.

[0009] In various embodiments, the branch device may include a plurality of branch devices associated with the branch circuit, and the energy measurement may be transmitted between the first device and each of the plurality of branch devices.

[0010] In various embodiments, the method and system may further include time synchronization and half-cycle synchronization of the first device and the branch device to enable synchronized information exchange between the first device and the branch device, including the energy measurement. The high-frequency characteristics of the monitored circuit may be synchronized with the low-frequency characteristics of the branch circuit. The synchronized high-frequency and low-frequency characteristics may be used to detect the occurrence of an arc fault on the branch circuit. Additionally, in some embodiments, the first device may detect an arc fault on the branch circuit and remotely control the branch device associated with the branch circuit where the arc fault is detected to de-energize the branch circuit.

[0011] In various embodiments, the method and system may further include: at the first device, measuring or obtaining a measurement of a high-frequency signal on the circuit monitored by the first sensor, the first device including a first memory, a first processor, and a first communication device for communicating with a first remote device; at the branch device, measuring or obtaining a measurement of a low-frequency signal on the associated branch circuit monitored by the second sensor, the branch device including a second memory, a second processor, and a second communication device for communicating with a remote device including the first device; and at the at least one branch device, determining a low-frequency characteristic based on the measured low-frequency signal on the branch circuit, and the first device or the branch device using the low-frequency characteristic together with the high-frequency characteristic to detect the occurrence of an arc fault on the branch circuit.

[0012] In another embodiment, the method and system may further include sending a message from the branch device to the first device if the branch device determines that the low-frequency signature of the branch circuit crosses or meets a low-frequency threshold. In response to the receipt of the message, the high-frequency signature may be transmitted from the first device to the branch device. The branch device may detect an arc fault on the branch circuit based on the high-frequency and low-frequency signatures of the branch circuit, and if an arc fault is detected on the branch circuit, may de-energize the associated branch circuit.

[0013] In another embodiment, the method and system may further include sending a message from the first device to the branch device if the high-frequency signature crosses or meets a high-frequency threshold at the first device. In response to the receipt of the message, if the low-frequency signature of the associated branch circuit crosses or meets a low-frequency threshold, the low-frequency signature may be transmitted from the branch device to the first device. The first device may detect an arc fault on the branch circuit based on the high-frequency and low-frequency signatures of the branch circuit. If the first device detects an arc fault on the branch circuit, the branch circuit may be de-energized via its associated branch device. Additionally, in some embodiments, if an arc fault is detected on the branch circuit, the first device may remotely control the branch device to de-energize the branch circuit.

[0014] In various embodiments, the method and system may further include energizing the branch circuit after a predetermined de-energization period expires, the predetermined de-energization period being initiated in response to an arc fault detected on the branch circuit (resulting in the branch circuit being de-energized by the branch device).

[0015] According to another embodiment, a method and system are provided for facilitating arc fault detection on an electrical system having a plurality of branch devices on different branch circuits. The method and system include measuring or obtaining a measurement of a low-frequency signal on a respective branch circuit monitored by a respective sensor on the electrical system at each of the plurality of branch devices. Each of the plurality of branch devices includes a memory, a processor, and a communication device for communicating with a remote device including a first device. The method and system may also determine a low-frequency signature at each of the plurality of branch devices based on the low-frequency signal measured on the respective branch circuit. Energy measurements may be transmitted between each of the plurality of branch devices and the first device, where the first device is configured to share a high-frequency signature of a high-frequency signal monitored upstream of the circuit on the branch circuit of the electrical system. The energy measurements include one of the low-frequency signature or the shared high-frequency signature. The low-frequency signature of the respective branch circuit, together with the shared high-frequency signature, is used to detect an arc fault on the respective branch circuit.

[0016] According to another embodiment, a method and system for restoring a load or branch circuit from an electrical system fault are provided. The method and system include maintaining and updating the number of attempts to energize the branch circuit by a processor or under the control of a processor after the branch circuit de-energizes in response to an arc fault detected on the branch circuit. The method and system also include, if the number of attempts to energize / re-energize the branch circuit meets or exceeds an attempt threshold, preventing or delaying the energization / re-energization of the branch circuit by a processor or under the control of a processor and notifying a user of a hazardous condition associated with the branch circuit or a device thereon.

[0017] According to another embodiment, a method and system for facilitating arc fault detection in a power distribution system having at least one branch circuit are provided. The method and system can include measuring an electrical signal on the power distribution system via at least one sensor of an upstream device, the upstream device being connected upstream of a branch device to at least one branch circuit; and determining a high-frequency signature from the measured electrical signal via a processor of the upstream device, the determined high-frequency signature being used by the upstream device or the branch device to detect the occurrence of an arc fault on at least one branch circuit.

[0018] In various embodiments, the upstream device can include a main switch or circuit breaker of a load center, and the branch device can include a circuit breaker, disconnect, wiring device, or circuit protection device of the branch circuit.

[0019] In various embodiments, information about the determined high-frequency signature or information about the occurrence of an arc fault detected on at least one branch circuit can be transmitted to a branch device of at least one branch circuit.

[0020] In various embodiments, the method and system can further include measuring an electrical signal on at least one branch circuit via a sensor associated with a branch device of at least one branch circuit; and determining a low-frequency signature based on the electrical signal measured on at least one branch circuit. The occurrence of an arc fault can be detected based at least on the determined high-frequency signature and the determined low-frequency signature.

[0021] In various embodiments, the method and system can further include: receiving, at a branch circuit device of at least one branch circuit, information about the determined high-frequency signature; synchronizing the determined high-frequency signature and the determined low-frequency signature; and detecting the occurrence of an arc fault on at least one branch circuit based on the synchronously determined high-frequency and low-frequency signatures. Additionally, in various embodiments, branch devices on each of a plurality of branch circuits can measure electrical signals and correspondingly determine low-frequency signatures, and detect arc faults on the respective branch circuits based on the determined high-frequency signatures from the upstream device and the respective determined low-frequency signatures.

[0022] In various embodiments, the method and system may further include: at an upstream device, receiving information of determined low-frequency characteristics from a branch device; synchronizing the determined high-frequency characteristics and the determined low-frequency characteristics; and detecting the occurrence of an arc fault on at least one branch circuit based on the synchronized determined high-frequency characteristics or and low-frequency characteristics. Additionally, in various embodiments, the upstream device may receive information of the determined low-frequency characteristics from branch devices of respective branch circuits from a plurality of downstream branch circuits, and detect an arc fault on the respective branch circuit based on the determined high-frequency characteristics from the upstream device and the determined low-frequency characteristics from the respective branch devices of the respective branch circuits.

[0023] According to an embodiment, a method may be provided to facilitate arc fault detection in a power distribution system including an upstream device and at least one downstream device on a branch circuit downstream of the upstream device. The method and system may include extracting high-frequency characteristics from a line current sensor or a line voltage sensor in the upstream device; extracting low-frequency characteristics or samples from a line current sensor or a line voltage sensor in at least one downstream device; and performing arc fault detection on the branch circuit based on the high-frequency characteristics and the low-frequency characteristics or samples.

[0024] According to an embodiment, a system may be provided for facilitating arc fault detection in a power distribution system including an upstream device and at least one downstream device on a branch circuit downstream of the upstream device. The system may include an upstream device for extracting high-frequency characteristics from a line current sensor or a line voltage sensor of the upstream device; and at least one downstream device for extracting low-frequency characteristics or samples from a line current sensor or a line voltage sensor of the downstream device. Arc fault detection of the branch circuit may be performed by the upstream device or the downstream device based on the high-frequency characteristics and the low-frequency characteristics or samples.

[0025] In various embodiments, a non-transitory computer medium storing computer-executable code is provided, which when executed by one or more processors of an upstream device, is configured to implement the methods described herein.

[0026] In an embodiment, methods and systems for restoring a load or a branch circuit from an electrical system fault are provided. The methods and systems may include: after expiration of a predetermined disconnection period initiated in response to an arc fault detected on a branch circuit, energizing the branch circuit at a branch device; in response to an arc fault detected on the branch circuit, using one or more computer processors to update a data value representing the number of times the branch circuit has been attempted to be energized; and when determining that the data value meets or exceeds an attempt threshold, preventing or delaying the energization of the branch circuit at the branch device.

[0027] In various embodiments, the method and system may further include: notifying a user of a dangerous condition associated with a branch circuit or a device thereon when it is determined that a data value meets or exceeds a trial threshold.

[0028] In various embodiments, the method and system may further include: detecting an arc fault on a branch circuit at a branch device or at a central monitoring device representative of the branch device, the branch device being a branch device among a plurality of branch devices on the branch circuit, and at the branch device, de-energizing the branch circuit in response to the detected arc fault on the branch circuit. Further, a predetermined de-energization period of the branch device has a duration sufficient to allow any other branch device downstream of the branch device to perform arc fault detection and de-energization operations before the branch device attempts to energize the branch circuit.

[0029] In various embodiments, a de-energization or tripping response time for performing a de-energization or tripping operation at a branch device to de-energize a branch circuit may be at least based on the size or current of a load connected to the branch circuit via the branch device. The method and system may further include: determining a de-energization or tripping response time of the branch device to de-energize the branch circuit at least based on the size or current drawn by the load connected to the branch device. Further, determining the de-energization or tripping response time may be at least based on the size of the load connected to the branch device relative to the size of the loads connected to other branch devices on the branch circuit or the current drawn by them to determine the de-energization or tripping response time of the branch device. Relative to other branch devices on the branch circuit, the de-energization or tripping response time of each branch device on the branch circuit may be shorter or faster for a larger load, or longer or slower for a smaller load.

[0030] In various embodiments, the method and system may further include: detecting a relative position of a detected arc fault along the branch circuit based on whether other branch devices on the detected branch circuit have an arc fault; and allowing branch devices upstream of the detected location of the arc fault to remain energized on the branch circuit or re-energize the branch circuit.

[0031] In various embodiments, the method and system may further include: if two or more branch devices among a plurality of branch devices on a branch circuit detect an arc fault on the branch circuit, de-energizing the entire branch circuit; and notifying a user of a dangerous condition associated with the branch circuit or a branch device thereon.

[0032] In various embodiments, an energization operation, an update operation, and a blocking or delaying operation are performed by a branch device. Further, the branch circuit includes a plurality of branch devices including the branch device, and each branch device is configured to perform an energization operation, an update operation, and a blocking or delaying operation.

[0033] In various embodiments, a branch circuit may include a plurality of branch devices including the branch device. Each branch device may be configured to perform an excitation operation, and a central monitoring device that communicates with and controls the branch device may be configured to perform or control an update operation and a blocking or delaying operation.

[0034] In various embodiments, a branch circuit is one of a plurality of branch circuits, and each branch circuit includes a plurality of branch devices. The method and system may further include: coordinating the execution or control of an excitation operation, an update operation, and a blocking or delaying operation via a central monitoring device that communicates with and controls each branch device on the branch circuit. Additionally, the branch devices on the branch circuit may include circuit breakers maintained in a load center. The central monitoring device may be located inside or outside the load center.

[0035] In various embodiments, the branch device may be a circuit protection device on the branch circuit.

[0036] In various embodiments, a non-transitory computer medium storing computer-executable code is provided, and when the code is executed by one or more processors of an upstream device, the code is configured to implement the methods described herein.

[0037] It should be understood that the foregoing general description and the following detailed description are merely exemplary and explanatory and do not limit the invention disclosed or claimed. The claims should enjoy their full scope, including equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Exemplary embodiments are described with reference to the accompanying drawings.

[0039] Figure 1 Schematic diagram of an exemplary protection system (for a power distribution system) according to an embodiment of the present invention, showing a main processing unit (MPU) and branch devices, including circuit breakers, metering devices, wiring devices, and other devices.

[0040] Figure 2A Functional block diagram of an exemplary main processing unit according to an embodiment of the present invention is shown.

[0041] Figure 2B Functional block diagram of an exemplary branch device according to another embodiment of the present invention is shown.

[0042] Figure 3 Exemplary wiring configuration / topology diagram of a protection system including a main processing unit and branch devices according to another embodiment of the present invention is shown.

[0043] Figure 4A Functional block diagram of an exemplary configuration of a protection system and its process according to an embodiment of the present invention, where arc fault detection (AFD) is performed by the branch device.

[0044] Figure 4B is a functional block diagram of an example configuration of a protection system and its process according to an embodiment of the present invention, where arc fault detection (AFD) is performed by a main processing unit.

[0045] Figure 5A Shows an example component and wiring configuration diagram of a protection system having a main processing unit and branch devices according to an embodiment of the present invention.

[0046] Figure 5B Shows an example component and wiring configuration diagram of a protection system having a main processing unit and branch devices according to an embodiment of the present invention.

[0047] Figure 6A and Figure 6B Shows an example data flow diagram according to an embodiment of the present invention, which shows the information coordination between the main processing unit and branch devices for protection system configuration.

[0048] Figure 6C and Figure 6D Shows an example data flow diagram according to an embodiment of the present invention, which shows the coordination between the main processing unit and branch devices for protection system configuration.

[0049] Figure 7 Shows a flowchart of an exemplary process according to an embodiment of the present invention, where high-frequency (HF) features (or components) are provided by the main processing unit to other devices including branch devices to perform arc fault detection.

[0050] Figure 8 Shows a flowchart of an example process of load or branch circuit restoration when a fault is eliminated and no longer exists according to an embodiment of the present invention.

[0051] Figure 9 Shows a flowchart of an example process of performing arc fault detection on one or more branch circuits using HF features (or components) determined upstream of one or more branch circuits or their branch devices according to an embodiment of the present invention.

[0052] Figure 10 Shows a fault condition downstream of a branch device according to one embodiment.

[0053] Figure 11 Shows a fault condition upstream of a branch device according to one embodiment.

[0054] Figure 12 Shows example components of a circuit protection device for a power distribution system according to one embodiment, such as an AFCI or other circuit breaker, disconnect switch, main switch (or circuit breaker), or other circuit protection and / or metering devices. Detailed implementation manners

[0055] An arc fault detection (AFD) method and system are provided for detecting the occurrence of an arc fault (AF) on one or more branch circuits (or multiple branch circuits) of an electrical system (such as a power distribution system). For example, the arc detection method and system can detect the occurrence (or non-occurrence) of an arc fault on a branch circuit based on, for example, high-frequency (HF) features (or components) and low-frequency (LF) features (or components) monitored on the branch circuit of the power distribution system. The types of features (or components) determined from high-frequency and low-frequency energy-related signal samples monitored from the electrical system using sensors can depend on the fault detection algorithm and can include, for example, zero crossings, broadband noise, randomness of current variations, and / or other well-known features for arc fault detection. Instead of determining (e.g., determining, calculating, operating, deriving, extracting, etc.) HF and LF features at the branch device of the corresponding branch circuit, the HF features can be determined outside the branch device, for example, by a main processing unit (MPU). The external HF can be used together with the low-frequency features monitored on the branch circuit to detect the occurrence of an arc fault on the branch circuit (or its line or phase) by the MPU or the branch device. In response to detecting an arc fault on the branch circuit, actions can be taken. These actions can include de-energizing the branch circuit, for example, by interrupting the power supplied to the branch circuit or its load (e.g., by the branch device performing a trip or switch operation, etc.), notifying the user or a central monitoring system of the condition, performing additional analysis, turning off the load on the branch circuit, or performing other actions to address the detected condition on the electrical system.

[0056] The "branch device" as used herein can include a circuit breaker, a metering device, a relay, a switching device or switch, a wiring device, a branch circuit device, and other electrical devices connected on or downstream of the branch circuit. The "wiring device" used here can include an electrical device that can be used as a connection or control point of a circuit, such as an electrical socket or plug, a switch, a light switch, or other lighting control devices, etc. The main processing unit (also referred to as "MPU") can be an intelligent or smart device that can be implemented through the main switch or circuit breaker in a distribution board (such as a load center, a distribution board, etc.), or can be implemented outside the distribution board. The MPU, the branch device, and other devices described herein can communicate using wired communication, wireless communication, or a combination thereof.

[0057] The AFD method and system of the present invention can provide various benefits / advantages. For example, since arc fault (AF) detection uses HF sensing to detect arc fault energy, the methods and systems described herein can provide a simplified solution for AF detection by making the HF component common to all branch devices of each phase or power line. This can eliminate the need to have AF or HF AFE (analog front end) components on each branch device and can reduce the burden on the processing unit of the branch device to process AF or HF signals. Additionally, HF features are computationally more intensive than LF features collected for low-frequency signals. Since each branch circuit or its associated branch device also measures LF signals for metering applications, the sensors and hardware circuits can be tuned for higher-precision low-frequency current measurement while keeping the processing unit simple, with reduced memory, processing speed, and power consumption.

[0058] Furthermore, expanding high-frequency and low-frequency functions between the microprocessor and the branch device can make the system and method intelligent and coordinated with household devices and is not limited to implementation on other devices within the circuit breaker or distribution panel. In the case of a potential nuisance trip, the system and method can also allow recovery from a potential nuisance trip and can reduce the impact of a potential nuisance trip on the customer (e.g., the user) or the customer's device / load while still providing protection for the customer's home.

[0059] In various embodiments, AF detection can be performed by the microprocessor of at least one branch circuit or a branch device on the branch circuit. For example, the HF feature or its information can be transferred / swapped from the MPU to the branch device to enable arc fault detection to be performed on the branch device. Alternatively, the LF feature or its information can be transferred / swapped from the branch device to the MPU to enable AF detection to be performed by the MPU. In either example case, the HF and LF characteristics can be synchronized to perform AF detection. Synchronization can include time and half-cycle synchronization between the MPU and the branch device to synchronize information such as energy-related measurements and other information for AF detection that is exchanged between the MPU and each branch device.

[0060] In various embodiments, high-frequency features and low-frequency features can use filtering and / or other signal processing techniques to determine the high-frequency and low-frequency features. The HF feature and the LF feature are provided as inputs to an AF detection state machine, algorithm, or process to detect the occurrence (or non-occurrence) of an arc fault on a circuit (e.g., a branch or other circuit).

[0061] In various embodiments, a branch circuit can include or contain a branch circuit and / or one or more wiring devices.

[0062] In various embodiments, the wiring device may belong to a remote control (RC) wiring device, which may include some communication for energy monitoring and opening and closing circuits. In various embodiments, the RC wiring devices may not have to take the form of a "circuit breaker" device as they may be switch devices. In various embodiments, the circuit breaker device may provide some additional protection such as thermal and magnetic protection against overload or short circuit. The wiring device may primarily be a switch, which may be remotely controlled to disconnect or close the load connected thereto.

[0063] In various embodiments, the system and method may implement a recovery process to re-energize a branch circuit that has been de-energized in response to detecting an arc fault on the branch circuit after a timeout period. The system and method may notify the user after the branch circuit has been re-energized a predetermined number of times to warn the user of a potential dangerous electrical condition on the branch device, the branch circuit, or the load connected to the branch circuit.

[0064] These and other exemplary AFD methods and systems and their related features of the present invention will be described in detail below with reference to the accompanying drawings.

[0065] In the context of AF detection, the high frequency (HF) signals generated during an arc fault in a particular branch are broadband and can be sensed and measured by each AF protection device connected in that branch. However, the HF signals are low enough such that the analog front end (AFE) of each branch device (e.g., an AFCI device) can have a gain of more than 50 (dB), which is significant amplification for seeing any high frequency generated from any branch. Each AFCI device can decide whether to trip on its own based on its own AFD algorithm and the detected LF signal. According to various embodiments, a centralized or coordinated arc fault detection method and system is provided with a common HF processing unit for branch devices such as branch circuit breakers and / or wiring devices. This method can reduce the components for each AF protection device to detect the HF content and calculate its characteristics.

[0066] For example, some branch devices that provide AF detection employ current sensors tuned for HF and LF signals. The sensor design may require a trade-off between the accuracy of low-frequency current and the sensitivity of high-frequency current. Such current sensors may require fewer turns of wire to reduce winding capacitance; however, fewer turns do not provide good low-frequency current readings. Thus, by eliminating the requirement for HF sensing, the accuracy of the sensor of the branch device for LF current can be improved, which can improve the metering measurements for temperature, frequency range, and load capacity.

[0067] In addition, since the HF signals are not processed locally, e.g., at each branch device, the processing units of these branch devices can be significantly reduced in memory and computation, which helps reduce power consumption and the cost of the microcontroller.

[0068] Since each branch device may be required to have a communication channel, metering can be performed on all branch devices, so that low-frequency sensors, AFEs, and processing software can be used; however, the configuration of the AF can be switched by software. Once the branch device is configured for AF detection, the main control unit can provide the processed HF features to these branch devices, and then these branch devices can use them together with the LF features in their own algorithms and decide whether to trip due to AF.

[0069] The AFD algorithm (also known as a process or method) may include two sets of inputs, for example, high-frequency features and low-frequency features. The AFD state machine allows decisions to be made based on these two sets of data and their previous states. Since the HF characteristics can be calculated outside the branch device, the AFD algorithm may need to extract these two sets of inputs in order to provide external data and synchronize it with the internally calculated LF characteristics. Without the HF characteristics, the AFD algorithm can ignore the LF characteristics for AF detection and instead use them for metering and power monitoring.

[0070] The configuration of each branch device can be selected based on the electrical code requirements at that time. However, some branches may not be configured with additional AF protection. These branches can detect, rather than interrupt the circuit, and they can notify the user of a potential AF and trigger a service request to investigate faults, faulty appliances, or non-compliant loads. At any time, if a branch shows continuous signs of a potential AF, an update to the software (SW) switch configuration of the AFD may be recommended or enabled, but at an additional cost. There is no need to replace the branch device.

[0071] Figure 1 An example protection system diagram for a power system (such as a distribution system) according to an embodiment. As Figure 1 shown, the protection system may include a main processing unit (MPU) 110, a plurality of branch devices 120, 130, and a bus system 112. In this example, the MPU 110 may be a main switch or a main circuit breaker that receives a power line from an upstream power source. The power line may include a plurality of electrical conductors, and the electrical conductors may include line 1 (L1), line 2 (L2), and neutral line (N).

[0072] The bus system 112 may include a communication bus and a power bus. The communication bus may be connected between the MPU 110 and the branch devices 120 to enable communication between them. The power bus may be connected between the MPU 110 and the branch devices 120 so that the power received at the MPU 110 (such as a main switch or circuit breaker) can be distributed from the power line to the branch circuit devices 120 and their associated branch circuits. As further shown, the branch circuit may further distribute power to other branch devices 120, such as wiring devices or other electrical devices connected thereto.

[0073] The microprocessor 110 may include a processor and a switch or tripping device (or similar device) for selectively connecting or disconnecting the branch devices 120, 130 to / from the power line. The MPU 110 may include (or be associated with) logic and processing components such as sensors (e.g., current sensors, voltage sensors, etc.), high-frequency (HF) sensors, digital signal processing (DSP) components (e.g., analog front end (AFE) and A / D converters, etc.), and communication channels (e.g., wired and / or wireless) for high-speed communication with the branch devices 120, 130. An example of a sensor such as a current sensor is shown by reference numeral 102, which may measure the current signals on L1 and L2.

[0074] Each branch device 120 may be communicatively connected to the microprocessor 110 via the communication bus of the system bus 112 and electrically connected to phase 1 (such as L1) or phase 2 (such as L2) and the neutral (N) bus via the power bus of the system bus 112. Each branch circuit device 120 may be configured to implement one or more functions, such as metering (M), ground fault (GF) protection, arc fault (AF) protection, AF and GF (also referred to as "dual function" or DF) protection, or a combination thereof. Metering may be available in each branch circuit device 220, but the GF and AF detection capabilities may be selected based on electrical code requirements and branch applications (including loads). The functions of the branch device 120 (e.g., M, AF+M, GF+M, DF+M, etc.) may be configured according to the electrical requirements of the relevant branch.

[0075] Each branch device 130 may be communicatively connected to the MPU 110 via wireless communication and electrically connected to the branch circuit downstream of the branch device 120. In this example, the branch device 130 may be a wiring device, such as an electrical socket or plug, which may have a load (e.g., user equipment) connected thereto.

[0076] In this example, the microprocessor 110 may also be configured to provide other short-circuit protection functions and coordinate load management with each branch device 120, 130, such as demand response and other faults, diagnostics, and load identification, etc. The MPU 110 may establish communication with each branch device 120, 130 (e.g., circuit breakers, wiring devices, etc.) connected further downstream in the power distribution system.

[0077] For AF detection, no additional components are required on the branch devices. AF detection can be enabled through software configuration settings that can allow the branch devices 120, 130 to receive and process HF signatures from the MPU 110. In another embodiment, the branch devices 120, 130 can transmit energy measurements for their associated branch circuit monitoring, such as low-frequency signatures or related information, to the MPU 110. The MPU 110 can perform AF detection on the branch circuits and take appropriate actions in the event of AF being detected on the branch circuits. For example, the MPU 110 can remotely control the branch devices associated with any branch circuit where an arc fault has been detected, or take other actions described herein in the event of a detected fault. The above is provided as an example, where arc fault detection and protection can be coordinated between the MPU 110 and the branch devices 120, 130. The MPU 110 and 120, 130 can be configured to coordinate arc fault detection for one or more branch circuits according to the various example methods described herein. In various embodiments, the MPU 110 can be configured to selectively enable AF detection and / or protection of branch circuits based on user selection / command, electrical system, a predetermined schedule or predetermined conditions on the MPU 110, branch devices 120, 130, residence or facility, and / or other conditions, either through the MPU 110 or under the control of the MPU 110, or through the branch devices or under the control of the branch devices.

[0078] GF detection can also be used for each of the branch devices 120, 130, but can be selectively enabled or disabled based on code requirements for different power distribution networks or network applications. According to embodiments of the present disclosure.

[0079] Figure 2A A functional block diagram of an example main processing unit or MPU 200 according to an embodiment of the present invention is shown. The MPU 200 can include a high-frequency (HF) analog front end (AFE) 210, an analog-to-digital converter (ADC) 214, HF signatures 220, and a communication channel 240.

[0080] The high-frequency AFE 210 can receive high-frequency signals output from radio frequency (RF) sensors, such as high-frequency current, voltage, or power sensors, which can monitor (or measure) energy / electrical signals in the desired high-frequency range on electrical system circuits. The high-frequency AFE 210 can perform signal conditioning on the high-frequency (HF) signals from the sensors. The HF AFE 210 can include analog amplifiers, operational amplifiers, filters, integrated circuits, and / or other components for signal conditioning.

[0081] The ADC 214 can convert the analog high-frequency signals into digital high-frequency signals (or their measurement samples).

[0082] It can be determined from high-frequency signals (e.g., determine, calculate, compute, derive, extract, etc., HF feature 220). The type of HF feature can depend on the AFD algorithm employed.

[0083] The communication channel 240 enables the microprocessor 200 to communicate / exchange information with remote devices (including branch devices) through wired and / or wireless communication. For example, the MPU 200 can transmit information for arc fault detection and protection. In one example, the MPU 200 can broadcast or transmit HF features, HF signals, information derived from HF features or signals (e.g., potential or preliminary arc fault detection), and other information described herein to one or more branch devices for arc fault detection at the MPU 200 or the branch devices. The MPU 200 can also send or receive other information that may be related to the operation or function of the MPU, the state of the power distribution system (including the monitored circuit), such as event data including fault or fault-related event data, acknowledgment messages (e.g., ACK, NACK, etc.) or other messages, synchronization information, etc.

[0084] Figure 2B A functional block diagram of an example branch device 250 according to an embodiment of the present invention is shown. The branch device 250 can include a low-frequency (LF) analog front end (AFE) 260, a ground fault (GF) analog front end (AFE), an analog-to-digital converter (ADC) 264, an LF feature 270, metering 272, protection fault detection 280, a switch unit 282, a communication channel 290, and remote control 292.

[0085] The low-frequency AFE 260 can receive low-frequency signals output by low-frequency sensors, such as low-frequency current, voltage, or power sensors, which can monitor (or measure) energy / electrical signals in the required low-frequency range on the circuit (e.g., branch circuit) of the electrical system. The low-frequency AFE 260 can perform signal conditioning on the low-frequency signals from the low-frequency sensors. The LF AFE 260 can include analog amplifiers, operational amplifiers, filters, integrated circuits, and / or other components for signal conditioning.

[0086] The GF AFE 262 can receive the signals output by a GF sensor, such as a GF current sensor, which can monitor (or measure) all current-carrying conductors (including the return path) on a phase of a power distribution system circuit, such as a branch circuit. The output signal of the GF sensor can reflect the presence or absence of leakage current on the monitored circuit. As those skilled in the art will understand, when the current through the current-carrying conductors (including the return path) is not zero, a ground fault may exist, which can reflect current leakage on the circuit. The GF AFE 262 can perform signal conditioning on the signals from the GF sensor. The GF AFE 262 can include an analog amplifier, an operational amplifier, a filter, an integrated circuit, and / or other components for signal conditioning.

[0087] The ADC 264 can convert the analog LF and GF signals into digital LF and GF signals (or their measurement samples) respectively for further processing. The GF signal can be monitored to determine the ground fault condition on the monitored circuit.

[0088] The LF features 270 can be determined from the low-frequency signals (e.g., determined, accounted, calculated, derived, extracted, etc.). The type of LF features can depend on the AFD algorithm employed.

[0089] The communication channel 290 can enable information communication with other devices through wired or wireless communication, including transmission, broadcasting, or reception. Other devices include microprocessors and, if needed, other branch devices on the same branch circuit, parallel branch circuits, or other branch circuits. For example, the branch device can transmit information for arc fault detection and protection. In one example, the branch device 250 can broadcast or transmit LF features, LF signals, information derived from LF features or signals (e.g., potential or preliminary fault detection), and other information described herein to the MPU for facilitating arc fault detection locally at the MPU or the branch device 250. The branch device 250 can also send or receive other information, which may be related to the operation or function of the branch device, the state of the power distribution system (including the monitored circuit), such as event data including fault or fault-related event data, acknowledgement messages (e.g., ACK, NACK, etc.) or other messages, synchronization information, etc.

[0090] The metering device 272 can process the low-frequency signals to measure and record the electrical parameters of the monitored electrical energy on the monitored circuit, such as current, voltage, power, usage, and / or other energy-related information derived therefrom. The metering information from the metering device 272 can be transmitted via the communication channel 290 to a remote device (e.g., a user device, a monitoring system, a home automation system, etc.) for reporting, further analysis, or further action.

[0091] The protection fault detection 280 can perform various fault detections, including but not limited to GF fault detection of the GF signal obtained from the GF sensor, AF detection using LF and HF features, or other operations for fault detection (including arc fault detection) and protection described herein. As described herein, the HF feature can be provided by a central system such as an MPU, which can be synchronized with the LF feature monitored by the branch device 250, such as time and half-cycle synchronization. Alternatively, the branch device 250 can transmit the LF feature 270 of the monitored branch circuit to the MPU so that the MPU can detect AF on the monitored branch circuit.

[0092] The switch unit 282 can be a switch trip device / apparatus that can energize or de-energize the branch circuit by connecting or disconnecting the branch circuit to / from the upstream power supply, respectively. In various embodiments, in response to the protection fault detection 280 detecting a fault, such as an arc fault or a ground fault or other fault condition, the switch unit 282 can be controlled to disconnect the branch circuit. The switch unit 282 can also be remotely controlled by a remote device such as an MPU, which can send a control message or signal that is received by the remote controller 292 via the communication channel 290 of the branch device 250. Thereafter, the remote controller 292 can control the switch unit 282 to energize or de-energize the branch circuit according to the control message or signal.

[0093] For example, when the microprocessor detects an arc fault on the branch circuit, the microprocessor can remotely control the branch device 250 to de-energize the associated branch circuit. In addition, after the fault no longer exists (or is detected) on the branch circuit, as part of the recovery process, the MPU or the branch device 250 can also energize / re-energize the branch device 250 via the switch unit 282. The switch unit 282 can also be locally controlled by the branch device 250 or remotely controlled by a remote device (including but not limited to an MPU) as part of a home automation system and method to control the energy usage on the branch circuit and the load connected thereto.

[0094] Figure 3 FIG. shows an example wiring configuration / topology 300 of a protection system including a main processing unit and branch devices according to another embodiment of the present invention. In this example, the protection system can include a main processing unit (MPU) 200, which can be the same as or similar to the MPU shown and described with reference to Figure 2A The protection system can also include a plurality of branch devices 250 and branch devices 350, and the branch device 250 can be the same as or similar to the branch device shown and described with reference to Figure 2B As shown Figure 3As shown, the MPU 200 can communicate by exchanging information with branch devices 250, 350 to coordinate arc fault detection and protection as described herein. Measurements from sensors can be received using wired or wireless communication.

[0095] The microprocessor 200 can receive an output high-frequency signal from a radio frequency / high-frequency sensor that monitors the line conductor L of an electrical system circuit. In this example, the MPU can be connected upstream of branch devices 250, 350 on a power distribution system, such as in a distribution panel, or can be connected external to an electrical device and receive measurements of the HF signal from an HF / RF sensor that is upstream of the branch circuit associated with branch devices 250, 350.

[0096] Branch device 250 can receive an output GF signal from a GF sensor that monitors the line conductor L and neutral conductor N (return path) on a branch circuit of a power distribution system, and output an LF signal from an LF sensor that monitors the line conductor L on an associated branch circuit of the electrical system. In this example, the branch circuit and the LF and GF sensors are located downstream of the circuit monitored by the RF / HF sensor.

[0097] Branch device 350 is similar to branch device 250, except that branch device 350 does not include GF detection capabilities and associated components. For example, branch device 350 can meter desired electrical parameters of the energy monitored on the line conductor L of an associated branch circuit using an LF sensor. Branch device 350 can also coordinate with the MPU to perform arc fault detection and protection as described herein.

[0098] Figure 4A A functional block diagram of an example configuration of a protection system and its process in accordance with an embodiment of the present invention is shown, where arc fault detection is performed by branch devices. As Figure 4A shown, a main processing unit (MPU) 400A and one or more branch devices 450A are provided. The main processing unit 400A can be configured to determine a high-frequency (HF) signature 410A (or component) or information thereof on a monitored circuit of an electrical system, or receive such information from another device. The MPU 400A can send (e.g., transmit, communicate, broadcast, etc.) the HF signature 410A to a plurality of branch devices, such as branch device 450A, for performing arc fault detection using the external HF signature received from the MPU 400A.

[0099] In this example, the branch device 450A can be configured to perform various functions and operations for detecting arc fault conditions (or signals), and, if needed, other conditions on an electrical system (e.g., a power distribution system or network). For example, the branch device 450A can be configured to communicate with a remote device (as shown in block 452A) to send and / or receive information via a communication channel through a communication device. As shown, the branch device 450A can receive information from a remote device such as the MPU 400A, such as the high-frequency (HF) signature 410A of the monitored circuit. The MPU 400A can be configured to monitor the HF signals on the circuit and can transmit information regarding the HF signature to one or more branch devices 450A for performing AF detection on the associated branch circuits. The information from the MPU 410A can be common information that is transmitted (e.g., broadcast or sent) to multiple branch devices 450A on the electrical system for detecting arc fault conditions on their respective branch circuits.‎

[0100] In addition, the branch device 450A can be configured to monitor the local low-frequency (LF) signals of the low-frequency signature 460A on the branch circuit. The branch device 450A can also be configured to implement an algorithm (or process) to perform arc fault detection and metering (M), as shown in block 470A. The branch device 450A can implement the AFD algorithm based on the externally determined HF signature 410A and the locally determined LF signature 460A to detect the occurrence (or non-occurrence) of an arc fault condition. In various embodiments, the externally determined HF signature 410A is synchronized with the locally determined LF signature 460A to facilitate arc fault detection.

[0101] The branch device 450A can also be configured to control a trip (or tripping) operation, as shown in block 480A, to protect the associated monitored circuit or components connected thereto, including the load. For example, if an arc fault condition is detected on the associated branch circuit, the branch circuit device 450A can cause the trip operation to be implemented through a switch, a trip unit / device, etc. to interrupt (or shut off) the power supply to the branch or load connected thereto.‎

[0102] Figure 4B A functional block diagram showing an example configuration of a protection system and its process according to an embodiment of the present invention, where arc fault detection is performed by a main processing unit or MPU. In this example, a remote device such as the MPU 400B can interact with multiple branch circuit devices 450B and can be configured to perform the determination of HF and LF signatures, enabling a more simplified configuration of each branch device 450B. For example, each branch device 450B can include a simplified protection and communication (COMMS) module where it processes LF samples and provides GF protection.‎

[0103] AsFigure 4B As shown, the branch device 450B can be configured to perform various functions and operations for detecting arc fault conditions (or signals), and if necessary, other conditions of the electrical system. For example, the branch device 450B can be configured to communicate with a remote device (as shown in block 452B) to send and / or receive information through a communication device. As further shown, in this example, the branch device 450B can send information (such as the LF sample 460B monitored on the associated branch circuit) to a remote device (such as the MPU 400B) having signal processing and communication capabilities. The MPU 400B can be configured to monitor the HF signal on the circuit to determine the HF signature 410B or obtain the HF signature from a remote or local device, and determine the LF signature 420B from the LF sample transmitted by the branch device 450B.

[0104] The MPU 400B can also be configured to perform AFD protection and metering 430B based on the HF signature 410B and / or the LF signature 420B. For example, the MPU 400B can be configured to perform arc fault detection based on the HF signature 410B and the LF signature 420B of the branch circuit associated with the branch device 450B. In the case of detecting an arc fault on the branch circuit, the MPU 400B can send a control signal (or command) to the branch device 450B to remotely control the branch device 450B to perform a tripping operation. In addition, the MPU 400B can be configured to perform metering based on the received LF sample 460A or the LF signature 420B determined therefrom. In various embodiments, when the MPU 400B detects an arc fault on the branch circuit associated with the selected branch circuit device 450B, the MPU can interact with multiple branch devices 450B and remotely control the tripping operation on the selected branch device 450B.

[0105] In addition, the branch device 450B can be configured to locally monitor the LF signal to obtain the LF sample 460B (e.g., LF signal sample) of the associated monitored branch circuit, and transmit the LF sample to the MPU 400B through communication 452B to perform arc fault detection and / or other operations, including but not limited to metering. As shown in block 470B, the branch device 450B can also be configured to implement GF protection and be remotely controlled. For example, the branch device 450B can detect a ground fault (GF) condition based on the monitored LF signal or an associated sample or the LF signature determined therefrom. The branch device 450B can also receive a control signal (or command) from the MPU 400B to control various operations or components of the branch device 450B.

[0106] The branch device 450B can also be configured to control a trip (or tripping) operation, as shown in block 480B, to protect the monitored circuit including the load or components connected thereto. For example, in the event of a detected fault, the branch circuit device 450B can cause the trip operation to be implemented through a switch or a trip unit / device to interrupt the power supply to the circuit (e.g., the branch circuit or the load connected thereto). In this example, when an arc fault is detected on the branch circuit associated with the branch device 450, the MPU 400B can send a control signal (command) to the branch device 450. The branch device 450B receives the control signal from the MPU 400B via communication 452B to perform the trip operation, and can accordingly implement the trip operation 480B to interrupt (or turn off) the power supply to the branch circuit associated with the branch device 450B (including components connected thereto, such as the load).‎

[0107] Figure 5A An example component and wiring configuration diagram of a protection system according to an embodiment of the present invention is shown. In this example configuration topology, there is a main processing unit (MPU) 500A and a plurality of branch devices 550A, where external HF features are used to perform arc fault detection on the branch circuit (or its line or phase). Each branch device 550A can be connected to the line conductors L1 or L2 and the neutral conductor N of the power bus system. In this example, the power bus system can be connected upstream to the MPU 500A, and the MPU 500A can be a main switch or circuit breaker. The branch devices 550A and the MPU 500A can communicate with each other through a communication channel using wireless and / or wired communication.‎

[0108] As Figure 5A shown, the microprocessor 500A can include a switch 510A. The MPU 500A can implement various functions and operations through or under the control of the processing unit of the MPU 500A (e.g., one or more processors), including determining the HF feature 520A and implementing software (SW) configuration protection 530A. The HF feature 520A can be determined by HF signals monitored on the circuit by sensors associated with or communicating with the MPU 500A. The SW configuration protection 530A can be configured to implement AF protection for the branch circuit through or under the control of the MPU 500A, as described herein.

[0109] Each branch device 550A can include a remote control (RC) switch 580A. The branch device 550A can implement various functions and operations, including determining the LF feature 560A through or under the control of the processing unit of the device 550A (e.g., one or more processors) and implementing protection and metering 570A. The LF feature 560A can be determined based on LF signals monitored by sensors associated with or communicating with the branch device 550A.

[0110] In this example, the branch device 550A is communicatively connected to the microprocessor 500A, which includes a processing unit for high-frequency functions. Compared with the example of Figure 1 , the same general topology can be provided, but with different network channels (e.g., wireless or wired) to facilitate communication between the MPU 500A and the branch circuit device 550A. The MPU 500A can be communicatively connected to each individual branch device and provide HF characteristic information to the branch device 550A configured to provide AF protection. In various embodiments, the MPU 500A can broadcast information about HF characteristics or other relevant information to remote devices including the branch device 550A. The branch circuit device 550A can be configured to implement an AFD algorithm to detect an arc fault condition based on external HF characteristics and locally determined LF characteristics, and in the case of detecting an arc fault on the branch circuit, perform a tripping operation via the RC switch 580A to interrupt (or turn off) the power supply to its associated branch circuit (including components connected thereto, such as loads). The RC switch 580A of each branch device 550A can also be remotely controlled by the MPU 500A to selectively turn on or off the power supply to its associated branch circuit.

[0111] In various embodiments, the HF characteristics can be processed in each half-cycle (HC) and provided to each branch device 550A within a time window sufficient for each branch device 550A to decide on AF protection within the required standard tripping time. The received high-frequency characteristics can also be synchronized with locally determined low-frequency characteristics to facilitate arc fault detection.

[0112] Figure 5B An example component and wiring configuration diagram of a protection system according to an embodiment of the present invention is shown. In this example configuration topology, there is a main processing unit (MPU) 500B and a plurality of branch devices 550B, where external HF characteristics are used to perform arc fault detection on the branch circuit (or its line or phase). The MPU 500B can be a main switch. Each branch device 550B can be connected to the line conductor L1 or L2 and the neutral conductor N of the power bus system. The power bus system can be connected upstream of the MPU500A, and the MPU 500A can be a main switch or a circuit breaker. The branch device 550B and the MPU 500B can communicate with each other through a communication channel using wireless and / or wired communication.

[0113] As Figure 5BAs shown, the microprocessor 500B may include a switch 510B. The MPU 500B may implement various functions and operations either through or under the control of the processing unit (e.g., one or more processors) of the MPU 500B, including determining HF features 520B and implementing protection and metering 530B. The HF features 520B may be determined from HF signals monitored on the circuit by sensors associated with or communicating with the MPU 500B.

[0114] Each branch device 550B may include a remote control (RC) switch 580B. The branch device 550B may implement various functions and operations either through or under the control of a processing unit (e.g., one or more processors), including determining LF samples 560B and implementing GF protection 570B. The LF samples may be obtained from LF signals monitored by sensors associated with or communicating with the branch circuit device 550B and transmitted to the MPU 500B through a communication channel.

[0115] In this example, as Figure 5B shown, the branch device 550B may sample the low-frequency current (e.g., by using sensors to monitor the low-frequency signal), pack it, and send it through a communication channel to the microprocessor 500B, which may determine the low-frequency features, aggregate and use the low-frequency features, and determine which branch device should trip based on the presence of an audio signal to mitigate potential fire hazards. For example, the MPU 500B may implement an AFD algorithm to detect an arc fault condition (or signal) on each branch circuit based on the HF features and LF features transmitted by the branch device 550B on or associated with the branch circuit. In the case of detecting an arc fault condition on a particular branch circuit, the MPU 500B may remotely control the branch device 550B associated with the particular branch circuit via its RC switch 580B to perform a tripping operation to interrupt (or turn off) the power supply to the branch circuit (including components connected thereto, such as loads). The RC switch 580B of each branch circuit device 550B may also be remotely controlled by the MPU 500B to selectively turn on or off the power supply to its associated branch circuit.

[0116] In this example, it is not necessary to run the AFD algorithm in each processing unit of the branch circuit device 550B, thereby further reducing the requirements for the low-cost processing units of the branch devices. In various embodiments, the received HF features are synchronized with the locally determined LF features to facilitate arc fault detection.

[0117] The microprocessor 500B may also be configured to determine metering information for each branch or the entire system. For example, metering information may be provided based on LF samples or other information received from the branch device 550B or locally monitored by the MPU 500B.

[0118] Figure 6A and Figure 6B FIG. showing an example data stream 600 of the coordination between the main unit and the branch devices of the protection system configuration according to an embodiment of the present invention. The main unit may be a main processing unit (or MPU) as described herein. In Figure 6A and Figure 6B , the MPU and the plurality of branch devices may interact to perform various processes or protocols, such as an authentication process at block 610, a time and half-cycle synchronization process at block 620, an energy monitoring process at block 630, and a fault detection process at block 640. For the purpose of discussion, Figure 6A and Figure 6B the data stream 600 will be described below with reference to the main processing unit or MPU and the branch devices (e.g., 1...n).

[0119] In the authentication process of block 610, the microprocessor may have a list of all devices registered by the installer during the debugging process or during the device installation process. At power-on, each branch device may be queried (e.g., query devices: Pan_ID01, ID02,... ID0N) and exchange keys and confirmation messages (e.g., ACK 01, ACK 02,... ACK 0N) to verify that all devices are present, started, and running. Any person skilled in the art may implement different authentication schemes to ensure that there are no fraudulent or counterfeit devices in the local network.

[0120] Once the authentication process of the frame 610 is completed, the time synchronization process can be carried out at the frame 620. For example, in the time and half-cycle synchronization process at the frame 620, it is important that each branch device is synchronized with the MPU. This can ensure that each data reported or exchanged between the MPU and the branch device is well correlated to facilitate the arc fault detection (AFD) algorithm or its process. The time synchronization can utilize a simple precise time synchronization algorithm, such as IEEE 1588.2008 or other proprietary algorithms. Precise time synchronization allows each branch device to have the same internal clock to perform synchronous acquisition of signals. Since each branch device is connected to the MPU and is in the same network, the network hop count between these devices and the MPU can be minimized. In addition to synchronizing the clocks of each branch device, the zero-crossing numbers can also be exchanged. Since all devices (e.g., the MPU and branch devices) are connected to the same AC power line, they can all see the same voltage zero-crossing, which can be used to synchronize their respective ACK (acknowledgment) messages relative to the zero-crossing value. Once all branch devices are synchronized with the MPU and they respond with the correct zero-crossing id / count, the time synchronization process at the frame 620 is completed, and each device can report measurement data or other data (possibly requiring a reference frame, such as the time between devices) to the MPU with the zero-crossing value. If the measurement data reported by any branch device has a different zero-crossing value, the MPU can initiate the time synchronization process with that specific device instead of synchronizing with all devices.

[0121] Next, in the energy monitoring process at the frame 630, after each branch device is synchronized with the MPU, it can follow a cyclic scheduler to report the installer-configured energy measurement values (e.g., active power, power factor, etc.) at the required rate. This example of the processing loop does not require the MPU to query the branch device, but it can confirm the reported values of the branch device and check its zero-crossing ID to detect any out-of-step phenomena that may occur over time. In this case, it can initiate the time synchronization process with that device.

[0122] As Figure 6BAs shown, during the fault detection process of block 640, once the MPU detects any high-frequency (HF) event from its high-frequency characteristics, it needs to know which branch device has also detected a fault. In this example case, the branch devices can only monitor low-frequency (LF) measurements and potential disturbances caused by load transitions or potential arc faults, where the arc faults are caused by a change in load impedance due to a broken wire or wiring. Both the MPU and the branch devices can process these characteristics every half cycle. Thus, once the high-frequency characteristics exceed a predetermined threshold for that half cycle or several half cycles, a broadcast message (e.g., an arc fault event) is sent to all branch devices to report the LF characteristics that may have also exceeded the predetermined threshold. If a branch device does not see any change in the LF characteristics, the device can respond with a NACK (see, for example Figure 6B for branch device 2 and N in). ‎

[0123] When a branch device detects that the low-frequency characteristics exceed a threshold, there are various implementation manners. In a first example, the arc fault state machine (or its process) can reside in or be implemented in the branch device, and request the HF characteristics from the MPU and make its own decision. For example, if a branch device sees that the LF characteristics exceed the threshold, the branch device can request the MPU to report the HF characteristics, and upon receiving these measurements (e.g., see Figure 6B for branch device 1 in). The branch device can run the AFD state machine to determine whether there is an arc fault. The MPU can continue to process the HF frequency characteristics and send them to the branch device regularly, and the branch device can process these characteristics in the AFD state machine to decide whether to disconnect the load. Once the branch device determines that there is a dangerous fault, the branch device can disconnect (e.g., load disconnect) the branch circuit or the load and notify the MPU that a fault detection and mitigation has occurred (e.g., ID 01: AF detection stopped). The MPU can request a report on the resumed energy monitoring from all branch devices (see, for example, broadcast continue monitoring). Another example of the fault detection process is described below with reference to Figure 6D Figure

[0124] Figure 6C and Figure 6D Figures Figure 6C and Figure 6D show an example data flow 650 of the coordination between the main unit and the branch devices of a protection system configuration according to an embodiment of the present invention. The main unit can be the main processing unit (or MPU) as described herein. In Figure 6C and Figure 6DThe data stream 650 will be described below with reference to the main processing unit or MPU and the branch devices (e.g., 1…n).

[0125] As Figure 6C shown, the authentication process at block 660, the time and half-cycle synchronization process at block 670, and the monitoring process at block 680 can be implemented in a similar or identical manner to the authentication process at block 610, the time and half-cycle synchronization process at block 620, and the monitoring process at block 630 in the example of the data stream 600 described above. Figure 6A

[0126] Turning Figure 6D to the example of the fault detection process at block 690, once the MPU detects any high-frequency (HF) event from its high-frequency signature, the MPU needs to know which branch device has also detected a fault. In this case, the branch device can only monitor the low-frequency measurements and potential disturbances caused by load transitions or potential arc faults, which are caused by a change in the load impedance due to a broken wire or cable. In this example, both the MPU and the branch device can process these characteristics every half-cycle. Therefore, once the HF signature exceeds a predetermined threshold for that half-cycle or a number of half-cycles, a broadcast message (e.g., an arc fault event) is sent to all branch devices to report the low-frequency signature that may have also exceeded the predetermined threshold. If the branch device does not see any change in the LF signature, the branch device can respond with a NACK (e.g., see branch devices 2 and N).

[0127] As previously described, there are different implementations when the branch device detects that the low-frequency signature exceeds the low-frequency threshold. In a second example, the arc fault state machine (or its process) can reside in or be implemented in the MPU, and a request for the LF signature, e.g., an LF event request, is reported by the branch device (e.g., see branch device 1) that detects a change in the LF signature that exceeds the threshold.‎

[0128] ​If the branch device detects that the low-frequency characteristics exceed the threshold, it can report these characteristic values and the zero-crossing ID to the microprocessor to synchronize these values with the high-frequency frequency values in the microprocessor, thereby entering the arc fault detection (AFD) state machine (or its process). For example, ID 01: Respond with low-frequency characteristics. The AFD state machine can determine whether these characteristics represent a transient of the load or a potential fault. If this is a potential fault, the MPU can send another dedicated request to the branch device to collect and report LF characteristics. For each set of LF characteristics, the AFD state machine can determine the level of the dangerous fault and decide to command the branch device to terminate the load (e.g., AF fault event) and eliminate the arc fault (e.g., load disconnection). Once the load is powered off and the HF characteristics drop below a predetermined threshold or do not indicate any potential faults, the monitoring process of monitoring energy measurement at block 680 can be resumed by notifying all branch devices to continue reporting energy measurement data based on their rates.‎

[0129] In the above Figure 6A and Figure 6B as well as Figure 6C and Figure 6D In the exemplary embodiments, if the microprocessor continues to detect high-frequency frequency characteristics exceeding a predetermined threshold, the microprocessor can broadcast a high-frequency event message or a low-frequency event request again (depending on the configured exemplary embodiment) to see if other branch devices detect low-frequency frequency characteristic change values exceeding a predetermined threshold. If neither can see anything, they can respond with a NACK, and the MPU can request an energy monitoring report.‎

[0130] Figure 7 FIG. shows a flowchart of an example process 700 according to an embodiment of the present invention, in which a main processing unit (or MPU) provides high-frequency (HF) characteristics (or components) to other devices including branch devices to perform coordinated arc fault detection.‎

[0131] Process 700 begins at block 702, where the branch device and its components are powered on. For example, a power-on reset (PoR) circuit can be used to power the processor of the branch device during the initial startup of the device.

[0132] In block 704, the MPU verifies the branch device. For example, as described above, the MPU can have a list of registered devices on the local network, including the branch device. The MPU can query each registered branch device, and the branch devices can exchange keys and confirmation messages so that the MPU can verify the existence, startup, and operation of the branch device. Various authentication schemes can be used to verify the existence and authenticity of devices on the local network.

[0133] In block 706, the microprocessor and the branch devices are synchronized. For example, as previously mentioned, time synchronization can utilize simple precise time synchronization algorithms such as IEEE 1588.2008 or other proprietary algorithms. Since each branch device is connected to the MPU and within the same network, the network hops between these devices and the MPU can be minimized. In addition to clock synchronization with each branch device, zero-crossing numbers can also be exchanged. Since all devices, the MPU, and the branch devices are connected to the same AC power line, they can all see the same voltage zero-crossing points, which can be used to synchronize their respective acknowledgment or ACK messages relative to the zero-crossing values. Once all branch devices are synchronized with the MPU and they respond with the correct zero-crossing id / count, the time synchronization process is complete, and each device can report measurement data with zero-crossing values to the MPU. If any branch device reports a measurement value with a different zero-crossing value, the MPU can initiate the time synchronization process with that specific device rather than all devices. Various time synchronization schemes can be employed to synchronize the MPU and the branch devices.

[0134] At block 710, energy monitoring is performed. For example, each branch device can follow a cyclic scheduler and report their energy measurements (such as active power, power factor, etc.) at a desired rate as configured by the installer. This processing loop does not require the MPU to query the branch devices, but it can confirm the reported values of the branch devices and check their zero-crossing IDs to detect any possible out-of-step phenomena that may occur over time. In such cases, it can initiate the time synchronization process with that device. It should be noted that other methods can be used to report energy measurements, including but not limited to other queries of the MPU or branch devices, etc.

[0135] The arc fault detection process can be performed by monitoring high-frequency (HF) and low-frequency (LF) characteristics by the microprocessor and the branch devices. For example, the MPU performs HF monitoring at block 720, and each branch device performs LF monitoring at block 730. In various embodiments, both the MPU and the branch devices can process these characteristics every half cycle. For example, at block 722, the MPU determines whether the HF characteristic crosses (or meets) a predetermined HF threshold. If not, the MPU continues with energy monitoring (such as block 710). Otherwise, if the HF characteristic exceeds the HF threshold within this half cycle or several half cycles, the MPU sends a broadcast message (such as an arc fault event) to each branch device.

[0136] In block 740, each branch device receives a broadcast message from the MPU and determines whether its locally monitored LF feature exceeds (or meets) a predetermined LF threshold to see if there is any change in the LF feature. If the branch device does not see any change in the LF feature (e.g., the LF feature does not cross the threshold), the device can respond with a NACK. If the branch device does see a change in the LF feature (e.g., the LF feature crosses the LF threshold), the branch device can implement different example embodiments of arc fault detection, such as: (1) in a first example, request the HF feature (or associated measurements / values) from the MPU, or (2) in a second example, report its LF feature (or associated measurements / values) and information for synchronizing the LF feature (e.g., zero crossing ID) to the MPU.

[0137] In blocks 742, 744, and 746, when the MPU sends a broadcast message and the LF feature of a particular branch device exceeds the LF threshold, the HF and LF features are synchronized, and the AFD state machine is executed to detect the occurrence / presence of an arc fault on the branch circuit associated with the branch device based on the synchronized HF and LF features, and to control the branch device to disconnect the circuit branch or the load thereon in the event of an arc fault being detected. As previously described, in a first example, the branch device can receive the HF feature requested from the MPU, synchronize the received HF feature and the local LF feature, detect the presence / occurrence of an arc fault based on the synchronized HF and LF features, and disconnect the circuit branch or the load (e.g., via a switch or a trip unit / device). Optionally, in a second example, the MPU can receive the LF feature and synchronization information (e.g., zero crossing ID, etc.) reported from the branch device, synchronize the received HF feature and the local LF feature, detect the presence / occurrence of an arc fault based on the synchronized HF and LF features, and remotely control the branch device to disconnect the circuit branch or the load (e.g., via a switch or a trip unit / device). These two AFD methods are provided as examples. According to various embodiments, the AFD state machine (or its process) can be executed at the MPU, the branch device, or other remote devices using an external HF feature.

[0138] Figure 8A flowchart of an example process 800 for load or branch circuit restoration in the case where a fault has disappeared and no longer exists, according to an embodiment of the present invention, is shown. For example, once a branch device disconnects a load due to a potential hazardous fault and the fault has been mitigated, it can attempt to reactivate the branch device load again after a certain time. If the fault still exists and the HF feature detects the same amount of change above a predetermined threshold, the MPU and the branch device can follow one of the example embodiments described herein to eliminate and mitigate the fault again and terminate the load. Otherwise, if the fault no longer exists, the load can be restored and operated, which can allow the user to continue working or using the load. This has been observed on certain loads that, during a certain operation, seem to generate signals similar to those generated by a hazardous arc fault (AF); however, these can be transient phenomena when the load switches from one operating mode to another. These transitions are the main factors for the branch device (such as an AFCI device) to experience a false trip, resulting in customer dissatisfaction. If these loads are restored to operation again and no longer generate fault signals, they can operate and provide services to the customer. However, if this situation continues to occur between several predetermined trials, the MPU can completely terminate the load and notify the customer to investigate the specific load or branch circuit together with a professional electrician. The example operations of process 800 are described below.

[0139] Process 800 begins at block 802, where the branch device is powered on and authentication, synchronization, and energy monitoring can be performed, as described herein. For example, at block 804, the branch device on the network is authenticated. At block 806, the MPU and the branch device are synchronized. At block 810, energy monitoring is performed by the MPU and the branch device.

[0140] At block 812, AF detection is performed to detect the presence / occurrence of an arc fault. If no AF of the branch device (or its associated branch circuit) is detected, process 800 returns to energy monitoring 810. Otherwise, if an AF is detected for at least one branch device, process 800 proceeds to block 820 for the branch device with the detected fault.

[0141] At block 820, the branch device is controlled to de-energize the circuit branch or the load thereon where the arc fault is detected. At block 822, a counter related to tracking the number of reactivation attempts, such as "attempts" (or other representative data values), is set to the number N, for example, attempts = N. As will be explained below, attempts can be the value or count of the maximum number of reactivation attempts after de-energizing before the problem is marked for further action in response to an AF detected in the branch circuit or the associated branch device.

[0142] At block 830, the branch device waits for a predetermined disconnection time period, such as a predetermined disconnection timeout period. For example, the branch device waits for a time period associated with the disconnection timeout period.

[0143] At block 840, the branch device determines whether the disconnection timeout period has been reached (or has expired). If the timeout period has not been reached, process 800 returns to block 830 and continues to wait for the predetermined timeout to complete. Otherwise, if the disconnection timeout has been reached or has passed, process 800 proceeds to block 850.

[0144] At block 850, the branch device determines whether the number of re - excitation attempts has reached zero, e.g., attempts = 0. If the number of attempts is not zero, e.g., attempts > 0, the branch device may energize the circuit branch or load and reduce the number of attempts (e.g., attempts = attempts – 1). In this way, the branch circuit and the load thereon can work again. Thereafter, process 800 returns to block 810 to perform energy monitoring of the circuit. Otherwise, when determining that the data value representing the number of times of attempting to energize the branch circuit meets or exceeds the attempt threshold (e.g., if the number of attempts is zero, e.g., attempts = 0), the branch device may take various actions. These actions may include preventing or delaying excitation / re - excitation at the branch device. The actions may also include notifying the customer to have a professional electrician (e.g., a technician, etc.) investigate the branch circuit or the load thereon at block 870, or other measures to investigate, analyze, or correct AF hazards of the branch circuit or the load thereon. Thereafter, process 800 terminates at block 880.

[0145] The disconnection time period and attempt processing can be performed for each branch device that has de - energized its associated branch circuit in response to AF detection. The number of attempts may also be time - limited, e.g., the number of attempts can be reset after a predetermined time period (or duration). Although the above - mentioned recovery or related processing (e.g., blocks 820 to 880) is described with reference to the branch device, the recovery processing and its operations can be performed by the MPU for each branch device, or can be performed through the cooperation between each branch device and the MPU. For example, attempt tracking can be performed by the branch device or the MPU. In the case of performing attempt tracking on the branch device / branch circuit, the MPU can control the operation of the relevant branch device as needed.

[0146] Figure 8 The above - mentioned fault recovery method and its related system are provided as examples. In various embodiments, the method and system may further include: at the branch device (e.g., Figure 1 120, 130, etc.) or a central (or centralized) monitoring device representing the branch device (e.g., Figure 1Detect an arc fault on a branch circuit at a branch device (such as the MPU 110, etc.), where the branch device is a branch device among multiple branch devices on the branch circuit, and in response to the detected arc fault on the branch circuit, de-energize the branch circuit at the branch device. Additionally, the predetermined opening time of the branch device can be a sufficient duration to allow any other branch device downstream of the branch device to perform arc fault detection and de-energization operations before the branch device attempts to energize the branch circuit.

[0147] In some embodiments, a data value (or its information) representing the number of attempts can be maintained and updated at the branch device or the central monitoring device. A data value representing the number of attempts can also be maintained and updated for the branch device and / or the branch circuit including multiple branch devices thereon (e.g., the cumulative number of attempts of all branch devices on the branch circuit). The delay or prevention of energization and the notification can be based on the number of attempts of the branch device and / or the branch circuit.

[0148] Furthermore, the de-energization or tripping response time for performing a de-energization or tripping operation at the branch device to de-energize the branch circuit can be at least based on the size or current of the load connected to the branch circuit through the branch device. The method and system can also include: determining the de-energization or tripping response time for the branch device to de-energize the branch circuit at least based on the size or current drawn by the load connected to the branch device. Additionally, determining the de-energization or tripping response time can be at least based on the size of the load connected to the branch device relative to the size of the loads connected to other branch devices on the branch circuit or the current drawn by them to determine the de-energization or tripping response time of the branch device. Relative to other branch devices on the branch circuit, the de-energization or tripping response time of each branch device on the branch circuit can be shorter or faster for a larger load, or longer or slower for a smaller load. In some embodiments, the response time can be calculated as a function of the size (or current draw) of the load of the branch device, or selected from a response time table according to the size (or current draw) of the load of the branch device. The response time can also depend on the load application, which can also be considered in the function or table of the response time.

[0149] In various embodiments, the method and system can further include: detecting the relative position of the detected arc fault along the branch circuit according to whether there is an arc fault in other branch devices on the detected branch circuit; and allowing the branch device upstream of the detection location of the arc fault to remain energized or re-energize the branch circuit on the branch circuit. The relative position of the arc fault on the branch circuit can be determined according to the information related to the presence or absence of the arc fault detected by the branch device on the branch circuit, where the relative position of each branch device relative to other devices on the branch circuit is known. Such information can be exchanged between the central monitoring device, the branch device, and other devices described herein.

[0150] In various embodiments, the method and system may further include: de-energizing an entire branch circuit if two or more of a plurality of branch devices on the branch circuit detect an arc fault on the branch circuit; and notifying a user of a dangerous condition associated with the branch circuit or a branch device thereon. For example, the detection of an arc fault by two or more branch devices may reflect the presence of an upstream arc fault, which may require de-energizing the entire branch circuit and notifying the user to inspect the branch circuit and its branch devices and connected loads.

[0151] As described above, the system and method may include: at a branch device, energizing the branch circuit after a predetermined de-energization period expires, the predetermined de-energization period being initiated in response to a detected arc fault on the branch circuit; updating, using one or more computer processors, a data value representing the number of times an attempt has been made to energize the branch circuit in response to the detected arc fault on the branch circuit; and preventing or delaying energization of the branch circuit at the branch device when it is determined that the data value meets or exceeds an attempt threshold.

[0152] In some embodiments, the energizing operation, the updating operation, and the preventing or delaying operation may be performed by the branch device. Additionally, the branch circuit may include a plurality of branch devices including the branch device, and each branch device may be configured to perform the energizing operation, the updating operation, and the preventing or delaying operation. ‎

[0153] In some embodiments, the branch circuit may include a plurality of branch devices including the branch device. Each branch device may be configured to perform the energizing operation, and a central monitoring device in communication with and controlling the branch device may be configured to perform or control the updating operation and the preventing or delaying operation. ‎

[0154] In some embodiments, there may be a plurality of branch circuits, each branch circuit including a plurality of branch devices. The method and system may further include: coordinating the performance or control of the energizing operation, the updating operation, and the preventing or delaying operation by a central monitoring device that communicates with and controls each branch device on the branch circuit. Additionally, the branch devices on the branch circuit may include circuit breakers maintained at a load center. The central monitoring device may be located inside or outside the load center and may be an MPU as described herein.

[0155] Figure 9 A flowchart of an example process 900 for performing arc fault detection of one or more branch circuits using HF features (or components) determined upstream of one or more branch circuits or their branch devices is shown, in accordance with an embodiment of the present invention. By way of example, process 900 will be described with reference to an upstream device and a branch device. In this example, the upstream device may be a main processing unit or MPU.

[0156] In block 910, an upstream device measures (or monitors) an electrical signal upstream of at least one branch circuit on a power distribution system via a sensor. The upstream device can be, for example, a main switch or circuit breaker of a load center or other circuit protection device, and the sensor can be a current sensor, a voltage sensor, or other sensor for measuring electrical characteristics of the electrical signal.

[0157] In block 920, the measured electrical signal is processed by a processor of the upstream device to determine high-frequency / HF features (or components).

[0158] In block 930, a branch device of at least one branch circuit measures an electrical signal on the at least one branch circuit via a sensor. For example, the branch device can be a circuit breaker, a disconnector, a wiring device, or other circuit protection device, and the sensor can be a current sensor, a voltage sensor, or other sensor for measuring electrical characteristics of the electrical signal.

[0159] In block 940, the measured electrical signal on the at least one branch circuit is processed by a processor of the branch device to determine high-frequency / HF features (or components).

[0160] In block 945, the high-frequency and low-frequency features of each branch circuit are synchronized.

[0161] In block 950, the upstream device or the branch device performs arc fault detection on at least one branch circuit based on the high-frequency features and low-frequency features. For example, in various embodiments, the upstream device can transmit (e.g., transfer) information of the determined HF features to the branch device such that the branch device can perform arc fault detection. Alternatively, one or more branch devices can transmit information of the determined LF features to the upstream device such that the upstream device can perform arc fault detection on their respective branch circuits (or monitored phases or lines).

[0162] In addition, the determined high-frequency features and low-frequency features can be synchronized and provided as inputs to an arc fault detection algorithm (or process) implemented on one or more processors to detect the occurrence of an arc fault on at least one branch circuit.

[0163] In block 960, in response to detecting an arc fault on at least one branch circuit, one or more actions can be taken (e.g., interrupting power supply to the branch via a switch or other interruption / switch configuration). For example, the branch device can interrupt power supply to at least one branch circuit, and / or the upstream device can interrupt power supply to at least one branch circuit. The power interruption of the branch device can be performed in response to locally executed arc fault detection or under remote control of the upstream device.

[0164] The above method is provided as an example, where the HF feature is determined outside the branch device, e.g., by an upstream device. The determined HF feature can be a common HF feature, which can be used for arc detection in one or more branch circuits or for arc fault detection by one or more branch devices.

[0165] Figure 10 and 11 An example scenario related to the above fault recovery method and system is shown. For example, when a branch circuit is de-energized and a timeout period for waiting to re-energize the circuit is set, there may still be a fault. In some cases, the decision of each branch device on when to de-energize the load may be different. Thus, in such a case, each branch device can coordinate with a central monitoring device such as an MPU to determine whether to de-energize its corresponding load. Optionally, each branch device can coordinate with other branch devices on the branch circuit to determine whether to de-energize the corresponding load.

[0166] In Figure 10 Example fault scenario 1000 is illustrated with reference to MPU 1010 and branch devices 1020, 1030A to 1030D connected on a branch circuit. Branch device 1120 can be a circuit breaker, which can be located at the load center. Branch devices 1030A to 1030D can be power outlets or plugs as shown, or other branch devices described herein. Each of branch devices 1030A to 1130D can have a load connected thereto, which can vary in size or the amount of current drawn. Each branch circuit 1030A to 1030D can include a switch or other power interruption device to energize or de-energize the portion of the branch circuit downstream of the branch device (including the load circuit), e.g., to turn on or off the upstream power supply of the portion of the branch circuit downstream of the branch device (including the load circuit).

[0167] In this scenario 1000, the fault is located downstream of the branch device (e.g., the load circuit of the branch device), where the decision to de-energize Figure 10 the last branch device 1030D shown can mitigate the fault by de-energizing the load, waiting for a period of time, and then re-energizing when the fault no longer exists (and then keeping the circuit / branch device energized). In this case, the electrical system can be a residence (or house). The fault can be eliminated by the homeowner disconnecting the faulty load from branch device 1030D, or if the load itself does not exhibit any faults during consecutive re-energization events due to the faulty noisy nature of the load.

[0168] In Figure 11In this example, a fault scenario 1100 is illustrated with reference to an MPU 1110 and branch devices 1120, 1130-1 to 1130-N (where N is the number of branch devices) connected to a branch circuit. The branch device 1120 can be a circuit breaker, which can be located at a load center. The branch devices 1130-1 to 1130-N can be power outlets or plugs as shown in the figure, or other branch devices described herein. Each of the branch devices 1130-1 to 1130-N can have a load connected thereto, and the load can vary in size or the amount of current drawn. Each of the branch circuits 1130-1 to 1130-N can include a switch or other power interruption device to energize or de-energize a portion of the branch circuit downstream of the branch device (including the load circuit), for example, to turn on or off the upstream power supply of the portion of the branch circuit downstream of the branch device (including the load circuit).

[0169] As Figure 11 shown in the fault scenario 1110, there is a fault upstream of the branch devices (e.g., 1130-3 and 1130-N) on the branch circuit protected by the circuit breaker 1120. In this scenario 1100, the fault can be detected by one or more of the branch devices 1130-3 and / or 1130-N, which are located downstream of the branch device, such as the circuit breaker 1120 and the branch device 1130-1. Depending on its load condition, one branch device may decide to de-energize the circuit faster than other branch devices. For example, in the case where load 3 is greater than load N, the branch device 1130-3 with load 3 can be configured to make a de-energizing decision faster than the branch device 1130-N with load N. Therefore, the timeout value can be configured to be large enough or sufficiently large (e.g., several seconds) so that other branch devices can also de-energize before attempting to re-energize the load again.

[0170] It should be noted that if more than one of the branch devices 1130-1 to 1130-N detects a fault, this can indicate a fault upstream of the branch device (e.g., upstream of 1130-3 and 1130-N). In this case, the entire branch circuit may need to be de-energized, and a notification can be output to the user (e.g., an electrician, etc.) via a user device or through a central monitoring device to investigate and repair the fault somewhere in the upstream connection of the branch device.

[0171] This cascading de-energizing decision can also help the user identify the location of the fault relative to the location of each branch device 1130 where the fault is identified and where the fault is not identified. Figure 10 and Figure 11Example scenarios are provided as examples of actions that can be taken based on when or by which device on the circuit a fault is detected. The actions in these examples can be applicable to other fault detection scenarios and are implemented by one or more branch devices along a branch circuit.

[0172] Figure 12 FIG. shows example components of a computer-implemented device (or system) 1200 for an electrical system according to one embodiment, such as an MPU, a branch device, or other devices with processing and communication capabilities.

[0173] System 1200 may include a memory 1210, a processor 1220, a communication device 1230, a clock 1240, a sensor 1250, and a switch 1260, and may be communicatively connected via wireless or wired communication. In this example, the various components may be communicatively connected via a bus 1270. The clock 1240 may be used to timestamp data or events with time values and synchronize operations within the device as well as operations with remote devices or systems. The communication device 1230 may include a transmitter and a receiver for wireless or wired communication with other remote devices.

[0174] The memory 1210 may store computer-executable code, programs, software, or instructions that, when executed by the processor, control the operation of the device 1200, including the various processes described herein. The memory 1210 may also store other data used by the device 1200 or its components to perform the operations described herein. Other data may include, but is not limited to, HF and / or LF characteristics (or components), arc fault detection programs / algorithms, or other fault detection programs / algorithms, and other data described herein.

[0175] The processor 1220, which interacts with other components of the computer-implemented device, is configured to control or implement the various operations and functions described herein.

[0176] The sensor 1250 is configured to measure electrical characteristics of an electrical signal on one or more conductors of a power distribution system or a portion thereof. The sensor 1050 may be a current sensor, a voltage sensor, or other sensors from which current or voltage or their representative waveform signals can be derived. The sensor 1250 may be configured to measure the desired frequency range of the monitored electrical characteristics. For example, in various embodiments, the sensor of an upstream device may be configured to measure electrical signals (and their waveforms) in the high-frequency range in the case of fault detection, while the sensor of a branch device may be configured to measure electrical signals (and their waveforms) in the low-frequency range in the case of fault detection.

[0177] Switch 1260 can be a switch for connecting or disconnecting the power supply to or from a part of an electrical system, such as a circuit like a branch circuit of a power distribution system. Switch 1260 can automatically trip or operate in response to a triggering event (e.g., a detected fault, a remote command, etc.), or be manually tripped or operated by a user. Switch 1260 can also be locally or remotely controlled to energize or de-energize a circuit or a device connected thereto.

[0178] Examples of components of a computer-implemented device were described above, such as a microprocessor, a branching device, or other devices having the processing and communication capabilities described herein. A computer-implemented device may or may not include Figure 12 all of the components, and may include other additional components to facilitate the operation of the processes and features described herein. For example, a computer-implemented device may also include an input device and an output device, signal conditioning circuitry, and so on.

[0179] The centralized or coordinated methods of arc fault detection (or aspects thereof) and fault recovery described herein can be used in different device topologies, which can include, for example, multiple wiring devices and a central device that are connected to receive power from a power distribution system. For example, the wiring devices can be configured to locally determine LF features, and the central device can be configured to determine common HF features, and these features can be used by the wiring devices or the central device to perform arc fault detection. The central device or the main processing device can be one of the multiple wiring devices, the most upstream wiring device among the multiple wiring devices, or a circuit protection device or other type of device connected to the power distribution system. Although wiring devices are described in this example, the topology can include wiring devices, circuit protection devices, other types of devices, or combinations thereof. The power distribution system can also be a polyphase system.

[0180] In addition, the various methods, processes, or algorithms described herein, including their operations or functions, can be executed or controlled by a central device / central monitoring device (e.g., an MPU), a branch device (e.g., a circuit breaker, a wiring device, etc.), or a combination thereof, which can involve cooperation between the central device / central monitoring device and the branch device, as well as cooperation between branch devices on the same or different branch circuits. It can be understood that various information can be transmitted and / or exchanged between the central device / central monitoring device, the branch device, and other devices described herein (e.g., user devices, etc.) for performing various operations or functions of the methods, processes, or algorithms described herein. Such information can include LF features, HF features, arc fault detection and the identity / location of the detection device, control commands or signals (e.g., performing actions including providing information, circuit excitation / de - excitation, etc.), the load size connected to the branch device, a predetermined disconnection timeout (or a timeout table selected therefrom), a de - excitation or trip response time (or a response time table selected therefrom), device location and operation parameters, information related thereto, or other information related to the operations and functions described herein.

[0181] It should also be understood that the exemplary embodiments disclosed and taught herein can be subject to various modifications and alternative forms. Thus, the use of singular terms, such as but not limited to "a", etc., is not intended to limit the number of items. In addition, the naming conventions for the various components, functions, features, thresholds, and other elements used herein are provided as examples and can be given different names or labels. The use of the term "or" is not limited to the exclusive "or" and can also mean "and / or".

[0182] It should be understood that the development of an actual, real - world commercial application incorporating aspects of the disclosed embodiments will require many implementation - specific decisions to achieve the developer's ultimate goal for the commercial embodiment. Such implementation - specific decisions can include, and may not be limited to, compliance with system - related, business - related, government - related, and other constraints, which can vary with a particular implementation, location, and time. Although 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.

[0183] Using the description provided herein, the example embodiments can be implemented as a machine, a process, or an article of manufacture by using standard programming and / or engineering techniques to produce programming software, firmware, hardware, or any combination thereof.

[0184] Any resulting program having computer-readable program code can be embodied on one or more tangible or non-transitory computer-usable media, such as a resident storage device, a smart card, or other removable storage device or a transmission device, thereby manufacturing a computer program product or article of manufacture according to an embodiment. Similarly, the terms "article of manufacture" and "computer program product" as used herein are intended to encompass a computer program that permanently or temporarily resides on any computer-usable or storage medium or any transmission medium that transmits such a program.

[0185] The processors, controllers or processing units described herein can be a processing system, which can include one or more processors, such as a CPU, a controller, an ASIC or other processing unit or circuitry, which controls or executes the operations of the devices or systems described herein. The memory / storage device can 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, etc., a semiconductor memory such as a RAM, a ROM, a PROMS, etc. The transmission medium or network includes, 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, telephone / modem-based network communication, hardwired / cable communication networks, satellite communication, and other fixed or mobile network systems / communication links.

[0186] The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and / or operation of possible implementations of various embodiments of the present invention. In this regard, each block in the flowchart or block diagram can represent a module, a segment of code, or a portion of code that includes one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions noted in the blocks may not occur in the order noted in the figures. For example, two blocks shown in succession may in fact be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and / or flowchart illustrations, and combinations of blocks in the block diagrams and / or flowchart illustrations, can be implemented by a system based on dedicated hardware that performs the specified functions or acts, or by a combination of dedicated hardware and computer instructions.

[0187] Although specific embodiments and applications of the present disclosure have been shown and described, it should be understood that the present disclosure is not limited to the exact construction and composition disclosed herein, and that various modifications, changes, and variations will be apparent from the foregoing description without departing from the invention as defined in the appended claims.

Claims

1. A method for facilitating arc fault detection on an electrical system, comprising: Providing high-frequency characteristics determined from a high-frequency signal on a circuit monitored by a first sensor of the electrical system, the high-frequency signal being measured or obtained by a first device configured to communicate with a first remote device, the first remote device including a branch device on a branch circuit downstream of the monitored circuit; Providing low-frequency characteristics determined from a low-frequency signal on the branch circuit monitored by a second sensor, the low-frequency signal being measured or obtained by the branch device; and Detecting the occurrence of an arc fault on the branch circuit based on the high-frequency characteristics and the low-frequency characteristics, wherein the operation of providing the high-frequency characteristics, the operation of providing the low-frequency characteristics, and the operation of detecting the occurrence of the arc fault are performed by the first device or the branch device.

2. The method according to claim 1, further comprising: Transmitting an energy measurement value between the first device and a branch device associated with the branch circuit, the energy measurement value including one of the high-frequency characteristics of the monitored circuit or information from which the high-frequency characteristics can be derived, or the low-frequency characteristics of the branch circuit or information from which the low-frequency characteristics can be derived, and the first device or the branch device detecting the occurrence of an arc fault on the branch circuit based on the high-frequency characteristics and the low-frequency characteristics of the branch circuit.

3. The method according to claim 2, wherein the branch device includes a plurality of branch devices associated with the branch circuit, and the energy measurement value is transmitted between the first device and each of the plurality of branch devices.

4. The method according to claim 2, further comprising: Time synchronizing and half-cycle synchronizing the first device and the branch device to allow exchange of synchronization information, including the energy measurement value, between the first device and the branch device.

5. The method according to claim 4, wherein the high-frequency characteristics of the monitored circuit are synchronized with the low-frequency characteristics of the branch circuit, and the synchronized high-frequency and low-frequency characteristics are used to detect the occurrence of an arc fault on the branch circuit.

6. The method according to claim 5, wherein the first device detects the occurrence of an arc fault on the branch circuit and remotely controls the branch device associated with the branch circuit where the arc fault is detected to de-energize the branch circuit.

7. The method according to claim 1, further comprising: Measuring or obtaining a measurement value of the high-frequency signal on the circuit monitored by the first sensor at the first device, the first device including a first memory, a first processor, and a first communication device for communicating with a first remote device; Measuring or obtaining a measurement value of the low-frequency signal on the associated branch circuit monitored by the second sensor at the branch device, the branch device including a second memory, a second processor, and a second communication device for communicating with a second remote device including the first device; and At the branch, determining low-frequency characteristics based on the measured low-frequency signal on the branch circuit, the low-frequency characteristics being used together with the high-frequency characteristics by the first device or the branch device to detect the occurrence of an arc fault on the branch circuit.

8. The method according to claim 7, further comprising: If the branch device determines that the low-frequency characteristic of the branch circuit crosses or meets a low-frequency threshold, a message is sent from the branch device to the first device; In response to the receipt of the message, the high-frequency characteristic is transmitted from the first device to the branch device; Based on the high-frequency and low-frequency characteristics of the branch circuit, an arc fault on the branch circuit is detected at the branch device; and If the branch device detects an arc fault on the branch circuit, the branch circuit is de-energized via the associated branch device.

9. The method according to claim 7, further comprising: If the high-frequency characteristic crosses or meets a high-frequency threshold at the first device, a message is sent from the first device to the branch device; In response to the receipt of the message, if the low-frequency characteristic of the associated branch circuit crosses or meets the low-frequency threshold, the low-frequency characteristic is transmitted from the branch device to the first device; Based on the high-frequency and low-frequency characteristics of the branch circuit, an arc fault on the branch circuit is detected at the first device; and If the first device detects an arc fault on the branch circuit, the branch circuit is de-energized via the associated branch device.

10. The method according to claim 9, wherein if an arc fault is detected on the branch circuit, the first device remotely controls the branch device to de-energize the branch circuit.

11. The method according to claim 1, further comprising: After a predetermined de-energization period expires, the branch circuit is energized at the branch device, the predetermined de-energization period being initiated in response to an arc fault detected on the branch circuit, the arc fault causing the branch circuit to be de-energized by the branch device.

12. The method according to claim 1, wherein the first device is located inside a switchboard.

13. The method according to claim 1, wherein the first device is located outside a switchboard.

14. The method according to claim 1, wherein the branch device includes a circuit breaker, a relay, a switching device, a wiring device, a lighting switch or a control device, or an electrical device connected to the relevant branch circuit.

15. A system for facilitating arc fault detection on an electrical system, comprising: A communication interface for communicating with a remote device; A memory ； and At least one processor in communication with the memory, configured to: Provide a high-frequency characteristic determined from a high-frequency signal on a circuit monitored by a first sensor of the electrical system, the high-frequency signal being measured or obtained by a first device configured to communicate with a first remote device, the first remote device including a branch device on a branch circuit downstream of the monitored circuit; Provide a low-frequency characteristic determined from a low-frequency signal on a branch circuit monitored by a second sensor, the low-frequency signal being measured or obtained by the branch device; and Detect the occurrence of an arc fault on the branch circuit based on the high-frequency and low-frequency characteristics, wherein the system includes the first device or the branch device.

16. The system according to claim 15, wherein an energy measurement value is transmitted between the first device and the branch device associated with the branch circuit, and the energy measurement value includes one of a high-frequency characteristic of the monitored circuit or information from which a high-frequency characteristic can be derived, or a low-frequency characteristic of the branch circuit or information from which a low-frequency characteristic can be derived, and the first device or the branch device detects an arc fault on the branch circuit based on the high-frequency and low-frequency characteristics of the branch circuit.

17. The system according to claim 16, wherein the branch device includes a plurality of branch devices associated with the branch circuit, and the energy measurement value is transmitted between the first device and each of the plurality of branch devices.

18. The system according to claim 16, wherein the system includes one of the first device and the branch device, and the processor is further configured to perform time synchronization and half-cycle synchronization with the other of the first device and the branch device, so as to enable the exchange of synchronization information, including energy measurement values, between the processor and the other of the first device and the branch device.

19. The system according to claim 18, wherein the high-frequency characteristic of the monitored circuit is synchronized with the low-frequency characteristic of the branch circuit, and the synchronized high-frequency and low-frequency characteristics are used to detect the occurrence of an arc fault on the branch circuit.

20. The system according to claim 19, wherein the system includes the first device, and the processor is further configured to detect an arc fault on the branch circuit and remotely control the branch device associated with the branch circuit where the arc fault is detected to de-energize the branch circuit.

21. The system according to claim 15, wherein the branch device is configured to: measure or obtain a measurement value of a low-frequency signal on the associated branch circuit monitored by a second sensor; and determine a low-frequency characteristic from the low-frequency signal measured on the branch circuit.

22. The system according to claim 21, wherein the system includes a branch device, wherein the first device is configured to transmit the high-frequency characteristic to the branch device in response to receiving a message from the branch device, and wherein the branch device of the branch circuit is configured to: send the message to the first device if the branch device determines that the low-frequency characteristic of the branch circuit crosses or meets a low-frequency threshold, receive the high-frequency characteristic from the first device, detect an arc fault on the branch circuit at the branch device based on the high-frequency and low-frequency characteristics of the branch circuit, and de-energize the branch circuit if an arc fault is detected on the branch circuit.

23. The system according to claim 21, wherein the system includes a first device, wherein the branch device is configured to transmit the low-frequency characteristic to the first device if it receives a message from the first device and the low-frequency characteristic of the associated branch circuit crosses or meets a low-frequency threshold, wherein the first device is configured to: transmit a message to the branch device if the high-frequency characteristic crosses or meets a high-frequency threshold, receive the low-frequency characteristic from the branch device, and Detecting an arc fault on a branch circuit based on high-frequency and low-frequency characteristics of the branch circuit, and wherein if an arc fault is detected on the branch circuit, a branch device associated with the branch circuit de-energizes the branch circuit.

24. The system of claim 23, wherein the processor is further configured to remotely control the branch device to de-energize the branch circuit in the event of an arc fault being detected on the branch circuit.

25. The system of claim 15, wherein the branch device is configured to energize the branch circuit after expiration of a predetermined de-energization period that is initiated in response to an arc fault detected on the branch circuit, the arc fault causing the branch circuit to be de-energized by the branch device.

26. The system of claim 15, wherein the first device is located inside a distribution panel.

27. The system of claim 15, wherein the first device is located outside the distribution panel.

28. The system of claim 15, wherein the branch device includes a circuit breaker, a relay, a switching device, a wiring device, a lighting switch, or a control device, or an electrical device connected to the associated branch circuit.

29. A non-transitory computer medium storing computer-executable code that, when executed by one or more processors of a first device or a branch device, implements a method for facilitating arc fault detection on an electrical system, the method comprising: Providing high-frequency characteristics determined from a high-frequency signal on a circuit monitored by a first sensor of the electrical system, the high-frequency signal being measured or obtained by a first device configured to communicate with a first remote device, the first remote device including a branch device on a branch circuit downstream of the monitored circuit; Providing low-frequency characteristics determined from a low-frequency signal on the branch circuit monitored by a second sensor, the low-frequency signal being measured or obtained by the branch device; and Detecting the occurrence of an arc fault on the branch circuit based on the high-frequency and low-frequency characteristics.

30. A method for facilitating arc fault detection on an electrical system having a plurality of branch devices on different branch circuits, comprising: Measuring or obtaining a measurement of a low-frequency signal on a respective branch circuit monitored by a respective sensor on the electrical system at each of the plurality of branch devices, each of the plurality of branch devices including a memory, a processor, and a communication device for communicating with a remote device including a first device; At each of the plurality of branch devices, determining low-frequency characteristics based on the low-frequency signal measured on the respective branch circuit; And Transmitting an energy measurement value between each branch device of the plurality of branch devices and the first device, the first device being configured to determine a common high-frequency characteristic based on a high-frequency signal monitored on a circuit upstream of the branch circuits on the electrical system, the energy measurement value including one of the low-frequency characteristics or the common high-frequency characteristic, the low-frequency characteristic of the respective branch circuit and the common high-frequency characteristic being used together to detect an arc fault on the respective branch circuit.

31. A system for facilitating arc fault detection on an electrical system having a plurality of branch devices on different branch circuits, comprising: Each of the plurality of branch devices includes a memory, a processor, and a communication device for communicating with a remote device including a first device, the processor configured to: Measure or obtain a measurement value of a low-frequency signal on a corresponding branch circuit monitored by a corresponding sensor on the electrical system; Determine a low-frequency characteristic from the low-frequency signal measured on the corresponding branch circuit; and Communicate an energy measurement value to the first device, the first device determining a common high-frequency characteristic based on a high-frequency signal monitored on a circuit upstream of the branch circuit on the electrical system, the energy measurement value including one of the low-frequency characteristic or the common high-frequency characteristic, the low-frequency characteristic of the corresponding branch circuit together with the common high-frequency characteristic being used to detect an arc fault on the corresponding branch circuit.

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