Circuit interrupting device fault duration monitor
Patent Information
- Application Number
- CN202411011906.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-07-27
- Filing Date
- 2024-07-26
- Publication Date
- 2025-01-28
Smart Images
Figure CN119382008A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to electronic circuit breakers, wiring devices, and other protective devices that can interrupt current flowing through the devices, and more particularly, to methods and systems for determining and monitoring the duration of transient events, such as the duration of a fault, in such monitoring and protection devices. Background Art
[0002] Modern protective devices, such as circuit breakers, wiring devices, and other devices that can interrupt the flow of current to a load, have components that can perform several functions not previously available in devices. For example, a CPU (e.g., a microcontroller) in an electronic circuit breaker allows the circuit breaker to function as both a ground fault circuit interrupting (GFCI) device and an arc fault circuit interrupting (AFCI) device. The CPU detects such faults by constantly sensing and sampling the line current and monitoring these samples for indications of a fault condition. Upon detecting a fault condition, the CPU outputs a trip signal to a trip unit, which trips or interrupts the current in the circuit breaker.
[0003] In circuit interrupting devices, the time it takes for the device to trip can provide an important indication of whether the device is functioning properly or if the device needs to be replaced. Tripping analysis typically involves measuring quantities that characterize the protection device, such as fault duration, current RMS and peak values, and the presence of transients. For fault duration, industry standards recommend using the zero crossing of the current waveform as the starting and / or ending point to measure fault duration. However, fault events can often start and end at non-zero crossings, and furthermore, the current waveform may contain large perturbations caused by the closing and opening of the trip unit contacts. Therefore, using zero crossing events presents a challenge for accurately determining fault duration.
[0004] Therefore, there is a need for a method to determine the duration of a transient event, such as a fault, in a circuit interrupting device that does not require the use of the zero crossings of the current or voltage waveform. Summary of the invention
[0005] Embodiments of the present disclosure provide systems and methods for determining and monitoring the duration of transient events, such as the duration of a fault, in circuit breakers, wiring devices, and other devices capable of interrupting current flow to a load. The system and method use the time derivative of a current or voltage waveform to determine the duration of a fault in such a circuit interruption device. In some embodiments, the system and method use the second-order derivative of the current or voltage waveform to determine the start and end times of the fault duration. In some embodiments, for the fault duration, the system and method derive the second-order derivative only for the portion of the current or voltage waveform within the start time window and the end time window that are close to the start and end times, respectively. Techniques for deriving second-order derivatives of waveforms are known in the art and can be implemented using any suitable programming language. The second-order derivative test reveals peaks, such as local maxima and local minima, within the start and end time windows, and the start and end time windows can be set or declared as the start and end times of the fault duration.
[0006] The above arrangement provides a unified and consistent way of determining fault duration that is more accurate than techniques that rely on waveform zero crossings. The above fault duration determination can be implemented locally within the circuit interrupting device to provide local monitoring of the fault duration of the device, or the circuit interrupting device can obtain the underlying waveform data and / or local fault duration determination and transmit it to an external system, such as a cloud computing environment, for analysis and modeling of fault duration. In the latter case, waveform data and / or local fault duration determinations from multiple devices collected over time under different operating conditions can be transmitted to an external system and analyzed and modeled. This analysis and modeling can then be used to provide remote support and monitoring of local circuit interrupting device fault durations through their digital twins. The analysis and modeling can also be used to further develop, optimize and improve device trip units and related components.
[0007] In general, in one aspect, embodiments of the present disclosure relate to a circuit interruption protection device. The device includes, in particular, a central processing unit (CPU) and a sensing circuit connected to the CPU. The sensing circuit is configured to sense a current or voltage waveform in the circuit interruption protection device, the current or voltage waveform being derived from an AC power source. The device also includes an analog-to-digital converter (ADC) coupled to the CPU and configured to acquire a current or voltage waveform sensed by the sensor circuit, and a fault detection module coupled to the ADC and configured to receive the current or voltage waveform acquired by the ADC. The fault detection module is operable to detect a fault event based on the current or voltage waveform. The device also includes a fault duration module coupled to the ADC and configured to receive the current or voltage waveform acquired by the ADC, the fault duration module being operable to obtain the duration of the fault event based on the current or voltage waveform. In some embodiments, the duration of the fault event is obtained by calculating a second-order derivative of a portion of the current or voltage waveform, finding a local maximum or local minimum of the portion of the current or voltage waveform, and setting the local maximum or local minimum as the start time or end time of the duration of the fault event.
[0008] In general, in another aspect, embodiments of the present disclosure relate to a method for determining the duration of a fault event in a circuit interruption protection device. The method includes, among other things, sensing a current or voltage waveform in the circuit interruption protection device at a sensor circuit of the circuit interruption protection device, the current or voltage waveform being derived from an AC power source. The method also includes acquiring the current or voltage waveform sensed by the sensor circuit at an analog-to-digital converter (ADC) of the circuit interruption protection device. The method also includes receiving the current or voltage waveform acquired by the ADC at a fault detection module of the circuit interruption protection device, the fault detection module being operable to detect a fault event based on the current or voltage waveform. The method also includes receiving the current or voltage waveform acquired by the ADC at a fault duration module of the circuit interruption protection device, the fault duration module being operable to obtain the duration of the fault event based on the current or voltage waveform. In some embodiments, the duration of the fault event is obtained by calculating a second-order derivative of a portion of the current or voltage waveform, finding a local maximum or local minimum of the portion of the current or voltage waveform, and setting the local maximum or local minimum as a start time or an end time of the duration of the fault event.
[0009] In general, in yet another aspect, embodiments of the present disclosure relate to a non-transitory computer-readable medium having stored thereon computer-readable instructions for determining the duration of a fault event in a circuit interruption protection device. When executed by a processor, the computer-readable instructions cause the processor to perform a process of sensing a current or voltage waveform in the circuit interruption protection device at a sensor circuit of the circuit interruption protection device, the current or voltage waveform being derived from an AC power source. The computer-readable instructions also cause the processor to perform a process of acquiring the current or voltage waveform sensed by the sensor circuit at an analog-to-digital converter (ADC) of the circuit interruption protection device. The computer-readable instructions also cause the processor to perform a process of receiving the current or voltage waveform acquired by the ADC at a fault detection module of the circuit interruption protection device, the fault detection module being operable to detect a fault event based on the current or voltage waveform. The computer-readable instructions also cause the processor to perform a process of receiving the current or voltage waveform acquired by the ADC at a fault duration module of the circuit interruption protection device, the fault duration module being operable to obtain the duration of the fault event based on the current or voltage waveform. In some embodiments, the duration of the fault event is obtained by calculating the second derivative of a portion of the current or voltage waveform, finding the local maximum or local minimum of the portion of the current or voltage waveform, and setting the local maximum or local minimum as the start time or end time of the fault event duration. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 An exemplary circuit breaker protection device that can perform fault duration determination according to an embodiment of the present disclosure is shown;
[0011] Figure 2 An exemplary external system that can perform fault duration determination according to an embodiment of the present disclosure is shown;
[0012] Figure 3A and 3B shows a waveform diagram illustrating an exemplary fault duration determination according to an embodiment of the present disclosure;
[0013] Figure 4 A flowchart of an exemplary method for performing fault duration determination according to an embodiment of the present disclosure is shown;
[0014] Figure 5A and 5B shows a close-up view of a waveform diagram illustrating fault duration determination according to an embodiment of the present disclosure; and
[0015] Figure 6 An exemplary general purpose CPU that may be used to implement various embodiments of the present disclosure is shown. DETAILED DESCRIPTION
[0016] This specification and the accompanying drawings illustrate exemplary embodiments of the present disclosure and should not be considered as limiting, and the claims define the scope of the present disclosure, including equivalents. Various mechanical, component, structural, electrical and operational changes may be made without departing from the scope of the present specification and the claims (including equivalents). In some cases, well-known structures and techniques are not shown or described in detail to avoid confusing the present disclosure. In addition, elements and related aspects thereof described in detail with reference to an embodiment may be included in other embodiments in which they are not specifically shown or described, as long as feasible. For example, if an element is described in detail with reference to an embodiment, and is not described with reference to a second embodiment, the element may still be required to be included in the second embodiment.
[0017] Reference now Figure 1 , shows an exemplary electronic circuit breaker 100 according to one or more embodiments of the present disclosure. In this example, the circuit breaker 100 is a dual-function AFCI / GFCI miniature circuit breaker, although embodiments of the present disclosure are equally applicable to other types of circuit breakers and circuit interruption protection devices. The circuit breaker 100 shown here has multiple functional components or modules represented in block diagram form, which allow the circuit breaker 100 to perform arc fault detection, ground fault detection and other functions. It should be understood that within the scope of the present disclosure, each box shown here (and in subsequent figures) can be divided into multiple constituent boxes, or multiple boxes can be combined into a single box. Similarly, it will be understood that within the scope of the present disclosure, each box can be implemented via software (e.g., programming), hardware (e.g., ASIC), or a combination of both.
[0018] As can be seen, the circuit breaker 100 includes a ground fault sensing circuit 102, an arc fault sensing signal 104, a current sensing circuit 106, and a trip unit 108 that communicate with the CPU 110. The CPU 110, which may be a microcontroller or other type of controller, includes at least one analog-to-digital converter (ADC) 112, a ground fault detection module 114, an arc fault detection module 116, a general fault detection module 118 that can detect short circuits and overload currents, etc., and a wired and / or wireless interface module 120. In some embodiments, the ADC 112 may also be a separate component from the CPU 110, and in either case, it should have sufficient resolution (e.g., 8 bits, 12 bits, 16 bits, etc.) and sampling speed (e.g., 50,000 samples / second). Other functional components and modules not explicitly shown, such as signal filtering and conditioning circuits, may also be included within the scope of the present disclosure. Similarly, one or more explicitly shown functional components and modules may be removed without departing from the present disclosure.
[0019] The operation of the circuit breaker 100 is generally well known in the art, so only a brief description is provided here. In general, the CPU 110 receives analog signals from the ground fault sensing circuit 102, the arc fault sensing circuit 104, the current sensing circuit 106, and other circuits capable of sensing AC power current and voltage. These analog signals may include current signals and voltage signals, which are sampled by the ADC 112 at a certain sampling rate, which is high enough for load identification and resolution and waveform amplitude detection. The ADC 112 converts each sample into a numerical value proportional to the sample amplitude and outputs these values as a time data series. The CPU 110 then processes the data sequence in a known manner to detect the occurrence of ground faults, arc faults, short circuits, etc. Upon detecting a fault condition, the CPU 110 sends a trip signal to the trip unit 108, which causes the trip unit to immediately interrupt the current flowing through the circuit breaker 100. The set / reset latch 122 allows a user to manually set / reset the circuit breaker 100 after a trip event.
[0020] According to one or more embodiments, a fault duration monitor 124 may be provided in the CPU 110 for detecting and monitoring the duration of a fault in the circuit breaker 100. Fault duration refers to the duration of a fault event, such as a ground fault event, an arc fault event, a short circuit event, an overcurrent event, and other current and voltage-based transient events that may be detected by a protection device such as the circuit breaker 100. The duration of a fault event reflects the time required for the protection device to clear the fault (i.e., interrupt the circuit), and generally includes detecting a fault current or voltage, determining whether a fault event exists, sending a trip signal to a trip unit to disconnect the trip mechanism, and disconnecting the contacts of the trip mechanism to clear the fault. In some embodiments, the duration of a fault event may be defined as Δt=t end –t start , where t start is the time when the fault event starts, t end is the time at which the protection device trips. As previously described, a fault event may often begin and end at non-zero crossings, and the current and / or voltage waveforms may also contain large disturbances caused by the closing / opening of the trip unit contacts, all of which may make it difficult to accurately perform edge detection to determine the fault duration. The fault duration monitor 124 overcomes the uncertainty associated with using zero crossings by performing edge detection based on the time derivative of the current and / or voltage waveforms to determine the fault duration.
[0021] More specifically, the fault duration monitor 124 uses the second derivative (or f" (x)) of the current and / or voltage waveform to perform edge detection to find the start and end times of the fault duration. This involves the fault duration monitor 124 taking samples of the current flowing through the circuit breaker 100 via the current sensing circuit 106 and the ADC 112. The samples may be obtained from the current or voltage waveform, and are preferably obtained at a sampling rate of 50k samples / second, although lower or higher sampling rates may be used depending on the particular application. The samples are then stored in the data memory 126 of the circuit breaker 100 for processing. In some embodiments, the sampling is performed on a continuous basis by the ADC 112, but at any given time, only a predetermined amount of data is stored in the circuit breaker 100, such as one second of samples, on a first-in, first-out basis. This helps to reduce the amount of data that needs to be stored and processed in the circuit breaker 100, thereby reducing the processing burden on the circuit breaker 100. Then, when a fault event occurs and the circuit breaker 100 trips, the fault duration monitor 124 uses the samples / data stored at the time of the trip to determine the fault duration.
[0022] In some embodiments, determining fault duration begins by running acquired data from the fault duration monitor 124 through a filter, such as a Butterworth low pass filter, to remove anomalies and noise. Other types of data filtering and signal conditioning techniques known in the art may also be used.
[0023] Next, the fault duration monitor 124 performs a basic threshold check to define a start time window and an end time window, wherein second order derivative based edge detection is performed, which further reduces the amount of data processing required. The start and end time windows are close to (enclose) the start and end times of the fault duration, respectively, so that only the waveform portions within these windows are processed to determine the start and end times. In some embodiments, the basic threshold check may include the fault duration monitor 124 searching forward from the beginning of the acquired data set and searching backward from the end of the data set until a current or voltage transient that exceeds a predefined threshold (e.g., 30%) of the nominal current or voltage amplitude (or magnitude) is found near each end of the data set. In some embodiments, RMS values may be used instead of transient amplitudes.
[0024] Once these two data points are found, the start and end time windows are established respectively by limiting the start time window to a predefined subset of data samples (e.g., 100 samples, 0.002 seconds, etc.) containing the first (start) data point and limiting the end time window to a predefined subset of data samples (e.g., 100 samples, 0.002 seconds, etc.) containing the second (end) data point. Thereafter, the fault duration monitor 124 derives second-order derivatives only for the data subsets within the start and end time windows. As previously described, various techniques are known in the art for obtaining second-order derivatives of waveform samples using any suitable programming language. Based on the second-order derivatives, the fault duration monitor 124 selects two points with the maximum transient amplitude (which may be a local maximum or a local minimum) within the start and end time windows, respectively, and sets these points as the start and end times of the fault duration. Depending on the specific implementation, the local maximum may be used for the start and end times, or the local minimum may be used for the start and end times. Alternatively, the local maximum may be used for the start time, while the local minimum may be used for the end time, or vice versa. Likewise, the above may be changed from one fault duration determination to another as desired. Typically, the significance of the local maximum or local minimum will determine which one is selected for the fault duration determination.
[0025] In some embodiments, the fault duration monitor 124 may declare an error via the CPU 110 if the fault duration determined by the fault duration monitor 124 exceeds a predefined threshold and / or does not meet certain predefined criteria. For example, the fault duration monitor 124 may declare an error if the fault duration determined by the fault duration monitor 124 exceeds a specified maximum value, or if a certain number of consecutive fault durations determined by the fault duration monitor 124 exceeds another (or the same) specified maximum value. When declaring an error, the fault duration monitor 124 may send a predefined visual, audible, and / or textual alarm to notify a user of the error, or provide an indication of the error on the circuit breaker 110. The fault duration monitor 124 may also automatically take one or more actions at this point via the CPU 110, such as disabling or locking the circuit breaker 100 (e.g., a denial of service state) or preventing the circuit breaker from being set / reset via the latch 122. The fault duration monitor 124 may also provide the error declaration along with the underlying current or voltage waveform data and the determined fault duration to one or more external systems for analysis and modeling, such as Figure 2 shown.
[0026] Figure 2A circuit breaker 100 connected to one or more external systems is shown, including a cloud computing environment 200, for analysis and modeling of fault duration. One or more cloud computing resources 202, such as database resources, processing resources, memory resources, network resources, etc., may be provided on the cloud computing environment 200. In this example, the cloud computing resources 202 may be used to host a digital twin 100' of the circuit breaker 100, which provides a virtual representation or simulation of the circuit breaker 100. The digital twin 100' operates based on data from sensors of the circuit breaker 100, which may be provided to the digital twin 100' directly or indirectly via a wired / wireless interface 120 of the circuit breaker 100. Based on the sensor data, the digital twin 100' may issue actuator and control signals to the circuit breaker 100 to control and operate the circuit breaker. In some embodiments, using the processing resources 202 in the cloud computing environment 200, the digital twin 100' may be used instead of (or in addition to) the circuit breaker 100 to perform the fault duration determination discussed herein. If the fault duration exceeds a specified maximum, or if a certain number of consecutive fault durations exceeds another (or the same) specified maximum, the digital twin 100' may declare an error and send an alarm notification. The digital twin 100' may also update the circuit breaker 100 (e.g., via a firmware update) with any operational adjustments or enhancements that may result from the fault duration determination.
[0027] In some embodiments, a transient event duration model 204 may be developed on a cloud computing environment 200 using computing resources 202 to simulate fault duration in a digital twin 100'. An initial or basic ("lite") version of the transient event duration model 204 may be developed based on basic waveform data and various control parameters of the circuit breaker 100. The data and control parameters may include, for example, fault duration, rated current and voltage, rated interrupting current and voltage, etc., as well as circuit breaker type, commissioning date, number of trips to date, and other information specific to the circuit breaker 100.
[0028] In some embodiments, the simulation and control system 206 can access and use the digital twin 100' for further analysis and modeling of fault duration and other aspects of the circuit breaker 100. Such analysis and modeling can then be used to provide remote support and monitoring of the circuit breaker 100 and other circuit interruption protection devices locally via the digital twin of the circuit breaker 100 and other circuit interruption protection devices. To this end, the simulation and control system 206 can be a private enterprise-level simulation and control system that can be used to manage the entire life cycle of the circuit breaker 100. Such a simulation and control system 206 can be used to perform more detailed or robust transient event duration modeling 208 based on waveform data and / or local fault duration determinations reported by multiple devices over time under different operating conditions. The reported waveform data and / or local fault duration data can be stored in a transient event duration data repository 210 along with its measured data. The simulation and control system 206 can also be used to compile the measured and reported data to generate a device health assessment 212 of the circuit breaker 100 and other circuit breakers and various circuit interruption protection devices.
[0029] In some embodiments, the simulation and control system 206 may also be used to perform optimizations 214 of the circuit breaker 100 and other circuit interruption protection devices. The optimizations 214 may result in overall device improvements 216 that may be incorporated into the design and manufacture of circuit interruption protection devices, as well as improvements in specific mechanisms (e.g., trip mechanisms) used in these devices. One of ordinary skill in the art will appreciate that the simulation and control system 206 and similar simulation and control systems may be used to achieve numerous additional benefits and advantages during the life cycle of a circuit interruption protection device without departing from the scope of the present disclosure.
[0030] Figure 3A and 3B The diagram illustrates how the second derivative of a derived current or voltage waveform can be used to perform edge detection by or in a miniature circuit breaker (MCB). In particular, Figure 3A A graph 300 is depicted showing a test waveform 302 generated by a waveform generator to demonstrate the fault duration discussed herein. Figure 3B Another graph 300" representing a second derivative of a test waveform 302 is depicted. In graphs 300 and 300", the vertical axis represents current magnitude (Amperes), the horizontal axis represents time, and the test waveform 302 is a 60 Hz waveform simulating a ground fault ("GF") current waveform.
[0031] refer to Figure 3A, at 304, the MCB is switched from the OFF state to the ON state to begin the fault duration determination. This is followed by an initial time interval 306 during which the MCB remains ON, but the ground fault current waveform 302 is OFF so that no current flows to the load. The ground fault current waveform 302 is thereafter applied to the MCB for a second time interval 308 to simulate the occurrence of a ground fault event. The MCB detects the simulated ground fault event and automatically trips at 310 to interrupt the current flow to the load.
[0032] exist Figure 3B The first derivative 302' and the second derivative 302" of the ground fault current waveform 302 are depicted in FIG. 1. It can be seen that the second derivative 302" produces two peaks (which may be local maximum or local minimum), one when the simulated ground fault current waveform 302 is applied to the MCB and the other when the MCB trips. Figure 3A ) and compared with the first derivative 302' of the ground fault current waveform 302, these peaks stand out clearly. Then, these two peaks can be set as the start time (t start ) and end time (t end ).
[0033] Figure 4 4 is a flow chart 400 representing a method that may be used by or with a circuit interruption protection device such as circuit breaker 100, and more particularly the fault duration monitor 124 therein, in accordance with an embodiment of the present disclosure. The method generally begins at 402 where a raw current or voltage waveform of the device is sampled, for example, at a rate of 50k samples / second. At 404, a predetermined amount of sample data is acquired and stored or otherwise saved in the device, for example, one second of data, on a first-in, first-out or rolling basis. This defines an initial start and end point of the waveform, thereby producing a finite data set for processing purposes. At 406, a Butterworth low pass filter or other filter and / or signal conditioning is applied to the waveform data to remove anomalies and noise. The filtered and / or conditioned data set is illustrated at 408.
[0034] At 410, a basic threshold check is performed on the acquired data set to define a start time window and an end time window, thereby further reducing the amount of data processing required. As previously described, the basic threshold check may include searching forward from the beginning of the acquired data set, and searching backward from the end of the data set to find a current (or voltage) transient near each end of the data set whose amplitude (or magnitude) exceeds a predefined threshold (e.g., 30%) of the nominal current (or voltage). The current (or voltage) transient near the beginning of the data set is represented at 412, and the current (or voltage) transient near the end of the data set is represented at 414. In some embodiments, the RMS value may be used instead of the transient amplitude (or magnitude).
[0035] At 420, the two data points 412 and 414 found are then used to establish a start time window 416 and an end time window 418, thereby creating a subset of data to be processed. As previously described, the start and end time windows 416 and 418 are close to the start and end times of the fault duration, respectively. As described above, processing only the data that falls within these windows 416 and 418 allows for faster and more efficient determination of the start and end times of the fault duration, thereby reducing the required computing power. In some embodiments, establishing the start and end time windows 416 and 418 involves limiting the start time window 416 to a predefined subset of data points (e.g., 100 data points, 0.002 seconds, etc.) that includes the start data point 412 and limiting the end time window 418 to a predefined subset of data points (e.g., 100 data points, 0.002 seconds, etc.) that includes the end data point 414.
[0036] At 422, second order derivatives are calculated for the data points within the start and end time windows 416 and 418 using techniques known in the art. The second order derivatives produce local maxima or local minima within each start and end time window 416 and 418, which can be used as the start and end times of the fault duration, respectively. The local maximum for the end time window 418 can be seen at 424. At 426, a search is performed to find the local maximum or local minimum within the start and end time windows 416 and 418. The local maximum or local minimum is a peak that stands out significantly compared to the remaining data in the start and end time windows 416 and 418. At 428, the local maximum or local minimum is set as the start time (t of the fault duration, respectively). start ) and end time (t end ).
[0037] Figure 5A and 5B 4 is a close-up view of a subset of data 408 in a graph showing the start and end time windows 416 and 418, respectively. As previously described, the vertical axis of the graph represents amplitude, while the horizontal axis represents time. Figure 5A As can be seen in FIG, the second derivative of the data subset 408 in the start time window 416 produces a local maximum at the peak 500. Similarly, in Figure 5B , the second derivative of the data subset 408 in the end time window 418 has produced a local maximum at the peak 502. These local maxima 500 and 502 are then set as the start time (t start ) and end time (t end ).
[0038] Figure 6 An exemplary CPU 600 that can be used to implement various embodiments of the present disclosure is shown. Generally speaking, any general-purpose CPU can be used in various embodiments of the present disclosure. For example, various embodiments of the present disclosure can be implemented as dedicated software executed in a CPU, such as Figure 6 600 in FIG. 600. CPU 600 may include a processor 620 connected to one or more storage devices 630. Memory 630 is typically used to store programs and data during operation of CPU 600. CPU 600 may also include a storage system 650 that provides additional storage capacity. The components of CPU 600 may be connected via an interconnection mechanism 640, which may include one or more buses. Interconnection mechanism 640 enables communications (e.g., data, instructions) to be exchanged between components of CPU 600.
[0039] The CPU 600 also includes one or more inputs 610 (e.g., for receiving data, instructions) and one or more outputs 660 (e.g., for providing data, instructions). In addition, the CPU 600 may include one or more interfaces (not shown) for connecting the CPU 600 to a communication network (in addition to or in lieu of the interconnection mechanism 640).
[0040] CPU 600 may include specially programmed dedicated hardware, such as an application specific integrated circuit (ASIC). Aspects of the present disclosure may be implemented with software, hardware, or firmware, or any combination thereof. In addition, these methods, actions, systems, system elements, and components thereof may be implemented as part of the above-mentioned CPU or as independent components.
[0041] Although CPU 600 is shown as an example of a type of CPU on which various aspects of the present disclosure may be implemented, it should be understood that various aspects of the present disclosure are not limited to such CPUs. Figure 6600 can be implemented on a CPU shown in FIG. 600. CPU 600 can be a general-purpose CPU programmable using a high-level programming language. CPU 600 can also be implemented using specially programmed dedicated hardware. In CPU 600, processor 620 is typically a commercially available processor, such as the STM32L412 MCU from STMicroelectronics discussed above.
[0042] In the above, reference is made to various embodiments. However, the scope of the present disclosure is not limited to the specifically described embodiments. On the contrary, any combination of the described features and elements, whether or not related to different embodiments, is considered to implement and practice the contemplated embodiments. In addition, although the embodiments may achieve advantages over other possible solutions or prior art, whether a given embodiment achieves a particular advantage does not limit the scope of the present disclosure. Therefore, the foregoing aspects, features, embodiments and advantages are merely illustrative and are not considered to be elements or limitations of the appended claims unless expressly stated in the claims.
[0043] The various embodiments disclosed herein may be implemented as systems, methods, or computer program products. Therefore, various aspects may take the form of a complete hardware embodiment, a complete software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects, which are generally referred to herein as "circuits," "modules," or "systems." In addition, various aspects may take the form of a computer program product contained in one or more computer-readable media, which has computer-readable program code contained thereon.
[0044] Any combination of one or more computer readable media may be utilized. The computer readable medium may be a non-transitory computer readable medium. The non-transitory computer readable medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or apparatus, or any suitable combination of the foregoing. The program code contained on the computer readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, fiber optic cable, RF, etc., or any suitable combination of the foregoing. The program code for performing the operations of various aspects of the present disclosure may be written in any combination of one or more programming languages.
[0045] Although various features are described above with reference to flowcharts and / or block diagrams, it will be understood by those skilled in the art that each block of the flowcharts and / or block diagrams and combinations of blocks in the flowcharts and / or block diagrams can be implemented by programming logic (e.g., program instructions, hardware logic, a combination of the two, etc.). In addition, executing such program instructions using a processor produces a machine capable of performing the functions or actions specified in one or more blocks of the flowcharts and / or block diagrams.
[0046] The flow charts and block diagrams in the accompanying drawings illustrate the possible architectures, functions and / or operations of various embodiments of the present disclosure. In this regard, each frame in the flow chart or block diagram may represent a module, a code segment or a code portion, which includes one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions annotated in the frame may not appear in the order annotated in the figure. For example, the two frames shown in succession can actually be performed substantially simultaneously, or these frames can sometimes be performed in reverse order, depending on the functions involved. It will also be noted that each frame in the block diagram and / or the flow chart illustration and the combination of frames in the block diagram and / or the flow chart illustration can be implemented by a system based on dedicated hardware or a combination of dedicated hardware and computer instructions that performs a specified function or action.
[0047] It should be understood that the above description is intended to be illustrative rather than limiting. After reading and understanding the above description, many other implementation examples are apparent. Although the present disclosure describes specific examples, it should be appreciated that the systems and methods of the present disclosure are not limited to the examples described herein, but can be implemented by modification within the scope of the appended claims. Therefore, the description and drawings should be considered illustrative rather than restrictive. Therefore, the scope of the present disclosure should be determined with reference to the appended claims and the full scope of the equivalents of these claims.
Claims
1. A circuit interruption protection device, comprising: Central Processing Unit (CPU); a sensing circuit connected to the CPU and configured to sense a current or voltage waveform in the circuit interruption protection device, the current or voltage waveform being derived from an AC power source; an analog-to-digital converter (ADC) coupled to the CPU and configured to acquire a current or voltage waveform sensed by the sensor circuit; a fault detection module coupled to the ADC and configured to receive a current or voltage waveform acquired by the ADC, the fault detection module being operable to detect a fault event based on the current or voltage waveform; as well as a fault duration module coupled to the ADC and configured to receive a current or voltage waveform acquired by the ADC, the fault duration module being operable to obtain a duration of a fault event based on the current or voltage waveform; The duration of the fault event is obtained by calculating the second-order derivative of a portion of the current or voltage waveform, finding the local maximum or local minimum of the portion of the current or voltage waveform, and setting the local maximum or local minimum as the start time or end time of the duration of the fault event.
2. The circuit interruption protection device according to claim 1, wherein: The second order derivative is calculated locally by the fault duration module.
3. The circuit interruption protection device according to claim 1, wherein: The second order derivative is calculated on an external system using a digital twin of the circuit interruption protection device.
4. The circuit interruption protection device according to claim 1, wherein: The portion of the current or voltage waveform is a window defined based on a transient amplitude of the current or voltage waveform exceeding a predefined threshold.
5. The circuit interruption protection device according to claim 4, wherein: The window includes a predefined subset of data points representing the current or voltage waveform, the predefined subset of data points including transient amplitudes exceeding the predefined threshold.
6. The circuit interruption protection device according to claim 1, wherein: If the duration of the fault event exceeds a specified maximum value, an error is declared.
7. The circuit interruption protection device according to claim 6, wherein: If a fault is declared, the CPU is operable to automatically take one or more actions in the circuit interruption protection device.
8. A method of determining the duration of a fault event in a circuit interruption protection device, the method comprising: At a sensor circuit of the circuit interruption protection device, sensing a current or voltage waveform in the circuit interruption protection device, the current or voltage waveform originating from an AC power source; acquiring, at an analog-to-digital converter (ADC) of the circuit interruption protection device, a current or voltage waveform sensed by the sensor circuit; At a fault detection module of the circuit interruption protection device, receiving a current or voltage waveform acquired by the ADC, the fault detection module being operable to detect a fault event based on the current or voltage waveform; as well as At a fault duration module of the circuit interruption protection device, a current or voltage waveform acquired by the ADC is received, and the fault duration module is operable to obtain a duration of a fault event based on the current or voltage waveform; The duration of the fault event is obtained by calculating the second-order derivative of a portion of the current or voltage waveform, finding the local maximum or local minimum of the portion of the current or voltage waveform, and setting the local maximum or local minimum as the start time or end time of the duration of the fault event.
9. The method according to claim 8, wherein: The second order derivative is calculated locally by the circuit interruption protection device.
10. The method according to claim 8, wherein: The second order derivative is calculated on an external system using a digital twin of the circuit interruption protection device.
11. The method of claim 8, further comprising defining the portion of the current or voltage waveform as a window based on a transient amplitude of the current or voltage waveform exceeding a predefined threshold.
12. The method according to claim 11, wherein: The window includes a predefined subset of data points representing the current or voltage waveform, the predefined subset of data points including transient amplitudes exceeding the predefined threshold.
13. The method of claim 8, further comprising declaring a fault in the circuit interruption protection device if the duration of the fault event exceeds a specified maximum value.
14. The method of claim 13, further comprising automatically taking one or more actions in the circuit interruption protection device if a fault is declared.
15. A non-transitory computer readable medium having stored thereon computer readable instructions for determining a duration of a fault event in a circuit interruption protection device, the computer readable instructions, when executed by a processor, causing the processor to perform the following process: At a sensor circuit of the circuit interruption protection device, sensing a current or voltage waveform in the circuit interruption protection device, the current or voltage waveform originating from an AC power source; acquiring, at an analog-to-digital converter (ADC) of the circuit interruption protection device, a current or voltage waveform sensed by the sensor circuit; At a fault detection module of the circuit interruption protection device, receiving a current or voltage waveform acquired by the ADC, the fault detection module being operable to detect a fault event based on the current or voltage waveform; as well as At a fault duration module of the circuit interruption protection device, a current or voltage waveform acquired by the ADC is received, and the fault duration module is operable to obtain a duration of a fault event based on the current or voltage waveform; The duration of the fault event is obtained by calculating the second-order derivative of a portion of the current or voltage waveform, finding the local maximum or local minimum of the portion of the current or voltage waveform, and setting the local maximum or local minimum as the start time or end time of the duration of the fault event.
16. The non-transitory computer readable medium of claim 15, wherein: The computer readable instructions cause the second order derivative to be calculated locally on the circuit interruption protection device.
17. The non-transitory computer readable medium of claim 15, wherein: The computer readable instructions cause the second order derivative to be calculated on an external system using a digital twin of the circuit interruption protection device.
18. The non-transitory computer readable medium of claim 15, wherein: The computer readable instructions define the portion of the current or voltage waveform as a window based on a transient amplitude of the current or voltage waveform exceeding a predefined threshold.
19. The non-transitory computer readable medium of claim 18, wherein: The window includes a predefined subset of data points representing the current or voltage waveform, the predefined subset of data points including transient amplitudes exceeding the predefined threshold.
20. The non-transitory computer readable medium of claim 15, wherein: The computer readable instructions cause a fault to be declared if the duration of the fault event exceeds a specified maximum value, and if a fault is declared, further cause one or more actions to be automatically taken in the circuit interruption protection device.