Series arc detection method and system using ferrite magnet ring to construct line boundary

Abstract

The invention discloses a series arc detection method and system for constructing a line boundary by using ferrite magnetic rings, and belongs to the technical field of power system relay protection, and the method comprises the steps: collecting single-end electrical quantity characteristics at a magnetic ring combination boundary; comparing the single-ended electrical quantity characteristics at the magnetic ring combination boundary with a starting value, when a starting criterion is met, processing the electrical quantity characteristics, and calculating the specific characteristic electrical quantity of the magnetic ring in the combination boundary; and comparing the calculated specific characteristic electrical quantity with a setting value, identifying a fault and removing the fault by the combined boundary when a series arc fault judgment condition is met, and performing no action when the fault judgment condition is not met. The method effectively identifies internal and external series arc faults, is not interfered by quick plugging and unplugging of a load, and realizes reliable detection of the series arc faults of the low-voltage power distribution system.

Description

Background Art

[0002] Electrical fires pose a great threat to people's lives and property. A large amount of research data shows that series fault arcs in low-voltage distribution lines are one of the main causes of electrical fires. Accurately, economically, and reliably detecting series arc faults is an important way to prevent electrical fires.

[0003] Currently, most of the single-terminal series arc fault detection methods based on single-terminal quantity characteristics are affected by various factors such as load types, and the detection accuracy is relatively low. Artificial intelligence detection methods based on characteristics such as the high-frequency content of fault current, harmonic composition, and peak-to-peak change require large-scale samples for training. Detection methods based on the random high-frequency components of arcs require high-precision current sensors due to the weak high-frequency components and difficult extraction, resulting in high costs.

[0004] At the same time, traditional series arc detection methods based on single-terminal quantities cannot accurately identify the fault location, which may cause misoperation of protection devices and lack selectivity in detection. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a series arc detection method and system that uses a ferrite magnetic ring to construct a line boundary in view of the above deficiencies in the prior art. By utilizing the additional characteristics of the magnetic ring combination boundary, series arc fault identification is realized, and the technical problems of difficult discrimination of series arc fault locations and difficult extraction of high-frequency components are solved.

[0006] The present invention adopts the following technical solutions: A series arc detection method that uses a ferrite magnetic ring to construct a line boundary includes the following steps: Collect the single-terminal electrical quantity characteristics at the magnetic ring combination boundary; Compare the single-terminal electrical quantity characteristics at the magnetic ring combination boundary with the starting value. When the starting criterion is met, process the electrical quantity characteristics and calculate the specific characteristic electrical quantity of the magnetic rings inside the combination boundary; Compare the calculated specific characteristic electrical quantity with the setting value. When the series arc fault discrimination condition is met, the combination boundary should identify the fault and trip. When the fault discrimination condition is not met, no action is taken.

[0007] Preferably, the single-terminal electrical quantity characteristic is the voltage drop characteristic of the magnetic rings inside the combination boundary.

[0008] Preferably, the magnetic ring combination boundary is installed at the port of the protected line.

[0009] Preferably, the magnetic ring combination boundary is installed outside the leakage protection device.

[0010] Preferably, the starting value is the effective value, amplitude, energy, and change rate of the magnetic ring voltage drop.

[0011] Preferably, the specific characteristic electrical quantity includes the peak value of the magnetic ring voltage drop, the amplitude at a specific frequency, the band energy, and the magnetic ring voltage drop after mathematical transformation.

[0012] Preferably, the discrimination condition for series arc faults is as follows: When the half-wave energy of the adjacent wave pressure difference of the inner magnetic ring is greater than the set value and the half-wave energy of the adjacent wave pressure difference of the outer magnetic ring is less than the set value, this half-wave is a fault half-wave.

[0013] Preferably, the half-wave energy is the average instantaneous energy of each sampling point within a half-wave , specifically:

[0014] where is the number of sampling points within a single half-wave, is the i instantaneous energy of each point of the adjacent wave pressure difference signal of the magnetic ring in the

[0015] Preferably, the setting basis of the protection setting value is that the protection does not malfunction reliably during an external series arc fault, and the protection for an internal series arc fault can operate.

[0016] In a second aspect, an embodiment of the present invention provides a series arc detection system using a ferrite magnetic ring to construct a line boundary, including: An acquisition module that acquires the single-ended electrical quantity characteristics at the boundary of the magnetic ring combination; A comparison module that compares the single-ended electrical quantity characteristics at the boundary of the magnetic ring combination with the starting value. When the starting criterion is met, the electrical quantity characteristics are processed to calculate the specific characteristic electrical quantity of the magnetic ring inside the combination boundary; A protection module that compares the calculated specific characteristic electrical quantity with the setting value. When the series arc fault discrimination condition is met, the combination boundary should identify the fault and trip. When the fault discrimination condition is not met, it does not operate.

[0017] In a third aspect, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the above-mentioned series arc detection method using a ferrite magnetic ring to construct a line boundary are implemented.

[0018] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium including a computer program. When the computer program is executed by a processor, the steps of the above-mentioned series arc detection method using a ferrite magnetic ring to construct a line boundary are implemented.

[0019] Fifth aspect, a chip includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the above-mentioned series arc detection method using a ferrite magnetic ring to construct a circuit boundary are implemented.

[0020] Sixth aspect, an embodiment of the present invention provides an electronic device including a computer program. When the computer program is executed by the electronic device, the steps of the above-mentioned series arc detection method using a ferrite magnetic ring to construct a circuit boundary are implemented.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects: A series arc detection method using a ferrite magnetic ring to construct a circuit boundary. Aiming at the problems that it is difficult to distinguish the fault location and extract the high-frequency characteristics of the traditional single-terminal measurement method for series arc faults in the current low-voltage distribution system, a series arc detection method of actively constructing a magnetic ring combination boundary is proposed. The proposed series arc detection method can install a magnetic ring combination boundary at a suitable position according to the topological structure of the protected object. The magnetic ring combination boundary can block the transmission of high-frequency components generated by series arcs, realize the isolation of high-frequency components in the fault interval, and thus ensure the selectivity of series arc fault location discrimination. At the same time, the additional characteristics of the magnetic ring combination boundary can amplify the fault characteristics, effectively solve the problem of difficult extraction of high-frequency components, and there is no need to install a high-precision current sensor. When internal and external faults occur in the protected object, the protection criterion can be constructed by using the difference in the additional characteristics of the combination boundary caused by the difference in high-frequency components inside and outside the area, so as to realize the accurate detection of series arc faults. At the same time, the effect of the electrical quantity detection method related to the difference in the additional characteristics of the magnetic ring combination boundary is better than the traditional single-terminal measurement method using the high-frequency components of the series arc current.

[0022] Furthermore, the magnetic ring combination boundary is flexible in configuration. The magnetic ring element has the characteristics of small volume, high convenience, and easy engineering practical application. It can be combined with other passive components according to actual requirements to form a magnetic ring combination boundary and design a specific impedance-frequency characteristic. The magnetic ring combination boundary can be installed on the outermost side of the protection interval, effectively avoiding affecting the correct operation of other protection devices.

[0023] Furthermore, the magnetic ring structure has an obvious amplification effect on the high-frequency fault characteristics of the arc current. By using the voltage drop characteristics of the magnetic rings inside the combination boundary, the use of high-precision current sensors in traditional methods can be overcome. When the system operates at power frequency (50Hz), the impedance value of the magnetic ring combination boundary is small; when the frequency range is 10k~200kHz, the impedance value of the magnetic ring combination boundary increases. When the arc current flows through the magnetic ring element, due to the characteristics of the magnetic ring combination boundary itself, the high-frequency characteristics of the magnetic ring voltage drop can further amplify the high-frequency components while retaining the high-frequency characteristics of the arc current, and the high-frequency characteristics of the magnetic ring voltage drop are more obvious.

[0024] Furthermore, the magnetic ring combination boundary can convert the system current signal into a voltage signal, which has more obvious characteristics than the arc current signal. Due to the amplification effect of the combination boundary's own characteristics on the high-frequency components of the arc current, when a series arc fault occurs, the magnetic ring voltage drop information has a large mutation. Using the magnetic ring voltage drop information as the starting signal of the starting element can improve the sensitivity. As long as the magnetic ring voltage drop amplitude during normal operation is avoided, the detection method can be correctly started.

[0025] Furthermore, the impedance frequency variation characteristics of the magnetic ring combination boundary show a monotonic characteristic that the impedance value increases with the frequency. The impedance is extremely small at the power frequency and relatively large at the high frequency. The characteristics of the magnetic ring boundary itself determine that it will not affect the normal operation of the system at the power frequency. In the high frequency band, the magnetic ring combination boundary can effectively block the transmission of high-frequency components. Therefore, when a series arc fault occurs, the voltage drop amplitude, effective value or energy at a specific frequency of the magnetic ring on the fault side is greater than that on the non-fault side. Based on this difference, the location of the series arc fault can be determined.

[0026] Furthermore, when a series arc fault occurs outside the zone at the exit of this level of line, the high-frequency components felt by this level of line are the richest. Therefore, as long as the protection setting avoids the specific characteristic electrical quantities of the magnetic ring felt by the protection of this level of line under the series arc fault outside the zone, the protection of the series arc fault outside the zone can be achieved without false operation, thereby ensuring the selectivity of the protection.

[0027] It can be understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0028] In summary, the present invention can effectively identify series arc faults inside and outside the zone, and is not affected by rapid plugging and unplugging of loads, thereby achieving reliable detection of series arc faults in low-voltage power distribution systems.

[0029] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 It is a schematic diagram of the topology of the low voltage distribution system under the combined boundary application; Figure 2 This is a schematic diagram of the current and magnetic ring voltage drop at the boundary when the trunk line in the area fails; Figure 3 It is the flowchart for detecting series arc faults in the low-voltage AC power distribution system of the present invention; Figure 4 It is the schematic wiring diagram of the series arc experiment platform; Figure 5 They are the measurement results of the instantaneous energy and half-wave energy of the magnetic rings on both sides of the combined boundary during the fault of the in-zone main line; Figure 6 They are the measurement results of the instantaneous energy and half-wave energy of the magnetic rings on both sides of the combined boundary during the fault of the in-zone branch; Figure 7 They are the measurement results of the instantaneous energy and half-wave energy of the magnetic rings on both sides of the combined boundary during the out-of-zone fault; Figure 8 They are the measurement results of the instantaneous energy and half-wave energy of the magnetic rings on both sides of the combined boundary during the rapid plugging and unplugging of the load; Figure 9 It is the schematic diagram of the computer device provided by an embodiment of the present invention; Figure 10 It is the block diagram of an electronic device provided by an embodiment of the present invention.

[0032] Among them, 60. Computer device; 61. Processor; 62. Memory; 63. Computer program; 600. Electronic device; 610. Processing unit; 620. Storage unit; 6201. Random access storage unit; 6202. Cache storage unit; 6203. Read-only storage unit; 6204. Program / utility; 6205. Program module; 630. Bus; 640. Display unit; 650. Input / output interface; 660. Network adapter; 700. External device. Specific embodiments

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0034] In the description of the present invention, it should be understood that the terms "include" and "comprise" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0035] It should also be understood that the terms used in the specification of the present invention are merely for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0036] It should be further understood that the term "and / or" used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present invention generally represents an "or" relationship between the contextually related objects.

[0037] It should be understood that although terms such as first, second, third, etc. may be used in the embodiments of the present invention to describe preset ranges, etc., these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0038] Depending on the context, the word "if" as used herein can be interpreted as "when" or "while" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detected (stated condition or event)" can be interpreted as "when determined" or "in response to determining" or "when detected (stated condition or event)" or "in response to detecting (stated condition or event)".

[0039] Schematic diagrams of various structures according to the disclosed embodiments of the present invention are shown in the drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of the various regions and layers shown in the figures and their relative sizes and positional relationships are merely exemplary, and may actually deviate due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0040] The present invention provides a series arc detection method using a ferrite magnetic ring to construct a line boundary. The application scenario of series arc detection is mostly on the user side of a low-voltage power distribution system, aiming to prevent electrical fires caused by series arcs. Since the user side is the terminal of the power distribution system, the magnetic ring combination boundary only needs to be installed at the entrance of the protected line, and the series arc detection can be realized by using single-ended electrical quantities. If it is necessary to detect whether a series arc occurs inside a specific component, magnetic ring combination boundaries can be installed at the entrances on both sides of the component. When there are internal and external faults in the protected component area, the specific electrical quantity differences of the magnetic rings inside the combination boundary are used to distinguish between internal and external faults.

[0041] Embodiment 1 Please refer to Figure 3 , a series arc detection method using a ferrite magnetic ring to construct a line boundary according to the present invention, designs a combination boundary based on the ferrite magnetic ring and applies it to the system line, and uses the additional characteristics of the boundary to realize the identification of series arc faults, including the following steps: S1. Install the designed magnetic ring combination boundary at the port of the protected line; The magnetic ring combination boundary should ensure that it does not affect the normal operation of the system, and at the same time does not affect the correct operation of other protection devices. For example, to avoid the influence of leakage current, the combination boundary should be installed outside the leakage protection device.

[0042] S2. Collect the single-ended electrical quantity characteristics at the magnetic ring combination boundary, specifically the voltage drop characteristics of the magnetic rings inside the combination boundary; S3. Compare the voltage drop characteristics of the magnetic rings inside the combination boundary obtained in step S2 with the starting value. When the starting criterion is met, the detection method is started; The starting value is the effective value, amplitude, energy, change rate, etc. of the magnetic ring voltage drop.

[0043] S4. Process the electrical quantity characteristics obtained in step S2 and calculate the specific characteristic electrical quantity of the magnetic rings inside the combination boundary.

[0044] The specific characteristic electrical quantity includes the peak value of the magnetic ring voltage drop, the amplitude at a specific frequency, the band energy, the magnetic ring voltage drop after mathematical transformation, etc.

[0045] S5. Compare the result calculated in step S4 with the setting value. When the series arc fault discrimination condition is met, the combination boundary should identify the fault and trip. If the fault discrimination condition is not met, the detection device does not operate.

[0046] The setting basis of the protection setting value is that the protection does not malfunction reliably during external series arc faults, and the protection can operate during internal series arc faults.

[0047] Those skilled in the art can understand that various aspects of the present invention can be implemented as a system, method, or program product. Therefore, various aspects of the present invention can be specifically implemented in the following forms: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or an implementation combining hardware and software aspects, which can be collectively referred to as "circuit", "module", or "platform".

[0048] Embodiment 2 The present invention provides a series arc detection system using a ferrite magnetic ring to construct a line boundary, which can be used to implement the above-mentioned series arc detection method using a ferrite magnetic ring to construct a line boundary. Specifically, the series arc detection system using a ferrite magnetic ring to construct a line boundary includes an acquisition module, a comparison module, and a protection module.

[0049] Among them, the acquisition module acquires the single-ended electrical quantity characteristics at the boundary of the magnetic ring combination; The comparison module compares the single-ended electrical quantity characteristics at the boundary of the magnetic ring combination with the starting value. When the starting criterion is met, the electrical quantity characteristics are processed to calculate the specific characteristic electrical quantity of the magnetic rings inside the combination boundary; The protection module compares the calculated specific characteristic electrical quantity with the setting value. When the series arc fault discrimination condition is met, the combination boundary should identify the fault and trip. When the fault discrimination condition is not met, it does not operate.

[0050] Embodiment 3 The present invention provides a terminal device, which includes a processor and a memory. The memory is used to store a computer program, and the computer program includes program instructions. The processor is used to execute the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Graphics Processing Units (GPU), Tensor Processing Units (TPU), Digital Signal Processors (DSP), Application Specific Integrated Circuits (ASIC), Field-Programmable Gate Arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions to implement the corresponding method flow or corresponding function. The processor described in the embodiments of the present invention can be used for the operation of the series arc detection method using a ferrite magnetic ring to construct a line boundary, including: Collect the single-ended electrical quantity characteristics at the boundary of the magnetic ring combination; compare the single-ended electrical quantity characteristics at the boundary of the magnetic ring combination with the starting value. When the starting criterion is met, process the electrical quantity characteristics and calculate the specific characteristic electrical quantity of the magnetic rings inside the combination boundary; compare the calculated specific characteristic electrical quantity with the setting value. When the series arc fault discrimination condition is met, the combination boundary should identify the fault and cut it off. When the fault discrimination condition is not met, no action is taken.

[0051] Please refer to Figure 9 , the terminal device is a computer device. The computer device 60 in this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the computer program 63 is executed by the processor 61, it implements the series arc detection method using a ferrite magnetic ring to construct a line boundary in the embodiment. To avoid repetition, it will not be elaborated here one by one. Alternatively, when the computer program 63 is executed by the processor 61, it implements the functions of each model / unit in the series arc detection system using a ferrite magnetic ring to construct a line boundary in the embodiment. To avoid repetition, it will not be elaborated here one by one.

[0052] The computer device 60 can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art can understand,Figure 9 This is merely an example of the computer device 60, and does not constitute a limitation on the computer device 60. It may include more or fewer components than those shown in the figure, or combine certain components, or have different components. For example, the computer device may also include input / output devices, network access devices, buses, etc.

[0053] The so-called processor 61 may be a central processing unit (CPU), or may also be other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0054] The memory 62 may be an internal storage unit of the computer device 60, such as the hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the computer device 60.

[0055] Furthermore, the memory 62 may also include both the internal storage unit and the external storage device of the computer device 60. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or will be output.

[0056] Please refer to Figure 10 , the terminal device is the electronic device 600, and the electronic device 600 is presented in the form of a general-purpose computing device. The components of the electronic device may include but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including the storage unit 620 and the processing unit 610), a display unit 640, etc.

[0057] Among them, the storage unit stores program code, which can be executed by the processing unit 610, so that the processing unit 610 executes the steps according to various exemplary embodiments of the present invention described in the method part of this specification. For example, the processing unit 610 can execute steps as shown in Figure 3 as shown.

[0058] The storage unit 620 may include a readable medium in the form of a volatile storage unit, such as a random access storage unit (RAM) 6201 and / or a cache storage unit 6202, and may further include a read-only storage unit (ROM) 6203.

[0059] The storage unit 620 may also include a program / utilities 6204 having a set (at least one) of program modules 6205. Such program modules 6205 include but are not limited to: an operating system, one or more application programs, other program modules, and program data. Each or some combination of these examples may include the implementation of a network environment.

[0060] The bus 630 may represent one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus structures.

[0061] The electronic device 600 may also communicate with one or more external devices 700 (such as a keyboard, a pointing device, a Bluetooth device, etc.), and may also communicate with one or more devices that enable a user to interact with the electronic device 600, and / or communicate with any device that enables the electronic device 600 to communicate with one or more other computing devices (such as a router, a modem). Such communication may be carried out through the input / output interface 650. Moreover, the electronic device 600 may also communicate with one or more networks (such as a local area network, a wide area network, and / or a public network, such as the Internet) through the network adapter 660. The network adapter 660 may communicate with other modules of the electronic device 600 through the bus 630. It should be understood that although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms, etc.

[0062] Embodiment 4 The present invention also provides a storage medium, specifically a computer-readable storage medium, which is a memory device in a terminal device and is used to store programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and, of course, the expandable storage medium supported by the terminal device. It can be any tangible medium that contains or stores a program, and this program can be used by or in combination with an instruction execution system, apparatus, or device. The computer-readable storage medium provides a storage space that stores the operating system of the terminal. And, in this storage space, one or more instructions suitable for being loaded and executed by a processor are also stored, and these instructions can be one or more computer programs (including program codes). It should be noted that more specific examples of the computer-readable storage medium here include: an electrical connection having one or more wires, a portable disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, an optical fiber, a portable compact disk read-only memory, an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0063] The computer-readable storage medium also includes a data signal propagated in a baseband or as part of a carrier wave, in which the readable program code is carried. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The readable storage medium can also be any readable medium other than the readable storage medium, and this readable medium can send, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium can be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, radio frequency, etc., or any suitable combination of the above.

[0064] The program code for performing the operations of the present invention can be written in any combination of one or more programming languages. The programming languages include object-oriented programming languages - such as Java, C++, etc., and also include conventional procedural programming languages - such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computing device, partially on the user's device, executed as an independent software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user's computing device through any type of network, including a local area network or a wide area network, or can be connected to an external computing device (for example, by using an Internet service provider to connect through the Internet).

[0065] One or more instructions stored in a computer-readable storage medium can be loaded and executed by a processor to implement the corresponding steps of the series arc detection method for constructing a line boundary using a ferrite magnetic ring in the above embodiments; one or more instructions in the computer-readable storage medium are loaded and executed by the processor to perform the following steps: Collect the single-ended electrical quantity characteristics at the boundary of the magnetic ring combination; compare the single-ended electrical quantity characteristics at the boundary of the magnetic ring combination with the starting value. When the starting criterion is met, process the electrical quantity characteristics and calculate the specific characteristic electrical quantity of the magnetic rings inside the combination boundary; compare the calculated specific characteristic electrical quantity with the setting value. When the series arc fault discrimination condition is met, the combination boundary should identify the fault and trip. When the fault discrimination condition is not met, no action is taken.

[0066] The databases involved in the embodiments provided in the present application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., and is not limited thereto. The processors involved in the embodiments provided in the present application may be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., and is not limited thereto.

[0067] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the present invention described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0068] Taking the occurrence of a series arc fault in a low-voltage distribution AC system as an example, verify the feasibility of the detection method proposed in the patent.

[0069] Step 1: Set the combination boundary; construct a magnetic ring combination boundary with the required characteristics. The specific requirement is that under power frequency conditions, the combination boundary does not affect the normal operation of the system. To avoid the boundary affecting the normal operation of the system, the installation position of the boundary is as Figure 1 shown, and the specific position is between the entrance of the protection interval of the low-voltage distribution system and the position of the leakage protection device to avoid the influence of leakage current.

[0070] Step 2: Collect the magnetic ring voltage drop information at the combination boundary and amplify the characteristics of the high-frequency current information. Figure 2The series arc current and the combined boundary magnetic ring voltage drop of a certain series arc fault in the low-voltage system are given. Compared with the original series arc current signal, the high-frequency characteristics of the fault are more obvious in the magnetic ring voltage drop. By using the magnetic ring voltage drop characteristics instead of the current characteristics, there is no need to install a high-precision current sensor.

[0071] Step 3: Set up a startup criterion; record the voltage drop information of the inner magnetic ring 1 u MR1 , after a series arc fault occurs, there will be a large mutation in the magnetic ring voltage drop. Therefore, the peak value of the magnetic ring voltage drop is used as the startup criterion. When u MR1 satisfies Equation (1), the detection process is started.

[0072] (1) Among them, δ set is the setting value of the startup criterion, which is set according to avoiding the magnetic ring voltage drop fluctuation during normal operation.

[0073] Step 4: Record the voltage drop information of the two magnetic rings within 1 s in units of half-waves u MR1 、 u MR2 . Subtract the adjacent cycle signals of the magnetic ring voltage drop, as shown in Equation (2), and denote Δ u MR as the adjacent wave voltage difference of the magnetic ring. Calculate the adjacent wave voltage differences Δ u MR1 ( n )、Δ u MR2 ( n ). Among them n =1,2,… N ; N is the number of sampling points within a single half-wave.

[0074] (2) During the actual operation of the power electronic type load, there is a phase break phenomenon in the current, which will generate high-frequency components. Only using the magnitude of the voltage drop of the magnetic ring is likely to cause misjudgment. For periodic signals, the value after subtracting adjacent cycles is 0.

[0075] Affected by the random arc high-frequency current, the high-frequency components of the inner magnetic ring voltage drop are different in each cycle. Therefore, after subtracting the adjacent cycle signals, the high-frequency information will not be completely eliminated. After subtracting the adjacent cycle signals of the outer magnetic ring voltage drop, its value is approximately 0. Using the adjacent wave voltage difference signal can eliminate the interference brought by the inherent harmonics of the system power supply and the "phase break" of the power electronic type load current.

[0076] Calculate the instantaneous energy of each point of the adjacent wave pressure difference signal of the i th half-wave magnetic ring, as shown in Equation (3). That is,

[0077] (3) Define the half-wave energy as the average instantaneous energy of each sampling point within a half-wave, as shown in Equation (4).

[0078] (4) The detection standard for series arc in low-voltage AC systems is that the number of faulty half-waves reaches a certain number. Define the half-wave energy as the fault characteristic electrical quantity to measure the half-wave state.

[0079] Step 5: Establish a series arc fault criterion. When the half-wave energy of the adjacent wave pressure difference of the inner magnetic ring is greater than the set value, and the half-wave energy of the adjacent wave pressure difference of the outer magnetic ring is less than the set value, this half-wave is considered a faulty half-wave, as shown in Equation (5).

[0080] (5) Wherein, W set is the set threshold for fault confirmation. According to the series arc detection requirements of the national standard GB14287.4 in 2014, when a fault arc occurs in 14 or more half-waves on the line within 1 s, the detection device should identify the fault and trip.

[0081] Experimental verification To verify the feasibility of the proposed detection method, a series arc experimental platform with multiple load branches is built in this embodiment. The principle wiring diagram is as shown in Figure 4 . This experimental platform uses an isolation transformer as the power supply, which can provide an AC voltage with a frequency of 50 Hz and an effective value of 220 V; the voltage probe is responsible for measuring and collecting the voltage drop information of the inner and outer magnetic rings; the sampling resistor selects a high-frequency resistor with a resistance value of 0.1 Ω, which is responsible for collecting the line current information; the arc generating device selects a point-contact fault arc generator (copper-carbon electrode) made according to the UL1699 standard; the power factor and impedance value of the load box are adjustable.

[0082] The following is an explanation and experimental verification with 4 common working conditions: As shown in Fault Scenario 1, a series arc fault occurs in the main line branch. At this time, switch S 1 is open and S 2 is open. Adjust the impedance value and power factor of the load box to simulate the fault conditions of various loads.

[0083] As shown in Fault Scenario 2, a series arc fault occurs in the main line branch. At this time, switch S 1 is closed and S 2 is open. Add a shielded loadZ 1 The operating power is 1500 W.

[0084] As shown in Fault Scenario 3, a series arc fault occurs in the external branch. At this time, switch S 1 is disconnected and S 2 is closed. The load Z 1 is used as the load of the external branch and its size is adjustable.

[0085] As shown in Scenario 4, the interference caused by load plugging and unplugging. This kind of situation is not a fault. At this time, S 2 is disconnected and the load Z 1 is used as the test load. The fast on-off of control switch S 1 is used to simulate the fast plugging and unplugging of the load.

[0086] Experimental tests are carried out on the schematic diagram of Scenario 1. The measurement results of the instantaneous energy and half-wave energy of the magnetic rings on both sides of the combined boundary during the in-zone main line fault are as Figure 5 shown. Among them, the load impedance value is 75 Ω and the power factor is 0.75. After the fault occurs, the instantaneous energy of the inner magnetic ring is greater than the magnetic ring energy of the outer magnetic ring. The instantaneous energy of the outer magnetic ring is approximately 0, and the half-wave energy satisfies the fault discrimination condition.

[0087] Tests are carried out on the schematic diagram of Scenario 2. The measurement results of the instantaneous energy and half-wave energy of the magnetic rings on both sides of the combined boundary during the in-zone branch fault are as Figure 6 shown. Figure 6 The instantaneous energy and half-wave energy of the inner and outer magnetic rings with the load power factor of the fault branch still being 0.75 are given; compared with Figure 5 , the measured instantaneous energy and half-wave energy of the inner magnetic ring have decreased. This shows that the normal load branch current has a certain attenuation effect on the high-frequency components of the fault branch current, but the size relationship of the half-wave energy of the two magnetic rings still satisfies the fault criterion.

[0088] Tests are carried out on the schematic diagram of Scenario 3. The measurement results of the instantaneous energy and half-wave energy of the magnetic rings on both sides of the combined boundary during the out-of-zone fault are as Figure 7 shown. After the out-of-zone series arc fault occurs, the instantaneous energy and half-wave energy of the inner magnetic ring are smaller than those of the outer magnetic ring and do not meet the fault criterion of the fault half-wave.

[0089] Tests are carried out on the schematic diagram of Scenario 4. The measurement results of the instantaneous energy and half-wave energy of the magnetic rings on both sides of the combined boundary during the fast plugging and unplugging of the load are as Figure 8As shown in the figure. At the moment when the load is inserted and removed, a large high-frequency component appears in the voltage drop of the inner magnetic ring, but the system returns to a stable operating state within three half-wave times. Since the line boundary only attenuates the high-frequency component and has basically no influence on the power-frequency signal transmission, only the half-wave corresponding to the moment of insertion or removal action satisfies the fault discrimination condition, without affecting the detection result.

[0090] In summary, the series arc detection method and system of the present invention using a ferrite magnetic ring to construct a line boundary effectively overcome the problems that it is difficult to discriminate series arc faults and extract high-frequency characteristics in the traditional single-terminal quantity detection method for series arc faults. The constructed magnetic ring combination boundary has a strong attenuation effect on the transmission of high-frequency components of series arcs, thereby causing differences in high-frequency components inside and outside the zone, and realizing the identification of series arc faults inside and outside the zone. At the same time, the additional voltage drop characteristic of the boundary can further enhance the intensity of high-frequency signals, overcoming the necessity of high-precision current sensors. This method focuses on the basic characteristic of the high-frequency component of series arc faults, is applicable to the working conditions where series arcs occur in the protected section, and effectively realizes the reliable detection of series arcs.

[0091] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the above-mentioned division of each functional unit and module is used as an example. In actual applications, the above-mentioned functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of the present application. The specific working process of the units and modules in the above system can refer to the corresponding process in the foregoing method embodiment and will not be repeated here.

[0092] In the above embodiments, the descriptions of each embodiment have their own emphases. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0093] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in the present invention can be implemented by electronic hardware, or by a combination of computer software and electronic hardware. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0094] In the embodiments provided by the present invention, it should be understood that the disclosed device / terminal and method can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections between each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical or other forms.

[0095] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0096] In addition, in each embodiment of the present invention, the functional units can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0097] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, to implement all or part of the processes in the above method embodiments of the present invention, it can also be completed by a computer program instructing relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0098] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses, and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or multiple blocks.

[0099] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that implement the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or multiple blocks.

[0100] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one flow Figure 1 one flow or multiple flows and / or blocks Figure 1 or multiple blocks.

[0101] The above content is only for explaining the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A series arc detection method using a ferrite magnetic ring to construct a line boundary, characterized in that: The following steps are involved: Collect the single-ended electrical quantity characteristics at the boundary of the magnetic ring combination; The single-ended electrical quantity characteristics at the boundary of the magnetic ring combination are compared with the start value. When the start criterion is met, the electrical quantity characteristics are processed to calculate the specific characteristic electrical quantity of the magnetic ring inside the combination boundary. The calculated specific characteristic electrical quantity is compared with the set value. When the series arc fault judgment condition is met, the combined boundary should identify the fault and cut off the fault. When the fault judgment condition is not met, no action will be taken.

2. The method for detecting series arcs using ferrite rings to construct line boundaries according to claim 1, characterized in that: The single-ended electrical quantity characteristic is the voltage drop characteristic of the magnetic ring inside the combined boundary.

3. The method for detecting series arcs using ferrite rings to construct line boundaries according to claim 1, characterized in that: The magnetic ring combination boundary is installed at the port of the protected line.

4. The method for detecting series arcs using ferrite magnetic rings to construct line boundaries according to claim 3, characterized in that: The magnetic ring combination boundary is installed on the outside of the leakage protection device.

5. The method for detecting series arcs using ferrite magnetic rings to construct line boundaries according to claim 1, characterized in that: The starting value is the effective value, amplitude, energy and rate of change of the magnetic ring voltage drop.

6. The method for detecting series arcs using ferrite rings to construct line boundaries according to claim 1, characterized in that: The specific characteristic electrical quantities include the peak value of the magnetic ring voltage drop, the amplitude at a specific frequency, the frequency band energy, and the magnetic ring voltage drop after mathematical transformation.

7. The method for detecting series arcs using ferrite rings to construct line boundaries according to claim 1, characterized in that: The conditions for judging a series arc fault are: When the half-wave energy of the adjacent wave pressure difference of the inner magnetic ring is greater than the set value, and the half-wave energy of the adjacent wave pressure difference of the outer magnetic ring is less than the set value, the half-wave is a fault half-wave.

8. The method for detecting series arcs using ferrite magnetic rings to construct line boundaries according to claim 7, characterized in that: Half-wave energy is the average instantaneous energy of each sampling point within a half-wave , specifically: in, is the number of sampling points in a single half-wave, For the i The instantaneous energy at each point of the adjacent wave pressure difference signal of a half-wave magnetic ring.

9. The method for detecting series arcs using ferrite rings to construct line boundaries according to claim 1, characterized in that: The basis for setting the protection setting value is that the protection is reliable and will not operate incorrectly when there is a series arc fault outside the zone, and the protection can operate when there is a series arc fault inside the zone.

10. A series arc detection system using ferrite magnetic rings to construct line boundaries, characterized in that: include: The acquisition module acquires the single-ended electrical quantity characteristics at the boundary of the magnetic ring combination; The comparison module compares the single-ended electrical quantity characteristics at the boundary of the magnetic ring combination with the start value. When the start criterion is met, the electrical quantity characteristics are processed to calculate the specific characteristic electrical quantity of the magnetic ring inside the combination boundary. The protection module compares the calculated specific characteristic electrical quantity with the set value. When the series arc fault judgment condition is met, the combined boundary should identify the fault and cut it off. When the fault judgment condition is not met, no action will be taken.

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