Arc light ground fault photoelectric synchronous detection method and application thereof

Abstract

The application relates to the technical field of relay protection, in particular to an arc ground fault photoelectric synchronous detection method and application thereof. Unlike a traditional threshold start, the waveform similarity of a current signal converted by a light signal and a fault phase current is introduced as a criterion, when the light intensity conversion signal is too large and the light conversion signal and the phase current signal have high similarity, it is judged that an arc ground fault occurs. The arc ground fault detection in the mode can set a low current threshold, even if an accidental non-fault light intensity increase phenomenon occurs in an application scene such as a switch cabinet, the waveform similarity between the current signal generated by the non-fault light intensity and the phase current signal is low, and false positives are not prone to occur. The application aims to solve the problem of how to realize arc ground fault detection without relying on a threshold value of a threshold value of an electric signal.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of relay protection, in particular to an arc grounding fault photoelectric synchronous detection method and application thereof. BACKGROUND

[0002] At present, the most commonly used detection method for arc grounding fault in switch cabinet in China is arc protection method, which is composed of voltage measurement and light measurement: light measurement is responsible for detecting the arc light generated by the accident arc, and positioning the part where the arc is generated when the arc light is greater than the set light intensity threshold; and the voltage measurement measures the current instantaneous value and judges whether it exceeds the set threshold. When both parts meet the requirements, it can be confirmed which position in the switch cabinet has arc grounding fault.

[0003] However, if there is a shielding situation in the switch cabinet, it is easy to cause the arc light to be too weak to reach the threshold, and if the threshold is lowered, the possibility of false positives will increase; and if arc high resistance grounding occurs in the switch cabinet, the instantaneous value of the electrical quantity will also decrease to the set threshold, so that the phenomenon of not being able to detect the arc grounding fault in the switch cabinet cannot be detected.

[0004] Therefore, there is a need for an arc grounding fault detection method that does not rely solely on threshold electrical signal threshold as a starting criterion to improve the reliability of arc grounding fault detection in closed, low light intensity and other application scenarios such as switch cabinet. SUMMARY

[0005] The main purpose of the present application is to provide an arc grounding fault photoelectric synchronous detection method, which aims to solve the problem of how to realize arc grounding fault detection without relying on threshold electrical signal threshold as a starting criterion.

[0006] To achieve the above purpose, the present application provides an arc grounding fault photoelectric synchronous detection method, which comprises:

[0007] S10, acquiring the current signal converted by the light signal collected by the photoelectric sensor and the phase current signal of the target phase in the to-be-measured circuit;

[0008] S20, calculating the waveform similarity corresponding to the current signal and the phase current signal:

[0009]

[0010] In the formula, is the waveform similarity, is the current signal, is the phase current signal of the jth phase, is and the covariance of and the variance of the variance of

[0011] S30, when detecting that the current signal is greater than a preset current threshold value, and the waveform similarity is greater than a preset waveform similarity threshold value, judging that an arc ground fault occurs.

[0012] Optionally, the S30 comprises:

[0013] firstly judging whether the current signal is greater than a preset current threshold value;

[0014] if yes, then judging whether the waveform similarity is greater than a preset waveform similarity threshold value;

[0015] if yes, then judging that an arc ground fault occurs.

[0016] Optionally, the S30 comprises:

[0017] simultaneously judging whether the current signal is greater than a preset current threshold value, and whether the waveform similarity is greater than a preset waveform similarity threshold value;

[0018] if both are yes, then judging that an arc ground fault occurs.

[0019] Optionally, the S10 is executed once every preset period, and the S20 is executed after each execution of the S10.

[0020] Optionally, the preset current threshold value is a dark current value corresponding to the photoelectric sensor.

[0021] Optionally, the S30 further comprises:

[0022] when detecting that the current signal is greater than a preset current threshold value, triggering an alarm signal.

[0023] Optionally, after the step of judging that an arc ground fault occurs, the method further comprises:

[0024] S40, controlling an outlet trip of the target phase.

[0025] In addition, to achieve the above-mentioned purposes, the present application also provides an arc ground fault photoelectric synchronous detection method as described in any one of the above, and an application in arc ground fault detection.

[0026] In addition, to achieve the above-mentioned purposes, the present application also provides a computer readable storage medium, and the computer readable storage medium stores a computer program, and the computer program is executed by a processor to realize the steps of the arc ground fault photoelectric synchronous detection method as described in any one of the above.

[0027] ​​In addition, to achieve the above-mentioned purpose, the application further provides a computer system, a switch cabinet or an arc ground fault detection device comprising the computer readable storage medium as described above.

[0028] The application has at least the following beneficial effects:

[0029] 1. Different from the traditional threshold start, the waveform similarity of the current signal converted from the light signal and the fault phase current is introduced as a criterion. When the light intensity conversion signal is too large and the light conversion signal has a high similarity with the phase current signal, it is determined that an arc ground fault occurs.

[0030] 2. The arc ground fault detection in this way can set a lower current threshold. Even if an accidental non-fault light intensity increase occurs in an application scene such as a switch cabinet, the waveform similarity between the current signal generated by the non-fault light intensity and the phase current signal is low, and false positives are not easy to occur. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Flowchart of the first embodiment of the arc ground fault photoelectric synchronous detection method of the application;

[0032] Figure 2 Architecture diagram of the simulation model involved in the embodiment of the application;

[0033] Figure 3 Simulated light signal conversion current diagram involved in the embodiment of the application;

[0034] Figure 4 Processed fault phase current diagram involved in the embodiment of the application;

[0035] Figure 5 Processed healthy phase current diagram involved in the embodiment of the application;

[0036] Figure 6 Real-time correlation coefficient diagram between the processed fault phase current and the simulated light signal conversion current signal involved in the embodiment of the application;

[0037] Figure 7 Real-time correlation coefficient diagram between the processed healthy phase current and the simulated light signal conversion current involved in the embodiment of the application;

[0038] Figure 8 Simulated light signal conversion current diagram involved in the embodiment of the application;

[0039] Figure 9 Processed fault phase current diagram involved in the embodiment of the application;

[0040] Figure 10 Processed healthy phase current diagram involved in the embodiment of the application;

[0041] Figure 11 A real-time correlation coefficient graph between the processed fault phase current and the current signal converted from the analog light signal, involved in the embodiment of the present application;

[0042] Figure 12 A real-time correlation coefficient graph between the processed healthy phase current and the current signal converted from the analog light signal, involved in the embodiment of the present application;

[0043] Figure 13 An architecture schematic diagram of a hardware running environment of a computer system, a switch cabinet or an arc ground fault detection device, involved in the embodiment of the present application.

[0044] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0045] In order to better understand the above technical solutions, the exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0046] First embodiment

[0047] With reference to Figure 1 The present embodiment provides an arc ground fault photoelectric synchronous detection method, which comprises the following steps:

[0048] S10, acquiring a current signal converted from a light signal collected by a photoelectric sensor and a phase current signal of a target phase in a to-be-tested circuit;

[0049] In this step, first, two kinds of signals are collected: a light signal collected by a photoelectric sensor and a phase current signal of a target phase in a to-be-tested circuit.

[0050] In the present embodiment, the to-be-tested circuit includes a multi-phase circuit, and any one phase in the multi-phase circuit is selected as the target phase. The collected light signal is converted into a current signal by using a photoelectric sensor designed to be sensitive to a special waveband.

[0051] In some optional implementations, a self-provided current transformer is used to simultaneously collect the current signals of each phase in the to-be-tested circuit. For the convenience of calculation, the current signals are subjected to absolute value processing to obtain the phase current signals referred to in this step.

[0052] S20, calculating a waveform similarity of the current signal and the phase current signal:

[0053]

[0054] In the formula, is a waveform similarity, is a current signal, is a phase current signal of the jth phase, is and a covariance of is a variance of is a variance of

[0055] In this step, it is worth noting that, unlike the conventional threshold starting criterion, the waveform similarity is used in the embodiment to detect the arc ground fault, without considering the amplitude of signal change, and only the current signal converted from the light signal and the change rule of the fault phase current waveform are used for judgment.

[0056] S30, when the current signal is greater than the preset current threshold and the waveform similarity is greater than the preset waveform similarity threshold, it is judged that the arc ground fault occurs.

[0057] In this step, since the light intensity is usually low in the closed and dark environment, there is almost no light signal, and the value of the current signal converted from the light signal collected by the photoelectric sensor is small. If the light intensity appears in the closed and dark environment, the converted current will rise, and the current signal is detected to increase, when it is greater than the preset current threshold, it means that the arc ground phenomenon occurs inside and causes the light intensity inside.

[0058] However, if the arc light is too weak due to the existence of shielding and other situations in the environment, which further leads to the current signal failing to reach the threshold, and blindly reducing the current threshold will increase the possibility of false positives. Therefore, the waveform similarity as described above is further introduced as a criterion, and the waveform matching method is used, without considering the amplitude of signal change, and the current signal converted from the light signal and the change rule of the fault phase current waveform (i.e. the waveform similarity) are used for judgment. When the waveform similarity is greater than the preset waveform similarity threshold, it is judged that the arc ground phenomenon occurs inside, that is, the arc ground fault occurs inside, and the arc ground fault detection is completed.

[0059] It should be noted that the principle of selecting the waveform similarity as the arc grounding fault detection criterion lies in that the essence of the arc grounding fault is that the fault current breaks through the insulating medium to generate the arc, and the light emission of the arc has a direct causal correlation with the change of the fault current. The physical characteristic determines that the current signal converted from the light signal and the fault phase current signal have strong synchronism in the waveform change law, and a large number of experiments have also verified this law. When the fault current increases, the arc energy increases, the light intensity increases, and the current signal converted from the light signal increases synchronously. When the fault current decreases, the arc energy decreases, the light intensity decreases, and the current signal converted from the light signal decreases synchronously. The physical correlation leads to high consistency of the waveforms of the two in the change trend, period and phase, and the waveform similarity is significantly increased.

[0060] In the technical scheme provided in the embodiment, unlike the traditional threshold start, the waveform similarity of the current signal converted from the light signal and the fault phase current is introduced as the criterion. When the light intensity conversion signal is too large and the similarity between the light conversion signal and the phase current signal is high, it is judged that the arc grounding fault occurs. The arc grounding fault detection in this way can set a lower current threshold. Even if the accidental non-fault light intensity increase phenomenon occurs in the application scene such as the switch cabinet, the waveform similarity between the current signal generated by the non-fault light intensity and the phase current signal is low, and false positives are not easy to occur.

[0061] Second embodiment

[0062] As an optional embodiment, based on the first embodiment, in the embodiment, step S30 includes:

[0063] S31, first judge whether the current signal is greater than a preset current threshold;

[0064] S32, if yes, then judge whether the waveform similarity is greater than a preset waveform similarity threshold;

[0065] S33, if yes, then judge that the arc grounding fault occurs.

[0066] In the embodiment, the judgment logic of the arc grounding fault is to first discriminate the current signal converted from the light signal collected by the photoelectric sensor, and then discriminate the waveform similarity of the two signals.

[0067] In this implementation, the two criteria have a progressive relationship. When the previous criterion is met, the execution subject saves the record that the previous criterion is met within a preset period. When the next criterion is also met within the preset period, it is judged that the arc grounding fault occurs.

[0068] This two-time judgment method can provide more redundancy for the execution subject to detect the arc grounding fault.

[0069] Third embodiment

[0070] As an optional embodiment, based on the first embodiment, in this embodiment, the step S30 comprises:

[0071] The step S34, simultaneously judges whether the current signal is greater than the preset current threshold, and whether the waveform similarity is greater than the preset waveform similarity threshold.

[0072] The step S35, if both are yes, it is judged that the arc ground fault occurs.

[0073] Different from the second embodiment, in this embodiment, the judgment logic of the arc ground fault is to simultaneously distinguish the current signal converted by the light signal collected by the photoelectric sensor and the waveform similarity of the circuit signal and the phase current signal.

[0074] In this embodiment, the two criteria are in parallel relationship, and the execution subject only makes one judgment, that is, in this judgment, both criteria are satisfied, and it is considered that the arc ground fault occurs.

[0075] It should be noted that in actual application process, the current signal converted by the light signal is judged to be greater than the current threshold, and the waveform similarity is judged to be greater than the waveform similarity threshold, and the two judgment processes can be performed simultaneously or not simultaneously, which is not limited in this embodiment. In other words, the execution subject is not concerned about the order of the results of the two criteria, but the execution subject needs to satisfy both criteria at the same time to consider that the arc ground fault occurs.

[0076] Unlike the judgment method in the second embodiment, this one-time judgment method can greatly improve the response instantaneity of the execution subject. For example, it is stipulated that the execution subject executes the judgment once every 0.02 seconds as a period, and as long as the above two criteria are satisfied at the same time, it is immediately judged that the arc ground fault occurs in this period.

[0077] Fourth embodiment

[0078] As an optional embodiment, based on the first embodiment, in this embodiment, the acquisition of the current signal converted by the light signal and the phase current signal in the step S10 is performed according to an interval period, and after acquiring the two signals each time, the waveform similarity calculation is performed once in this period.

[0079] In this embodiment, the waveform similarity is calculated once every preset period, so that when the current signal greater than the preset current threshold occurs inside, the waveform similarity calculated in this period can be called immediately to perform threshold discrimination, so as to improve the response instantaneity of the execution subject.

[0080] Fifth embodiment

[0081] As an optional embodiment, based on any of the preceding embodiments, the method in this embodiment can be applied in a switch cabinet, which is characterized by being closed, dark, and having almost no light signal, and the photoelectric sensor conversion current is only some dark current inside, so the dark current value is taken as the preset current threshold, and when the light intensity change in the switch cabinet causes the current signal to be greater than the dark current value, the criterion is met.

[0082] Sixth embodiment

[0083] As an optional embodiment, based on any of the preceding embodiments, in step S30, the method further comprises:

[0084] Step S36, when it is detected that the current signal is greater than the preset current threshold, triggering an alarm signal

[0085] In this implementation, if it is detected that the current signal is greater than the preset current threshold, it means that the light intensity in the environment has increased, and at this time, whether it is judged as an arc ground fault or not, an alarm signal is triggered to prompt that an abnormality has occurred in the environment.

[0086] Seventh embodiment

[0087] As an optional embodiment, based on any of the preceding embodiments, after step S30, the method further comprises:

[0088] S40, controlling the outlet of the target phase to trip.

[0089] In this implementation, if it is judged that an arc ground fault has occurred, the outlet of the target phase is controlled to trip to eliminate the arc ground.

[0090] Eighth embodiment

[0091] As a verification embodiment, based on the arc ground fault photoelectric synchronous detection method involved in any of the preceding embodiments, in this embodiment, a simulation model is provided and the effectiveness of the detection is verified.

[0092] Reference Figure 2 In this embodiment, the simulation model is set to have an arc ground fault occur in the feeder phase at 0.0822s, the arc length is 5cm, and the grounding resistance is set to 5 ohms, which is approximately a metallic ground.

[0093] Collecting light signals with a photoelectric sensor; converting the collected light signals into current signals with a photoelectric sensor designed to be sensitive to a special waveband, to obtain a simulated light signal conversion current graph as shown in Figure 3

[0094] Collecting three-phase current signals and processing them to obtain a three-phase current signal graph as shown in Figure 4 ​The processed fault phase current graph shown.

[0095] With a calculation period of 5 ms, the correlation coefficient of the data in the previous 5 ms is recalculated every 1 ms, and the real-time correlation coefficient of the converted current signal of the photoelectric sensor and the three-phase current is calculated to obtain, for example, Figures 5-8 The processed healthy phase current graph, the real-time correlation coefficient (i.e., the waveform similarity) graph between the processed fault phase current and the converted current signal of the simulated light signal, the real-time correlation coefficient graph between the processed healthy phase current and the converted current of the simulated light signal, and the converted current graph of the simulated light signal are shown respectively.

[0096] It can be seen that the arc is extinguished at 97 ms in the information, and the arc extinguishing signal appears at 107 ms in the detection device, which is consistent with the test result.

[0097] Ninth embodiment

[0098] As a verification embodiment, based on the arc ground fault photoelectric synchronous detection method involved in any of the preceding embodiments, the present embodiment provides a simulation model and verifies the effectiveness of the detection.

[0099] Also based on the simulation model in the eighth embodiment, in the PSCAD simulation model, the feeder L1, phase A, is set to have an arc ground fault at 0.0822 s, and the arc length is 5 cm. At this time, the ground resistance is set to 500 ohms, which corresponds to a large resistance grounding.

[0100] Also with a calculation period of 5 ms, the correlation coefficient of the data in the previous 5 ms is recalculated every 1 ms, and the real-time correlation coefficient of the converted current signal of the photoelectric sensor and the three-phase current is calculated to obtain, for example, Figures 9-12 The processed fault phase current graph, the processed healthy phase current graph, the real-time correlation coefficient graph between the processed fault phase current and the converted current signal of the simulated light signal, and the real-time correlation coefficient graph between the processed healthy phase current and the converted current signal of the simulated light signal are shown.

[0101] It can be seen that the arc is extinguished at 117 ms in the information, and the arc extinguishing signal appears at 127 ms in the detection device, which is consistent with the test result.

[0102] In addition, as an implementation scheme, the present embodiment also provides an arc ground fault photoelectric synchronous detection method as described in any of the preceding embodiments, for application in arc ground fault detection.

[0103] In addition, those skilled in the art can understand that all or part of the processes in the method of implementing the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program. The computer program includes program instructions, and the computer program can be stored in a storage medium, which is a computer readable storage medium. The program instructions are executed by at least one processor in the computer system, the switch cabinet or the arc ground fault detection device to realize the process steps of the above-mentioned embodiment of the method.

[0104] Therefore, the present application also provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to realize each step of the arc ground fault photoelectric synchronous detection method according to the above-mentioned embodiment.

[0105] The computer readable storage medium can be a U disk, a mobile hard disk, a read-only memory (ROM), a magnetic disk or an optical disk, and various computer readable storage media that can store program codes.

[0106] In addition, as an implementation solution, Figure 13 The hardware running environment of the computer system, the switch cabinet or the arc ground fault detection device involved in the embodiment of the present application is shown in the schematic diagram of the architecture.

[0107] As shown in the schematic diagram of the architecture, Figure 13 The computer system, the switch cabinet or the arc ground fault detection device can include a processor 1001 such as a CPU, a memory 1005, a user interface 1003, a network interface 1004 and a communication bus 1002. The communication bus 1002 is used to realize the connection and communication between the components. The user interface 1003 can include a display screen (Display) and an input unit such as a keyboard (Keyboard). The optional user interface 1003 can also include a standard wired interface and a wireless interface. The network interface 1004 can optionally include a standard wired interface and a wireless interface (such as a WI-FI interface). The memory 1005 can be a high-speed RAM memory or a stable memory (non-volatile memory) such as a magnetic disk memory. The memory 1005 can also be a storage device independent of the aforementioned processor 1001.

[0108] Those skilled in the art can understand that Figure 13 The architecture of the computer system, the switch cabinet or the arc ground fault detection device shown in the schematic diagram does not constitute a limitation on the computer system, the switch cabinet or the arc ground fault detection device, and can include more or fewer components than the diagram, or combine certain components, or different component arrangements.

[0109] As shown in the schematic diagram of the architecture, Figure 13The computer system, the switch cabinet or the arc light ground fault detection device shown can include an operating system, a network communication module, a user interface module and a computer program in the memory 1005 as a storage medium. Among them, the operating system is a program that manages and controls the hardware and software resources of the computer system, the switch cabinet or the arc light ground fault detection device, and the running of the computer program and other software or programs.

[0110] In Figure 13 In the computer system, the switch cabinet or the arc light ground fault detection device shown, the user interface 1003 is mainly used for connecting the terminal and communicating data with the terminal; the network interface 1004 is mainly used for the background server and communicating data with the background server; and the processor 1001 can be used to call the computer program stored in the memory 1005.

[0111] In this embodiment, the computer system, the switch cabinet or the arc light ground fault detection device comprises a memory 1005, a processor 1001 and a computer program stored in the memory and executable on the processor, wherein:

[0112] When the processor 1001 calls the computer program stored in the memory 1005, the following operations are performed:

[0113] S10, acquiring the current signal converted by the light signal collected by the photoelectric sensor and the phase current signal of the target phase in the circuit to be measured;

[0114] S20, calculating the waveform similarity corresponding to the current signal and the phase current signal:

[0115]

[0116] In the formula, is the waveform similarity, is the current signal, is the phase current signal of the jth phase, is and is the covariance of is is the variance of is is the variance of

[0117] S30, when it is detected that the current signal is greater than the preset current threshold and the waveform similarity is greater than the preset waveform similarity threshold, it is judged that the arc light ground fault occurs.

[0118] When the processor 1001 calls the computer program stored in the memory 1005, the following operations are performed:

[0119] First, it is judged whether the current signal is greater than the preset current threshold;

[0120] If yes, it is judged whether the waveform similarity is greater than a preset waveform similarity threshold value.

[0121] If yes, it is judged that an arc light ground fault occurs.

[0122] When the processor 1001 invokes the computer program stored in the memory 1005, the following operations are performed:

[0123] It is simultaneously judged whether the current signal is greater than a preset current threshold value and whether the waveform similarity is greater than a preset waveform similarity threshold value.

[0124] If both are yes, it is judged that an arc light ground fault occurs.

[0125] When the processor 1001 invokes the computer program stored in the memory 1005, the following operations are performed:

[0126] S10 is performed once every preset period, and S20 is performed after each execution of S10.

[0127] When the processor 1001 invokes the computer program stored in the memory 1005, the following operations are performed:

[0128] The preset current threshold value is a dark current value corresponding to the photoelectric sensor.

[0129] When the processor 1001 invokes the computer program stored in the memory 1005, the following operations are performed:

[0130] When it is detected that the current signal is greater than a preset current threshold value, an alarm signal is triggered.

[0131] When the processor 1001 invokes the computer program stored in the memory 1005, the following operations are performed:

[0132] S40, controlling the outlet of the target phase to trip.

[0133] It should be noted that the storage medium provided by the embodiments of the present application is a storage medium used to implement the method of the embodiments of the present application, and therefore based on the method introduced in the embodiments of the present application, the specific structure and modification of the storage medium can be understood by those skilled in the art, and therefore will not be described here. Any storage medium used by the method of the embodiments of the present application belongs to the scope of the present application.

[0134] Those skilled in the art will appreciate that embodiments of the application can be readily used as a method, a system or a computer program product. Accordingly, the application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the application can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer-readable program code.

[0135] The application is described in relation to flow diagrams and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It is understood that each flow and / or block in the flow diagrams and / or block diagrams, and combinations of flows and / or blocks in the flow diagrams and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processor or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flow diagrams and / or block diagrams block or blocks. Figure 1 one or more flows and / or blocks Figure 1 means for carrying out the function specified by the block or blocks in the flow diagram and / or block diagram.

[0136] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the flow diagrams and / or block diagrams block or blocks. Figure 1 one or more flows and / or blocks Figure 1 means for carrying out the function specified by the block or blocks in the flow diagram and / or block diagram.

[0137] The computer program instructions can also be loaded into a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the flow diagrams and / or block diagrams block or blocks. Figure 1 one or more flows and / or blocks Figure 1 means for carrying out the function specified by the block or blocks in the flow diagram and / or block diagram.

[0138] It should be noted that any reference signs placed between parentheses in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. This application can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0139] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0140] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. An arc ground fault photoelectric synchronous detection method, characterized in that, The method comprises the following steps: S10, acquiring a current signal converted by a light signal collected by a photoelectric sensor and a phase current signal of a target phase in a circuit to be measured; S20, calculating waveform similarity corresponding to the current signal and the phase current signal; ； In the formula, For waveform similarity, It is a current signal. Let j be the phase current signal of phase j. for and covariance, for variance for The variance; S30, judging that an arc ground fault occurs when it is detected that the current signal is greater than a preset current threshold and the waveform similarity is greater than a preset waveform similarity threshold.

2. The method of claim 1, wherein, The S30 comprises: firstly judging whether the current signal is greater than the preset current threshold; if yes, then judging whether the waveform similarity is greater than the preset waveform similarity threshold; if yes, then judging that the arc ground fault occurs.

3. The method of claim 1, wherein, The S30 comprises: simultaneously judging whether the current signal is greater than the preset current threshold and whether the waveform similarity is greater than the preset waveform similarity threshold; if both are yes, then judging that the arc ground fault occurs.

4. The method of claim 1, wherein, S10 is executed once every preset period, and S20 is executed after each execution of S10.

5. The method according to any one of claims 1 to 4, characterized in that, The preset current threshold is a dark current value corresponding to the photoelectric sensor.

6. The method of claim 5, wherein, The S30 further comprises: triggering an alarm signal when it is detected that the current signal is greater than the preset current threshold.

7. The method according to any one of claims 1 to 4, wherein After the step of judging that the arc ground fault occurs, the method further comprises: S40, controlling an outlet of the target phase to trip.

8. Application of the arc ground fault photoelectric synchronous detection method according to any one of claims 1 to 4 in arc ground fault detection.

9. A computer-readable storage medium, characterized in that, A computer program is stored on the computer readable storage medium, and the computer program is executed by a processor to realize the steps of the arc ground fault photoelectric synchronous detection method according to any one of claims 1 to 7.

10. A computer system comprising the computer readable storage medium according to claim 9.

11. A switch cabinet comprising the computer readable storage medium according to claim 9.

12. An arc ground fault detection device comprising the computer readable storage medium according to claim 9.

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