Living organism electric shock recognition method, controller and residual current protection device

Abstract

The present application relates to the field of guaranteeing personal safety and power supply stability in low-voltage distribution network, and proposes a biological body electric shock identification method, a controller and a residual current protection device. According to the fact that the current presents a unique periodic function with an increasing trend 2-3 cycles after the animal body is electrically shocked, the total residual current of 1.5 cycles is sampled through a sliding window, and the total residual current of 1.5 cycles is subtracted from the same point in the 1.5-cycle basic residual current database, so that the electric shock current waveform can be obtained. The human body electric shock protection can be performed by determining the half-wave effective value of the electric shock current waveform. The scheme has the advantages of simple implementation, small calculation amount, wide application range, fast identification rate and the like, can accurately identify human body electric shock and prevent misoperation, and has important significance for ensuring the safety of power utilization and the reliability of power supply.

Description

Technical Field

[0001] This invention relates to the field of ensuring personal safety and power supply stability in low-voltage distribution networks, and particularly to a bioelectric shock identification method, controller, and residual current protection device based on the effective value of the sliding half-wave. Background Technology

[0002] Low-voltage power grids primarily employ residual current protection devices (RCDs) for personal electric shock protection. Currently used RCDs use the fundamental amplitude of the residual current as the tripping criterion. If the residual current reference value is set too low (e.g., 30mA), in humid weather conditions, the insulation level of the electrical circuit decreases significantly, leading to an increase in the residual current to ground. This causes the RCD to reach its protection threshold, resulting in frequent false trips. To ensure reliable power supply, some users increase the residual current protection reference value to several hundred mA, or even manually disable the RCD to protect power supply reliability. When a personal electric shock occurs, the RCD may fail to trip correctly, leading to an electric shock accident and seriously threatening the user's safety.

[0003] To address the problem of difficulty in determining the protection threshold of existing residual current protection devices, leading to their failure to operate or malfunction, numerous methods for identifying electric shock characteristics have been proposed. These mainly include incremental detection, impedance method, BP neural network detection, least squares support vector machine detection, adaptive algorithm residual current detection, and Hilbert-Huang transform for electric shock current detection. Among these, BP neural networks and support vector machines (SVM) improve upon empirical methods by using the electric shock current amplitude as a basis. However, due to sample dependence, they struggle to accurately determine electric shock accidents when the type of electric shock or line parameters change. Adaptive algorithm residual current detection and Hilbert-Huang transform separate noise and natural residual current from the detection signal to extract the electric shock accident current, but their implementation is complex and their engineering application is challenging. Summary of the Invention

[0004] The purpose of this invention is to provide a method for identifying electric shock to a living organism, a controller, and a residual current protection device.

[0005] To achieve the above objectives, a first aspect of the present invention provides a method for identifying electric shock in a biological body, comprising:

[0006] Obtain the total residual current and fundamental current;

[0007] Obtain the current amplitude of the fundamental current of the total residual current;

[0008] The current amplitude is compared with the operating current threshold.

[0009] If the current amplitude is less than the operating current threshold, then a sliding time window is used to sample the first waveform of the total residual current fundamental current for a preset number of periods.

[0010] Subtract the preset waveform at the same location from the first waveform to obtain the electric shock current;

[0011] The effective value of the electric shock current is calculated by half-wave to obtain a first ratio of the effective value of the second half-wave current to the effective value of the first half-wave current and a second ratio of the effective value of the third half-wave current to the effective value of the second half-wave current.

[0012] The type of electric shock is determined based on the first ratio and the second ratio, and electric shock protection measures are implemented according to the type of electric shock.

[0013] The basic residual current database is a collection of waveforms obtained by sampling at a preset time window when the fundamental current of the total residual current is positive.

[0014] In this embodiment of the invention, the preset time window has the same time length as the preset quantity period.

[0015] In this embodiment of the invention, the time length is 1.5 current cycles.

[0016] In this embodiment of the invention, obtaining the total residual fundamental current includes:

[0017] The total residual current fundamental current is filtered using a fast Fourier filter algorithm to remove integer harmonic currents from the total residual current fundamental current.

[0018] In this embodiment of the invention, the method further includes:

[0019] Before calculating the half-wave RMS value of the electric shock current, the half-wave RMS value of the electric shock current is determined:

[0020] After acquiring new sample points of the electric shock current, the value of the first sample point in the sampling sequence is removed sequentially.

[0021] The corresponding new valid value is obtained by calculating based on the sampled value.

[0022] In this embodiment of the invention, the effective values ​​of the first three half-waves of the electric shock current are expressed as follows:

[0023]

[0024] The first ratio is:

[0025] The second ratio is:

[0026] Among them, I h1 I h2 I h3 These are the effective current values ​​of the first half-wave, the second half-wave, and the third half-wave, respectively. N is the number of sampling points for the half-wave current, and sqr represents calculating the arithmetic square root.

[0027] In this embodiment of the invention, determining the type of electric shock based on the first ratio and the second ratio, and then implementing electric shock protection measures according to the type of electric shock, includes:

[0028] If the first ratio is greater than or equal to the first preset value, and the second ratio is greater than or equal to the second preset value, then the electric shock type is determined to be animal body electric shock.

[0029] Control the residual current protection device to perform electric shock protection actions.

[0030] In this embodiment of the invention, the method further includes:

[0031] If the current amplitude is greater than or equal to the operating current threshold, the residual current protection device is controlled to perform an electric shock protection action.

[0032] A second aspect of the present invention provides a controller configured to perform the above-described bioelectric shock recognition method.

[0033] A third aspect of the present invention provides a residual current protection device, comprising:

[0034] Circuit breakers; and

[0035] The aforementioned controller.

[0036] The above technical solution is applicable to the protection of biological bodies from electric shock under various electric shock methods, electric shock paths and environmental factors. It can accurately and quickly identify electric shock to animal bodies and non-animal bodies, realize electric shock protection, and ensure the safety of electricity use and the reliability of power supply.

[0037] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0038] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0039] Figure 1 An example flowchart of a bio-electric shock identification method according to an embodiment of the present invention is illustrated;

[0040] Figure 2 The schematic diagram illustrates a typical electric shock current waveform in an animal body; and

[0041] Figure 3 The diagram illustrates a typical electrical current waveform in a plant. Detailed Implementation

[0042] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0043] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0044] If the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0045] Figure 1 An example flowchart of a biological electric shock identification method according to an embodiment of the present invention is shown. Figure 2 The schematic diagram illustrates a typical electric shock current waveform in an animal body; and Figure 3 The diagram illustrates a typical electrical current waveform in a plant.

[0046] The overall inventive concept of this invention proposes a method for identifying electric shock based on the effective value of a sliding half-wave. First, using zero-crossing as a criterion, a preset number (e.g., 1.5) of residual current cycles are sampled as the base residual current. Then, the total residual current for a preset number (e.g., 1.5) of cycles is sampled through a sliding time window. Finally, the total residual current sampled over 1.5 cycles is subtracted from the base residual current sampled over 1.5 cycles at the same potential, thus canceling out the base residual current waveform. This yields a discrete waveform constituting the electric shock current in a biological body. The effective value of the half-wave of this discrete waveform is then calculated. Based on the changing pattern of the ratio of the effective half-wave values, the type of electric shock can be accurately determined. Figure 2 The typical electric shock current waveforms of animals shown indicate that the current exhibits a unique increasing trend over 2-3 cycles after an electric shock; according to Figure 3 The typical electric shock current waveform of a plant shown indicates that the electric shock current of a plant is a stable sine wave; therefore, the change pattern of the effective value of the half-wave can be used to quickly identify electric shock.

[0047] like Figure 1 As shown, in this embodiment of the invention, the bio-electrocution identification method may include:

[0048] In step S101, the fundamental current of the total residual current is obtained. Specifically, as shown below... Figure 2 As shown, the total residual current X(t) contains the fundamental current and integer harmonic currents (mainly odd harmonics such as 3rd, 5th, and 7th). These harmonics affect the identification of electric shock characteristics in the human body. Therefore, a Fast Fourier Transform (DFT) filtering algorithm can be used to filter out the integer harmonic currents from the total residual current obtained from the residual current protection device, yielding the fundamental current h(t) of the total residual current.

[0049] For example, suppose the DFT of an N-point finite-length sequence x(n) is:

[0050] in

[0051] First, divide the sequence x(n) into two groups based on the parity of n: odd-numbered terms x(2r+1) and even-numbered terms x(2r). The number of points in each group is N / 2-1, i.e.:

[0052]

[0053] This process is repeated to continuously decompose long-sequence DFTs into short-sequence DFTs.

[0054] In step S102, the current amplitude of the fundamental current of the total residual current is obtained.

[0055] In step S103, the current amplitude is compared with the operating current threshold.

[0056] In step S104, if the current amplitude is less than the operating current threshold, the first waveform of the total residual current fundamental current for a preset number of periods is sampled using a sliding time window.

[0057] In step S105, the preset waveforms at the same points in the basic residual current database are subtracted from the first waveform to obtain the electric shock current;

[0058] Specifically, the total residual current waveform for 1.5 complete cycles can be sampled using a sliding time window. The electric shock current s(t) can be obtained by subtracting the residual current baseline database c(t) from the two cycles at the same location, i.e.:

[0059] s(t) = h(t) - c(t)

[0060] The basic residual current database is a collection of waveforms sampled within a preset time window, using the moments when the fundamental current of the total residual current is positive as sampling points. Specifically, if the amplitude I... S <I ref Therefore, the sampling start point can be set when h(i)*h(i+1)≥0 (i.e., during the positive half-cycle of the current), and 1.5 cycles of waveform can be selected as the basic residual current database c(t). The preset time window and the preset number of cycles can have the same length, for example, both being 1.5 current cycles. Of course, the preset number of cycles can also be greater than 1.5 current cycles.

[0061] In this embodiment of the invention, the amplitude I of the total residual current fundamental current h(t) can be further adjusted. S Make a judgment if I S ≥I ref Then the residual current protection device operates (e.g., power is cut off) (step S109), wherein I ref The operating current threshold I is set based on the residual current. S To sample the total residual current amplitude in real time. To ensure power supply reliability, and considering the actual operating conditions on site, I ref A value of 150mA is recommended.

[0062] In step S106, the half-wave RMS value of the electric shock current is determined. Specifically, the half-wave RMS value of the electric shock current s(t) can be determined. The moving average method can be used to calculate the RMS value, that is, after a new sample point is collected, the first sample point value in the sampling sequence is removed sequentially, and then the corresponding new RMS value is obtained based on the sampled value. Personal electric shock protection needs to be fast. Based on the above principle and with improvements, using the change of the half-wave RMS value over half a cycle as the judgment basis can improve the operating speed of the residual current protection device and better protect personal safety.

[0063] For example, half-cycle electric shock current signals s(1), s(2)...s(T / 2) can be sampled, where T is the sampling period. Therefore, the effective value of the half-wave can be expressed by the following formula:

[0064]

[0065] Here, sqr(·) represents finding the arithmetic square root of the term in parentheses.

[0066] In step S107, the effective value of half-wave current is calculated to obtain a first ratio of the effective value of the second half-wave current to the effective value of the first half-wave current and a second ratio of the effective value of the third half-wave current to the effective value of the second half-wave current.

[0067] Specifically, the effective value of the electric shock current s(t) is calculated using half-wave methods. The effective values ​​of the first three half-waves of the electric shock current can be expressed as:

[0068]

[0069] The ratio of the second half-wave to the first half-wave is:

[0070]

[0071] The ratio of the third half-wave to the second half-wave is:

[0072]

[0073] Among them, I h1 I h2 I h3 These are the effective current values ​​of the first half-wave, the second half-wave, and the third half-wave, respectively. N is the number of sampling points for the half-wave current, and sqr represents calculating the arithmetic square root.

[0074] In step S108, the type of electric shock is determined based on the first ratio and the second ratio, so as to perform electric shock protection measures according to the type of electric shock.

[0075] Specifically, if the first ratio is greater than or equal to the first preset value, and the second ratio is greater than or equal to the second preset value, then the electric shock type is determined to be animal body electric shock;

[0076] Control the residual current protection device to perform electric shock protection actions.

[0077] For example, statistical analysis can be performed based on experimental data. If it is necessary to identify electric shock to animals and non-animals and achieve precise protection against electric shock to animals, the following conditions must be met: α≥0.35, β≥0.2. At this time, the residual current protection device will operate (e.g., power off). In other cases, the residual current protection device will not operate.

[0078] Therefore, in this embodiment of the invention, a human body protection model that also takes into account the protection of residual current is proposed:

[0079]

[0080] Among them, I ref The operating current threshold set for the residual current of the foundation is 150mA, and to ensure power supply reliability, a value of 150mA is recommended based on the actual operating conditions on site. S The function is used to sample the total residual current amplitude in real time. A function value of 1 indicates a fault has occurred and the residual current protection device will activate. A function value of 0 indicates no fault has occurred and the residual current protection device will not activate.

[0081] In this embodiment of the invention, a controller is provided, which can be configured to execute the bio-electric shock recognition method of any of the above embodiments, or to run the above-described human body protection model.

[0082] In this embodiment of the invention, a residual current protection device is provided, which may include:

[0083] Circuit breakers; and

[0084] The controller described in the above embodiments.

[0085] Those skilled in the art will understand that, in order to highlight the main points of the embodiments of the present invention, other common accessories in the residual current protection device are not described in detail.

[0086] In an embodiment of the present invention, a machine-readable storage medium is provided, on which instructions are stored, which, when executed by a processor, cause the processor to implement the bio-electrocution recognition method of any of the above embodiments.

[0087] The beneficial effects of the embodiments of the present invention may include:

[0088] (1) It can accurately identify electric shock to animals and non-animals, improving the safety and reliability of electricity supply and avoiding false alarms and refusal to operate.

[0089] (2) It has a wide range of applications and is suitable for the protection of animals from electric shock under various electric shock methods, electric shock paths and environmental factors.

[0090] (3) The implementation method is simple, the amount of calculation is small, and it is easy to implement in engineering applications;

[0091] (4) Fast recognition speed, only 3 half-wave cycles (0.03s) are needed to identify animal body electric shock.

[0092] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0093] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations 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, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0094] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0095] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0096] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0097] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0098] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0099] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0100] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for identifying electric shock in biological organisms, characterized in that, Comprising: filtering the total residual current fundamental current using a fast Fourier filtering algorithm to filter out each integer harmonic current in the total residual current fundamental current; obtaining a current amplitude of the total residual current fundamental current; comparing the current amplitude with an action current threshold value; if the current amplitude is less than the action current threshold value, using a sliding time window to sample a first waveform of a preset number of periods of the total residual current fundamental current; subtracting a preset waveform of an equipotential point in a basic residual current database from the first waveform to obtain a touch current; performing half-wave effective value calculation on the touch current to obtain a first ratio of a current effective value of a second half-wave to a current effective value of a first half-wave and a second ratio of a current effective value of a third half-wave to the current effective value of the second half-wave in the first three half-waves of the touch current; determining a touch type according to the first ratio and the second ratio to perform a touch protection measure according to the touch type; wherein the basic residual current database is a set of waveforms sampled at preset time windows with the time of the total residual current fundamental current being positive as a sampling point; The living body touch identification method further comprises: Before performing half-wave effective value calculation on the touch current, performing half-wave effective value judgment on the touch current: After collecting a new sample point of the touch current, sequentially remove the first sample point value in the sampling sequence; According to the sampling value, calculate the corresponding new effective value; wherein the effective value of the current of the first three half-waves of the touch current is expressed as: The first ratio is: The second ratio is: wherein I h1 , I h2 , I h3 are the current effective values of the first, second and third half wave, respectively, N is the number of half wave current sampling points, sqr denotes the calculation of the arithmetic square root; wherein the determining a touch type according to the first ratio and the second ratio to perform a touch protection measure according to the touch type comprises: if the first ratio is greater than or equal to a first preset value and the second ratio is greater than or equal to a second preset value, determining that the touch type is animal body touch; controlling the residual current protection device to perform a touch protection action.

2. The bioelectric shock recognition method according to claim 1, characterized by, The preset time window has the same time length as the preset number of periods.

3. The bioelectric identification method according to claim 2, wherein The time length is 1.5 current periods.

4. The bioelectric shock recognition method according to claim 1, characterized by, Further comprising: if the current amplitude is greater than or equal to the action current threshold value, controlling the residual current protection device to perform a touch protection action.

5. A controller characterized by comprising: configured to perform the living body touch identification method according to any one of claims 1 to 4.

6. A residual current protective device, characterized in that Comprising: a circuit breaker; and the controller according to claim 5.

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