A low power consumption leakage protection detection device and method

Abstract

The present application belongs to the technical field of leakage protection, and discloses a low-power leakage protection detection device and method, the device comprises a first current transformer, a second current transformer, a simulated leakage module, a leakage detection module and a tripping module; the live wire and the neutral wire pass through the first current transformer; the live wire passes through the second current transformer; the first current transformer, the leakage detection module and the tripping module are connected in sequence; the simulated leakage module is respectively connected to the neutral wire, the second current transformer, the leakage detection module and the tripping module; the present application can reduce the power consumption consumed by the leakage self-detection under the premise of ensuring the power supply safety, that is, the self-detection reliability.

Description

Technical Field

[0001] The present application relates to the technical field of leakage protection, and in particular to a low-power leakage protection detection device and method. Background Art

[0002] A leakage protection device, also known as a leakage circuit breaker or leakage protection switch, is a safety device used to detect leakage in electrical circuits and quickly cut off power to prevent electrical accidents. Its main function is to protect personal safety and equipment safety, and prevent electric shock accidents or fires caused by leakage.

[0003] In order to verify the working status of the leakage protector, the prior art usually installs a self-test module on the leakage protector, and controls the self-test module to determine whether the leakage protector can work normally at regular intervals. However, in the periodic self-test, if the detection cycle interval is long, there may be missed detection, that is, failure between two detections. At this time, using it will cause electric shock, and the reliability of the detection is poor; if the detection interval is short, it will lead to high power consumption. Summary of the invention

[0004] The present application provides a low-power leakage protection detection device and method, which can reduce the power consumption consumed by leakage self-detection while ensuring power supply safety, that is, self-detection reliability.

[0005] In a first aspect, an embodiment of the present application provides a low-power leakage protection detection device, including a first current transformer, a second current transformer, a simulation leakage module, a leakage detection module and a trip module;

[0006] The live wire and the neutral wire run through the first current transformer; the live wire runs through the second current transformer;

[0007] The first current transformer, the leakage detection module and the tripping module are connected in sequence; the simulation leakage module is connected to the neutral line, the second current transformer, the leakage detection module and the tripping module respectively;

[0008] The simulated leakage module is used to send a simulated leakage signal to the neutral line when receiving the live line current of the second current transformer; within a first preset time after sending the simulated leakage signal, if it is detected that the live line current of the second current transformer becomes 0, a closing signal is sent to the tripping module to enable the tripping module to perform a power supply operation;

[0009] Within a first preset time after the closing signal is sent, if the live current of the second current transformer is received, a simulated leakage signal is sent to the neutral line at a first frequency; within a first preset time after the simulated leakage signal is sent, if it is detected that the live current of the second current transformer has not become 0, a leakage detection fault alarm is performed;

[0010] The leakage detection module is used to send a trip signal to the trip module when receiving the leakage current of the first current transformer, so that the trip module performs a trip operation.

[0011] Furthermore, the simulation leakage module is also used to perform a leakage detection fault alarm if the live wire current of the second current transformer is not received within a first preset time period after the closing signal is sent.

[0012] Furthermore, the simulated leakage module is also used to send a self-test signal to the trip module at a second frequency if the live wire current of the second current transformer is received within a first preset time after the closing signal is sent; the first frequency is a multiple of the second frequency;

[0013] The tripping module is also used for: within a second preset time period after receiving the self-test signal, if a tripping signal is received, not performing a tripping operation, and feeding back tripping record information to the simulation leakage module.

[0014] Furthermore, the simulation leakage module is also used to perform a leakage detection fault alarm if no tripping record information of the tripping module is received within a second preset time period after the self-test signal is sent.

[0015] Further, the analog leakage module includes a digital signal processing unit, a digital-to-analog conversion unit and a current source unit;

[0016] The digital signal processing unit is used to generate a leakage digital signal according to a preset leakage current parameter;

[0017] The digital-to-analog conversion unit is used to convert the leakage digital signal into a leakage analog signal as a leakage analog waveform;

[0018] The current source unit is used to adjust the current source according to the leakage simulation waveform so as to generate a simulation leakage signal.

[0019] Furthermore, the simulation leakage module also includes a current sampling unit and a signal analysis unit;

[0020] The current sampling unit is used to sample the analog leakage signal generated by the current source unit to obtain a sampled analog signal, and convert the sampled analog signal into a sampled digital signal;

[0021] The signal analysis unit is used to perform spectrum analysis on the sampled digital signal using a fast Fourier transform algorithm to obtain an effective leakage current characteristic; determine whether the effective leakage current characteristic conforms to a preset leakage current characteristic; if not, adjust the preset leakage current parameter according to the distance between the effective leakage current characteristic and the preset leakage current characteristic.

[0022] Furthermore, the signal analysis unit is also used to filter the sampled digital signal based on a digital filtering algorithm before performing spectrum analysis on the sampled digital signal, so as to eliminate noise and interference in the sampled digital signal.

[0023] Furthermore, the device also includes a host computer;

[0024] The simulation leakage module is also used to send the cumulative use time and working environment information of the leakage detection module and the tripping module to the host computer according to the preset time interval;

[0025] The host computer is used to input the accumulated usage time and working environment information into the trained response time prediction model, obtain the predicted response time and send it to the simulation leakage module;

[0026] The leakage simulation module is also used to add the predicted response time and the preset error time to obtain a target preset time length; and update the first preset time length according to the target preset time length.

[0027] Furthermore, the simulated leakage module is also used to calculate the trip response time according to the moment when the live wire current of the second current transformer becomes 0 after sending the simulated leakage signal, and obtain multiple trip response times; and send each trip response time and the historical accumulated usage time and historical working environment information of the corresponding moment to the host computer;

[0028] The host computer is also used to train the machine learning model according to each tripping response time and the corresponding historical cumulative usage time and historical working environment information to obtain a trained response time prediction model.

[0029] Furthermore, the leakage detection module is also used to send the received leakage current of the first current transformer to the leakage simulation module; the signal analysis unit is also used to extract the current leakage current characteristics of the leakage current based on the wavelet transform algorithm or the fast Fourier transform algorithm, and update the preset leakage current characteristics according to the current leakage current characteristics.

[0030] In a second aspect, an embodiment of the present application provides a low-power leakage protection detection method, including:

[0031] When receiving the live wire current of the second current transformer, sending a simulated leakage signal to the neutral wire;

[0032] Within a first preset time after sending the simulated leakage signal, if it is detected that the live wire current of the second current transformer becomes 0, a closing signal is sent to the trip module to enable the trip module to perform a power supply operation;

[0033] Within a first preset time period after the closing signal is sent, if the live wire current of the second current transformer is received, a simulated leakage signal is sent to the neutral wire at a first frequency;

[0034] Within a first preset time period after the simulated leakage signal is sent, if it is detected that the live wire current of the second current transformer has not become 0, a leakage detection fault alarm is performed.

[0035] Furthermore, the method further comprises: if the live wire current of the second current transformer is not received within a first preset time period after the closing signal is sent, performing a leakage detection fault alarm.

[0036] Further, the method further comprises: within a first preset time length after the closing signal is sent, if the live wire current of the second current transformer is received, sending a self-test signal to the trip module at a second frequency, so that the trip module feeds back the trip record information when receiving the trip signal within a second preset time length after receiving the self-test signal;

[0037] The first frequency is a multiple of the second frequency.

[0038] Furthermore, the method further comprises: if the tripping record information of the tripping module is not received within a second preset time period after the self-test signal is sent, a leakage detection fault alarm is performed.

[0039] Furthermore, the steps of generating the simulated leakage signal specifically include:

[0040] Generate a leakage digital signal according to preset leakage current parameters;

[0041] Convert the leakage digital signal into a leakage analog signal and use it as a leakage analog waveform;

[0042] The current source is adjusted according to the leakage simulation waveform to generate a simulation leakage signal.

[0043] Furthermore, the method also includes:

[0044] Sampling the analog leakage signal to obtain a sampled analog signal, and converting the sampled analog signal into a sampled digital signal;

[0045] The fast Fourier transform algorithm is used to perform spectrum analysis on the sampled digital signal to obtain the effective leakage current characteristics;

[0046] It is determined whether the effective leakage current characteristic meets the preset leakage current characteristic; if not, the preset leakage current parameter is adjusted according to the distance between the effective leakage current characteristic and the preset leakage current characteristic.

[0047] Furthermore, the method also includes: before performing spectrum analysis on the sampled digital signal, filtering the sampled digital signal based on a digital filtering algorithm to eliminate noise and interference in the sampled digital signal.

[0048] Furthermore, the method also includes:

[0049] Input the accumulated usage time and working environment information of the leakage detection module and the tripping module into the trained response time prediction model according to the preset time interval to obtain the predicted response time;

[0050] The predicted response time and the preset error time are added to obtain the target preset duration and update the first preset duration.

[0051] Furthermore, the method also includes: after sending the simulated leakage signal, calculating the tripping response time according to the moment when the live wire current of the second current transformer becomes 0; training a machine learning model according to each tripping response time and the corresponding historical accumulated usage time and historical working environment information to obtain a trained response time prediction model.

[0052] Furthermore, the method also includes: acquiring the leakage current of the first current transformer; extracting the current leakage current characteristics of the leakage current based on the wavelet transform or fast Fourier transform algorithm, and updating the preset leakage current characteristics according to the current leakage current characteristics.

[0053] In summary, compared with the prior art, the technical solution provided in the embodiment of the present application has at least the following beneficial effects:

[0054] A low-power leakage protection detection device provided in an embodiment of the present application can determine whether the power supply circuit is working by setting a second current transformer penetrated by the live wire; the present application regards the moment when the live wire current of the second current transformer is received as the power supply start-up moment, and sends an analog leakage signal to force detection once at this time. If the leakage detection module and the tripping module work normally, they can trip normally to make the live wire current become 0, and then close the tripping and start self-checking at the first frequency; the present application performs a forced self-check once at the start of power supply and then performs a periodic self-check, so that the power supply circuit does not perform self-checking when it is not working. On the premise of ensuring power supply safety, that is, the reliability of self-checking, the power consumption consumed by leakage self-checking is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A structural diagram of a low-power leakage protection detection device provided for an exemplary embodiment of the present application.

[0056] Figure 2 An internal structure diagram of a leakage simulation module provided for an exemplary embodiment of the present application.

[0057] Figure 3 An internal structure diagram of a simulation leakage module provided for yet another exemplary embodiment of the present application.

[0058] Figure 4 A structural diagram of a low-power leakage protection detection device provided as another exemplary embodiment of the present application.

[0059] Figure 5 A flowchart of a low-power leakage protection detection method provided for an exemplary embodiment of the present application.

[0060] Figure 6 A flowchart of the preset leakage current parameter adjustment steps provided for an exemplary embodiment of the present application.

[0061] Figure 7 A flowchart of a first preset duration update step provided for an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0062] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0063] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of this application.

[0064] See also Figure 1 The embodiment of the present application provides a low-power leakage protection detection device, including a first current transformer, a second current transformer, a simulated leakage module, a leakage detection module and a tripping module; the live wire and the neutral wire pass through the first current transformer; the live wire passes through the second current transformer; the first current transformer, the leakage detection module and the tripping module are connected in sequence; the simulated leakage module is respectively connected to the neutral wire, the second current transformer, the leakage detection module and the tripping module.

[0065] Specifically, the live wire runs through the second current transformer, which means that as long as there is current passing through the live wire, a corresponding live wire current will be generated on the second current transformer, and the first current transformer surrounds the neutral wire and the live wire, and the currents of the neutral wire and the live wire cancel each other out. Therefore, leakage current is only generated when the currents of the neutral wire and the live wire are not equal.

[0066] The analog leakage module is used to send an analog leakage signal to the neutral line when receiving the live current of the second current transformer; within the first preset time after sending the analog leakage signal, if it is detected that the live current of the second current transformer becomes 0, a closing signal is sent to the tripping module to enable the tripping module to perform a power supply operation; within the first preset time after sending the closing signal, if the live current of the second current transformer is received, a analog leakage signal is sent to the neutral line at a first frequency; within the first preset time after sending the analog leakage signal, if it is detected that the live current of the second current transformer does not become 0, a leakage detection fault alarm is performed. It is worth noting that the analog leakage signal is not sent all the time, but is a signal with a certain duration / length. The specific signal duration or length can be preset or adaptively adjusted.

[0067] The leakage detection module is used to send a trip signal to the trip module when receiving the leakage current of the first current transformer, so that the trip module performs a trip operation.

[0068] The trip module includes a control unit and a switch unit. The control unit is used to receive the signal of the simulation leakage module and the signal of the leakage detection module, and control the on and off of the switch unit according to the received signal.

[0069] There are two main types of switch units: electromagnetic and electronic. Electromagnetic switch mechanisms use electromagnets to attract or release to turn the power on and off; electronic switch mechanisms use semiconductor switch devices (such as thyristors, triodes, etc.) as switch elements.

[0070] Specifically, for the simulated leakage module, because the second current transformer only surrounds the live wire, when the live wire current is received, it is considered that there is current transmission on the live wire, that is, the power supply circuit is considered to have entered the working state. At this time, a simulated leakage signal is sent to the neutral wire to make the currents of the neutral and live wires unequal, so that the first current transformer generates a leakage current and transmits it to the leakage detection module. After receiving the leakage current, the leakage detection module controls the tripping module to trip, that is, to cut off the connection between the power supply circuit and the load.

[0071] Since it takes a certain amount of time for the leakage current to be generated and for the leakage detection module to react and perform the tripping operation, the present application requires the simulated leakage module to monitor whether the live wire current becomes 0 within the first preset time period after sending the simulated leakage signal; if the tripping module successfully performs the tripping operation, the neutral wire and the live wire will be disconnected, and the second current transformer will no longer sense the live wire current. At this time, the simulated leakage module will believe that the leakage detection module and the tripping module can work normally, and will control the tripping module to release the tripping state and perform the power supply operation. If the tripping module can perform the power supply operation normally, it is believed that the switching between the two working states of the tripping module is normal, and the power can be officially supplied and the simulated leakage signal can be sent at the first frequency for leakage self-detection.

[0072] That is to say, the trigger condition for sending the simulated leakage signal for the first time is the "live wire current", and the trigger condition for sending the simulated leakage signal subsequently is the "first frequency", that is, when the fixed cycle moment arrives.

[0073] However, no matter how many times the simulated leakage signal is sent, once the live wire current is not detected to be 0, that is, the simulated leakage signal does not normally trigger the tripping operation of the tripping module, it is considered that at least one of the leakage detection module or the tripping module has failed; however, since it is a leakage detection fault discovered during the self-test stage, the power supply circuit does not actually leak electricity. At this time, only a leakage detection fault alarm can be performed, and whether to perform additional power-off operations on the power supply circuit can be decided by the user who receives the alarm.

[0074] The above-mentioned embodiment provides a low-power leakage protection detection device, which can determine whether the power supply circuit is working by setting a second current transformer penetrated by the live wire; the application regards the moment when the live wire current of the second current transformer is received as the power supply start-up moment, and sends an analog leakage signal to force detection once. If the leakage detection module and the tripping module work normally, they can trip normally to make the live wire current become 0, and then close the tripping and start self-test at the first frequency; the application performs a forced self-test once at the start of power supply and then performs a periodic self-test, so that the power supply circuit does not perform self-test when it is not working. On the premise of ensuring power supply safety, that is, the reliability of self-test, the power consumption consumed by leakage self-test is reduced.

[0075] In some embodiments, the leakage simulation module is further configured to perform a leakage detection fault alarm if the live wire current of the second current transformer is not received within a first preset time period after the closing signal is sent.

[0076] During the leakage self-test process, in addition to the situation where the trip module fails to trip normally, there may also be a fault situation that cannot be restored after tripping. Therefore, this application makes the simulation leakage module perform a leakage detection fault alarm if it detects that the closure fails to successfully restore the current transmission on the live wire after controlling the trip module to close.

[0077] It is worth noting that the operation of sending a closing signal is performed during the operation of the power supply circuit. The analog leakage module sends a simulated leakage signal and detects that the live wire current has dropped to 0. If no simulated leakage signal is sent but the live wire current becomes 0, it is considered that the power supply circuit has ended its operation, and the entire leakage protection detection device will also stop working and self-checking.

[0078] In one embodiment, the simulated leakage module is further used to send a self-test signal to the trip module at a second frequency if the live wire current of the second current transformer is received within a first preset time after the closing signal is sent; the first frequency is a multiple of the second frequency.

[0079] The tripping module is also used for not performing a tripping operation and feeding back tripping record information to the simulation leakage module if a tripping signal is received within a second preset time length after the self-test signal is received.

[0080] Specifically, in order to ensure the reliability of leakage self-test, the first frequency of leakage self-test during the operation of the power supply line is usually set to a relatively large value. Since leakage self-test directly leads to tripping, setting the first frequency too high may increase the degree of wear and tear on the trip switch, that is, increase the probability of leakage detection fault alarm; therefore, the present application sends a self-test signal to the trip module at a second frequency during the leakage simulation process of the first frequency, and the sending time of the self-test signal is consistent with the sending time of the simulated leakage signal, but since the first frequency is a multiple of the second frequency, the self-test signal is not sent every time the simulated leakage signal is sent.

[0081] For example, the first cycle corresponding to the first frequency is to send a simulated leakage signal once every 10 minutes, and the first frequency is 3 times the second frequency. The second cycle corresponding to the second frequency is to send a self-test signal once every 30 minutes, that is, after every two simulated leakage signals, when the simulated leakage signal is sent for the third time, a self-test signal will also be sent to the trip module synchronously; so that the trip module only performs tripping for the first two times within each 30 minutes, and the tripping record is fed back for the third time; thereby, while realizing leakage self-test, the number of tripping is appropriately reduced, and the loss of the trip switch is alleviated.

[0082] It is worth noting that since the analog leakage signal is sent to the neutral line, it needs to pass through the first current transformer and the leakage detection module to affect the tripping module, and the self-test signal is sent directly to the tripping module. Therefore, the time when the tripping module receives the tripping signal must be after the time when the self-test signal is received. Therefore, the tripping module sets a second preset time length. The tripping signals received within the second preset time length after receiving the self-test signal are all considered to be triggered by the analog leakage signal.

[0083] In practical applications, the second preset time length is much shorter than the first preset time length, and the specific value can be determined through simulation.

[0084] Furthermore, the simulation leakage module is also used to perform a leakage detection fault alarm if no tripping record information of the tripping module is received within a second preset time period after the self-test signal is sent.

[0085] Specifically, the tripping record information is also the content that the tripping module needs to feedback normally. If the tripping record information after sending the self-test signal is not fed back in time, the simulated leakage module also believes that there is a problem with the operation of the tripping module and an alarm is required.

[0086] See also Figure 2In some embodiments, the leakage simulation module includes a digital signal processing unit, a digital-to-analog conversion unit, and a current source unit. The digital signal processing unit is used to generate a leakage digital signal according to a preset leakage current parameter.

[0087] Among them, the preset leakage current parameters include characteristic representations of the signal, including signal amplitude, signal waveform (such as rectangular wave, triangle wave, sawtooth wave, etc.), signal rate, signal-to-noise ratio, etc.

[0088] The digital-to-analog conversion unit is used to convert the leakage digital signal into a leakage analog signal as a leakage analog waveform.

[0089] The current source unit is used to adjust the current source according to the leakage simulation waveform so as to generate a simulation leakage signal.

[0090] Specifically, it was found during the actual generation that the simulated leakage signal generated by the simulated leakage module during the power-on detection was inconsistent with the actual leakage signal, resulting in the leakage detection module being unable to identify the leakage current and thus missing the detection, that is, because the simulated waveform signal was too perfect, the actual leakage current may not be a standard signal waveform. Therefore, this application generates a simulated leakage signal by presetting the leakage current parameters, through digital signal processing, digital-to-analog conversion, and current source adjustment, to simulate the real leakage current as much as possible.

[0091] For further information, see Figure 3 ,The simulation leakage module also includes a current sampling unit and a signal analysis unit.

[0092] The current sampling unit is used to sample the analog leakage signal generated by the current source unit to obtain a sampled analog signal, and convert the sampled analog signal into a sampled digital signal.

[0093] The signal analysis unit is used to perform spectrum analysis on the sampled digital signal using a fast Fourier transform algorithm to obtain an effective leakage current characteristic; determine whether the effective leakage current characteristic conforms to a preset leakage current characteristic; if not, adjust the preset leakage current parameter according to the distance between the effective leakage current characteristic and the preset leakage current characteristic.

[0094] The effective leakage current characteristics or the preset leakage current characteristics include: each frequency component and characteristic parameters such as the amplitude, phase, center frequency and cutoff frequency of each frequency component.

[0095] The simplest way to calculate the distance between the effective leakage current feature and the preset leakage current feature is to calculate the absolute difference between the two values, that is, |x1-x2|, but this is only applicable when there is only one characteristic parameter. In multidimensional space, you can use: 1. Euclidean distance to measure the straight-line distance between two points. The formula is ; 2. Manhattan distance, also known as city block distance, is the sum of the absolute wheelbases of two points in the standard coordinate system. The formula is |x1-x2|+|y1-y2|+...; where x1 and y1 are preset leakage current characteristics, and x2 and y2 are effective leakage current characteristics.

[0096] In addition to the distance calculation formula mentioned above, the correlation coefficient can also be used to measure the linear correlation between two variables. Commonly used ones are the Pearson correlation coefficient, the Jaccard similarity coefficient, and the Mahalanobis distance.

[0097] Among them, the Pearson correlation coefficient is between -1 (complete negative correlation) and 1 (complete positive correlation). The Jaccard similarity coefficient is used to measure the similarity of two sets and calculate the ratio of the intersection size to the union size of the two sets. The Mahalanobis distance takes into account the correlation between data features and is applicable to situations where there is correlation between features.

[0098] Specifically, after obtaining the distance between the two characteristics, the value in the preset leakage current parameter is adjusted according to the distance between the different characteristics; for example, if the amplitude in the effective leakage current characteristic is smaller than the amplitude of the preset leakage current characteristic, the amplitude in the preset leakage current parameter is appropriately increased, and the specific degree of increase can be determined by setting gears for different distances; since the preset leakage current parameter is used to represent the characteristic parameter of the digital signal, and here both the effective leakage current characteristic, the preset leakage current characteristic and the distance between the two characteristics are obtained based on the analog signal analysis, therefore, when adjusting the preset leakage current parameter, it is necessary to additionally consider the relationship between the conversion of digital signals and analog signals.

[0099] For example, during sampling, the characteristic parameters of an analog signal, such as frequency and amplitude, are converted into a sequence of discrete time points and quantization levels. During quantization, the continuous amplitude values ​​of an analog signal are converted into a finite number of amplitude levels of a digital signal. During digital-to-analog conversion, the characteristic parameters of a digital signal are mapped back to the continuous amplitude and time variations of an analog signal.

[0100] After obtaining the distance between the two characteristics, it is possible to infer the direction (increase or decrease) in which a certain parameter in the corresponding preset leakage current parameter needs to be adjusted. The degree of adjustment can be achieved by setting a gear range for the distance. The adjustment step can also be fixed, that is, only increasing and decreasing a fixed value each time, and then performing signal generation and sampling analysis again, and repeating the iteration until the distance between the effective leakage current characteristic and the preset leakage current characteristic is less than a threshold or the two characteristics are equal.

[0101] The above-mentioned embodiment, based on the control of the generation of the simulated leakage signal based on the preset leakage current parameters, adds a feedback mechanism to determine whether the generated simulated leakage signal meets expectations. If not, the preset leakage current parameters are adjusted, thereby further improving the similarity between the simulated leakage signal and the real leakage signal during power supply and reducing the leakage probability of self-detection.

[0102] Furthermore, the signal analysis unit is also used to filter the sampled digital signal based on a digital filtering algorithm before performing spectrum analysis on the sampled digital signal, so as to eliminate noise and interference in the sampled digital signal.

[0103] Specifically, since the generation process of the analog leakage signal is easily affected by noise, the signal-to-noise ratio of the analog leakage signal is reduced, and Fourier transform is a mathematical method for converting time domain signals into frequency domain signals. If the sampled digital signal obtained from the analog leakage signal contains noise, these noises will produce additional frequency components in the frequency domain results after Fourier operation, thereby masking the characteristics of the signal itself. By filtering and denoising in advance, the impact of noise on spectrum analysis can be reduced, making the spectrum clearer and facilitating the analysis and identification of the main components of the signal.

[0104] Moreover, noise may produce misleading peaks after Fourier transform, which do not represent the true frequency components of the signal but are interference from noise. Filtering can reduce this distortion and make the Fourier transform result more reliable.

[0105] Secondly, in digital signal processing, if the frequency component of the signal exceeds the Nyquist frequency (half the sampling frequency), frequency aliasing will occur. Filtering can remove the frequency components above the Nyquist frequency to prevent aliasing and ensure that the spectrum after Fourier transformation is a true reflection of the original signal.

[0106] Furthermore, in the process of analog-to-digital conversion, due to the limitation of the number of quantization bits, quantization noise may be introduced into the converted sampled digital signal. Filtering can remove noise and reduce the impact of quantization error on the signal spectrum. Digital filtering algorithms can effectively remove or weaken the noise in the sampled digital signal and improve the signal-to-noise ratio (SNR). It helps to observe the frequency domain characteristics of the signal more clearly, especially when the signal amplitude is small and the noise level is high.

[0107] Therefore, the above embodiment performs denoising filtering on the sampled digital signal before performing spectrum analysis on the sampled digital signal, which can improve the quality of signal processing and ensure the accuracy and reliability of effective leakage current feature calculation.

[0108] In some embodiments, see Figure 4 , the leakage protection detection device also includes a host computer.

[0109] The simulated leakage module is also used to send the accumulated usage time and working environment information of the leakage detection module and the tripping module to the host computer according to a preset time interval.

[0110] Among them, the accumulated usage time includes the usage time of the leakage detection module and the usage time of the trip module. After replacing any one of the modules due to a leakage detection fault alarm, additional operation is required to simulate the leakage module to clear the usage time of the corresponding module recorded therein and re-accumulate it to ensure the authenticity of the accumulated usage time.

[0111] The working environment information includes the temperature and humidity of the environment in which the leakage protection detection equipment is located.

[0112] The host computer is used to input the accumulated usage time and working environment information into the trained response time prediction model, obtain the predicted response time and send it to the leakage simulation module.

[0113] The leakage simulation module is also used to add the predicted response time and the preset error time to obtain a target preset time length; and update the first preset time length according to the target preset time length.

[0114] Specifically, the first preset duration is related to the accuracy of the leakage self-test. If it is set too long, it means that the tripping reaction time of the leakage protection can be longer, and it is difficult to achieve a good protection effect when leakage actually occurs. If it is set too short, as the use time of the leakage detection module and the tripping module increases and the working environment is affected, the reaction speed becomes slower and slower, which will inevitably lead to an increase in the probability of leakage detection fault alarm. Therefore, this application uses the response time prediction model trained in the upper computer to predict the reasonable response time of the leakage self-test based on the cumulative use time of the leakage detection module and the tripping module and the working environment information, and then adds it to the allowed error time as the first preset duration of the leakage detection fault alarm.

[0115] The above embodiment sets the first preset duration of the leakage detection fault alarm based on the accumulated usage time of the leakage detection module and the trip module and the working environment information, which can reduce the false alarm probability of the leakage self-detection and improve the accuracy of the leakage self-detection.

[0116] In some embodiments, the simulated leakage module is also used to calculate the tripping response time according to the moment when the live wire current of the second current transformer becomes 0 after sending the simulated leakage signal, and obtain multiple tripping response times; and send each tripping response time and the historical accumulated usage time and historical working environment information of the corresponding moment to the host computer.

[0117] The host computer is also used to train the machine learning model according to each tripping response time and the corresponding historical cumulative usage time and historical working environment information to obtain a trained response time prediction model.

[0118] Among them, the machine learning model can adopt supervised learning models such as linear regression model, logistic regression model, decision tree model, random forest model, support vector machine (SVM) model, naive Bayes, K-Nearest Neighbors (KNN) model, etc.

[0119] Specifically, the response time prediction model of the present application can be trained according to the actual response time recorded by the simulated leakage module. The simulated leakage module starts timing when the simulated leakage signal is sent, and ends timing when the live wire current is detected to become 0, and the recorded duration is used as the tripping response time; at the same time, the (historical) accumulated usage time and (historical) working environment information of the leakage detection module and the tripping module when the simulated leakage signal is sent are sent to the host computer for training the machine learning model, so that the model can learn the changing relationship between the response time and the influence of usage time and environmental information.

[0120] In some embodiments, the leakage detection module is further used to send the received leakage current of the first current transformer to the leakage simulation module. The signal analysis unit is further used to extract the current leakage current characteristics of the leakage current based on the wavelet transform algorithm or the fast Fourier transform algorithm, and update the preset leakage current characteristics according to the current leakage current characteristics.

[0121] Specifically, the simulated leakage module will analyze the leakage current and update the preset leakage current characteristics only when it does not send a simulated leakage signal but still receives the leakage current; therefore, the leakage current received by the leakage detection module at this time is the leakage current generated when the power supply circuit actually leaks, and is worth analyzing and updating.

[0122] During the specific implementation process, in addition to the leakage protection detection equipment being affected by the usage time and working environment, the power supply circuit itself will also age with the increase in usage time, resulting in changes in the leakage current. Therefore, if the preset leakage current characteristics remain unchanged, it will affect the adjustment accuracy of the preset leakage current parameters and the effectiveness of the leakage self-detection.

[0123] Therefore, the present application analyzes the actual leakage current received to achieve dynamic update of the preset leakage current characteristics, thereby ensuring the adjustment accuracy of the preset leakage current parameters and the authenticity of the simulated leakage signal.

[0124] See also Figure 5Another embodiment of the present application provides a low-power leakage protection detection method, including:

[0125] Step S11, when receiving the live line current of the second current transformer, sending a simulated leakage signal to the neutral line.

[0126] Step S12: within a first preset time after sending the simulated leakage signal, if it is detected that the live wire current of the second current transformer becomes 0, a closing signal is sent to the trip module to enable the trip module to perform a power supply operation.

[0127] Step S13: within the first preset time period after the closing signal is sent, if the live line current of the second current transformer is received, a simulated leakage signal is sent to the neutral line at a first frequency.

[0128] Step S14: within a first preset time period after sending the simulated leakage signal, if it is detected that the live wire current of the second current transformer has not become 0, a leakage detection fault alarm is performed.

[0129] Specifically, when the live wire current is received, it is considered that there is current transmission on the live wire, that is, it is considered that the power supply circuit starts to enter the working state. At this time, an analog leakage signal is sent to the neutral wire to make the currents of the neutral wire and the live wire unequal, thereby causing the first current transformer to generate a leakage current, and the tripping module is controlled to trip based on the leakage current, that is, to cut off the connection between the power supply circuit and the load.

[0130] Since it takes a certain amount of time to generate leakage current, react to leakage current and perform tripping operation, the present application monitors whether the live wire current becomes 0 within the first preset time period after sending the analog leakage signal; if the tripping operation is successfully performed, the neutral wire and the live wire will be disconnected, and the live wire current will no longer be sensed. At this time, it is considered that the leakage protection detection device is working normally, the tripping state is released, and the power supply operation is performed. If the power supply operation can be performed normally, it is considered that the tripping module can realize the switching between the two working states of tripping and power supply normally, and the power can be officially supplied and the analog leakage signal can be sent at the first frequency for leakage self-test.

[0131] That is to say, the trigger condition for sending the simulated leakage signal for the first time is the "live wire current", and the trigger condition for sending the simulated leakage signal subsequently is the "first frequency", that is, when the fixed cycle moment arrives.

[0132] However, no matter how many times the simulated leakage signal is sent, if the live wire current is not detected to be 0, that is, the simulated leakage signal does not trigger the tripping operation normally, it is considered that the leakage protection detection device has a fault; however, since the leakage detection fault is discovered during the self-test stage, the power supply circuit does not actually leak electricity. At this time, only a leakage detection fault alarm can be performed, and whether to perform additional power-off operations on the power supply circuit can be decided by the user who receives the alarm.

[0133] The above embodiment provides a low-power leakage protection detection method, which regards the moment when the live wire current of the second current transformer is received as the power supply start-up moment, and sends an analog leakage signal for forced detection once. If the live wire current can be normally tripped to become 0, the trip is closed again and self-check is started at the first frequency. The present application performs a forced self-check once at the time of power supply startup and then performs a periodic self-check, so that the power supply circuit does not perform self-check when it is not working. On the premise of ensuring power supply safety, that is, the reliability of self-check, the power consumption consumed by leakage self-check is reduced.

[0134] In some embodiments, the method further includes: if the live wire current of the second current transformer is not received within a first preset time period after the closing signal is sent, performing a leakage detection fault alarm.

[0135] In some embodiments, the method further includes: within a first preset time after sending the closing signal, if the live wire current of the second current transformer is received, a self-test signal is sent to the trip module at a second frequency, so that when the trip module receives the trip signal within a second preset time after receiving the self-test signal, the trip module feeds back the trip record information.

[0136] The first frequency is a multiple of the second frequency.

[0137] Specifically, in order to ensure the reliability of leakage self-test, the first frequency of leakage self-test during the operation of the power supply line is usually set to a relatively large value. Since leakage self-test directly leads to tripping, setting the first frequency too high may increase the degree of wear and tear on the trip switch, that is, increase the probability of leakage detection fault alarm; therefore, the present application sends a self-test signal to the trip module at a second frequency during the leakage simulation process of the first frequency, and the sending time of the self-test signal is consistent with the sending time of the simulated leakage signal, but since the first frequency is a multiple of the second frequency, the self-test signal is not sent every time the simulated leakage signal is sent.

[0138] For example, the first cycle corresponding to the first frequency is to send a simulated leakage signal once every 10 minutes, and the first frequency is 3 times the second frequency. The second cycle corresponding to the second frequency is to send a self-test signal once every 30 minutes, that is, after every two simulated leakage signals, when the simulated leakage signal is sent for the third time, a self-test signal will also be sent to the trip module synchronously; so that the trip module only performs tripping for the first two times within each 30 minutes, and the tripping record is fed back for the third time; thereby, while realizing leakage self-test, the number of tripping is appropriately reduced, and the loss of the trip switch is alleviated.

[0139] In some embodiments, the method further includes: if no tripping record information of the tripping module is received within a second preset time period after the self-test signal is sent, performing a leakage detection fault alarm.

[0140] Specifically, the tripping record information is also the content that the tripping module needs to feedback normally. If the tripping record information after sending the self-test signal is not fed back in time, it is also considered that there is a problem with the operation of the tripping module and an alarm needs to be issued.

[0141] In some embodiments, the steps of generating the simulated leakage signal specifically include:

[0142] Step S112, generating a leakage digital signal according to a preset leakage current parameter.

[0143] Among them, the preset leakage current parameters include characteristic representations of the signal, including signal amplitude, signal waveform (such as rectangular wave, triangle wave, sawtooth wave, etc.), signal rate, signal-to-noise ratio, etc.

[0144] Step S113, converting the leakage digital signal into a leakage analog signal as a leakage analog waveform.

[0145] Step S114, adjusting the current source according to the leakage simulation waveform to generate a simulated leakage signal.

[0146] Specifically, it was found during the actual generation that the simulated leakage signal generated during the power-on detection was inconsistent with the actual leakage signal, resulting in the leakage detection module being unable to identify the leakage current and thus missing the detection, that is, because the simulated waveform signal was too perfect, the actual leakage current may not be a standard signal waveform. Therefore, this application generates a simulated leakage signal by presetting the leakage current parameters, through digital signal processing, digital-to-analog conversion, and current source adjustment, to simulate the real leakage current as much as possible.

[0147] In some embodiments, see Figure 6 , the method further comprises:

[0148] Step S21, sampling the analog leakage signal to obtain a sampled analog signal, and converting the sampled analog signal into a sampled digital signal.

[0149] Step S22, using a fast Fourier transform algorithm to perform spectrum analysis on the sampled digital signal to obtain effective leakage current characteristics; wherein the effective leakage current characteristics or preset leakage current characteristics include: each frequency component and its amplitude, phase, center frequency and cutoff frequency and other characteristic parameters.

[0150] Step S23, determining whether the effective leakage current characteristic meets the preset leakage current characteristic; if not, adjusting the preset leakage current parameter according to the distance between the effective leakage current characteristic and the preset leakage current characteristic.

[0151] The simplest way to calculate the distance between the effective leakage current feature and the preset leakage current feature is to calculate the absolute difference between the two values, that is, |x1-x2|, but this is only applicable when there is only one characteristic parameter. In multidimensional space, you can use: 1. Euclidean distance to measure the straight-line distance between two points. The formula is ; 2. Manhattan distance, also known as city block distance, is the sum of the absolute wheelbases of two points in the standard coordinate system. The formula is |x1-x2|+|y1-y2|+...; where x1 and y1 are preset leakage current characteristics, and x2 and y2 are effective leakage current characteristics.

[0152] In addition to the distance calculation formula mentioned above, the correlation coefficient can also be used to measure the linear correlation between two variables. Commonly used ones are the Pearson correlation coefficient, the Jaccard similarity coefficient, and the Mahalanobis distance.

[0153] Among them, the Pearson correlation coefficient is between -1 (complete negative correlation) and 1 (complete positive correlation). The Jaccard similarity coefficient is used to measure the similarity of two sets and calculate the ratio of the intersection size to the union size of the two sets. The Mahalanobis distance takes into account the correlation between data features and is applicable to situations where there is correlation between features.

[0154] Specifically, after obtaining the distance between the two characteristics, the value in the preset leakage current parameter is adjusted according to the distance between the different characteristics; for example, if the amplitude in the effective leakage current characteristic is smaller than the amplitude of the preset leakage current characteristic, the amplitude in the preset leakage current parameter is appropriately increased, and the specific degree of increase can be determined by setting gears for different distances; since the preset leakage current parameter is used to represent the characteristic parameter of the digital signal, and here both the effective leakage current characteristic, the preset leakage current characteristic and the distance between the two characteristics are obtained based on the analog signal analysis, therefore, when adjusting the preset leakage current parameter, it is necessary to additionally consider the relationship between the conversion of digital signals and analog signals.

[0155] In some embodiments, the method further includes: before performing spectrum analysis on the sampled digital signal, filtering the sampled digital signal based on a digital filtering algorithm to eliminate noise and interference in the sampled digital signal.

[0156] Specifically, since the generation process of the analog leakage signal is easily affected by noise, the signal-to-noise ratio of the analog leakage signal is reduced, and Fourier transform is a mathematical method for converting time domain signals into frequency domain signals. If the sampled digital signal obtained from the analog leakage signal contains noise, these noises will produce additional frequency components in the frequency domain results after Fourier operation, thereby masking the characteristics of the signal itself. By filtering and denoising in advance, the impact of noise on spectrum analysis can be reduced, making the spectrum clearer and facilitating the analysis and identification of the main components of the signal.

[0157] In some embodiments, see Figure 7 , the method further comprises:

[0158] Step S31, inputting the accumulated usage time and working environment information of the leakage detection module and the tripping module into the trained response time prediction model according to the preset time interval to obtain the predicted response time.

[0159] Step S32, adding the predicted response time and the preset error time to obtain the target preset time length and updating the first preset time length.

[0160] Specifically, the first preset duration is related to the accuracy of the leakage self-test. If it is set too long, it means that the tripping reaction time of the leakage protection can be longer, and it is difficult to achieve a good protection effect when leakage actually occurs. If it is set too short, as the use time of the leakage detection module and the tripping module increases and the working environment is affected, the reaction speed becomes slower and slower, which will inevitably lead to an increase in the probability of leakage detection fault alarm. Therefore, this application uses a trained response time prediction model to predict the reasonable response time of the leakage self-test based on the cumulative use time of the leakage detection module and the tripping module and the working environment information, and then adds it to the allowed error time as the first preset duration of the leakage detection fault alarm.

[0161] In some embodiments, the method also includes: after sending the simulated leakage signal, calculating the tripping response time according to the moment when the live wire current of the second current transformer becomes 0; training a machine learning model according to each tripping response time and the corresponding historical accumulated usage time and historical working environment information to obtain a trained response time prediction model.

[0162] In some embodiments, the method further comprises:

[0163] Acquire the leakage current of the first current transformer; extract the current leakage current characteristics of the leakage current based on wavelet transform or fast Fourier transform algorithm, and update the preset leakage current characteristics according to the current leakage current characteristics.

[0164] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0165] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A low-power leakage protection detection device, characterized in that: It includes a first current transformer, a second current transformer, a simulation leakage module, a leakage detection module and a tripping module; The live wire and the neutral wire pass through the first current transformer; the live wire passes through the second current transformer; The first current transformer, the leakage detection module and the tripping module are connected in sequence; the simulated leakage module is connected to the neutral line, the second current transformer, the leakage detection module and the tripping module respectively; The simulated leakage module is used to send a simulated leakage signal to the neutral line when receiving the live line current of the second current transformer; within a first preset time after sending the simulated leakage signal, if it is detected that the live line current of the second current transformer becomes 0, send a closing signal to the tripping module to enable the tripping module to perform a power supply operation; Within the first preset time after the closing signal is sent, if the live current of the second current transformer is received, the simulated leakage signal is sent to the neutral line at a first frequency; within the first preset time after the simulated leakage signal is sent, if it is detected that the live current of the second current transformer has not become 0, a leakage detection fault alarm is performed; The leakage detection module is used to send a trip signal to the trip module when receiving the leakage current of the first current transformer, so that the trip module performs a trip operation.

2. The low-power leakage protection detection device according to claim 1 is characterized in that: The simulated leakage module is further configured to perform a leakage detection fault alarm if the live wire current of the second current transformer is not received within the first preset time period after the closing signal is sent.

3. The low-power leakage protection detection device according to claim 2 is characterized in that: The simulated leakage module is further used to send a self-test signal to the trip module at a second frequency if the live wire current of the second current transformer is received within the first preset time after the closing signal is sent; the first frequency is a multiple of the second frequency; The trip module is further configured to: within a second preset time period after receiving the self-test signal, if the trip signal is received, not perform the trip operation, and feed back the trip record information to the simulated leakage module.

4. The low-power leakage protection detection device according to claim 3 is characterized in that: The simulated leakage module is further configured to generate a leakage detection fault alarm if the tripping record information of the tripping module is not received within the second preset time period after the self-test signal is sent.

5. The low-power leakage protection detection device according to claim 1, characterized in that: The analog leakage module includes a digital signal processing unit, a digital-to-analog conversion unit and a current source unit; The digital signal processing unit is used to generate a leakage digital signal according to a preset leakage current parameter; The digital-to-analog conversion unit is used to convert the leakage digital signal into a leakage analog signal as a leakage analog waveform; The current source unit is used to adjust the current source according to the leakage simulation waveform so as to generate the simulated leakage signal.

6. The low-power leakage protection detection device according to claim 5, characterized in that: The simulated leakage module also includes a current sampling unit and a signal analysis unit; The current sampling unit is used to sample the analog leakage signal generated by the current source unit to obtain a sampled analog signal, and convert the sampled analog signal into a sampled digital signal; The signal analysis unit is used to perform spectrum analysis on the sampled digital signal using a fast Fourier transform algorithm to obtain effective leakage current characteristics; Determining whether the effective leakage current characteristic meets the preset leakage current characteristic; If not, adjusting the preset leakage current parameter according to the distance between the effective leakage current characteristic and the preset leakage current characteristic.

7. The low-power leakage protection detection device according to claim 6, characterized in that: The signal analysis unit is also used to filter the sampled digital signal based on a digital filtering algorithm before performing spectrum analysis on the sampled digital signal to eliminate noise and interference in the sampled digital signal.

8. The low-power leakage protection detection device according to claim 6, characterized in that: It also includes the host computer; The simulated leakage module is also used to send the accumulated usage time and working environment information of the leakage detection module and the tripping module to the host computer according to a preset time interval; The host computer is used to input the accumulated usage time and the working environment information into a trained response time prediction model, obtain a predicted response time and send it to the simulation leakage module; The leakage simulation module is further used to add the predicted response time and the preset error time to obtain a target preset time length; and to update the first preset time length according to the target preset time length.

9. The low-power leakage protection detection device according to claim 8, characterized in that: The simulated leakage module is also used to calculate the trip response time according to the moment when the live wire current of the second current transformer becomes 0 after sending the simulated leakage signal, and obtain multiple trip response times; and send each of the trip response times and the historical accumulated usage time and historical working environment information at the corresponding moment to the host computer; The host computer is also used to train a machine learning model according to each of the tripping response times and the corresponding historical accumulated usage time and the historical working environment information to obtain the trained response time prediction model.

10. The low-power leakage protection detection device according to claim 6, characterized in that: The leakage detection module is further used to send the received leakage current of the first current transformer to the leakage simulation module; The signal analysis unit is further used to extract the current leakage current characteristics of the leakage current based on a wavelet transform algorithm or a fast Fourier transform algorithm, and update the preset leakage current characteristics according to the current leakage current characteristics.

11. A low-power leakage protection detection method, characterized in that: include: When receiving the live line current of the second current transformer, sending a simulated leakage signal to the neutral line; Within a first preset time after sending the simulated leakage signal, if it is detected that the live wire current of the second current transformer becomes 0, a closing signal is sent to the trip module so that the trip module performs a power supply operation; Within the first preset time after sending the closing signal, if the live line current of the second current transformer is received, sending the simulated leakage signal to the neutral line at a first frequency; Within the first preset time period after sending the simulated leakage signal, if it is detected that the live wire current of the second current transformer has not become 0, a leakage detection fault alarm is performed.

12. The low power consumption leakage protection detection method according to claim 11, characterized in that: Also includes: If the live wire current of the second current transformer is not received within the first preset time period after the closing signal is sent, a leakage detection fault alarm is performed.

13. The low power consumption leakage protection detection method according to claim 12, characterized in that: Also includes: If the live wire current of the second current transformer is received within the first preset time after the closing signal is sent, a self-test signal is sent to the tripping module at a second frequency, so that the tripping module feeds back tripping record information when receiving a tripping signal within the second preset time after receiving the self-test signal; The first frequency is a multiple of the second frequency.

14. The low power consumption leakage protection detection method according to claim 13, characterized in that: Also includes: If the tripping record information of the tripping module is not received within the second preset time period after the self-test signal is sent, a leakage detection fault alarm is performed.

15. The low power consumption leakage protection detection method according to claim 11, characterized in that: The steps of generating the simulated leakage signal specifically include: Generate a leakage digital signal according to preset leakage current parameters; Converting the leakage digital signal into a leakage analog signal as a leakage analog waveform; The current source is adjusted according to the leakage simulation waveform to generate the simulated leakage signal.

16. The low power consumption leakage protection detection method according to claim 15, characterized in that: Also includes: Sampling the analog leakage signal to obtain a sampled analog signal, and converting the sampled analog signal into a sampled digital signal; Performing spectrum analysis on the sampled digital signal using a fast Fourier transform algorithm to obtain effective leakage current characteristics; Determining whether the effective leakage current characteristic meets the preset leakage current characteristic; If not, adjusting the preset leakage current parameter according to the distance between the effective leakage current characteristic and the preset leakage current characteristic.

17. The low power consumption leakage protection detection method according to claim 16, characterized in that: Also includes: Before performing spectrum analysis on the sampled digital signal, the sampled digital signal is filtered based on a digital filtering algorithm to eliminate noise and interference in the sampled digital signal.

18. The low power consumption leakage protection detection method according to claim 11, characterized in that: Also includes: Inputting the accumulated usage time and working environment information of the leakage detection module and the tripping module into the trained response time prediction model according to the preset time interval to obtain the predicted response time; The predicted response time and the preset error time are added to obtain a target preset duration and update the first preset duration.

19. The low power consumption leakage protection detection method according to claim 18, characterized in that: Also includes: After sending the simulated leakage signal, calculating the trip response time according to the moment when the live wire current of the second current transformer becomes 0; A machine learning model is trained according to each of the tripping response times and the corresponding historical accumulated usage time and historical working environment information to obtain the trained response time prediction model.

20. The low power consumption leakage protection detection method according to claim 16, characterized in that: Also includes: Obtaining a leakage current of a first current transformer; A current leakage current feature of the leakage current is extracted based on a wavelet transform or a fast Fourier transform algorithm, and the preset leakage current feature is updated according to the current leakage current feature.

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