Portable clamp meter with metering wiring analysis function

Abstract

The invention discloses a portable clamp meter with a metering wiring analysis function, which relates to the technical field of electric power detection and measurement instruments, comprises a clamp meter shell, an MCU (Microprogrammed Control Unit) and a power supply, and is internally provided with a voltage detection circuit and a current detection circuit. The first interface and the second interface of the current clamp are connected with the voltage detection circuit, and the MCU is connected with the 485 communication module, the SD card and the external screen so as to realize data acquisition and display. The clamp meter is further provided with a current acquisition circuit, an electric energy metering circuit and an electric energy meter data reading circuit, so that accurate measurement of current and voltage is ensured. Through the interface of the current clamp, the equipment can carry out current loop transformation ratio and polarity test, and the MCU can calculate multiple indexes such as electric energy and power. Meanwhile, the 485 communication module is used for reading data of the electric energy meter and comparing the data so as to verify the normal working state of the electric energy meter. The clamp meter is suitable for monitoring and maintenance of an electric power system and equipment, and promotes the development of a portable electric power metering technology.

Description

Technical Field

[0001] The invention relates to the technical field of electric power detection and measuring instruments, and in particular to a portable clamp meter with a metering wiring analysis function. Background Art

[0002] In modern power systems, the accuracy and reliability of electric energy metering are crucial. With the development of the power market and the advancement of electric energy metering technology, the standardization and normalization of electric energy metering wiring management are becoming increasingly demanding. However, in actual operation, there are still a series of technical problems such as voltage loss, current interruption, and unconventional wiring. These problems not only affect the reliable collection of information from the electric energy meter, but may also lead to inaccurate electricity bill measurement, thus having a negative impact on fair transactions between the power supplier and the user.

[0003] Voltage loss (e.g., voltage loss due to loose wiring or faults) will directly cause the energy meter to not work properly, resulting in loss of power usage information or miscalculation. Current interruption (including current sensor failure or line disconnection) will also affect the collection of real-time data, causing inaccurate metering and having a significant impact on the final electricity bill. In addition, common unconventional wiring (such as temporary wiring, improper wiring, etc.) will also make energy metering complicated and difficult to accurately evaluate and monitor.

[0004] Currently, most clamp ammeters on the market can only measure basic power parameters at fixed current and voltage acquisition ports, which limits their application in more complex and variable field conditions. Although some metering wiring analyzers can provide multifunctional metering analysis, they are often bulky or complex in function and poor in portability. In actual work, the field use of such equipment is limited, which is not conducive to rapid response and decision-making.

[0005] In addition, many devices rely on remote data analysis, which, although capable of processing large amounts of data, cannot meet the needs of on-site staff to obtain and evaluate metering wiring information in a timely manner. This delay not only affects the real-time and effectiveness of energy metering, but also reduces the efficiency of metering wiring analysis.

[0006] In order to adapt to the needs of various environments and places, it is urgent to develop a clamp meter that is convenient and fast on-site and has measurement and wiring analysis functions. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a portable clamp meter with a measurement wiring analysis function.

[0008] The technical solution adopted by the present invention is:

[0009] A portable clamp meter with a metering wiring analysis function comprises a clamp meter housing, an MCU and a power supply are installed in the clamp meter housing; the MCU is connected to a voltage detection circuit and a current detection circuit, the voltage detection circuit is connected to a first current clamp interface and a second current clamp interface outside the clamp meter housing, and the current detection circuit is connected to a voltage detection interface outside the clamp meter housing;

[0010] The MCU is also connected to a 485 communication module, an SD card, and a screen that is exposed outside the clamp meter housing; the power supply is connected to the MCU, a voltage detection circuit, a current detection circuit, a 485 communication module, an SD card, and a screen.

[0011] Further, the power supply includes a battery, a power interface circuit connected to the battery, a 12V to 5V step-down circuit connected to the power interface circuit, and a 5V to 3.3V step-down circuit connected to the 12V to 5V step-down circuit;

[0012] The battery is connected to the MCU, 485 communication module, SD card, and screen power supply through the power interface circuit, 12V to 5V step-down circuit, and 5V to 3.3V step-down circuit in sequence; the battery is connected to the voltage detection circuit and current detection circuit in sequence through the power interface circuit and 12V to 5V step-down circuit.

[0013] Furthermore, the portable clamp meter with measurement wiring analysis function also includes a current acquisition circuit, which is connected to the MCU and the 5V to 3.3V step-down circuit of the power supply respectively.

[0014] Furthermore, the portable clamp meter with metering wiring analysis function also includes an electric energy metering circuit, which is respectively connected to the MCU, the voltage detection circuit, the current acquisition circuit, and the 12V to 5V step-down circuit of the power supply.

[0015] Furthermore, the portable clamp meter with metering wiring analysis function also includes an electric energy meter data reading circuit, and the electric energy meter data reading is respectively connected to the MCU, the 485 communication module, and the 12V to 5V step-down circuit of the power supply.

[0016] Furthermore, the portable clamp meter with metering wiring analysis function also includes a screen interface circuit, which is respectively connected to the MCU, the screen, and the 12V to 5V step-down circuit of the power supply.

[0017] Furthermore, the portable clamp meter with metering wiring analysis function performs current loop ratio and polarity tests through the first current clamp interface and the second current clamp interface, and the MCU is connected to the primary current and the secondary current through the first current clamp interface and the second current clamp interface respectively to obtain the results of the current loop ratio and polarity tests.

[0018] Furthermore, the portable clamp meter with metering wiring analysis function uses machine learning algorithms to perform pattern recognition and anomaly detection on data to achieve fault warning; fault warnings include: polarity error, abnormal circuit ratio;

[0019] The current signal I(t) and the voltage signal V(t) are sampled by ADC and discretized into digital signals I[n] and V[n]. The sampled I[n] and V[n] data are standardized to facilitate processing by the machine learning model:

[0020]

[0021] In the formula, x represents the original data point, that is, the sampled current data I[n] or voltage data V[n]; x norm represents the data value obtained after standardization; μ is the mean of the data; σ is the standard deviation of the data;

[0022] Model training includes the following processes:

[0023] Use classification algorithms to train common fault modes, including polarity errors, abnormal circuit ratios, and short or open circuits;

[0024] Select time domain and frequency domain features. Time domain features include: mean, variance, and peak value of the signal. Frequency domain features include: harmonic amplitude and frequency offset.

[0025] Using the eigenvector F:

[0026] F=[P,Q,THD,f fundamental ,...]

[0027] Among them, P represents the mean of the signal; Q represents the variance of the signal; f fundamental Indicates the fundamental frequency;

[0028] THD is the total harmonic distortion, and the calculation formula is:

[0029]

[0030] Where, |X(1)| is the fundamental amplitude; |X(k)| is the kth harmonic amplitude;

[0031] Use tools in the Python environment to train the model, quantize the trained model, and embed it into the MCU;

[0032] The MCU runs the trained model in real time and outputs classification results based on the input feature vector F. The classification results include: normal operation, polarity error, and abnormal loop ratio.

[0033] Furthermore, the portable clamp meter with metering wiring analysis function performs metering by using the first interface of the current clamp and the voltage detection interface together. The MCU forms metering data by calculating electric energy metering, current, voltage, active power, and reactive power. At the same time, the MCU reads the metering data of the electric energy meter through the 485 communication module, and tests whether the electric energy meter is working normally by comparing the metering data with the metering data of the electric energy meter.

[0034] Furthermore, the MCU is replaced with an ARM or embedded DSP with floating-point computing capability and equipped with a high-speed analog-to-digital converter ADC, and the data processing process includes the following steps:

[0035] Step 1, data sampling: the current signal I(t) and the voltage signal V(t) are sampled by ADC and discretized into digital signals I[n] and V[n];

[0036] The formula used is as follows:

[0037] I[n]=I(t)|t=n·T s , V[n]=V(t)|t=n·T s ;

[0038] Where, T s is the adoption period, T s =1 / f s , f s is the sampling frequency; t is the sampling time; n is the current sampling point index;

[0039] Step 2: Calculate active power P and reactive power Q in real time. The calculation formula is as follows:

[0040]

[0041] Where N is the number of sampling points; I'[n] is the 90° phase shift of the current signal, which is achieved using Fast Fourier Transform FFT;

[0042] Step 3: Use FFT to perform spectrum analysis on the signal. The calculation formula is as follows:

[0043]

[0044] Where X(k) is the kth harmonic component in the frequency domain; N is the number of sampling points; x[n] is the sampling value of the signal; e -j2πkn / N is a complex exponential function, j is an imaginary unit, 2πkn / N represents the phase at frequency k, and creates a rotation factor with frequency k.

[0045] The portable clamp meter with measurement wiring analysis function has the following beneficial effects:

[0046] Versatility: The clamp meter integrates multiple functions such as current detection, voltage detection, energy metering and data analysis. Users only need one device to complete multiple tests, reducing the burden of carrying equipment.

[0047] Portability: The portable design allows the clamp meter to be tested in different places and environments, making it convenient for on-site use, especially suitable for electrical maintenance and on-site testing work.

[0048] Accurate data collection and analysis: Through the processing power of the MCU, it can collect current and voltage data in real time and perform intelligent analysis to provide accurate energy metering, power calculation and current loop ratio test results.

[0049] Communication capability: The integrated 485 communication module enables the clamp meter to exchange data with external devices (such as computers or other monitoring systems), facilitating data recording and remote monitoring, and improving the flexibility and convenience of use.

[0050] Data storage and playback: The built-in SD card can store test data. Users can play back and analyze data at any time, making it convenient to record the historical operating data of electrical equipment.

[0051] User-friendly interface: Equipped with an external screen for real-time data monitoring and decision making, improving the convenience of operation.

[0052] Electricity meter verification: By comparing with the electricity meter data, the working status of the electricity meter can be effectively checked, the accuracy of power measurement is ensured, and the reliability of the electricity meter is improved.

[0053] Safety: The equipment is designed with electrical safety in mind, reducing risks during use and providing a safe and reliable electrical measurement solution.

[0054] This portable clamp meter with measurement wiring analysis function can greatly improve work efficiency and accuracy in the fields of electrical engineering, equipment maintenance and power monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0056] Figure 1 This is a schematic diagram of the overall structure of the portable clamp meter with measurement wiring analysis function;

[0057] Figure 2 is a circuit diagram of a power interface circuit of the present invention;

[0058] Figure 3 The circuit diagram of the 12V to 5V step-down circuit of the present invention;

[0059] Figure 4 The circuit diagram of the 5V to 3.3V step-down circuit of the present invention;

[0060] Figure 5 is a circuit diagram of a current detection circuit of the present invention;

[0061] Figure 6 is a circuit diagram of a voltage detection circuit of the present invention;

[0062] Figure 7 1 is a circuit diagram of the current collection circuit of the present invention;

[0063] Figure 8 The circuit diagram of the power generation energy metering circuit;

[0064] Fig. 9 This is the circuit diagram of the MCU;

[0065] Fig.10 A circuit diagram for reading data from an electric energy meter according to the present invention;

[0066] Fig.11 It is a circuit diagram of the SD card of the present invention;

[0067] Fig.12 is a circuit diagram of the screen interface circuit of the present invention;

[0068] Fig.13 This is a schematic diagram of the usage status of the portable clamp meter with measurement wiring analysis function. DETAILED DESCRIPTION

[0069] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0070] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents some embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features and technical solutions in the embodiments can be combined with each other without conflict. It should be noted that similar numbers and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0071] Example 1

[0072] This embodiment provides a portable clamp meter with a metering wiring analysis function. The portable clamp meter with a metering wiring analysis function includes a clamp meter housing, such as Figure 1 As shown, the clamp meter housing is equipped with an MCU and a power supply; the MCU is connected to the voltage detection circuit and the current detection circuit, the voltage detection circuit is connected to the current clamp first interface and the current clamp second interface outside the clamp meter housing, and the current detection circuit is connected to the voltage detection interface outside the clamp meter housing. The MCU is also connected to a 485 communication module, an SD card, and a screen that is exposed outside the clamp meter housing; the power supply is connected to the MCU, the voltage detection circuit, the current detection circuit, the 485 communication module, the SD card, and the screen.

[0073] The power supply in this embodiment includes a battery, a power interface circuit connected to the battery, a 12V to 5V step-down circuit connected to the power interface circuit, and a 5V to 3.3V step-down circuit connected to the 12V to 5V step-down circuit.

[0074] The power interface circuit is the starting point of the entire detection end power system. All power supplies for the components of the detection end are obtained from this interface. Figure 2 As shown, U1, U2, and U13 in the power interface circuit are all key terminals. U1 is designed as the main interface for connecting the battery, responsible for introducing the DC power provided by the battery into the detection end; U2 is specifically used to connect the battery charging port, allowing external charging devices to charge the battery through this interface to ensure that the detection end can still maintain sufficient power after long-term operation; U15, as a switch interface, can not only control the on and off of the power supply, but also make necessary adjustments and stabilization of the battery voltage. Finally, the battery voltage processed by U15 is output through its second pin. The output stable voltage will serve as the main power input for other circuits of the detection end to ensure that each component can work normally and perform at its best.

[0075] like Figure 3 As shown in the figure, the 12V to 5V step-down circuit uses the LMR14050SD DAR step-down chip labeled U7. The input of the chip comes from the power interface circuit. The 12V voltage of the power interface circuit is filtered by the two capacitors C31 and C29 to enter the second pin of U7; the control circuit composed of R62 and R63 controls the pin 3 of U7 to control the output of 5V voltage. The two resistors R42 and R15 divide the output voltage and output it to the FB pin of U7 to achieve the function of controlling the output voltage. The 5V voltage is filtered by the two capacitors C30 and C25 and output to provide power for the subsequent circuits.

[0076] like Figure 4As shown in the figure, the 5V to 3.3V step-down circuit uses the TPRT9013 step-down chip labeled U4. The input of this chip comes from the 12V to 5V step-down circuit. The 5V voltage of the 12V to 5V step-down circuit is filtered by the C60 capacitor and then enters the No. 1 pin of U4. After filtering by the C59 capacitor, it outputs 3.3V. The 3.3V of the subsequent circuits are all output from here.

[0077] In this embodiment, the battery is connected to the MCU, 485 communication module, SD card, and screen power supply through the power interface circuit, the 12V to 5V step-down circuit, and the 5V to 3.3V step-down circuit in sequence; the battery is connected to the voltage detection circuit and the current detection circuit in sequence through the power interface circuit and the 12V to 5V step-down circuit, so as to realize power supply to each component.

[0078] The current detection circuit in this embodiment is used for current detection. Figure 5 As shown, this part U53 is the first interface of the current clamp, and the first interface of the current clamp is a current transformer, which can be used for AC current. The signal of the current transformer is converted into a voltage signal after passing through the R152 sampling resistor, and then enters the U48 operational amplifier after filtering by the C71 capacitor, and after amplification, it is filtered by the RC filter circuit composed of R136 and C88, and then filtered by C88 with content, and then connected to the PA0 pin of the MC U through the ADC1 network label.

[0079] The voltage detection circuit in this embodiment is used for voltage detection. Figure 6 As shown, this part U16 is a voltage interface. After the voltage to be measured is transmitted to the voltage transformer L6 at both ends, it is filtered through capacitors C74 and C75 so as to obtain the corresponding voltage data later.

[0080] Furthermore, the portable clamp meter with measurement wiring analysis function also includes a current acquisition circuit, which is connected to the MCU and the 5V to 3.3V step-down circuit of the power supply. Figure 7 As shown, the current acquisition circuit is used for current acquisition. This part of current acquisition is different from Figure 6 The current sensing circuit shown in Figure 6 The current detection circuit in it is used to cooperate with the current acquisition circuit to perform secondary current loop polarity and transformation ratio analysis; the current acquisition circuit is the main circuit for electric energy metering. The U52 interface of this part is used to connect the current transformer. The current transformer data is output through the 1 and 2 pins in U52 and then filtered through C120 and C121 for subsequent MCU acquisition.

[0081] Furthermore, the portable clamp meter with metering wiring analysis function also includes an electric energy metering circuit, which is respectively connected to the MCU, the voltage detection circuit, the current acquisition circuit, and the 12V to 5V step-down circuit of the power supply. Figure 8 As shown, the function of the energy metering circuit is to process the collected current and voltage data. Its main core is the single-phase energy collection chip U51. Pins 4, 5, 6, 7, 8, and 9 in U51 are used to collect the required current and voltage signals. This part of the power supply comes from the 5V voltage output by the 12V to 5V step-down circuit of the power supply. The voltage of the chip is divided into two types, one is digital power supply and the other is 5V power supply. The digital power supply comes from the direct output of node 2. The analog power supply also comes from the 5V voltage output by the 12V to 5V step-down circuit of the power supply, but after passing through a 10R resistor and filtering through two capacitors C112 and C113, it is used as the power input of U51. In addition, the chip also adds a crystal oscillator circuit, which is composed of C114, X3 and C115 to provide a clock signal for U51. The current collection circuit outputs to pins 6 and 7 of U51. The voltage detection circuit is connected to pins 8 and 9 of the U51 chip through the two network labels UAP and UAN to obtain the corresponding voltage data and energy data.

[0082] Further, such as Fig. 9 As shown, the MCU in this embodiment uses STM32F103RCT6 as the core of the entire device. STM32F103RCT6 not only has a large storage space, but also has a powerful computing power, which enables it to easily cope with complex data processing tasks. In terms of power supply, STM32F103RC T6 uses a stable 3.3V power supply, which comes from a 5V to 3.3V step-down circuit to ensure the stable operation of the MCU and the accuracy of data processing. The basic circuit of the MCU operation requires an external high-speed crystal oscillator circuit, a power-on reset circuit, a startup mode selection circuit, a power decoupling circuit, and a program download circuit. In some circuits, H1 is a program download circuit. C8, C9 and X2 form an external high-speed crystal oscillator circuit, C122, C123, C124, C25 form a power filter circuit, and R3, SW1, C12 form a reset circuit.

[0083] The connection between STM32F103RCT6 and other parts is also very close. It is connected to the 485 communication module through the energy meter data reading circuit. The energy meter data reading circuit is connected to the MCU, 485 communication module, and the 12V to 5V step-down circuit of the power supply. Fig.10As shown, P8 in the data reading circuit of the electric energy meter is a 485 interface. By connecting the interface to the external 645 protocol to MODBUS module, the data can be read out. After the data is read out, it enters the 6 and 7 pins of U50, and then the RS 485 signal is converted into a TTL signal that can be read by the MCU through U50. The converted TTL signal is connected to the PA2 and PA3 pins of the MCU through the 1 and 4 pins of U50.

[0084] STM32F103RCT6 is connected to the screen through the screen interface circuit, which is connected to the MCU, the screen, and the 12V to 5V step-down circuit of the power supply. Fig.12 As shown, the screen interface circuit is used for human-computer interaction. U18 in the screen interface circuit is the screen interface, and its power comes from node 2. Pins 2 and 3 of U18 serve as the communication interface between the screen and the MCU and are connected to pins PA9 and PA10 of the MCU.

[0085] In addition, the circuit diagram of the SD card in this embodiment is as follows Fig.11 As shown, CARD1 is an SD card holder, in which the power supply is 3.3V, and the power supply comes from a 5V to 3.3V step-down circuit. The storage of files is managed using FATFS. By outputting data to the SD card, users can easily perform various complex processing and analysis on the data, and are no longer limited to the limited data operation functions within the system.

[0086] Example 2

[0087] Based on the portable clamp meter with metering wiring analysis function provided in Example 1, in this embodiment, the current loop ratio and polarity test are performed through the first interface of the current clamp and the second interface of the current clamp, and the MCU is connected to the primary current and the secondary current through the first interface of the current clamp and the second interface of the current clamp respectively to obtain the results of the current loop ratio and polarity test.

[0088] This portable clamp meter with metering wiring analysis function uses machine learning algorithms to perform pattern recognition and anomaly detection on data to achieve fault warning; fault warnings include: polarity error, abnormal circuit ratio;

[0089] The current signal I(t) and the voltage signal V(t) are sampled by ADC and discretized into digital signals I[n] and V[n]. The sampled I[n] and V[n] data are standardized to facilitate processing by the machine learning model:

[0090]

[0091] In the figure, x represents the original data point, i.e., the sampled current data I[n] or voltage data V[n];

[0092] x norm represents the data value obtained after standardization; μ is the mean of the data; σ is the standard deviation of the data.

[0093] Model training includes the following processes:

[0094] Use classification algorithms such as support vector machines (SVMs) or lightweight neural networks to train common fault modes; faults include: polarity errors, abnormal loop ratios, and short circuits or open circuits.

[0095] Select time domain and frequency domain features. The time domain features include: mean, variance, and peak-to-peak value of the signal; the frequency domain features include: harmonic amplitude and frequency offset.

[0096] Using the eigenvector F:

[0097] F=[P,Q,THD,f fundamental ,...]

[0098] Among them, P represents the mean of the signal; Q represents the variance of the signal; f fundamental Indicates the fundamental frequency;

[0099] THD is the total harmonic distortion, and the calculation formula is:

[0100]

[0101] Where |X(1)| is the fundamental amplitude; |X(k)| is the kth harmonic amplitude.

[0102] Finally, use tools such as TensorFlow or Scikit-learn in the Python environment to train the model, quantize the trained model and embed it into the MCU. The model reasoning process is as follows: The MCU runs the trained model in real time and outputs the classification results based on the input feature vector F. The classification results include: normal operation, polarity error, and abnormal loop ratio.

[0103] Example 3

[0104] Based on the portable clamp meter with metering wiring analysis function provided in Example 1, in this embodiment, measurement is performed by using the first interface of the current clamp and the voltage detection interface together, and the MCU forms metering data by calculating electric energy measurement, current, voltage, active power, and reactive power; at the same time, the MCU reads the metering data of the electric energy meter through the 485 communication module, and tests whether the electric energy meter is working normally by comparing the metering data with the metering data of the electric energy meter.

[0105] Specifically, the MCU is replaced with an ARM or embedded DSP with floating-point computing capabilities, such as TI's TMS320 series, and a high-speed analog-to-digital converter ADC is configured to improve the current and voltage sampling accuracy and rate.

[0106] The data processing process includes the following steps:

[0107] Step 1, data sampling: the current signal I(t) and the voltage signal V(t) are sampled by ADC and discretized into digital signals I[n] and V[n];

[0108] The formula used is as follows:

[0109] I[n]=I(t)|t=n·T s , V[n]=V(t)|t=n·T s ;

[0110] Where, T s is the adoption period, T s =1 / f s , f s is the sampling frequency; t is the sampling time; n is the current sampling point index.

[0111] Step 2: Calculate active power P and reactive power Q in real time. The calculation formula is as follows:

[0112]

[0113]

[0114] Where N is the number of sampling points; I'[n] is the 90° phase shift of the current signal, which is achieved using Fast Fourier Transform FFT;

[0115] Step 3: Use FFT to perform spectrum analysis on the signal. The calculation formula is as follows:

[0116]

[0117] Where X(k) is the kth harmonic component in the frequency domain; N is the number of sampling points; x[n] is the sampling value of the signal; e -j2πkn / N is a complex exponential function, j is an imaginary unit, 2πkn / N represents the phase at frequency k, and creates a rotation factor with frequency k.

[0118] In summary, in combination with Embodiment 1 to Embodiment 3, as Figure 1 and Fig.13As shown, when the portable clamp meter with metering wiring analysis function is in use, the first interface of the current clamp and the second interface of the current clamp are used for current loop ratio and polarity test. The results of the current loop ratio and polarity test are obtained by connecting the first interface of the current clamp and the second interface of the current clamp to the primary current and the secondary current respectively. The second interface of the current clamp and the voltage detection interface can be used together to realize the metering function. This function is used in combination with the 485 communication module to read the metering data of the electric energy meter through the 485 communication module. After comparison, it can be tested whether the electric energy meter is working normally.

[0119] In addition, the two interfaces of the portable clamp meter with metering wiring analysis function can also select current clamps with various ratios to achieve the function of wide-range current measurement. In addition, the current interface can also be connected to a flexible high-current coil for measurement, so as to measure the current of objects such as copper plates.

[0120] At the same time, it should be pointed out that the above description is only a typical embodiment of the present invention and does not limit the present invention in any form. Any changes made to the above embodiments based on the ideas and technical essence of the present invention are within the protection scope of the present invention.

Claims

1. A portable clamp meter with measurement wiring analysis function, characterized in that: The invention comprises a clamp meter housing, in which an MCU and a power supply are installed; the MCU is connected to a voltage detection circuit and a current detection circuit, the voltage detection circuit is connected to a first current clamp interface and a second current clamp interface outside the clamp meter housing, and the current detection circuit is connected to a voltage detection interface outside the clamp meter housing; The MCU is also connected to a 485 communication module, an SD card, and a screen that is exposed outside the clamp meter housing; the power supply is connected to the MCU, a voltage detection circuit, a current detection circuit, a 485 communication module, an SD card, and a screen.

2. The portable clamp meter with measurement wiring analysis function according to claim 1, characterized in that: The power supply includes a battery, a power interface circuit connected to the battery, a 12V to 5V step-down circuit connected to the power interface circuit, and a 5V to 3.3V step-down circuit connected to the 12V to 5V step-down circuit; The battery is connected to the MCU, 485 communication module, SD card, and screen power supply through the power interface circuit, 12V to 5V step-down circuit, and 5V to 3.3V step-down circuit in sequence; the battery is connected to the voltage detection circuit and current detection circuit in sequence through the power interface circuit and 12V to 5V step-down circuit.

3. The portable clamp meter with measurement wiring analysis function according to claim 2 is characterized in that: The portable clamp meter with a metering wiring analysis function also includes a current acquisition circuit, which is connected to the MCU and a 5V to 3.3V step-down circuit of a power supply respectively.

4. The portable clamp meter with measurement wiring analysis function according to claim 3 is characterized in that: The portable clamp meter with metering wiring analysis function also includes an electric energy metering circuit, which is respectively connected to the MCU, the voltage detection circuit, the current acquisition circuit, and the 12V to 5V step-down circuit of the power supply.

5. The portable clamp meter with measurement wiring analysis function according to claim 2, characterized in that: The portable clamp meter with metering wiring analysis function also includes an electric energy meter data reading circuit, which is respectively connected to the MCU, the 485 communication module, and the 12V to 5V step-down circuit of the power supply.

6. The portable clamp meter with measurement wiring analysis function according to claim 2, characterized in that: The portable clamp meter with a metering wiring analysis function also includes a screen interface circuit, which is respectively connected to the MCU, the screen, and a 12V to 5V step-down circuit of a power supply.

7. The portable clamp meter with measurement wiring analysis function according to claim 1, characterized in that: The portable clamp meter with metering wiring analysis function performs current loop ratio and polarity tests through the first current clamp interface and the second current clamp interface. The MCU is connected to the primary current and the secondary current through the first current clamp interface and the second current clamp interface respectively to obtain the results of the current loop ratio and polarity tests.

8. The portable clamp meter with measurement wiring analysis function according to claim 6, characterized in that: This portable clamp meter with metering wiring analysis function uses machine learning algorithms to perform pattern recognition and anomaly detection on data to achieve fault warning; fault warnings include: polarity error, abnormal circuit ratio; The current signal I(t) and the voltage signal V(t) are sampled by ADC and discretized into digital signals I[n] and V[n]. The sampled I[n] and V[n] data are standardized to facilitate processing by the machine learning model: In the formula, x represents the original data point, that is, the sampled current data I[n] or voltage data V[n]; x norm represents the data value obtained after standardization; μ is the mean of the data; σ is the standard deviation of the data; Model training includes the following processes: Use classification algorithms to train common fault modes, including: polarity errors, abnormal circuit ratios, and short circuits or open circuits; Select time domain and frequency domain features. Time domain features include: mean, variance, peak-to-peak value of the signal. Frequency domain features include: harmonic amplitude and frequency offset. Using the eigenvector F: F=[P,Q,THD,f fundamental ,...] Among them, P represents the mean of the signal; Q represents the variance of the signal; f fundamental Indicates the fundamental frequency; THD is the total harmonic distortion, and the calculation formula is: Where, |X(1)| is the fundamental amplitude; |X(k)| is the kth harmonic amplitude; Use tools in the Python environment to train the model, quantize the trained model, and embed it into the MCU; The MCU runs the trained model in real time and outputs classification results based on the input feature vector F. The classification results include: normal operation, polarity error, and abnormal loop ratio.

9. The portable clamp meter with measurement wiring analysis function according to claim 1, characterized in that: The portable clamp meter with metering wiring analysis function performs metering by using the first interface of the current clamp and the voltage detection interface together. The MCU forms metering data by calculating electric energy metering, current, voltage, active power, and reactive power. At the same time, the MCU reads the metering data of the electric energy meter through the 485 communication module, and tests whether the electric energy meter works normally by comparing the metering data with the metering data of the electric energy meter.

10. The portable clamp meter with measurement wiring analysis function according to claim 9, characterized in that: The MCU is replaced with an ARM or embedded DSP with floating-point computing capability and configured with a high-speed analog-to-digital converter ADC. The data processing process includes the following steps: Step 1, data sampling: the current signal I(t) and the voltage signal V(t) are sampled by ADC and discretized into digital signals I[n] and V[n]; The formula used is as follows: I[n]=I(t)|t=n·T s ,V[n]=V(t)|t=n·T s ; Where, T s is the adoption period, T s =1 / f s , f s is the sampling frequency; t is the sampling time; n is the current sampling point index; Step 2: Calculate the active power P and reactive power Q in real time. The calculation formula is as follows: Where N is the number of sampling points; I'[n] is the 90° phase shift of the current signal, which is achieved using Fast Fourier Transform FFT; Step 3: Use FFT to perform spectrum analysis on the signal. The calculation formula is as follows: Where X(k) is the kth harmonic component in the frequency domain; N is the number of sampling points; x[n] is the sampling value of the signal; e -j2πkn / N is a complex exponential function, j is an imaginary unit, 2πkn / N represents the phase at frequency k, and creates a rotation factor with frequency k.

Images