Current monitoring device

Abstract

The invention is applicable to the field of current monitoring, and provides a current monitoring device, which comprises a front-end monitoring unit, a rear-end analysis unit and a power supply unit, the front-end monitoring unit comprises an open-close type current sensing module, a data acquisition and transmission module and a dual-CT energy supply module, and the rear-end analysis unit comprises a wireless data receiving module and a terminal analysis module. According to the invention, the front-end monitoring unit adopts a combination scheme of mechanical support integration and shielding design, and the open-close type current sensing module and the dual-CT energy supply module are fixed in parallel through a mechanical support, so that component offset caused by vibration is avoided; the first shielding cable and the second shielding cable reduce electromagnetic interference in the signal transmission process, and in cooperation with a closed annular structure (a hinge and a fixing buckle) of the open-close type current sensing module, the influence of the external electromagnetic environment on sensing signals is reduced. The ultra-wide range is switched stably, and the measurement continuity is better; the system is high in integration level, convenient to maintain and suitable for multi-scene application.

Description

Technical Field

[0001] This invention belongs to the field of current monitoring, and particularly relates to a current monitoring device. Background Technology

[0002] Insufficient anti-interference and structural stability: The sensing components of existing current measurement equipment are mostly distributed without dedicated mechanical installation and shielding structures, making them susceptible to electromagnetic interference. Furthermore, the components are prone to vibration and displacement, resulting in poor signal transmission accuracy and difficulty in stable measurement under complex working conditions.

[0003] Poor reliability of range switching: Traditional range switching switches lack reliable mechanical positioning and anti-loosening design, which can easily lead to poor contact after long-term use, resulting in low switching reliability and affecting the continuity and accuracy of multi-range measurement.

[0004] Poor integration and maintainability: Multi-channel measurement requires splicing multiple devices, lacks an integrated mechanical structure, and occupies a large space; the core unit lacks a dedicated heat dissipation structure, which makes it prone to performance degradation during long-term operation, and component replacement and maintenance are inconvenient and costly.

[0005] Therefore, a current monitoring device is needed to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a current monitoring device to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A current monitoring device includes a front-end monitoring unit and a back-end analysis unit; the front-end monitoring unit includes an openable current sensing module, a data acquisition and transmission module, and a dual-CT power supply module; the back-end analysis unit includes a wireless data receiving module and a terminal analysis module.

[0009] The signal output terminal of the openable current sensing module is electrically connected to the signal input terminal of the data acquisition and transmission module through a first shielded cable. The power output terminal of the dual CT power supply module is electrically connected to the power interface of the data acquisition and transmission module through a second shielded cable. The wireless transmitter of the data acquisition and transmission module and the wireless receiver of the wireless data receiving module are connected through a wireless communication protocol signal. The signal output terminal of the wireless data receiving module is electrically connected to the signal input terminal of the terminal analysis module through a USB interface cable.

[0010] The openable current sensing module and the dual CT power supply module are fixed side by side by a mechanical bracket and are jointly sleeved on the primary lead being measured. The data acquisition and transmission module is fixed to the side of the mechanical bracket by bolts.

[0011] A further technical solution is that the opening and closing current sensing module includes two symmetrical semi-circular sensing coils, a size adjustment ring, and an opening and closing fixing buckle.

[0012] Based on Faraday's law of electromagnetic induction, the output induced voltage of the open-close current sensing module satisfies the following relationship with the measured primary current: The formula for calculating the induced signal of the sensing coil is as follows:

[0013] ;

[0014] in, : Sensor coil output induced voltage (unit: V); : Frequency of the measured current (unit: Hz); Number of turns of the sensor coil (typical value is 500-2000 turns, depending on the range design). Cross-sectional area of ​​the sensing coil core (unit: ); Vacuum permeability ( ); Relative magnetic permeability of the iron core (typical value of 1500-3000 for high silicon steel sheets); The measured primary current (unit: A); The air gap length after the coil is closed (the opening and closing structure is optimized through a snap-fit ​​mechanism). ); : Length of the magnetic circuit of the iron core (unit: m);

[0015] This formula demonstrates how a closed-loop structure (hinge + retaining clip) improves magnetic circuit integrity—by reducing the air gap. Reduce magnetic resistance to induce voltage More stable, less susceptible to external electromagnetic interference The impact was weakened, and the final signal error was controlled within 1%.

[0016] The size adjustment ring is made of rubber with a Shore hardness of 50-70. Its inner diameter adaptive range (10mm-50mm) is determined by the elastic deformation characteristics of the rubber. The adaptive deformation calculation of the size adjustment ring must meet the following requirements:

[0017] ;

[0018] in, : Inner diameter variation (unit: m), maximum achievable (Reduced from 50mm to 30mm); The clamping force (in N) of the adjusting ring on the conductor must meet the following requirements: (Ensure no slippage and no damage to the wires); : Original inner diameter of the adjusting ring (unit: m); Rubber elastic modulus (corresponding to Shore hardness of 50 degrees) 70 degrees corresponds (Derived from the empirical formula of Shore hardness-elastic modulus). Cross-sectional area of ​​the adjusting ring (unit: );

[0019] Two semi-circular sensing coils are connected at one end by a hinge and at the other end by a detachable fastener, forming a closed ring structure.

[0020] The size adjustment ring is fitted inside the semi-circular sensing coil and is engaged with the inner wall of the coil by an elastic buckle.

[0021] The signal lead of the sensing coil is soldered to the signal terminal, and the signal terminal is fixedly connected to the connector of the first shielded cable through a threaded structure.

[0022] In a further technical solution, the data acquisition and transmission module includes a microcontroller main control chip, an analog-to-digital conversion unit, and a first wireless transmission chip;

[0023] The analog-to-digital converter (ADC) unit uses a 16-bit high-precision ADC chip, and its quantization error and sampling accuracy satisfy the quantization accuracy formula for analog-to-digital converters (ADCs):

[0024] ;

[0025] in, ADC quantization voltage error (unit: V); ADC reference voltage (typically 3.3V or 5V); ADC bit width (in this invention) Therefore ); Current measurement error (unit: A); Sensing module sensitivity (unit: V / A, derived from formula) Derivation, typical values ​​0.1V / A-10V / A);

[0026] when , hour, , By combining the software calibration algorithm of the microcontroller main control chip, the error can be further reduced to ;

[0027] To avoid signal aliasing, the sampling rate must meet the Nyquist criterion and be optimized in conjunction with the dynamic characteristics of the measured current. The ADC sampling rate adaptation formula is as follows:

[0028] ;

[0029] in, ADC sampling rate (unit: SPS); The highest harmonic frequency in the measured current (unit: Hz);

[0030] In this invention, the microcontroller main control chip adjusts via control pins. (Range 128SPS-32768SPS): When measuring microcurrents of 5µA-1A, ,set up When measuring high currents of 1A-30A, ,set up This enables measurement continuity over an ultra-wide measurement range;

[0031] The signal input terminal of the analog-to-digital converter is soldered to the output terminal of the first shielded cable, and the signal output terminal of the analog-to-digital converter is electrically connected to the I / O interface of the microcontroller main control chip through PCB board traces.

[0032] The communication interface of the first wireless transmission chip is electrically connected to the corresponding interface of the microcontroller main control chip via the SPI bus, and the antenna interface of the first wireless transmission chip is connected to an external antenna via a feeder line.

[0033] The power pin of the microcontroller main control chip is electrically connected to the output end of the second shielded cable through a voltage regulator circuit.

[0034] A further technical solution is that the dual-CT power supply module includes two openable power supply coils, a rectifier and filter unit, a DC-DC converter unit, and a backup lithium battery;

[0035] The two switching power supply coils employ a redundant design, and the total induced current satisfies the calculation formula for the induced current of the dual-CT power supply coil:

[0036] ;

[0037] in, Total induced current of the two coils (unit: A); , Induced current in a single coil (unit: A); , Coil ratio (typical value 1000:5, i.e.) ); : The primary current being measured (unit: A).

[0038] when hour, After rectification and filtering unit (efficiency) The output DC current is then released. It can meet the power consumption requirements of the data acquisition and transmission module. The power supply requirements of )

[0039] when When the dual CTs are underpowered, the system automatically switches to backup lithium battery power, and the power supply time meets the calculation formula for backup lithium battery power supply time.

[0040] ;

[0041] in, Power supply time (unit: h); Lithium battery capacity (unit: Ah, typical value 2Ah-5Ah); Rated voltage of lithium battery (unit: V, typical value 3.7V); DC-DC conversion efficiency (typical value 90%) Module power consumption (unit: W);

[0042] when , , hour, (Approximately 7 days) to ensure continuous power supply in extreme low-current scenarios;

[0043] Two open-ended power supply coils are electrically connected to the two input terminals of the rectifier and filter unit via wires. The output terminal of the rectifier and filter unit is divided into two paths: one path is directly connected to the input terminal of the DC-DC conversion unit, and the other path is connected to the charging and discharging interface of the backup lithium battery through the charging management chip.

[0044] The output end of the DC-DC conversion unit is soldered to the input end of the second shielded cable, and the voltage detection pin of the DC-DC conversion unit is electrically connected to the microcontroller main control chip of the data acquisition and transmission module through a wire.

[0045] In a further technical solution, the wireless data receiving module includes a second wireless transmission chip and a signal conditioning unit;

[0046] To accommodate current signals of different ranges, the amplification factor of the signal conditioning unit (operational amplifier) ​​can be adjusted via hardware resistors or software control. The formula for the amplification factor of the signal conditioning unit is as follows:

[0047] ;

[0048] in, Voltage amplification factor (typical value 1-1000 times); Feedback resistance (unit: Ω) Input resistance (unit: Ω);

[0049] When measuring microampere-level signals, (Amplify mV-level signals to V-level to match the ADC input range); When measuring ampere-level signals, (To avoid signal saturation), in conjunction with the software calibration of the terminal analysis module, accurate acquisition of full-range signals can be achieved;

[0050] The received power of LoRa / NB-IoT wireless transmission satisfies the formula for the relationship between wireless transmission power and distance:

[0051] ;

[0052] in, Received power (unit: dBm); Transmit power (unit: dBm, this invention uses microcontroller PWM pin for graded control, range -10dBm-20dBm); , Transmit / receive antenna gain (unit: dBi, typical value 2dBi-5dBi); Transmission distance (unit: m); Radio wavelength (unit: m) , LoRa band 868MHz corresponds to ); System losses (unit: dB, typical value 2dB-5dB);

[0053] when , , At that time, transmission distance hour (Higher than LoRa receiver sensitivity by 148dBm), meeting the needs of long-distance scenarios such as photovoltaic power plants and industrial workshops;

[0054] The receiving antenna of the second wireless transmission chip is connected to an external receiving antenna via a feeder, and the signal output terminal of the second wireless transmission chip is electrically connected to the input terminal of the signal conditioning unit via PCB traces.

[0055] The output end of the signal conditioning unit is soldered with a USB interface female connector, which can be detachably connected to the USB interface of the terminal analysis module through a USB male and female connector structure.

[0056] In a further technical solution, the size adjustment ring is made of rubber with a Shore hardness of 50-70 degrees, and the ring body has evenly distributed elastic openings. The inner diameter of the adjustment ring can adaptively expand and contract within the range of 10mm-50mm.

[0057] Shore A hardness and elastic modulus of rubber materials The following empirical relationship must be satisfied (applicable to Shore hardness range of 50-70 degrees), unit: ;

[0058] When Shore hardness = 50 degrees When Shore hardness = 70, This ensures that the adjusting ring has sufficient elasticity (to adapt to different wire diameters) and can provide a stable clamping force;

[0059] Number of elastic openings on the adjusting ring To meet the requirement of uniform deformation and avoid local stress concentration, the optimal formula for the number of elastic openings is as follows:

[0060] ;

[0061] in, The spacing between adjacent openings (in meters) must meet the following requirements. (10mm) to avoid uneven deformation caused by excessive spacing; Maximum inner diameter of the adjusting ring (unit: m, this invention) );

[0062] Substitution Therefore, the design A uniformly distributed elastic opening ensures that the stress deviation of the ring body is minimized when the inner diameter expands or contracts from 10mm to 50mm. ;

[0063] The opening and closing type fixing buckle includes a hook and a groove that are compatible with each other. The end of the hook is provided with an elastic locking tongue, which is engaged and fixed with the positioning hole of the groove.

[0064] The opening and closing type fixing buckle includes a hook and a groove that are adapted to each other. The end of the hook is provided with an elastic locking tongue, which is engaged and fixed with the positioning hole of the groove.

[0065] In a further technical solution, the analog-to-digital conversion unit adopts a 16-bit high-precision ADC chip, and its sampling rate is adjusted by the control pin of the microcontroller main control chip.

[0066] The transmission power of the first wireless transmission chip The duty cycle of the microcontroller's PWM pin Hierarchical control requires satisfying the relationship between the wireless transmission chip's transmit power and the PWM duty cycle:

[0067] ;

[0068] in: Maximum transmit power of the chip (unit: dBm, this invention) ); PWM duty cycle (range 0.1-1.0);

[0069] Design of 5-level power control: close range ( )set up ( ); Mid-range ( )set up ( ); long distance ( )set up ( Achieving a balance between communication stability and power consumption;

[0070] The first wireless transmission chip supports LoRa or NB-IoT communication protocols, and its transmission power is controlled in stages through the PWM pin of the microcontroller main control chip.

[0071] Compared with the prior art, the beneficial effects of the present invention are:

[0072] This invention achieves a dual improvement in anti-interference capability and structural stability: the front-end monitoring unit adopts a combination of "mechanical support integration + shielding design". The openable current sensing module and the dual CT power supply module are fixed in parallel by mechanical supports to avoid component displacement caused by vibration; the first and second shielded cables reduce electromagnetic interference during signal transmission. Combined with the closed ring structure (hinge + fixing buckle) of the openable current sensing module, the influence of the external electromagnetic environment on the sensing signal is reduced. In complex working conditions such as industrial workshops and new energy power plants, the signal transmission accuracy error can be controlled within 1%, solving the problems of "easy displacement and weak anti-interference" of traditional distributed components.

[0073] This invention features stable switching across an ultra-wide measurement range, resulting in superior measurement continuity. Utilizing a 16-bit high-precision ADC chip (analog-to-digital converter) and an adjustable sampling rate design, combined with adaptive power supply from a dual-CT power module (dual power coils + backup lithium battery), the device can cover an ultra-wide measurement range of 5µA-30A. Eliminating the need for traditional mechanical range switches, the microcontroller-based main control chip provides graded control of the ADC sampling rate and wireless transmission power. Coupled with filtering and amplification by the signal conditioning unit, it avoids poor contact issues during range switching, achieving smooth switching between microampere-level weak currents and ampere-level large currents, ensuring the continuity and accuracy of multi-range measurements.

[0074] This invention features high integration and convenient maintenance, adapting to various application scenarios: the front-end unit integrates sensing, data acquisition, and power supply modules, while the back-end connects quickly to the terminal analysis module via a USB interface. Multi-channel measurements eliminate the need for multiple devices to be spliced ​​together, reducing space usage by over 60% compared to traditional solutions. A size adjustment ring (10mm-50mm adaptive) accommodates different diameter conductors, eliminating the need to replace dedicated sensing components. Vulnerable components (such as the wireless transmission chip and USB interface) are secured with bolts or snap-fit ​​designs, eliminating the need for complete disassembly during maintenance. Maintenance time is reduced to one-third of traditional equipment, significantly lowering operating costs. It can be widely applied in scenarios such as precision laboratory measurements, multi-branch monitoring of photovoltaic inverters, and equipment monitoring in industrial production lines.

[0075] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0076] Figure 1 This is a block diagram showing the overall module connection of the present invention;

[0077] Figure 2 This is a connection block diagram of the data acquisition and transmission module of the present invention;

[0078] Figure 3 This is a connection block diagram of the dual-CT power supply module of the present invention;

[0079] Figure 4 This is a connection block diagram of the wireless data receiving module of the present invention.

[0080] In the diagram: 1. Front-end monitoring unit; 11. Opening / closing current sensing module; 12. Data acquisition and transmission module; 121. Microcontroller main control chip; 122. Analog-to-digital converter unit; 123. First wireless transmission chip; 13. Dual CT power supply module; 131. Opening / closing power supply coil; 132. Rectifier and filter unit; 133. DC-DC converter unit; 134. Backup lithium battery; 2. Back-end analysis unit; 21. Wireless data receiving module; 211. Second wireless transmission chip; 212. Signal conditioning unit; 22. Terminal analysis module. Detailed Implementation

[0081] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0082] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0083] Example 1

[0084] like Figure 1-4 As shown, this embodiment of the invention provides a current monitoring device, including a front-end monitoring unit 1 and a back-end analysis unit 2;

[0085] Front-end monitoring unit configuration: The openable current sensing module 11 uses a high-sensitivity iron-core semi-circular sensing coil, and the size adjustment ring uses nitrile rubber with a Shore hardness of 60 (compatible with 10mm-20mm commonly used laboratory wires); the microcontroller main control chip 121 of the data acquisition and transmission module 12 uses STM32L431RCT6 (low power consumption suitable for long-term laboratory monitoring), the analog-to-digital conversion unit 122 uses ADS1115 (16-bit precision, sampling rate set to 128SPS, suitable for microampere-level signal acquisition), and the first wireless transmission chip 123 uses the LoRa protocol SX1278 (short distance, low power consumption, transmission distance set to within 50 meters); the openable power supply coil 131 of the dual CT power supply module 13 uses a Φ20mm toroidal coil, and the backup lithium battery 134 uses an 18650 type 3.7V / 2000mAh battery (to ensure 3 hours of emergency power supply in case of power failure).

[0086] Selecting a switchable current sensing module turn, High silicon steel coil ( ), from the formula ,have to ;ADC design of the data acquisition and transmission module From the formula ,have to After software calibration, it dropped to Dual-CT power supply module Backup lithium battery From the formula ,have to .

[0087] Back-end analysis unit configuration: The second wireless transmission chip 211 of the wireless data receiving module 21 is paired with the front-end SX1278; the signal conditioning unit 212 uses a PA2340 operational amplifier (with amplification factor set to 100 times to adapt to weak signal conditioning); the terminal analysis module 22 uses an industrial panel PC (with LabVIEW monitoring software installed to display current waveforms and values ​​in real time).

[0088] Installation and use: The openable current sensing module 11 and the dual CT power supply module (13) are fixed side by side by a plastic mechanical bracket and together installed on the test wire (such as the power supply wire of the circuit board) in the laboratory. The data acquisition and transmission module 12 is fixed to the side of the bracket by M3 bolts. The rear wireless data receiving module 21 is connected to the tablet computer by a USB cable. After the device is turned on, the software can collect current signals in the range of 5µA-1A in real time with an accuracy better than 0.5%.

[0089] In this embodiment, the openable current sensing module is selected. turn, High silicon steel coil ( ), from the formula have to ;ADC design of the data acquisition and transmission module From the formula ,have to After software calibration, it dropped to Dual-CT power supply module Backup lithium battery From the formula ,have to Back-end analysis unit: Signal conditioning unit is set up (formula ), wireless transmission ( ,formula The terminal analysis module is equipped with LabVIEW software to display 5µA-1A current waveforms in real time.

[0090] Shielding effectiveness Errors caused by electromagnetic interference This meets the laboratory's need for high-precision measurement of weak currents.

[0091] Example 2

[0092] The difference between this embodiment and embodiment 1 is as follows: Front-end monitoring unit optimization: Four sets of front-end monitoring units 1 are integrated into a multi-channel machine made of cold-rolled steel plate, and the inner wall of the chassis is provided with an inclined heat dissipation air duct (in conjunction with an axial fan, with a wind speed of 1.2m / s to avoid high temperature inside the inverter cabinet in summer); the size adjustment ring of the openable current sensing module 11 is made of silicone with a Shore hardness of 50 degrees, and the first wireless transmission chip 123 is changed to BC95 of the NB-IoT protocol; the openable power supply coil 131 of the dual CT power supply module 13 is selected as a Φ50mm large-size coil (to be compatible with high-current photovoltaic cables), and the backup lithium battery (134) is expanded to 3.7V / 5000mAh (to ensure 8 hours of emergency power supply).

[0093] Backend analysis unit optimization: The wireless data receiving module 21 integrates 4 NB-IoT receiving channels, and the signal conditioning unit 212 amplification factor is set to 10 times (to adapt to the large current signal of 0.5A-30A of photovoltaic inverter); the terminal analysis module 22 uses a server-level computer (installed with a photovoltaic monitoring platform, supporting parallel display of 4 current data, storage of historical data and abnormal alarms, such as triggering SMS alarm when the current change exceeds 10%).

[0094] In this embodiment, the front-end monitoring unit comprises four sets of front-end components integrated into a heatsink chassis, including a hinged current sensing module. turn, ( ), ADC settings , Dual-CT power supply module Backup lithium battery ( Wireless transmission uses the NB-IoT protocol. ( ), from the formula ,have to hour Back-end analysis unit: Signal conditioning unit is set up The terminal analysis module is equipped with a photovoltaic monitoring platform, which supports parallel monitoring of 4 channels of current from 0.5A to 30A. When the current change exceeds 10%, an SMS alarm is triggered.

[0095] The multi-channel integrated design can simultaneously monitor the current of 4 MPPT branches of the photovoltaic inverter. The NB-IoT wireless transmission eliminates the need for wiring, making it suitable for outdoor distributed installation scenarios in photovoltaic power plants. The combination of heat dissipation ducts and large-size power supply coils ensures stable operation of the device in outdoor environments ranging from -20℃ to 60℃.

[0096] Example 3

[0097] The difference between this embodiment and Embodiment 2 is as follows: Upgraded structural materials: The mechanical support of the front-end monitoring unit 1 is now made of 304 stainless steel (increasing load-bearing capacity to 5kg, suitable for heavy-duty industrial wires); the housing of the data acquisition and transmission module 12 is made of aluminum alloy (enhancing impact resistance and heat dissipation); the hooks and slots of the opening and closing fixing buckle are both made of manganese steel (to avoid wear caused by long-term opening and closing). ,formula ,have to (One flexible opening), and an IP65 waterproof sealing ring added to the data interface (suitable for humid and dusty industrial workshop environments).

[0098] Backend Analysis Unit: Wireless Transmission ( ), from the formula ,have to hour The terminal analysis module supports 24-hour continuous storage, reducing troubleshooting time to less than 5 minutes.

[0099] Maintenance design optimization: The core components such as the analog-to-digital conversion unit 122 and the first wireless transmission chip 123 adopt a drawer-type quick-release structure (fixed by buckles, disassembly time <2 minutes); the spare lithium battery 134 of the dual CT power supply module 13 is equipped with an independent replacement compartment (replacement can be made without disconnecting the main cable), and the DC-DC conversion unit (133) is equipped with a voltage indicator light (to intuitively judge the power supply status and facilitate fault diagnosis).

[0100] In this embodiment, the metal material and waterproof design enhance the device's adaptability to industrial environments, while the quick-release structure and fault indication function significantly reduce maintenance difficulty. It can meet the requirements of 24-hour continuous operation of industrial production lines (with an annual failure rate controlled within 5%) and is compatible with the current monitoring needs of equipment such as motors and frequency converters.

[0101] Working principle and usage process of this invention:

[0102] Phase 1: Device initialization and mechanical installation;

[0103] Mechanical Assembly: Select the module configuration corresponding to the embodiment based on the test scenario, and fix the opening and closing current sensing module 11 and the dual CT power supply module 13 side by side using a mechanical bracket. Adjust the size adjustment ring to match the diameter of the test lead (from the formula). ,Sure ), closing and opening type fixing buckle (ensuring Ensure that the elastic locking tongue is engaged in the positioning hole of the slot, and the coil forms a closed loop); the data acquisition and transmission module 12 is fixed to the side of the bracket with bolts. After checking that each module is not loose, the entire front end unit is sleeved on the primary lead to be measured.

[0104] Electrical connection: In the back-end analysis unit, the external receiving antenna of the wireless data receiving module 21 is installed in a location with good signal (such as a high place in the laboratory or the roof of the photovoltaic power station control room), and is connected to the terminal analysis module 22 via a USB interface cable; the monitoring software of the terminal analysis module is turned on to complete the communication pairing with the wireless data receiving module (LoRa protocol requires matching frequency and spreading factor, NB-IoT protocol requires access to the operator network).

[0105] System self-test: Power on the front-end monitoring unit is activated; the dual-CT power supply module prioritizes sensing for power. When switching lithium batteries, the microcontroller main control chip 121 triggers a self-test program to check the working status of the analog-to-digital conversion unit 122, the wireless transmission chip 123, and the DC-DC conversion unit 133. If the self-test passes, it sends a "ready signal" to the terminal analysis module; otherwise, it sends a fault code.

[0106] Phase 2: Current signal acquisition and processing;

[0107] Signal sensing: After the conductor under test is energized, the semi-circular sensing coil of the openable current sensing module 11 induces a current. Generating weak voltage signals The signal is transmitted to the data acquisition and transmission module 12 through the welded and fixed signal terminals and the first shielded cable;

[0108] Analog-to-digital conversion: The analog-to-digital conversion unit 122 receives analog voltage signals and adjusts the sampling rate according to the control instructions of the microcontroller main control chip 121 (e.g., high sampling rate for microampere-level signals, low sampling rate for ampere-level signals). DC is set according to... Sampling, analog signal The signal is converted into a digital signal and transmitted to the microcontroller main control chip 121 through the PCB board traces. After filtering and calibration by the microcontroller, standardized current data is generated.

[0109] Data preprocessing: The microcontroller main control chip 121 filters (removes high-frequency noise) and calibrates (corrects errors according to the preset sensor coil ratio coefficient) the digital signal to generate standardized current data (unit: A or µA). At the same time, it reads the voltage detection signal of the DC-DC conversion unit 133 to determine the power supply status and record it.

[0110] Phase 3: Data Transmission and Analysis;

[0111] Wireless transmission: The microcontroller main control chip 121 sends standardized current data to the first wireless transmission chip 123 via the SPI bus, adjusting according to the scenario. The data is transmitted to the back-end wireless data receiving module 21 using wireless communication protocols (LoRa / NB-IoT);

[0112] Signal conditioning and reception: After receiving data, the second wireless transmission chip 211 of the wireless data receiving module 21 transmits it to the signal conditioning unit 212. The signal is amplified and filtered to further optimize the signal quality before being transmitted to the terminal analysis module 22 via a USB interface cable.

[0113] Terminal Analysis: The monitoring software of the terminal analysis module displays the current value and waveform curve in real time. Thresholds can be set (such as overcurrent threshold and current fluctuation threshold). When the current exceeds the threshold, an alarm is triggered (audio-visual alarm or SMS alarm). At the same time, it automatically stores historical data (archived by minute / hour) and supports data export (format: Excel, CSV) and trend analysis (such as photovoltaic current daily change curve and production line current load analysis).

[0114] Phase 4: Anomaly Handling and Maintenance;

[0115] Power supply anomaly handling: If the dual CT power supply module is not receiving enough power ( The voltage detection pin of the DC-DC converter unit 133 sends a low voltage signal to the microcontroller. The microcontroller automatically switches to backup lithium battery power and sends a "low battery warning" to the terminal to remind maintenance personnel to check the tested wires or replace the lithium battery in time.

[0116] Signal anomaly handling: Troubleshooting communication links using terminal software ( Does it satisfy the formula? The system indicates the location of the fault (e.g., "Front-end wireless module fault"), and maintenance personnel can replace the component using the quick-release mechanism.

[0117] Routine maintenance: Regularly (e.g., monthly) check the tightness of the hinged locking clips, the sealing of the shielded cable connectors, and clean the dust from the terminal analysis module interfaces; replace the spare lithium battery annually to ensure reliable emergency power supply.

[0118] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A current monitoring device comprising a front-end monitoring unit (1) and a back-end analysis unit (2), characterized in that: The front-end monitoring unit (1) comprises an open-close current sensing module (11), a data acquisition and transmission module (12) and a double-CT power supply module (13), and the back-end analysis unit (2) comprises a wireless data receiving module (21) and a terminal analysis module (22); The signal output end of the open-close current sensing module (11) is electrically connected with the signal input end of the data acquisition and transmission module (12) through a first shielded cable, and the power supply output end of the double-CT power supply module (13) is electrically connected with the power supply interface of the data acquisition and transmission module (12) through a second shielded cable, The wireless transmitting end of the data acquisition and transmission module (12) is connected with the wireless receiving end of the wireless data receiving module (21) through a wireless communication protocol signal, and the signal output end of the wireless data receiving module (21) is electrically connected with the signal input end of the terminal analysis module (22) through a USB interface cable; The open-close current sensing module (11) and the double-CT power supply module (13) are fixed side by side through a mechanical support and are collectively sleeved on the measured primary conductor, and the data acquisition and transmission module (12) is fixed on the side surface of the mechanical support through a bolt.

2. The current monitoring device of claim 1, wherein: The open-close current sensing module (11) comprises two symmetrical semicircular sensing coils, a size adjusting ring and an open-close fixing buckle; One end of the two semicircular sensing coils is rotatably connected through a hinge, and the other end is detachably connected through the open-close fixing buckle, so as to form a closed ring structure; The size adjusting ring is sleeved on the inner side of the semicircular sensing coil and is clamped with the inner wall of the coil through an elastic buckle; The signal lead-out wire of the sensing coil is welded to the signal connection terminal, and the signal connection terminal is fixedly connected with the joint of the first shielded cable through a threaded structure.

3. The current monitoring device of claim 1, wherein: The data acquisition and transmission module (12) comprises a single-chip microcomputer master control chip (121), an analog-digital conversion unit (122) and a first wireless transmission chip (123); The signal input end of the analog-digital conversion unit (122) is welded with the output end of the first shielded cable, and the signal output end of the analog-digital conversion unit (122) is electrically connected with the I / O interface of the single-chip microcomputer master control chip (121) through PCB wiring; The communication interface of the first wireless transmission chip (123) is electrically connected with the corresponding interface of the single-chip microcomputer master control chip (121) through an SPI bus, and the antenna interface of the first wireless transmission chip (123) is connected with an external antenna through a feeder; The power supply pin of the single-chip microcomputer master control chip (121) is electrically connected with the output end of the second shielded cable through a voltage stabilizing circuit.

4. The current monitoring device of claim 1, wherein: The double-CT power supply module (13) comprises two open-close power supply coils (131), a rectifier and filter unit (132), a DC-DC conversion unit (133) and a backup lithium battery (134); The two open-close power supply coils (131) are respectively electrically connected with the two input ends of the rectifier and filter unit (132) through wires, the output end of the rectifier and filter unit (132) is divided into two paths, one path is directly electrically connected with the input end of the DC-DC conversion unit (133), and the other path is electrically connected with the charge-discharge interface of the backup lithium battery (134) through a charge management chip, The output end of the DC-DC conversion unit (133) is welded with the input end of the second shielded cable, and the voltage detection pin of the DC-DC conversion unit (133) is electrically connected with the single-chip microcomputer master control chip (121) of the data acquisition and transmission module (12) through a wire.

5. The current monitoring device of claim 1, wherein: The wireless data receiving module (21) comprises a second wireless transmission chip (211) and a signal conditioning unit (212); The receiving antenna of the second wireless transmission chip (211) is connected with an external receiving antenna through a feeder, and the signal output end of the second wireless transmission chip (211) is electrically connected with the input end of the signal conditioning unit (212) through PCB board wiring; The output end of the signal conditioning unit (212) is welded with a USB interface female seat, and is detachably connected with the USB interface of the terminal analysis module (22) through a USB male-female head structure.

6. The current monitoring device of claim 2, wherein: The size adjusting ring is made of rubber material with a Shore hardness of 50-70 degrees, and elastic openings are uniformly arranged on the ring body, and the inner diameter of the adjusting ring can be self-adaptively expanded and contracted within a range of 10mm-50mm. The opening and closing type fixing buckle comprises a clamping hook and a clamping groove which are adapted to each other, and the clamping hook is provided with an elastic lock tongue at the tail end, and the lock tongue is clamped and fixed with the positioning hole of the clamping groove.

7. The current monitoring device of claim 3, wherein: The analog-digital conversion unit (122) adopts a 16-bit high-precision ADC chip, and the sampling rate thereof is adjusted through the control pin of the single-chip microcomputer master control chip (121). The first wireless transmission chip (123) supports LoRa or NB-IoT communication protocol, and the transmission power thereof is controlled in stages through the PWM pin of the single-chip microcomputer master control chip (121).

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