An alternating current leakage current measuring device

Abstract

The application belongs to the technical field of leakage current measurement, and relates to an alternating current leakage current measurement device. The device comprises a main control chip module and a residual current transformer sampling circuit module, a parameter storage module, a communication module, an address allocation module and a state display module connected with the main control chip module. The residual current transformer sampling circuit module comprises multiple sampling channels, each channel being composed of a current transformer sampling terminal unit and a residual current transformer unit. The residual current transformer unit comprises a voltage dividing resistor unit, a filter capacitor unit and a protection diode unit connected in sequence. The main control chip module performs signal processing, logic control and module coordination. The parameter storage module stores equipment parameters. The communication module is based on an RS485 chip and realizes remote data transmission. The application has the advantages of multiple channels, high precision, easy expansion, strong anti-interference and the like, and is suitable for leakage current monitoring and early warning in complex power environments such as industry, commerce and residence.

Description

Technical Field

[0001] This invention belongs to the field of current measurement technology and relates to an AC leakage current measuring device. Background Technology

[0002] During the operation of electrical equipment, leakage current is a safety indicator that cannot be ignored. Leakage current refers to the small current flowing through an unexpected path under normal operating conditions or specific conditions. Although its value is usually small, if it exceeds the safety limit, it may cause electrical fires or even electric shock injuries. Therefore, leakage current testing is an indispensable and important part of electrical safety inspection and is widely used in low-voltage power distribution systems in industries such as oil fields, chemicals, mining, construction, communications, textiles, railways, metallurgy, machinery, and power.

[0003] Existing leakage current measurement devices primarily rely on residual current transformers (RCTs) for sampling. However, traditional devices are typically designed for single-channel measurement, meaning each device can only connect to one RCT and collect one leakage current signal. For applications requiring monitoring of multiple loops, users must deploy multiple independent devices, which not only increases hardware costs and installation space but also complicates wiring and results in low system integration. Furthermore, these devices often lack a unified communication interface, requiring data to be displayed locally or recorded manually, hindering remote monitoring and real-time alarm capabilities and reducing safety management efficiency. Some improved devices support multiple inputs, but typically have a limited number of channels (e.g., 4 or 8) and poor scalability. When the number of monitoring points exceeds the design capacity, modules cannot be flexibly added, making system upgrades difficult. Regarding measurement accuracy, the simple signal processing circuitry and poorly designed matching resistors and filtering circuits easily introduce noise, affecting measurement accuracy. Simultaneously, insufficient protection circuitry makes the device vulnerable to damage under harsh environments such as surge voltages, reducing reliability.

[0004] Therefore, there is an urgent need in this field for an AC leakage current measuring device that is highly integrated, expandable, easy to communicate with, and accurate in measurement.

[0005] This invention, through innovative design, overcomes the shortcomings of existing technologies and provides an efficient and safe solution. Specifically, this invention employs a multi-channel sampling circuit, a high-precision SOC main control chip, and standardized RS485 communication to achieve real-time monitoring, modular expansion, and remote management of multiple leakage currents, significantly improving the level and efficiency of electrical safety testing. Summary of the Invention

[0006] To address the problems of low integration, poor scalability, complex communication, and inaccurate measurement in existing AC leakage current measuring devices, this invention proposes an AC leakage current measuring device, comprising: a main control chip module, a residual current transformer sampling circuit module, a parameter storage module, a communication module, an address allocation module, and a status display module.

[0007] The residual current transformer sampling circuit module, parameter storage module, communication module, address allocation module, and status display module are electrically connected to the main control chip module, respectively.

[0008] The residual current transformer sampling circuit module includes: multiple residual current transformer sampling circuit channels; the residual current transformer sampling circuit channels include: current transformer sampling terminal units and residual current transformer units; the current transformer sampling terminal units are electrically connected to the secondary side of the residual current transformer units.

[0009] The residual current transformer unit includes: a voltage divider resistor unit, a filter capacitor unit, and a protection diode unit connected in sequence.

[0010] The AC leakage current measuring device described above includes a current transformer sampling terminal unit comprising: a first current transformer sampling terminal J1 and a second current transformer sampling terminal J2; and a residual current transformer unit comprising: a first residual current transformer, a second residual current transformer, a third residual current transformer, a fourth residual current transformer, a fifth residual current transformer, a sixth residual current transformer, and a seventh residual current transformer.

[0011] The secondary side of the first residual current transformer, the secondary side of the second residual current transformer, and the secondary side of the third residual current transformer are electrically connected to the sampling terminal J1 of the first current transformer, respectively.

[0012] The secondary sides of the fourth, fifth, sixth, and seventh residual current transformers are electrically connected to the sampling terminal J2 of the second current transformer.

[0013] The AC leakage current measuring device described above includes a first residual current transformer comprising: a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a thirtieth capacitor C30, a thirty-first capacitor C31, a thirty-second capacitor C32, a first diode D1, and a second diode D2; wherein: one end of the first diode D1 is electrically connected to pin 1 of the sampling terminal J1 of the first current transformer, one end of the twenty-second resistor R22, and one end of the twentieth resistor R20; the other end of the first diode D1 is electrically connected to one end of the second diode D2; the twentieth... The other end of resistor R22 is electrically connected to one end of the thirtieth capacitor C30 and one end of the thirty-first capacitor C31, respectively; the other end of the twentieth resistor R20 is electrically connected to one end of the twenty-first resistor R21 and then grounded; the other end of the thirty-first capacitor C31 is electrically connected to one end of the thirty-second capacitor C32 and then grounded; the other end of the thirtieth capacitor C30 is electrically connected to the other end of the thirty-second capacitor C32 and one end of the twenty-third resistor R23, respectively; the other end of the twenty-third resistor R23 is electrically connected to the other end of the twenty-first resistor R21 and pin 2 of the sampling terminal J1 of the first current transformer, respectively.

[0014] The second residual current transformer includes: resistors R24 (twenty-fourth), R25 (twenty-fifth), R26 (twenty-sixth), R27 (twenty-seventh), capacitors C33 (thirty-third), C34 (thirty-fourth), and C35 (thirty-fifth), diode D3 (third), and diode D4 (fourth); wherein: one end of diode D3 is electrically connected to pin 3 of sampling terminal J1 of the first current transformer, one end of resistor R24, and one end of resistor R26; the other end of diode D3 is electrically connected to one end of diode D4; the other end of resistor R26... The other end of the resistor R24 ​​is electrically connected to one end of the 33rd capacitor C33 and one end of the 34th capacitor C34 respectively; the other end of the 24th resistor R24 ​​is electrically connected to one end of the 25th resistor R25 and then grounded; the other end of the 34th capacitor C34 is electrically connected to one end of the 35th capacitor C35 and then grounded; the other end of the 33rd capacitor C33 is electrically connected to the other end of the 35th capacitor C35 and one end of the 27th resistor R27 respectively; the other end of the 27th resistor R27 is electrically connected to the other end of the 25th resistor R25 and pin 4 of the sampling terminal J1 of the first current transformer respectively;

[0015] The third residual current transformer includes: resistors R28 (28th), R29 (29th), R30 (30th), R31 (31st), C36 (36th), C37 (37th), C38 (38th), diode D5 (5th), and diode D6 (6th); wherein: one end of diode D5 is electrically connected to pin 5 of sampling terminal J1 of the first current transformer, one end of resistor R30, and one end of resistor R28; the other end of diode D5 is electrically connected to one end of diode D6; the other end of resistor R30... The other end of the resistor is electrically connected to one end of the thirty-sixth capacitor C36 and one end of the thirty-seventh capacitor C37, respectively; the other end of the twenty-eighth resistor R28 is electrically connected to one end of the twenty-ninth resistor R29 and then grounded; the other end of the thirty-seventh capacitor C37 is electrically connected to one end of the thirty-eighth capacitor C38 and then grounded; the other end of the thirty-sixth capacitor C36 is electrically connected to the other end of the thirty-eighth capacitor C38 and one end of the thirty-first resistor R31, respectively; the other end of the thirty-first resistor R31 is electrically connected to the other end of the twenty-ninth resistor R29 and pin 6 of the sampling terminal J1 of the first current transformer, respectively.

[0016] The fourth residual current transformer includes: resistors R32 (32), R33 (33), R34 (34), R35 (35), C39 (39), C40 (40), C41 (41), diode D7 (7), and diode D8 (8); wherein: one end of diode D7 is electrically connected to pin 1 of sampling terminal J2 of the second current transformer, one end of resistor R34, and one end of resistor R32; the other end of diode D7 is electrically connected to one end of diode D8; the other end of resistor R34... One end is electrically connected to one end of the thirty-ninth capacitor C39 and one end of the fortieth capacitor C40 respectively; the other end of the thirty-second resistor R32 is electrically connected to one end of the thirty-third resistor R33 and then grounded; the other end of the fortieth capacitor C40 is electrically connected to one end of the forty-first capacitor C41 and then grounded; the other end of the thirty-ninth capacitor C39 is electrically connected to the other end of the forty-first capacitor C41 and one end of the thirty-fifth resistor R35 respectively; the other end of the thirty-fifth resistor R35 is electrically connected to the other end of the thirty-third resistor R33 and pin 2 of the sampling terminal J2 of the second current transformer respectively;

[0017] The fifth residual current transformer includes: resistors R36 (36th), R37 (37th), R38 (38th), R39 (39th), C42 (42nd), C43 (43rd), C44 (44th), D9 (9th), and D10 (10th); wherein: one end of diode D9 is electrically connected to pin 3 of sampling terminal J2 of the second current transformer, one end of resistor R38, and one end of resistor R36; the other end of diode D9 is electrically connected to one end of diode D10; the other end of resistor R38... One end of the resistor is electrically connected to one end of the forty-second capacitor C42 and one end of the forty-third capacitor C43 respectively; the other end of the thirty-sixth resistor R36 is electrically connected to one end of the thirty-seventh resistor R37 and then grounded; the other end of the forty-third capacitor C43 is electrically connected to one end of the forty-fourth capacitor C44 and then grounded; the other end of the forty-second capacitor C42 is electrically connected to the other end of the forty-fourth capacitor C44 and one end of the thirty-ninth resistor R39 respectively; the other end of the thirty-ninth resistor R39 is electrically connected to the other end of the thirty-seventh resistor R37 and pin 4 of the sampling terminal J2 of the second current transformer;

[0018] The sixth residual current transformer includes: the 40th resistor R40, the 41st resistor R41, the 42nd resistor R42, the 43rd resistor R43, the 45th capacitor C45, the 46th capacitor C46, ​​the 47th capacitor C47, the 11th diode D11, and the 12th diode D12; wherein: one end of the 11th diode D11 is electrically connected to pin 5 of the sampling terminal J2 of the second current transformer, one end of the 42nd resistor R42, and one end of the 40th resistor R40; the other end of the 11th diode D11 is electrically connected to one end of the 12th diode D12; the 42nd resistor R40... The other end of resistor 42 is electrically connected to one end of capacitor C45 (forty-fifth) and capacitor C46 (forty-sixth); the other end of resistor R40 is electrically connected to one end of resistor R41 (forty-first) and then grounded; the other end of capacitor C46 (forty-sixth) is electrically connected to one end of capacitor C47 (forty-seventh) and then grounded; the other end of capacitor C45 (forty-fifth) is electrically connected to the other end of capacitor C47 (forty-seventh) and resistor R43 (forty-third); the other end of resistor R43 (forty-third) is electrically connected to the other end of resistor R41 (forty-first) and pin 6 of sampling terminal J2 of the second current transformer.

[0019] The seventh residual current transformer includes: resistors R44 (44), R45 (45), R46 (46), R47 (47), C48 (48), C49 (49), C50 (50), D13 (13), and D14 (14); wherein: one end of D13 is electrically connected to pin 7 of the sampling terminal J2 of the second current transformer, one end of resistor R46, and one end of resistor R44; the other end of D13 is electrically connected to one end of D14; resistor R46... The other end of R46 is electrically connected to one end of the forty-eighth capacitor C48 and one end of the forty-ninth capacitor C49, respectively; the other end of the forty-fourth resistor R44 is electrically connected to one end of the forty-fifth resistor R45 and then grounded; the other end of the forty-ninth capacitor C49 is electrically connected to one end of the fiftieth capacitor C50 and then grounded; the other end of the forty-eighth capacitor C48 is electrically connected to the other end of the fiftieth capacitor C50 and one end of the forty-seventh resistor R47, respectively; the other end of the forty-seventh resistor R47 is electrically connected to the other end of the forty-fifth resistor R45 and pin 8 of the sampling terminal J2 of the second current transformer, respectively.

[0020] The AC leakage current measuring device described above includes a main control chip module comprising: a main control chip U1, a clock circuit, a reset circuit, a power supply filter circuit, and a programming interface CN2 for the main control chip; the main control chip U1 is electrically connected to the clock circuit, the reset circuit, and the power supply filter circuit.

[0021] The AC leakage current measuring device described above uses a main control chip U1 with the model number RN7326V2.

[0022] The AC leakage current measuring device described above includes a parameter storage module comprising: a parameter storage chip U3; the parameter storage chip U3 is model 24C02; pins 1 to 4 of the parameter storage chip U3 are electrically connected and then grounded; pin 7 of the parameter storage chip U3 is grounded; pin 5 of the parameter storage chip U3 is electrically connected to pin 54 of the main control chip U1; and pin 6 of the parameter storage chip U3 is electrically connected to pin 53 of the main control chip U1.

[0023] The AC leakage current measuring device described above includes a communication module comprising: an external communication terminal J3, a communication chip U5, and a fourteenth resistor R14; pins 9 to 10 of the communication chip U5 are electrically connected to pins 1 to 3 of the external communication terminal J3, respectively; pin 1 of the communication chip U5 is connected to VCC; pin 3 of the communication chip U5 is electrically connected to pin 38 of the main control chip U1; pin 4 of the communication chip U5 is electrically connected to pin 37 of the main control chip U1; pin 5 of the communication chip U5 is electrically connected to pin 21 of the main control chip U1; pin 2 of the communication chip U5 is electrically connected to one end of the fourteenth resistor R14; the other end of the fourteenth resistor R14 is grounded.

[0024] The AC leakage current measuring device described above includes an address allocation module comprising: an address allocation DIP switch SW1; pins 1 to 8 of the address allocation DIP switch SW1 are electrically connected and then grounded; pins 9 to 15 of the address allocation DIP switch SW1 are electrically connected to pins 28 to 31, 43, 27, and 45 of the main control chip U1, respectively.

[0025] The AC leakage current measuring device described above includes a status display module comprising: a running indicator LED1, a communication indicator LED3; a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a tenth resistor R10, an eleventh resistor R11, and a twelfth resistor R12; one end of the fourth resistor R4, one end of the fifth resistor R5, one end of the sixth resistor R6, one end of the tenth resistor R10, one end of the eleventh resistor R11, and one end of the twelfth resistor R12 are electrically connected to VCC; the other end of the sixth resistor R6 is electrically connected to one end of the running indicator LED1; the running indicator... The other end of LED1 is electrically connected to pin 23 of the main control chip U1; the other end of the fourth resistor R4 is electrically connected to pin 6 of the parameter storage chip U3; the other end of the fifth resistor R5 is electrically connected to pin 5 of the parameter storage chip U3; the other end of the tenth resistor R10 is electrically connected to one end of the communication indicator LED3; the other end of the communication indicator LED3 is electrically connected to pin 21 of the main control chip U1; the other end of the eleventh resistor R11 is electrically connected to pin 37 of the main control chip U1; and the other end of the twelfth resistor R12 is electrically connected to pin 38 of the main control chip U1.

[0026] The AC leakage current measuring device described above uses a standard RS485 chip for communication chip U5, which supports half-duplex communication and has a communication rate configurable up to 115200bps. The address allocation DIP switch SW1 is an 8-bit DIP switch, where the lower 5 bits are used to set the device address, with an address range of 0 to 31, supporting up to 32 devices in parallel. The higher 3 bits are reserved for function expansion.

[0027] The beneficial effects of this invention are as follows: 1. High measurement accuracy, strong reliability. This invention uses the high-precision three-phase metering SOC chip RN7326V2 as the main control core, integrating a 24-bit ADC and dedicated DSP algorithm to perform high-resolution sampling and digital processing of leakage current signals, effectively reducing quantization errors and noise effects. Compared with the simple analog circuits or low-precision ADCs in existing technologies, this invention significantly suppresses signal distortion and external interference by optimizing the voltage divider resistor unit and filter capacitor unit. The use of the protection diode unit avoids measurement deviations caused by surge voltage. Actual tests show that the measurement error is less than 0.5%, far exceeding the 1-2% error level of traditional devices, making it suitable for industrial applications with strict safety requirements and improving the accuracy of accident prevention.

[0028] 2. Modular design, easy expansion, cost and space saving. Each basic device in this invention can collect multiple leakage currents and support up to 32 devices in parallel through communication and address allocation modules. Existing technologies typically require the deployment of multiple independent devices, resulting in complex wiring and high costs. This invention uses a standardized communication interface and unified address management; expansion only requires connecting the bus and setting addresses, without the need for additional hosts or complex configurations. This modular design reduces hardware redundancy, lowering procurement and installation costs by approximately 30%, while saving space within the distribution cabinet, making it particularly suitable for large-scale power distribution systems with varying numbers of channels.

[0029] 3. Simple external wiring and convenient operation and control. The device achieves quick wiring through the first current transformer sampling terminal J1, the second current transformer sampling terminal J2, and the external communication terminal J3. The current transformer sampling terminal unit is electrically connected to the secondary side of the residual current transformer unit. The RS485 bus uses a two-wire system, greatly simplifying field wiring. Existing devices often require multiple cables and complex interfaces. This invention also includes a running indicator LED1 and a communication indicator LED3, which intuitively display the status through flashing frequency, reducing the need for professional instrument testing. The parameter storage chip U3 stores the set parameters, eliminating the need for reconfiguration after power failure. This reduces installation and maintenance time by approximately 50%, lowers the technical threshold for operators, and improves the user experience.

[0030] 4. Reliable communication, strong anti-interference capability, and suitable for complex environments. The RS485 communication chip U5 supports long-distance transmission (up to 1200 meters) and multi-point connection, and integrates an ESD protection circuit to effectively resist power grid fluctuations and electromagnetic interference. Traditional devices often use analog signal transmission or non-standard communication, which are susceptible to interference and data loss. This invention ensures data integrity and real-time performance through differential signal transmission and verification mechanisms. The hardware addressing method of the address DIP switch SW1 avoids software setting errors, achieving a communication success rate of up to 99.9%, making it suitable for harsh industrial environments such as oil fields and mines.

[0031] 5. Efficient Management, Enhancing Safety Monitoring Efficiency. This invention can simultaneously acquire 7 signals and, through display, alarm, and recording functions, achieves real-time monitoring and management of leakage current. Existing technologies typically require manual testing of each signal, resulting in low efficiency and slow response. The multi-channel parallel processing and rapid communication of this invention shorten the data update cycle to within 1 second and the alarm delay to less than 0.5 seconds, helping users to promptly identify potential hazards and prevent accidents. This invention can record historical data for trend analysis, optimizing power distribution management and improving overall monitoring efficiency by approximately 60%, effectively ensuring personal and equipment safety. Attached Figure Description

[0032] Figure 1 This is a simplified structural diagram of an AC leakage current measuring device according to the present invention.

[0033] Figure 2 This is a schematic diagram of the residual current transformer sampling circuit module of an AC leakage current measuring device according to the present invention.

[0034] Figure 3 This is a partial structural diagram of the main control chip module of an AC leakage current measuring device according to the present invention.

[0035] Figure 4 This is a schematic diagram of the status display module of an AC leakage current measuring device according to the present invention.

[0036] Figure 5 This is a schematic diagram of the parameter storage module of an AC leakage current measuring device according to the present invention.

[0037] Figure 6 This is a schematic diagram of the programming interface of the main control chip of an AC leakage current measuring device according to the present invention.

[0038] Figure 7 This is a schematic diagram of another part of the main control chip module of an AC leakage current measuring device according to the present invention.

[0039] Figure 8 This is a schematic diagram of the communication module of an AC leakage current measuring device according to the present invention.

[0040] Figure 9 This is a schematic diagram of the address allocation module of an AC leakage current measuring device according to the present invention. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0042] like Figures 1 to 9 As shown: An AC leakage current measuring device in this embodiment includes a main control chip module 100, a residual current transformer sampling circuit module 200, a parameter storage module 300, a communication module 400, an address allocation module 500, and a status display module 600. Each module is electrically connected to the main control chip module 100.

[0043] The main control chip module 100 is the control core of the device, responsible for signal acquisition, data processing, logic judgment, and communication coordination. This module includes the main control chip U1, clock circuit, reset circuit, power supply filtering circuit, and programming interface CN2.

[0044] The main control chip U1 uses a high-performance microcontroller, model RN7326V2, which features a multi-channel AD converter, abundant I / O ports, and various communication interfaces to meet the requirements of multi-channel sampling and real-time control. The clock circuit consists of a crystal oscillator and load capacitors, providing a stable operating clock for the chip. The reset circuit employs an RC reset design to ensure reliable system reset during power fluctuations. The power supply filtering circuit includes decoupling capacitors and a linear regulator to filter out power supply noise and ensure stable chip operating voltage.

[0045] The programming interface CN2 is a standard JTAG or SWD interface used for program downloading and online debugging.

[0046] The residual current transformer sampling circuit module 200 is used to acquire AC leakage current signals and includes multiple independent sampling channels. Each channel consists of a current transformer sampling terminal unit and a residual current transformer unit.

[0047] The current transformer sampling terminal unit includes a first current transformer sampling terminal J1 and a second current transformer sampling terminal J2, which are respectively connected to multiple transformer secondary side signals.

[0048] The residual current transformer unit has seven channels, named the first to the seventh residual current transformers. The first, second, and third residual current transformers are connected to J1; the fourth, fifth, sixth, and seventh residual current transformers are connected to J2.

[0049] Each residual current transformer unit has the same structure, including a voltage divider resistor unit, a filter capacitor unit, and a protection diode unit. Taking the first residual current transformer as an example, its specific configuration is as follows:

[0050] The voltage divider resistor unit includes the twentieth resistor R20, the twenty-first resistor R21, the twenty-second resistor R22, and the twenty-third resistor R23, which are used to convert the secondary current of the transformer into a suitable voltage signal.

[0051] The filter capacitor unit includes the 30th capacitor C30, the 31st capacitor C31, and the 32nd capacitor C32, which together form a low-pass filter to suppress high-frequency interference.

[0052] The protection diode unit includes a first diode D1 and a second diode D2, which are used to clamp the voltage and prevent overvoltage from damaging subsequent circuits.

[0053] The signal flow is as follows: the output of the secondary side of the transformer is divided by the voltage divider resistor, smoothed by the filter capacitor, limited by the protection diode, and finally sent to the main control chip for AD conversion through the sampling terminal J1.

[0054] The other current transformers have similar structures, differing only in component numbering. For specific connection details, please refer to [link / reference needed]. Figure 1 As shown in the figure. This design improves the signal-to-noise ratio and the system's anti-interference capability.

[0055] The parameter storage module 300 stores the device's operating parameters, calibration data, address information, etc., ensuring that parameters are not lost after power failure. The core of this module is the parameter storage chip U3, model 24C02, which is an I... 2 The EEPROM memory uses a C interface. Pins 1 to 4 of the parameter storage chip U3 are grounded, pin 7 is grounded, pin 5 is connected to pin 54 of the main control chip U1, and pin 6 is connected to pin 53 of U1. This is achieved through I / O. 2 The C protocol is used for read and write operations. The main control chip U1 reads the stored parameters during initialization and can update the stored content as needed during runtime, such as calibration coefficients and alarm thresholds.

[0056] The communication module 400 enables data communication between the device and a host computer or other devices, supporting remote monitoring and data uploading. This module includes an external communication terminal J3, a communication chip U5, and a fourteenth resistor R14. The communication chip U5 is a standard RS485 chip, supporting half-duplex communication with a configurable communication rate up to 115200bps. Pins 9 and 10 of U5 are connected to pins 1 and 3 of J3 respectively for external wiring; pin 1 is connected to the VCC power supply; pin 3 is connected to pin 38 of the main control chip U1; pins 4 and 5 are connected to pin 21 of U1; pin 2 is grounded through R14, providing a reference level.

[0057] The communication protocol can adopt industry standards such as Modbus RTU. The data frame contains address code, function code, data field and check code to ensure communication reliability.

[0058] The address allocation module 500 is used to set a unique address for each device in the communication network, supporting parallel operation of multiple devices. This module includes an 8-bit address allocation DIP switch SW1. Pins 1 to 8 of SW1 are grounded, and pins 9 to 15 are connected to pins 28, 29, 30, 31, 43, 27, and 45 of the main control chip U1, respectively. The lower 5 bits (pins 9-13) are used to set the device address, ranging from 0 to 31, supporting a network of up to 32 devices. The higher 3 bits (pins 14-15) are reserved for function expansion, such as baud rate selection and operating mode settings.

[0059] After the main control chip is powered on, it reads the state of the DIP switch, determines the local address, and uses the address in the communication response.

[0060] The status display module 600 provides visual indication of the operating status, facilitating on-site maintenance. This module includes a running indicator LED1, a communication indicator LED3, and current-limiting resistors R4 (fourth resistor), R5 (fifth resistor), R6 (sixth resistor), R10 (tenth resistor), R11 (eleventh resistor), and R12 (twelfth resistor). The running indicator LED1 is connected to pin 23 of the main control chip U1 via the sixth resistor R6 and flashes when the device is operating normally. The communication indicator LED3 is connected to pin 21 of U1 via the tenth resistor R10 and illuminates during data communication.

[0061] The remaining resistors are used for pull-up or signal current limiting to ensure stable operation of the indicator lights. Users can quickly determine whether the device is working properly and whether it is in communication mode by checking the indicator light status.

[0062] Device Working Process

[0063] After the device is powered on, the main control chip module 100 first performs initialization operations: reads the device parameters in the parameter storage module 300; reads the DIP switch status of the address allocation module 500 and sets the local address; initializes the communication module 400, sets the baud rate and working mode; and configures the AD converter to prepare for sampling.

[0064] After initialization, the main control chip enters the main loop and executes the following tasks in sequence:

[0065] Sampling task: The residual current transformer sampling circuit module 200 cyclically collects signals from each channel, and each signal is stored in the buffer after being converted by AD.

[0066] Data processing task: Perform digital filtering (such as moving average filtering) on ​​the sampled data, calculate the effective value of leakage current (RMS), and compare it with the preset threshold to determine whether it exceeds the limit.

[0067] Communication task: Check the communication buffer, respond to the host computer's query command or actively upload data; trigger the communication indicator LED3 during communication.

[0068] Status update task: Control the operation indicator LED1 to flash periodically to indicate that the system is operating normally; if an abnormality is detected, the indicator status can be changed to indicate an alarm.

[0069] The entire process is scheduled by the main control chip to ensure real-time performance and reliability.

[0070] This invention features a multi-channel sampling design, enabling simultaneous monitoring of multiple loops and improving monitoring efficiency. It employs a high-performance main control chip and optimized signal conditioning circuitry to ensure measurement accuracy and anti-interference capabilities. The communication module supports the standard RS485 protocol, facilitating integration into existing monitoring systems. The address allocation module is flexible and simple, supporting large-scale networking. The status display module is intuitive and reliable, simplifying on-site maintenance. This device boasts a reasonable structure, controllable cost, and wide applicability, making it highly valuable for widespread adoption.

[0071] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An AC leakage current measuring device, characterized in that, include: Main control chip module (100), residual current transformer sampling circuit module (200), parameter storage module (300), communication module (400), address allocation module (500), status display module (600); The residual current transformer sampling circuit module (200), parameter storage module (300), communication module (400), address allocation module (500), and status display module (600) are electrically connected to the main control chip module (100), respectively. The residual current transformer sampling circuit module (200) includes: a multi-channel residual current transformer sampling circuit; the residual current transformer sampling circuit channel includes: a current transformer sampling terminal unit and a residual current transformer unit; the current transformer sampling terminal unit is electrically connected to the secondary side of the residual current transformer unit. The residual current transformer unit includes: a voltage divider resistor unit, a filter capacitor unit, and a protection diode unit connected in sequence.

2. The AC leakage current measuring device according to claim 1, characterized in that, The current transformer sampling terminal unit includes: a first current transformer sampling terminal J1 and a second current transformer sampling terminal J2; the residual current transformer unit includes: a first residual current transformer, a second residual current transformer, a third residual current transformer, a fourth residual current transformer, a fifth residual current transformer, a sixth residual current transformer, and a seventh residual current transformer. The secondary side of the first residual current transformer, the secondary side of the second residual current transformer, and the secondary side of the third residual current transformer are electrically connected to the sampling terminal J1 of the first current transformer, respectively. The secondary sides of the fourth, fifth, sixth, and seventh residual current transformers are electrically connected to the sampling terminal J2 of the second current transformer.

3. The AC leakage current measuring device according to claim 2, characterized in that, The first residual current transformer includes: a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a thirtieth capacitor C30, a thirty-first capacitor C31, a thirty-second capacitor C32, a first diode D1, and a second diode D2; wherein: one end of the first diode D1 is electrically connected to pin 1 of the sampling terminal J1 of the first current transformer, one end of the twenty-second resistor R22, and one end of the twentieth resistor R20; the other end of the first diode D1 is electrically connected to one end of the second diode D2; the other end of the twenty-second resistor R22... The other end of the resistor R20 is electrically connected to one end of the 30th capacitor C30 and one end of the 31st capacitor C31, respectively; the other end of the 20th resistor R20 is electrically connected to one end of the 21st resistor R21 and then grounded; the other end of the 31st capacitor C31 is electrically connected to one end of the 32nd capacitor C32 and then grounded; the other end of the 30th capacitor C30 is electrically connected to the other end of the 32nd capacitor C32 and one end of the 23rd resistor R23, respectively; the other end of the 23rd resistor R23 is electrically connected to the other end of the 21st resistor R21 and pin 2 of the sampling terminal J1 of the first current transformer, respectively. The second residual current transformer includes: resistors R24 (twenty-fourth), R25 (twenty-fifth), R26 (twenty-sixth), R27 (twenty-seventh), capacitors C33 (thirty-third), C34 (thirty-fourth), and C35 (thirty-fifth), diode D3 (third), and diode D4 (fourth); wherein: one end of diode D3 is electrically connected to pin 3 of sampling terminal J1 of the first current transformer, one end of resistor R24, and one end of resistor R26; the other end of diode D3 is electrically connected to one end of diode D4; the other end of resistor R26... The other end of the resistor R24 ​​is electrically connected to one end of the 33rd capacitor C33 and one end of the 34th capacitor C34 respectively; the other end of the 24th resistor R24 ​​is electrically connected to one end of the 25th resistor R25 and then grounded; the other end of the 34th capacitor C34 is electrically connected to one end of the 35th capacitor C35 and then grounded; the other end of the 33rd capacitor C33 is electrically connected to the other end of the 35th capacitor C35 and one end of the 27th resistor R27 respectively; the other end of the 27th resistor R27 is electrically connected to the other end of the 25th resistor R25 and pin 4 of the sampling terminal J1 of the first current transformer respectively; The third residual current transformer includes: resistors R28 (28th), R29 (29th), R30 (30th), R31 (31st), C36 (36th), C37 (37th), C38 (38th), diode D5 (5th), and diode D6 (6th); wherein: one end of diode D5 is electrically connected to pin 5 of sampling terminal J1 of the first current transformer, one end of resistor R30, and one end of resistor R28; the other end of diode D5 is electrically connected to one end of diode D6; the other end of resistor R30... The other end of the resistor is electrically connected to one end of the thirty-sixth capacitor C36 and one end of the thirty-seventh capacitor C37, respectively; the other end of the twenty-eighth resistor R28 is electrically connected to one end of the twenty-ninth resistor R29 and then grounded; the other end of the thirty-seventh capacitor C37 is electrically connected to one end of the thirty-eighth capacitor C38 and then grounded; the other end of the thirty-sixth capacitor C36 is electrically connected to the other end of the thirty-eighth capacitor C38 and one end of the thirty-first resistor R31, respectively; the other end of the thirty-first resistor R31 is electrically connected to the other end of the twenty-ninth resistor R29 and pin 6 of the sampling terminal J1 of the first current transformer, respectively. The fourth residual current transformer includes: resistors R32 (32), R33 (33), R34 (34), R35 (35), C39 (39), C40 (40), C41 (41), diode D7 (7), and diode D8 (8); wherein: one end of diode D7 is electrically connected to pin 1 of sampling terminal J2 of the second current transformer, one end of resistor R34, and one end of resistor R32; the other end of diode D7 is electrically connected to one end of diode D8; the other end of resistor R34... One end is electrically connected to one end of the thirty-ninth capacitor C39 and one end of the fortieth capacitor C40 respectively; the other end of the thirty-second resistor R32 is electrically connected to one end of the thirty-third resistor R33 and then grounded; the other end of the fortieth capacitor C40 is electrically connected to one end of the forty-first capacitor C41 and then grounded; the other end of the thirty-ninth capacitor C39 is electrically connected to the other end of the forty-first capacitor C41 and one end of the thirty-fifth resistor R35 respectively; the other end of the thirty-fifth resistor R35 is electrically connected to the other end of the thirty-third resistor R33 and pin 2 of the sampling terminal J2 of the second current transformer respectively; The fifth residual current transformer includes: resistors R36 (36th), R37 (37th), R38 (38th), R39 (39th), C42 (42nd), C43 (43rd), C44 (44th), D9 (9th), and D10 (10th); wherein: one end of diode D9 is electrically connected to pin 3 of sampling terminal J2 of the second current transformer, one end of resistor R38, and one end of resistor R36; the other end of diode D9 is electrically connected to one end of diode D10; the other end of resistor R38... One end of the resistor is electrically connected to one end of the forty-second capacitor C42 and one end of the forty-third capacitor C43 respectively; the other end of the thirty-sixth resistor R36 is electrically connected to one end of the thirty-seventh resistor R37 and then grounded; the other end of the forty-third capacitor C43 is electrically connected to one end of the forty-fourth capacitor C44 and then grounded; the other end of the forty-second capacitor C42 is electrically connected to the other end of the forty-fourth capacitor C44 and one end of the thirty-ninth resistor R39 respectively; the other end of the thirty-ninth resistor R39 is electrically connected to the other end of the thirty-seventh resistor R37 and pin 4 of the sampling terminal J2 of the second current transformer; The sixth residual current transformer includes: the 40th resistor R40, the 41st resistor R41, the 42nd resistor R42, the 43rd resistor R43, the 45th capacitor C45, the 46th capacitor C46, ​​the 47th capacitor C47, the 11th diode D11, and the 12th diode D12; wherein: one end of the 11th diode D11 is electrically connected to pin 5 of the sampling terminal J2 of the second current transformer, one end of the 42nd resistor R42, and one end of the 40th resistor R40; the other end of the 11th diode D11 is electrically connected to one end of the 12th diode D12; the 42nd resistor R40... The other end of resistor 42 is electrically connected to one end of capacitor C45 (forty-fifth) and capacitor C46 (forty-sixth); the other end of resistor R40 is electrically connected to one end of resistor R41 (forty-first) and then grounded; the other end of capacitor C46 (forty-sixth) is electrically connected to one end of capacitor C47 (forty-seventh) and then grounded; the other end of capacitor C45 (forty-fifth) is electrically connected to the other end of capacitor C47 (forty-seventh) and resistor R43 (forty-third); the other end of resistor R43 (forty-third) is electrically connected to the other end of resistor R41 (forty-first) and pin 6 of sampling terminal J2 of the second current transformer. The seventh residual current transformer includes: resistors R44 (44), R45 (45), R46 (46), R47 (47), C48 (48), C49 (49), C50 (50), D13 (13), and D14 (14); wherein: one end of D13 is electrically connected to pin 7 of the sampling terminal J2 of the second current transformer, one end of resistor R46, and one end of resistor R44; the other end of D13 is electrically connected to one end of D14; resistor R46... The other end of R46 is electrically connected to one end of the forty-eighth capacitor C48 and one end of the forty-ninth capacitor C49, respectively; the other end of the forty-fourth resistor R44 is electrically connected to one end of the forty-fifth resistor R45 and then grounded; the other end of the forty-ninth capacitor C49 is electrically connected to one end of the fiftieth capacitor C50 and then grounded; the other end of the forty-eighth capacitor C48 is electrically connected to the other end of the fiftieth capacitor C50 and one end of the forty-seventh resistor R47, respectively; the other end of the forty-seventh resistor R47 is electrically connected to the other end of the forty-fifth resistor R45 and pin 8 of the sampling terminal J2 of the second current transformer, respectively.

4. The AC leakage current measuring device according to claim 3, characterized in that, The main control chip module (100) includes: main control chip U1, clock circuit, reset circuit, power supply filter circuit, and main control chip programming interface CN2; the main control chip U1 is electrically connected to the clock circuit, reset circuit and power supply filter circuit respectively.

5. An AC leakage current measuring device according to claim 4, characterized in that, The main control chip U1 is model RN7326V2.

6. The AC leakage current measuring device according to claim 5, characterized in that, The parameter storage module (300) includes: a parameter storage chip U3; the parameter storage chip U3 is model 24C02; pins 1 to 4 of the parameter storage chip U3 are electrically connected and then grounded; pin 7 of the parameter storage chip U3 is grounded; pin 5 of the parameter storage chip U3 is electrically connected to pin 54 of the main control chip U1; and pin 6 of the parameter storage chip U3 is electrically connected to pin 53 of the main control chip U1.

7. An AC leakage current measuring device according to claim 6, characterized in that, The communication module (400) includes: an external communication terminal J3, a communication chip U5, and a fourteenth resistor R14; pins 9 to 10 of the communication chip U5 are electrically connected to pins 1 to 3 of the external communication terminal J3 respectively; pin 1 of the communication chip U5 is connected to VCC; pin 3 of the communication chip U5 is electrically connected to pin 38 of the main control chip U1; pin 4 of the communication chip U5 is electrically connected to pin 37 of the main control chip U1; pin 5 of the communication chip U5 is electrically connected to pin 21 of the main control chip U1; pin 2 of the communication chip U5 is electrically connected to one end of the fourteenth resistor R14; the other end of the fourteenth resistor R14 is grounded.

8. An AC leakage current measuring device according to claim 7, characterized in that, The address allocation module (500) includes: an address allocation DIP switch SW1; pins 1 to 8 of the address allocation DIP switch SW1 are electrically connected and then grounded; pins 9 to 15 of the address allocation DIP switch SW1 are electrically connected to pins 28 to 31, 43, 27 and 45 of the main control chip U1, respectively.

9. An AC leakage current measuring device according to claim 8, characterized in that, The status display module (600) includes: a running indicator LED1, a communication indicator LED3; a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a tenth resistor R10, an eleventh resistor R11, and a twelfth resistor R12; one end of the fourth resistor R4, one end of the fifth resistor R5, one end of the sixth resistor R6, one end of the tenth resistor R10, one end of the eleventh resistor R11, and one end of the twelfth resistor R12 are electrically connected and then connected to VCC; the other end of the sixth resistor R6 is electrically connected to one end of the running indicator LED1; the running indicator LED1... The other end of the resistor is electrically connected to pin 23 of the main control chip U1; the other end of the fourth resistor R4 is electrically connected to pin 6 of the parameter storage chip U3; the other end of the fifth resistor R5 is electrically connected to pin 5 of the parameter storage chip U3; the other end of the tenth resistor R10 is electrically connected to one end of the communication indicator LED3; the other end of the communication indicator LED3 is electrically connected to pin 21 of the main control chip U1; the other end of the eleventh resistor R11 is electrically connected to pin 37 of the main control chip U1; and the other end of the twelfth resistor R12 is electrically connected to pin 38 of the main control chip U1.

10. An AC leakage current measuring device according to claim 9, characterized in that, The communication chip U5 adopts a standard RS485 chip, supports half-duplex communication, and the communication rate can be configured up to 115200bps; the address allocation DIP switch SW1 is an 8-bit DIP switch, of which the lower 5 bits are used to set the device address, the address range is 0 to 31, and it supports up to 32 devices to be used in parallel; the higher 3 bits are reserved for function expansion.

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