A power distribution internet electric sensing terminal communication system and method for single-point or multi-point device failure prevention of all-link disconnection

Abstract

This invention discloses a communication system and method for power distribution IoT electrical sensing terminals to prevent full-link disconnection in the event of single-point or multi-point device failures. It relates to the field of power distribution IoT and, by adding a power supply timing synchronization control circuit, achieves synchronous and rapid power on / off of core loads, eliminating abnormal interference signals at the source. It also incorporates a terminal-autonomous fault isolation unit to achieve precise and rapid disconnection of faulty nodes, completely blocking the fault propagation path. This invention does not require modification of the original network architecture and communication protocol. While retaining supercapacitor backup power supply and meeting standard power supply indicators, it overcomes the industry challenge of a single-point failure paralyzing the entire bus. It can quickly self-heal without waiting for capacitor discharge, significantly improving the stability and fault tolerance of the power distribution sensing network. It is suitable for RS485 bus networking and maintenance scenarios for power distribution electrical sensing terminals and is fully compatible with three types of terminal devices: miniature intelligent current sensing modules, low-voltage rail-mounted current sensing modules, and low-voltage panel-mounted current sensing modules.

Description

Technical Field

[0001] This invention belongs to the field of power distribution Internet of Things (IoT) technology, and particularly relates to a power distribution IoT electrical sensing terminal communication system and method for preventing full-link disconnection in the event of single-point or multi-point equipment failure. Background Technology

[0002] In the process of large-scale construction of smart distribution networks and distribution IoT, RS485 bus has become the mainstream networking communication method for distribution IoT electrical sensing terminals due to its advantages such as simple wiring, long transmission distance, strong anti-interference ability, low hardware cost, and convenient networking. It is widely used for centralized collection, data transmission and remote control of electrical parameters such as current, voltage, temperature, residual current and harmonics of distribution lines. It is also the standard communication method for three types of distribution IoT electrical sensing terminals in China Southern Power Grid.

[0003] According to the mandatory requirements of the technical specifications for distribution IoT electrical sensing terminals of China Southern Power Grid, distribution IoT sensing terminals must have complete backup communication capabilities. In the event of a main power outage, they must ensure uninterrupted communication links and uninterrupted data acquisition and uploading for 30 seconds, guaranteeing the continuity and integrity of distribution network monitoring data. Simultaneously, the terminals must meet various testing requirements, including electromagnetic compatibility, insulation performance, environmental adaptability, and mechanical performance, and possess comprehensive event recording, fault recording, and protection linkage functions. Currently, the industry commonly uses supercapacitors as backup power supply units to provide short-term power to the terminal's core components to meet this mandatory technical requirement, and the backup power supply must ensure complete uploading of fault information after a power outage.

[0004] Existing traditional RS485 bus cascaded power distribution sensor terminals have unavoidable technical shortcomings: during the backup discharge of the supercapacitor, the power supply circuit lacks a synchronous control mechanism, making it prone to asynchronous operation where the MCU main control chip shuts down first while the RS485 isolation chip continues to be powered. In this situation, the main control chip loses its control function, the isolation chip lacks standardized signal drive, resulting in erratic output levels, distorted communication messages, continuous occupation of RS485 bus resources, disruption of bus communication timing, and damage to normal communication levels, creating persistent bus interference. This is the root cause of bus failures and violates electromagnetic compatibility and stable communication standards.

[0005] Due to the inherent limitations of the RS485 bus topology, when a single terminal experiences the aforementioned signal anomaly or passive disconnection, the fault interference signal will rapidly propagate and spread along the bus, directly blocking the entire communication loop. This causes a batch of normally operating terminals on the bus to lose connection and data acquisition to be interrupted, ultimately leading to a complete link paralysis. Such faults cannot recover quickly on their own; RS485 bus communication can only return to normal after the supercapacitor of the faulty terminal has completely discharged and the isolation chip has lost power and stopped interfering. Depending on the capacity of the supercapacitor, the duration of the circuit disconnection can range from a few minutes to as long as 30 minutes, severely affecting the real-time performance, continuity, and stability of distribution network operation monitoring. This significantly increases the difficulty and workload of on-site maintenance and troubleshooting, failing to meet the control requirements of efficient power grid operation and maintenance and rapid self-healing.

[0006] Existing technologies only focus on supercapacitor backup power to achieve power outage recovery, without making innovative improvements to address power supply timing misalignment and fault propagation. Most of them adopt a reactive approach of passively waiting for capacitor discharge and manually checking and replacing faulty terminals. This approach cannot balance backup communication compliance with bus fault resistance capabilities, nor can it fundamentally block the propagation path of single-point faults. It is difficult to meet the Southern Power Grid's requirements for high reliability, low fault impact, rapid self-healing, and long-term stable operation of distribution IoT terminals, nor can it match the standard indicators of a 10-year design lifespan and stable operation under all working conditions. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a power distribution IoT electrical sensing terminal communication system and method for preventing full-link disconnection in the event of single-point or multi-point device failures, thus solving the problems in the background technology.

[0008] This invention provides the following technical solution: A power distribution IoT electrical sensor terminal communication system for preventing full-link disconnection in the event of single-point or multi-point device failures includes: The supercapacitor backup power supply unit is used to provide 30 seconds of uninterrupted power supply to the core terminal devices when the main power supply fails. The power supply timing synchronization control unit is electrically connected to the supercapacitor backup power supply unit, the MCU main control chip and the RS485 isolation chip respectively. It is used to synchronously supply the backup power output of the supercapacitor to the MCU main control chip and the RS485 isolation chip to ensure that the two loads are powered on and off synchronously, and the time difference between the on and off of the two power supplies does not exceed 1ms. The autonomous fault isolation execution unit is connected in series between the terminal RS485 communication interface and the main RS485 bus. It uses a digital isolation chip with a default low output level to monitor the terminal's own power supply status, bus communication level, and message transmission stability in real time. When the terminal power supply is abnormal, the communication signal is distorted, or the bus is interfered with, the faulty terminal is physically isolated from the main bus.

[0009] Preferably, the autonomous fault isolation execution unit includes a signal, and the power supply timing synchronization control unit includes a voltage regulator circuit and a timing control circuit. The voltage regulator circuit is used to stabilize the input voltage within the operating voltage range of the MCU main control chip and the RS485 isolation chip. The timing control circuit adopts a high-precision timer and MOS transistor switching linkage design to accurately control the on and off times of the two power supplies.

[0010] The system includes a monitoring module, a fault determination module, and a high-speed electronic switch. The signal monitoring module is used to collect bus level signals, communication message signals, and local power supply voltage signals. The fault determination module is electrically connected to the signal monitoring module and has a built-in three-level progressive fault determination logic based on the Modbus-RTU communication protocol. The high-speed electronic switch is electrically connected to the fault determination module and is connected in series in the RS485 communication line.

[0011] Preferably, the response time of the high-speed electronic switch is no more than 10ms and has a one-way interlocking function, remaining in an open state until the fault is cleared and the power is restored for reset.

[0012] Preferably, the digital isolation chip is a π130U3x series three-channel digital isolator, which maintains a low level at the output terminal when the input side is not powered and the output side is powered.

[0013] Preferably, a power distribution IoT electrical sensing terminal communication system for preventing full-link disconnection in the event of single-point or multi-point device failure includes the following steps: When the main power supply is working normally, the power supply timing synchronization control unit is powered by the main power supply, and at the same time provides a stable operating voltage for the MCU main control chip and the RS485 isolation chip; When the main power supply fails, it automatically switches to the supercapacitor backup power supply mode to continue to synchronously supply power to the MCU main control chip and RS485 isolation chip, maintaining uninterrupted communication for 30 seconds. When the supercapacitor voltage discharges to a preset threshold of 2.5V, the power supply timing synchronization control unit simultaneously cuts off the power supply to the MCU main control chip and the RS485 isolation chip, with the time difference between the two power outages not exceeding 1ms.

[0014] Preferably, an autonomous fault isolation method for a power distribution IoT electrical sensor terminal communication system designed to prevent full-link disconnection in the event of single-point or multi-point device failures includes the following steps: S1: After the terminal is powered on, it completes hardware initialization, software initialization and bus status self-test. The high-speed electronic switch is turned on by default, and the terminal is connected to the RS485 bus. S2: Synchronously collect three types of signals with a fixed period of 10ms: local power supply voltage, RS485 bus differential level and Modbus-RTU communication message; S3: Perform a three-level progressive fault judgment according to priority from high to low: If the local power supply voltage is lower than 2.5V and lasts for more than 50ms, or there are CRC check errors in more than 3 consecutive frames, or the bus differential voltage deviates from the range of 200mV to 6V and lasts for more than 100ms, it is judged as a persistent fault. S4: Perform millisecond-level physical layer isolation, disconnect the electrical connection between the faulty terminal and the main bus, record the fault event and lock the isolation status. If it is within the 30-second backup power supply period, prioritize uploading the fault information. S5: Enter low-power silent monitoring state, collect its own power supply and bus status every 100ms. If 10 consecutive collections are normal, enter the recovery judgment. S6: When the power supply of the machine is stable above 2.5V for 1 second, the bus level is normal for 1 second, and there are no abnormalities after 3 consecutive tests, the high-speed electronic switch will be automatically turned on to restore normal communication of the terminal.

[0015] Preferably, when multiple terminals on the bus fail simultaneously, the autonomous fault isolation execution unit of each terminal independently executes the fault determination and isolation steps without affecting each other, and the terminal that fails first is isolated first.

[0016] Preferably, when the supercapacitor voltage drops below 2.0V, the MCU operation becomes unstable, and only a pure hardware-based isolation unit without an MCU can be used. The fault isolation steps are as follows: the digital isolation chip is a π130U3x series three-channel digital isolator. When any signal is abnormal, the signal of the 485 communication port is kept at a low level through the three-channel digital isolator and kept in an isolated state until the terminal is powered on and reset.

[0017] Preferably, the communication system is fully compatible with the Modbus-RTU communication protocol, without requiring any changes to the original RS485 bus networking architecture and master station communication commands, and is compatible with the three types of power distribution IoT electrical sensing terminals specified by China Southern Power Grid: miniature intelligent current sensing modules, low-voltage rail-mounted current sensing modules, and low-voltage panel-mounted current sensing modules.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention is a communication system and method for power distribution IoT electrical sensing terminals designed to prevent full-link disconnection in the event of single-point or multi-point device failures. It conforms to the mandatory specifications of power distribution IoT electrical sensing terminals of China Southern Power Grid, retains a supercapacitor backup power supply unit, and can stably maintain uninterrupted communication for 30 seconds after the main power supply of the terminal is cut off. This ensures that fault information and monitoring data are uploaded normally and the communication link remains uninterrupted during the power outage. At the same time, it meets all test requirements such as power supply indicators, insulation performance, electromagnetic compatibility, and environmental adaptability, taking into account both compliance and practicality.

[0019] Based on the innovative design of power supply timing synchronization, the power supply of the MCU main control chip and the RS485 isolation chip can be started and stopped synchronously, completely eliminating problems such as abnormal level, message distortion and bus crowding caused by uneven discharge timing of supercapacitors. This eliminates the cause of failure from the source, meets the control requirements of power grid electromagnetic compatibility and stable communication, and avoids interference signals affecting the entire bus.

[0020] By using an independent and autonomous terminal isolation unit, local rapid disconnection of single-point faults is achieved, blocking the transmission path of interference signals. This fundamentally solves the problem of batch disconnection of the entire circuit and bus paralysis caused by the abnormality of a single device. The data acquisition, switch linkage, event recording, and protection functions of normal terminals are not affected in any way, ensuring uninterrupted power distribution monitoring.

[0021] Abandoning the drawbacks of traditional solutions that require waiting for the supercapacitor to fully discharge before communication can be restored, the bus becomes uninterrupted immediately after the faulty terminal is isolated, without the need to wait several minutes to 30 minutes. This achieves second-level self-healing of the communication link, ensuring continuous and uninterrupted data acquisition and fault monitoring, and reducing the workload of on-site maintenance.

[0022] No changes to the existing bus wiring or adjustments to the master station communication commands are required. It is fully compatible with the existing network architecture, Modbus-RTU communication protocol, and three types of sensor terminal models of China Southern Power Grid. The hardware modifications are minimal and the cost is controllable. It is suitable for various indoor and outdoor installation environments, reduces the difficulty of operation and maintenance, and comprehensively improves the fault tolerance and operational stability of the power distribution sensor network, meeting the 10-year design life requirements of the terminal. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0024] Fig. 1 This is a schematic diagram of the overall design of the communication system of the present invention. Fig. 2 This is the truth table of the default low-level output digital isolation chip used in this invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0027] Example refer to Figs. 1-2 A power distribution IoT electrical sensing terminal communication system for preventing full-link disconnection in the event of single-point or multi-point device failure includes: a supercapacitor backup power supply unit, used to provide uninterrupted power supply to the core devices of the terminal for 30 seconds when the main power supply fails; a power supply timing synchronization control unit, electrically connected to the supercapacitor backup power supply unit, the MCU main control chip and the RS485 isolation chip respectively, used to synchronously supply the backup power output of the supercapacitor to the MCU main control chip and the RS485 isolation chip, ensuring that the two loads are powered on and off synchronously, and the time difference between the on and off of the two power supplies does not exceed 1ms; and an autonomous fault isolation execution unit, connected in series between the terminal RS485 communication interface and the main RS485 bus, using a digital isolation chip with a default low output level, used to monitor the terminal's own power supply status, bus communication level and message transmission stability in real time, and when an abnormal power supply, communication signal distortion and interference with the bus are detected, autonomously execute a disconnection action of no more than 10ms to physically isolate the faulty terminal from the main bus.

[0028] The power supply timing synchronization control unit includes a voltage regulator circuit and a timing control circuit. The voltage regulator circuit is used to stabilize the input voltage within the operating voltage range of the MCU main control chip and the RS485 isolation chip. The timing control circuit adopts a high-precision timer and MOS transistor switching linkage design to accurately control the on and off times of the two power supplies.

[0029] The power supply timing synchronization control unit is also electrically connected to the main power supply circuit. When the main power supply is in normal operation, it is powered by the main power supply. When the main power supply fails, it automatically switches to supercapacitor backup power supply. In both power supply modes, the MCU main control chip and RS485 isolation chip are kept in power supply synchronization.

[0030] The autonomous fault isolation execution unit includes: a signal monitoring module for acquiring bus level signals, communication message signals, and local power supply voltage signals; a fault determination module electrically connected to the signal monitoring module, which incorporates a three-level progressive fault determination logic based on the Modbus-RTU communication protocol to determine whether a terminal has malfunctioned and is interfering with the bus based on the acquired signals; and a high-speed electronic switch electrically connected to the fault determination module and connected in series in the RS485 communication line to perform a disconnection action when the fault determination module determines a fault. The response time of the high-speed electronic switch is no more than 10ms, and it has a one-way interlocking function, remaining in an open state until the fault is cleared and the power is restored. The digital isolation chip is a π130U3x series three-channel digital isolator. When the input side of this MCU chip is not powered (power supply voltage is below 2.0V) and the output side is powered, the output terminal remains in a low-level state. The communication system is fully compatible with the Modbus-RTU communication protocol and requires no modification to the original RS485 bus networking architecture and master station communication commands. The communication system is compatible with three types of distribution IoT electrical sensing terminals specified by China Southern Power Grid: miniature intelligent current sensing modules, low-voltage rail-mounted current sensing modules, and low-voltage panel-mounted current sensing modules.

[0031] A power supply timing synchronization control method for a power distribution IoT electrical sensor terminal communication system designed to prevent full-link disconnection in the event of single-point or multi-point device failures includes the following steps: When the main power supply is working normally, the power supply timing synchronization control unit is powered by the main power supply, and at the same time provides a stable operating voltage for the MCU main control chip and the RS485 isolation chip; When the main power supply fails, it automatically switches to the supercapacitor backup power supply mode to continue to supply power to the MCU main control chip and RS485 isolation chip synchronously, maintaining uninterrupted communication for 30 seconds. When the supercapacitor voltage discharges to a preset threshold, the power supply timing synchronization control unit simultaneously cuts off the power supply to the MCU main control chip and the RS485 isolation chip, with the time difference between the two power outages not exceeding 1ms.

[0032] According to claim 9, the power supply timing synchronization control method is characterized in that the preset threshold is 2.5V, and when the supercapacitor voltage is lower than 2.50V, a synchronous power-off action is triggered.

[0033] An autonomous fault isolation method for a power distribution IoT electrical sensor terminal communication system designed to prevent full-link disconnection in the event of single-point or multi-point device failures includes the following steps: S1: After the terminal is powered on, the autonomous fault isolation execution unit completes hardware initialization, software initialization and bus status self-test. The high-speed electronic switch is turned on by default, and the terminal is connected to the RS485 bus. S2: Synchronously collect three types of signals with a fixed period of 10ms: local power supply voltage, RS485 bus differential level and Modbus-RTU communication message; S3: Perform a three-level progressive fault determination according to priority from high to low. If any level determines that the fault is persistent, the fault isolation action is immediately executed. S4: Perform millisecond-level physical layer isolation, disconnect the electrical connection between the faulty terminal and the main bus, record the fault event, and lock the isolation state; S5: Enters low-power silent monitoring state, continuously monitoring its own power supply status and bus status; S6: When the fault is detected to be resolved and the bus status is normal, the recovery action is automatically executed and the terminal is reconnected to the bus.

[0034] The three-level progressive fault determination described in step S3 specifically includes: S31: Level 1 Local Power Supply Abnormality Judgment: If the local power supply voltage is lower than 2.5V and the duration exceeds 50ms, it is judged as a continuous power supply abnormality fault; S32: Second-level communication message anomaly judgment: If the CRC check of three or more consecutive Modbus-RTU messages is incorrect, it is judged as a persistent communication anomaly fault. S33: Third-level bus level abnormality judgment: If the bus differential voltage deviates from the standard range of 200mV to 6V and the duration exceeds 100ms, it is judged as a continuous bus interference fault.

[0035] The fault isolation action described in step S4 specifically includes: S41: The fault determination module simultaneously outputs a low-level signal to the high-speed electronic switch, and the two MOS transistors are turned off synchronously, completely cutting off the terminal RS485 communication interface from the main bus physical layer. S42: Set the fault isolation flag and lock the high-speed switch status to open; S43: Write the fault type, occurrence time, power supply voltage at the time of the fault, and bus level information into the terminal's internal Flash; S44: If it is in the 30-second backup power supply period after the main power supply fails, the fault information will be uploaded first before entering the silent state.

[0036] The silent monitoring state described in step S5 specifically includes: S51: Disable unnecessary peripherals, retain only ADC acquisition and timer functions, and minimize terminal power consumption; S52: Collects the local power supply voltage and bus differential voltage every 100ms; S53: If 10 consecutive data acquisitions show that the power supply and bus level are normal, then proceed to the fault recovery judgment stage.

[0037] The automatic recovery action described in step S6 specifically includes: S61: When the following three conditions are met simultaneously: the local power supply voltage is stable above 2.5V for 1 second, the bus differential voltage is stable within the range of 200mV to 6V for 1 second, and there are no abnormalities in the bus level detection for 3 consecutive times, the fault is determined to be eliminated. S62: Simultaneously outputs a high-level signal to the high-speed electronic switch, turns on the two MOSFETs synchronously, and reconnects the terminal to the bus; S63: Clear all fault counters and flags, restoring all normal functions of the terminal; S64: Record the fault recovery time to form a complete fault event chain.

[0038] When multiple terminals on the bus fail simultaneously, each terminal's autonomous fault isolation execution unit independently performs fault determination and isolation steps without affecting each other, and the terminal that fails first is isolated first.

[0039] As one possible implementation, when the supercapacitor voltage drops below 2.0V, the MCU operation becomes unstable, or the MCU is without power, a pure hardware-based isolation unit without an MCU can be used. The fault isolation steps are as follows: The digital isolation chip is a π130U3x series three-channel digital isolator. When any signal is abnormal, the three-channel digital isolator keeps the signal of the 485 communication port at a low level and maintains the isolation state until the terminal is powered on and reset. The system composition and components mainly include: This circuit is an electrically isolated RS485 communication interface circuit, consisting of a TP8485 RS485 transceiver, a multi-channel digital isolator π130U31, a bus surge protection circuit, and a fail-safe bias network. It achieves electrical isolation and differential signal transmission between the main control unit (MCU) side and the bus side. System composition: RS485 transceiver connection: The RO pin of U6 is connected to the VIA pin of U4, the DI pin is connected to the VIB pin of U4, and the DE and RE pins are shorted and connected to the VIC pin of U4. Isolation chip output connection: The VOA pin of U4 is connected to the source of Q4, the VOB pin is connected to the source of Q5, and the VOC pin is connected to the DE / RE pins of U6. High-speed switch connection: The drain of Q4 is connected to the A line of the main RS485 bus, and the drain of Q5 is connected to the B line of the main RS485 bus; the gates of Q4 and Q5 are connected to the PB0 and PB1 pins of U5, respectively. Signal monitoring connections: Bus line A is connected to the ADC1 pin of U5 after being divided by resistor R8. Bus line B is connected to the ADC2 pin of U5 after being divided by resistor R9. The VOA and VOB pins of U4 are connected to the UART_RX and UART_TX pins of U5 respectively for message parsing. The 3.3V power supply is connected to the ADC3 pin of U5.

[0040] The specific steps of the autonomous fault isolation method are as follows: S1: The A / B differential signal terminals of the TP8485 transceiver are respectively connected to bidirectional TVS surge suppression devices to absorb transient overvoltages on the bus side; at the same time, terminal A is connected to DC5V through a pull-up resistor network, and terminal B is connected to DGND through a pull-down resistor network to achieve fail-safe bias in the bus idle state and avoid misjudgment at the receiving end.

[0041] S2: The digital isolator is a dual-channel π130U31. Its primary power supply VDD1 is connected to the MCU power supply, and its secondary power supply VDD2 is connected to the TP8485 transceiver DC5V. The power supplies on both sides are completely isolated from the ground, cutting off the ground loop current and realizing an electrical isolation barrier.

[0042] S3: The primary signal channels of the digital isolator are connected to the RS485_TX, RS485_EN, and RS485_RX pins of the MCU, respectively, and the secondary signal channels are connected to the DI, DE / RE, and RD pins of the TP8485 transceiver, respectively, to realize isolated transmission of data transmission, transmission and reception control, and data reception signals.

[0043] S4: Under normal operating conditions, the MCU sends data via RS485_TX, which is then isolated by a digital isolator and input to the DI pin of the TP8485. Simultaneously, by setting the DE / RE pin via RS485_EN, the TP8485 enters transmit mode, converting single-ended data into differential signals and outputting them to the A / B bus. During reception, the TP8485 converts the bus differential signals into single-ended data, which is then isolated by a digital isolator and transmitted to the RS485_RX pin of the MCU.

[0044] S5: When the MCU supply voltage is below 2.0V and the main control unit cannot operate normally, the physical isolation barrier of the digital isolator is unaffected by the MCU power supply status, always maintaining electrical isolation between the circuits on both sides; the TVS protection circuit and Fail-Safe bias network on the bus side are independently powered by DC5V, continuously providing surge protection and stable bus bias; when the MCU side pins enter the position state, the digital isolator π130U31 outputs a low level, putting the DE / RE pins of TP8485 in the off mode, and the A / B terminals of TP8485 enter a high-impedance state, avoiding the injection of interference signals into the bus, ensuring the safety of bus-side devices and the stability of the communication link. This avoids affecting the normal communication of other devices on the bus, while not disrupting the differential bias state of the bus.

[0045] To verify the combined effectiveness of the power supply timing synchronization control unit and the autonomous fault isolation unit, the following comprehensive tests were conducted in accordance with the Southern Power Grid Distribution IoT Electrical Sensing Terminal Technical Specifications: Main power supply sudden power failure test: Test conditions: When 32 terminals are working normally, the main power supply is suddenly disconnected, and the power supply voltage of the MCU and RS485 isolation chip are measured simultaneously with an oscilloscope.

[0046] Test results: The two voltages dropped synchronously with a time difference of <0.8ms; after the supercapacitor maintained power supply for 30s, the two voltages were cut off synchronously; there were no abnormal interference signals on the bus, and communication with other terminals was normal as monitored from the background.

[0047] Single terminal failure simulation test: Test conditions: A terminal MCU crash was intentionally created, causing the RS485 transceiver to output garbled characters.

[0048] Test results: The autonomous fault isolation unit detected consecutive CRC errors within 12ms and immediately cut off the bus connection; the communication of the remaining 31 terminals on the bus was completely normal, and data acquisition was uninterrupted.

[0049] Multi-point fault simulation test: Test conditions: 32 units online simultaneously, simulating a power supply failure in 3 terminals.

[0050] Test results: The isolation unit of each terminal independently performed the disconnection action within 10ms; the bus communication remained normal and continued to discharge until the voltage dropped below 2.0V and the process was completely lost; no mass disconnection occurred.

[0051] Electromagnetic compatibility testing: Test standards: GB / T17626.2 (electrostatic discharge), GB / T17626.4 (electrical fast transient / burst), GB / T17626.5 (surge).

[0052] Test results: The system works normally, with no false or missed isolation, and meets the electromagnetic compatibility requirements of the power grid.

[0053] High and low temperature cycling test: Test conditions: 100 cycles of high and low temperatures from -40℃ to +80℃, with each cycle lasting 2 hours.

[0054] Test results: The system performance was stable, with no significant changes in synchronization time difference and isolation response time.

[0055] It passed the main power failure test, single terminal fault simulation test, multi-point fault simulation test, electromagnetic compatibility test and high and low temperature cycle test, and all performance indicators met the technical specifications of China Southern Power Grid.

[0056] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0057] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A power distribution IoT electrical sensing terminal communication system for preventing full-link disconnection in the event of single-point or multi-point equipment failure, characterized in that, include: The supercapacitor backup power supply unit is used to provide 30 seconds of uninterrupted power supply to the core terminal devices when the main power supply fails. The power supply timing synchronization control unit is electrically connected to the supercapacitor backup power supply unit, the MCU main control chip and the RS485 isolation chip respectively. It is used to synchronously supply the backup power output of the supercapacitor to the MCU main control chip and the RS485 isolation chip to ensure that the two loads are powered on and off synchronously, and the time difference between the on and off of the two power supplies does not exceed 1ms. The autonomous fault isolation execution unit is connected in series between the terminal RS485 communication interface and the main RS485 bus. It uses a digital isolation chip with a default low output level to monitor the terminal's own power supply status, bus communication level, and message transmission stability in real time. When an abnormal power supply to the terminal or a distorted communication signal that interferes with the bus is detected, the unit will autonomously execute a disconnection action within 10ms to physically isolate the faulty terminal from the main bus.

2. The power distribution IoT electrical sensing terminal communication system for preventing full-link disconnection in the event of single-point or multi-point equipment failure as described in claim 1, characterized in that, The power supply timing synchronization control unit includes a voltage regulator circuit and a timing control circuit. The voltage regulator circuit is used to stabilize the input voltage within the operating voltage range of the MCU main control chip and the RS485 isolation chip. The timing control circuit adopts a high-precision timer and MOS transistor switching linkage design to accurately control the on and off times of the two power supplies.

3. The power distribution IoT electrical sensing terminal communication system for preventing full-link disconnection in the event of single-point or multi-point equipment failure as described in claim 1, characterized in that, The autonomous fault isolation execution unit includes a signal monitoring module, a fault determination module, and a high-speed electronic switch; the signal monitoring module is used to collect bus level signals, communication message signals, and local power supply voltage signals; the fault determination module is electrically connected to the signal monitoring module and has a built-in three-level progressive fault determination logic based on the Modbus-RTU communication protocol; the high-speed electronic switch is electrically connected to the fault determination module and is connected in series in the RS485 communication line.

4. A power distribution IoT electrical sensing terminal communication system for preventing full-link disconnection in the event of single-point or multi-point equipment failure, as described in claim 3, is characterized in that... The high-speed electronic switch has a response time of no more than 10ms and a one-way interlocking function, remaining in the open state until the fault is cleared and the power is restored for reset.

5. A power distribution IoT electrical sensing terminal communication system for preventing full-link disconnection in the event of single-point or multi-point equipment failure, as described in claim 1, is characterized in that... The digital isolation chip is a π130U3x three-channel digital isolator. When the input side is not powered and the output side is powered, the output terminal remains at a low level.

6. A power supply timing synchronization control method for a communication system according to any one of claims 1-5, characterized in that, Includes the following steps: When the main power supply is working normally, the power supply timing synchronization control unit is powered by the main power supply, and at the same time provides a stable operating voltage for the MCU main control chip and the RS485 isolation chip; When the main power supply fails, it automatically switches to the supercapacitor backup power supply mode to continue to supply power to the MCU main control chip and RS485 isolation chip synchronously, maintaining uninterrupted communication for 30 seconds. When the supercapacitor voltage discharges to a preset threshold of 2.5V, the power supply timing synchronization control unit simultaneously cuts off the power supply to the MCU main control chip and the RS485 isolation chip, with the time difference between the two power outages not exceeding 1ms.

7. An autonomous fault isolation method based on the communication system according to any one of claims 1-5, characterized in that, Includes the following steps: S1: After the terminal is powered on, it completes hardware initialization, software initialization and bus status self-test. The high-speed electronic switch is turned on by default, and the terminal is connected to the RS485 bus. S2: Synchronously collect three types of signals with a fixed period of 10ms: local power supply voltage, RS485 bus differential level and Modbus-RTU communication message; S3: Perform a three-level progressive fault judgment according to priority from high to low: If the local power supply voltage is lower than 2.5V and lasts for more than 50ms, or there are CRC check errors in more than 3 consecutive frames, or the bus differential voltage deviates from the range of 200mV to 6V and lasts for more than 100ms, it is judged as a persistent fault. S4: Perform millisecond-level physical layer isolation, disconnect the electrical connection between the faulty terminal and the main bus, record the fault event and lock the isolation status. If it is in the 30-second backup power supply period, the fault information will be uploaded first. S5: Enter low-power silent monitoring state, collect its own power supply and bus status every 100ms. If 10 consecutive collections are normal, enter the recovery judgment. S6: When the power supply of the machine is stable above 2.5V for 1 second, the bus level is normal for 1 second, and there are no abnormalities after 3 consecutive tests, the high-speed electronic switch will be automatically turned on to restore normal communication of the terminal.

8. The autonomous fault isolation method according to claim 7, characterized in that, When multiple terminals on the bus fail simultaneously, each terminal's autonomous fault isolation execution unit independently performs fault determination and isolation steps without affecting each other, and the terminal that fails first is isolated first.

9. The autonomous fault isolation method according to claim 7, characterized in that, For a hardware-based isolation unit without an MCU, the fault isolation steps are as follows.

10. A power distribution IoT electrical sensing terminal communication system for preventing full-link disconnection in the event of single-point or multi-point equipment failure, as described in claim 1, is characterized in that... The communication system is fully compatible with the Modbus-RTU communication protocol, requiring no modification to the original RS485 bus networking architecture and master station communication commands. It is also compatible with three types of power distribution IoT electrical sensing terminals specified by China Southern Power Grid: miniature intelligent current sensing modules, low-voltage rail-mounted current sensing modules, and low-voltage panel-mounted current sensing modules.

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