Rural power grid overhead line loop closing and power switching detection system and working method

Abstract

The invention discloses a rural power grid overhead line loop closing and battery replacing detection system and a working method. The system comprises two groups of acquisition units and a main control terminal which are respectively arranged at the wire inlet sides of two paths of power supplies to be closed. The acquisition unit acquires a voltage amplitude in real time by using a voltage induction module and a precise true virtual value converter, and locks a waveform crossing moment through a signal capture module based on a preset unified voltage threshold value to generate time characteristic data; and meanwhile, a potential reference system of three phases relative to a protection ground wire and a neutral wire is established. The data is transmitted to the master control terminal through a wireless encryption link, the master control terminal calculates a phase angle difference based on the time characteristic data, calculates a voltage difference in combination with a voltage amplitude, and verifies the phase sequence consistency by using a statistical analysis algorithm. And the logic judgment module compares the calculation result with a preset threshold value, and generates a loop closing permission instruction only when the condition is met. According to the invention, through distributed time domain feature capture and multi-dimensional phase sequence verification, accurate study and judgment and intelligent safety early warning of rural power grid loop closing operation are realized.

Description

Technical Field

[0001] This invention relates to the field of power supply technology, specifically to a detection system and working method for loop-connected power swapping of rural overhead power lines. Background Technology

[0002] With the advancement of rural power grid modernization and the widespread integration of distributed renewable energy, the requirements for the reliability of power distribution networks are increasingly stringent. During line maintenance, load cutover, fault isolation, or grid architecture adjustments in the distribution network, a loop-connection power transfer method is currently used to avoid power outages for users. This involves temporarily paralleling two previously independent power lines to achieve a smooth load transfer. Before performing the loop-connection operation, it is essential to ensure that the two lines to be connected meet strict paralleling conditions, including equal voltage amplitude, identical phase, and consistent phase sequence. Forcing a loop connection when these conditions are not met can lead to anything from massive steady-state circulating currents causing protection devices to trip to, in severe cases, asynchronous short circuits, resulting in line burnout or even catastrophic equipment damage.

[0003] Currently, loop closure detection for 10kV distribution networks relies on offline power flow calculations at the dispatching master station or measurements taken by on-site maintenance personnel using portable phase comparators. However, in practical applications of rural overhead lines, the aforementioned existing technical solutions face the following long-standing unresolved technical challenges: First, rural power grid lines are often characterized by large power supply radii, long lines, and complex wire diameters, and their impedance parameters are greatly affected by environmental factors such as temperature and humidity. Existing power flow calculations are mostly based on static theoretical models, which cannot accurately reflect the real-time impedance changes at the loop closure point.

[0004] Current market research indicates a lack of integrated devices capable of simultaneously and in real-time detecting the three-phase voltage, corresponding line voltage difference, phase angle, and phase angle difference of the branches on both sides of the loop to be closed. Existing methods are highly susceptible to uncontrollable circulating currents after loop closure due to inaccurate parameter control, and it is difficult to achieve visualized status monitoring. Furthermore, phase detection has weak anti-interference capabilities, and its accuracy is severely affected by harmonics.

[0005] With the increasing penetration of distributed photovoltaic and other new energy sources in rural power grids, the harmonic content in the power grid has increased significantly. Traditional portable phase comparators mostly rely on the principle of voltage zero-crossing detection to determine the phase relationship. This principle is highly susceptible to the influence of power grid harmonic distortion, causing the waveform zero-crossing point to drift, thus leading to phase measurement errors. In the absence of a high-precision time-domain synchronization mechanism, existing technologies struggle to accurately capture the minute phase difference between the two power sources on a millisecond-level time scale.

[0006] In summary, in order to address the problems of high risk of loop-closing operation, inaccurate parameter detection, and difficulty in phase sequence identification in complex rural power grid environments, the applicant proposes a loop-closing power swapping detection system and working method for rural overhead lines. Summary of the Invention

[0007] This invention addresses the shortcomings of existing technologies by proposing a loop-loop battery swapping detection system for rural overhead power lines. The specific technical solution of this system is as follows: A detection system for closed-loop power swapping of rural overhead power lines, characterized in that: Includes the data acquisition unit and the main control terminal; The main control terminal establishes wireless communication connections with the two sets of acquisition units respectively; The two sets of acquisition units are respectively set on the two power input lines of the loop to be closed, for distributed data monitoring; The acquisition unit is equipped with a voltage sensing module, a signal acquisition module, and a wireless transmission module; The voltage sensing module is used to collect the voltage amplitude signal of the corresponding line in real time; The signal acquisition module is used to capture the time information when the voltage waveform crosses the preset unified voltage threshold value to generate time feature data. The main control terminal is equipped with a data processing module and a logic judgment module; The data processing module is used to receive the voltage amplitude signal and time characteristic data through wireless communication, calculate the phase angle difference between the two power input lines based on the time characteristic data, and calculate the voltage difference and phase sequence relationship in combination with the voltage amplitude signal. The logic judgment module is used to compare the calculated voltage difference, phase angle difference and phase sequence relationship with the preset loop closing condition threshold. If the comparison results all meet the preset conditions, an indication signal that allows loop closing is generated.

[0008] To better realize the present invention, it can be further: The data processing module is equipped with a phase sequence logic parsing unit, which is configured as follows: The two sets of acquisition units are controlled to establish potential reference systems for phase A, phase B, and phase C relative to the protective ground line PE and the neutral line N, respectively, so as to form a total of 12 signal channels to be tested covering the two power supply input sides. Based on the unified voltage threshold, the waveform crossing time of the 12 groups of signal channels under test is locked, and a phase sequence feature vector reflecting the potential timing characteristics of each phase is generated based on the crossing time. A statistical analysis algorithm is used to calculate the matching degree between the phase sequence characteristic vectors of the two power supply input lines, and the A, B, and C three-phase correspondence of the two power supply input lines is derived based on the combinational logic with the highest matching degree.

[0009] Furthermore, the acquisition unit also includes a signal conditioning module, which has a built-in AC / DC converter configured to convert low-voltage analog signals with a frequency range of 0 to 460 kHz into DC voltage signals.

[0010] Furthermore, the acquisition unit also includes a temperature and humidity acquisition module, which includes a capacitive humidity sensor and a thermocouple-to-digital converter with cold junction compensation function. The data processing module is configured to perform temperature drift compensation on the voltage amplitude signal based on the collected ambient temperature data.

[0011] Furthermore, the acquisition unit is equipped with a dual-mode power supply interface, which includes a long-term monitoring power supply interface for connecting the photovoltaic panel and the rechargeable battery, and a temporary maintenance power supply interface for connecting an independent lithium battery pack.

[0012] Furthermore: the voltage sensing module is equipped with a high-voltage isolation transformer and a signal conditioning circuit; The signal conditioning circuit integrates an AC / DC converter, which is configured to convert the AC analog signal stepped down by the high-voltage isolation transformer into a DC voltage signal within a frequency response range of 0 to 460 kHz, and control the overall measurement error within ±3%.

[0013] Furthermore, the acquisition unit also integrates an environmental sensing module, which includes a capacitive humidity sensor and a thermocouple-to-digital converter with cold junction compensation function; the main control terminal is configured to receive the temperature and humidity digital signals output by the environmental sensing module, and to perform environmental drift correction on the voltage amplitude signal based on the temperature and humidity digital signals.

[0014] The specific technical solution for the working method of a loop-connected battery swapping detection system for rural overhead power lines is as follows: A working method for a rural overhead power line loop-swapping detection system, characterized in that: Includes the following steps: S1: The acquisition unit uses a voltage sensing module to sense the three-phase AC signal of the high-voltage line in real time, and after the high-voltage signal is stepped down by a voltage transformer, it is input to the signal conditioning circuit of the AC / DC converter. S2: The signal conditioning circuit processes the stepped-down analog signal within a frequency response range of 0 to 460 kHz, outputs the effective voltage value data corresponding to the three-phase line in real time, and controls the overall measurement error within a preset range. S3: A unified voltage threshold value is preset in the signal acquisition modules of the two sets of acquisition units, and the unified voltage threshold value is used as the reference level for waveform time-domain feature comparison of the dual power supplies; S4: The signal acquisition module monitors the three-phase voltage waveform in real time, locks the moment when the waveform amplitude crosses the unified voltage threshold, records the rising edge trigger moment and the falling edge end moment respectively, and generates time feature data containing timestamps. S5: The acquisition unit establishes potential reference systems for phases A, B, and C relative to the protective ground wire PE and the neutral wire N, respectively, forming 12 sets of signal channels to be measured, and statistically generates phase sequence feature vectors that reflect the potential timing characteristics of each phase based on the time feature data. S6: The acquisition unit uses a wireless transmission module to package the voltage RMS data, time characteristic data and phase sequence characteristic vector, and sends them to the main control terminal in real time through a wireless communication link; S7: After receiving the data, the data processing module of the main control terminal calculates the phase angle difference by comparing the waveform crossing time difference of the corresponding phases of the two power supplies based on the same time reference. Simultaneously, the voltage amplitude difference is calculated based on the aforementioned effective voltage value data; S8: The data processing module calls the phase sequence logic parsing unit, uses a statistical analysis algorithm to calculate the matching degree between the phase sequence feature vectors on both sides, and derives the A, B, and C three-phase correspondence of the two power supply input lines based on the matching degree to verify the phase sequence consistency. S9: The logic judgment module of the main control terminal will perform a multi-dimensional comparison between the calculated phase angle difference, voltage amplitude difference and phase sequence consistency results and the preset loop closing condition threshold. Only when all parameters meet the preset conditions will a loop closing indication signal be generated.

[0015] To better realize the present invention, it can be further: The system also includes step S10: when the logic judgment module determines that any one of the phase angle difference, voltage amplitude difference, or phase sequence consistency does not meet the preset loop closing conditions, or when the system self-test detects a sensor failure or communication interruption device fault, an alarm trigger signal is immediately generated. The main control terminal responds to the alarm trigger signal by issuing an audible and visual warning and visually displays the specific parameter deviation value or device fault code that caused the loop closing to be prohibited on the display interface.

[0016] Furthermore: The main control terminal's storage unit is pre-loaded with a fault handling strategy library. When the alarm trigger signal is generated, the main control terminal automatically retrieves the fault handling strategy library based on the current fault code or parameter deviation type, matches the corresponding fault location suggestions and solutions, and displays them synchronously with the alarm information on the display interface.

[0017] The beneficial effects of the present invention are as follows: First, the present invention abandons the traditional voltage zero-crossing detection method and adopts a time-domain feature capture technology based on a preset unified voltage threshold value.

[0018] This technology calculates the phase difference by locking the moment when the waveform crosses a specific threshold, effectively avoiding zero-crossing drift caused by harmonic distortion due to distributed power supply in rural power grids. Combined with a built-in single-chip precision true RMS AC / DC converter and high-frequency response signal conditioning circuit, it ensures accurate measurement of voltage amplitude and phase angle within a wide frequency band of 0–460kHz, solving the problem of large deviations in loop parameters caused by relying solely on theoretical calculations or low-end instruments.

[0019] Secondly, addressing the potential single-phase grounding hazards or neutral point potential drift issues in rural overhead power lines, this invention innovatively constructs 12 signal channels covering phases A, B, and C relative to the protective ground wire (PE) and the neutral wire (N), respectively. By generating and statistically analyzing multi-dimensional phase sequence feature vectors, the system can accurately identify the line phase sequence through logical deduction when the grounding state is unstable or there is interference, effectively preventing asynchronous closing or phase-to-phase short circuit accidents caused by line voltage misleading.

[0020] Third, the system integrates an environmental sensing module that includes a capacitive humidity sensor and cold junction compensation. The main control terminal can correct the voltage amplitude signal for environmental drift based on the real-time collected temperature and humidity data, effectively overcoming the impact of harsh outdoor environments on electrical parameter measurements in rural power grids and ensuring the long-term stability and consistency of the test data under different seasons and climatic conditions.

[0021] Fourth, this invention changes the traditional operation mode that relies on human experience to make judgments. It automatically compares the voltage difference, phase angle difference and phase sequence consistency through the logic judgment module of the main control terminal, and generates a loop closing instruction only when the preset threshold is met.

[0022] Simultaneously, combined with a pre-built fault handling strategy library, the device can not only issue audible and visual alarms when conditions are not met, but also simultaneously present specific fault location suggestions and solutions. This visualized intelligent guidance lowers the technical threshold for on-site maintenance personnel and significantly improves fault diagnosis efficiency and the safety of loop-closing operations. Attached Figure Description

[0023] Figure 1 This is a system diagram of the present invention; Figure 2 This is a flowchart of the process of the present invention. Detailed Implementation

[0024] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] A specific technical solution for a rural overhead power line loop-to-loop battery swapping detection system is as follows: Figure 1 As shown: The system mainly consists of two sets of data acquisition units and one main control terminal. The two sets of data acquisition units are installed at the power inlets on both sides of the line to be closed, and the main control terminal is held by maintenance personnel as a handheld or vehicle-mounted device.

[0026] Both sets of acquisition units are encapsulated in an insulated shell and are designed with clamps for mounting on 10kV overhead conductors.

[0027] Each acquisition unit integrates a voltage sensing module, a signal acquisition module, a wireless transmission module, an environmental sensing module, and a power supply module.

[0028] The voltage sensing module uses a high-precision electromagnetic voltage transformer. The primary side of the voltage sensing module directly senses the three-phase AC signal of the high-voltage line, and the secondary side outputs a stepped-down low-voltage analog signal to achieve electrical isolation between the high-voltage side and the low-voltage measurement circuit.

[0029] A signal conditioning circuit is connected between the signal acquisition module and the voltage sensing module within the acquisition unit. The core component of this signal conditioning circuit is a monolithic precision true RMS AC / DC converter. This converter is manufactured using laser correction technology and has a full-scale measurement range of 200mV RMS, with an operating frequency response range covering 0Hz to 460kHz.

[0030] Through this converter, the acquisition unit can convert the complex AC waveform after step-down into a high-precision DC voltage signal. The overall measurement error is controlled within ±3% by the hardware circuit, ensuring accurate acquisition of the fundamental voltage amplitude under the harmonic interference environment of rural power grid.

[0031] To achieve high-precision phase and phase sequence detection, the signal acquisition module is implemented using a high-speed microcontroller or FPGA chip.

[0032] This module has a pre-set uniform voltage threshold, which is a fixed level reference point based on the system's rated voltage. The signal acquisition module is configured to monitor the input waveform in real time. When it detects that the voltage waveform amplitude crosses the uniform voltage threshold, it immediately triggers an internal high-precision timer to record the timestamps of the rising edge trigger time and the falling edge end time. These two timestamps form the basis for generating time feature data for subsequent time-domain analysis.

[0033] The acquisition unit also integrates an environmental sensing module, which consists of a capacitive humidity sensor and a thermocouple-to-digital converter. The thermocouple-to-digital converter is connected to a K-type thermocouple probe and has a built-in cold junction temperature compensation circuit, enabling it to convert analog temperature signals into digital signals with a resolution of 0.25°C. The wireless transmission module uses an industrial-grade wireless communication chip to package and transmit the acquired voltage data, time characteristic data, and environmental data.

[0034] In terms of power supply structure, the acquisition unit is equipped with a dual-mode power supply interface to adapt to different field operation requirements. The first interface is a long-term monitoring power supply interface, which is connected to a photovoltaic panel with a rated power of 100W and a rechargeable battery with a capacity of 32Ah, suitable for long-term field monitoring. The second interface is a temporary maintenance power supply interface, designed with a pluggable structure, for direct connection to an independent high-energy lithium battery pack, suitable for short-term temporary live-line work.

[0035] The main control terminal mainly consists of a central processing unit, a wireless communication receiving module, a storage unit, and a human-machine interaction display screen.

[0036] The central processing unit (CPU) internally operates a data processing module and a logic judgment module. The data processing module embeds a phase sequence logic analysis unit, which logically establishes multi-dimensional signal channels through software algorithms. Specifically, this includes the potential reference systems of phases A, B, and C relative to the protective ground (PE) and neutral (N), respectively. The storage unit contains a pre-built fault handling strategy library, which includes text descriptions, location suggestions, and solutions for different fault codes such as voltage exceeding limits, phase sequence errors, and communication interruptions.

[0037] The working principle is as follows: after the system is started, the two sets of acquisition units first use voltage transformers to sense high voltage signals, and then use precision true RMS converters to filter out harmonic interference in a wide frequency range to obtain accurate voltage amplitude.

[0038] Meanwhile, the environmental sensing module collects temperature and humidity data, and the main control terminal corrects the voltage amplitude for environmental drift based on this data, eliminating impedance parameter errors in rural power grid lines caused by temperature changes.

[0039] In the phase detection stage, the two sets of acquisition units do not simply compare the zero-crossing points, but rather use high-speed acquisition technology to lock the specific moment when the waveform crosses the threshold value based on a preset unified voltage threshold value, so as to avoid the zero-crossing point drift problem caused by waveform distortion.

[0040] In the phase sequence identification stage, the system does not rely on a single line voltage, but instead constructs a total of 12 signal channels covering the three phases A, B, and C relative to the PE line and N line.

[0041] The acquisition unit generates a phase sequence feature vector containing the timing characteristics of these channels and sends it to the main control terminal.

[0042] After receiving the data, the data processing module of the main control terminal calculates the precise phase angle difference by comparing the timestamp difference of the waveforms on both sides. On the other hand, it uses a statistical analysis algorithm to compare the matching degree of the phase sequence characteristic vectors on both sides, thereby deriving the correct A, B, and C three-phase correspondence in a complex grounding environment.

[0043] Finally, the logic judgment module compares the calculated voltage difference, phase angle difference, and phase sequence relationship with the preset loop closure condition thresholds. If the conditions are met, the screen displays that loop closure is allowed; if not, the system not only issues an audible and visual alarm, but also automatically retrieves specific maintenance guidelines from the fault strategy library, such as suggesting troubleshooting branch circuits for A-phase grounding faults, thereby realizing intelligent detection and safety protection throughout the entire process of rural power grid loop closure operations.

[0044] The specific technical solution for the working method of a rural overhead power line loop-swapping detection system is as follows: Includes the following steps: S1: The acquisition unit uses a voltage sensing module to sense the three-phase AC signal of the high-voltage line in real time. After the high-voltage signal is stepped down by a voltage transformer, it is input to a signal conditioning circuit that integrates a single-chip precision true RMS AC / DC converter. S2: The signal conditioning circuit processes the stepped-down analog signal within a frequency response range of 0 to 460 kHz, outputs the effective voltage value data corresponding to the three-phase line in real time, and controls the overall measurement error within a preset range. S3: A unified voltage threshold value is preset in the signal acquisition modules of the two sets of acquisition units, and the unified voltage threshold value is used as the reference level for waveform time-domain feature comparison of the dual power supplies; S4: The signal acquisition module monitors the three-phase voltage waveform in real time, locks the moment when the waveform amplitude crosses the unified voltage threshold, records the rising edge trigger moment and the falling edge end moment respectively, and generates time feature data containing timestamps. S5: The acquisition unit establishes potential reference systems for phases A, B, and C relative to the protective ground wire PE and the neutral wire N, respectively, forming 12 sets of signal channels to be measured, and statistically generates phase sequence feature vectors that reflect the potential timing characteristics of each phase based on the time feature data. S6: The acquisition unit uses a wireless transmission module to package the voltage RMS data, time characteristic data and phase sequence characteristic vector, and sends them to the main control terminal in real time through a wireless communication link; S7: After receiving the data, the data processing module of the main control terminal calculates the phase angle difference by comparing the waveform crossing time difference of the corresponding phases of the two power supplies based on the same time reference. Simultaneously, the voltage amplitude difference is calculated based on the aforementioned effective voltage value data; S8: The data processing module calls the phase sequence logic parsing unit, uses a statistical analysis algorithm to calculate the matching degree between the phase sequence feature vectors on both sides, and derives the A, B, and C three-phase correspondence of the two power supply input lines based on the matching degree to verify the phase sequence consistency. S9: The logic judgment module of the main control terminal will perform a multi-dimensional comparison between the calculated phase angle difference, voltage amplitude difference and phase sequence consistency results and the preset loop closing condition threshold, and generate a loop closing indication signal only when all parameters meet the preset conditions. S10: When the logic judgment module determines that any one of the phase angle difference, voltage amplitude difference, or phase sequence consistency does not meet the preset loop closing condition, or when the system self-test detects a sensor failure or communication interruption device fault, an alarm trigger signal is immediately generated. The main control terminal responds to the alarm trigger signal by issuing an audible and visual warning, and displays the specific parameter deviation value or device fault code that caused the loop closure to be prohibited on the display interface. At this time, the main control terminal further automatically retrieves the pre-set fault handling strategy library in the storage unit based on the current fault code or parameter deviation type, matches the corresponding fault location suggestions and solutions, and displays them synchronously with the alarm information on the display interface.

[0045] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A detection system for closed-loop power swapping of rural overhead power lines, characterized in that: Includes the data acquisition unit and the main control terminal; The main control terminal establishes wireless communication connections with the two sets of acquisition units respectively; The two sets of acquisition units are respectively set on the two power input lines of the loop to be closed, for distributed data monitoring; The acquisition unit is equipped with a voltage sensing module, a signal acquisition module, and a wireless transmission module; The voltage sensing module is used to collect the voltage amplitude signal of the corresponding line in real time; The signal acquisition module is used to capture the time information when the voltage waveform crosses the preset unified voltage threshold value to generate time feature data. The main control terminal is equipped with a data processing module and a logic judgment module; The data processing module is used to receive the voltage amplitude signal and time characteristic data through wireless communication, calculate the phase angle difference between the two power input lines based on the time characteristic data, and calculate the voltage difference and phase sequence relationship in combination with the voltage amplitude signal. The logic judgment module is used to compare the calculated voltage difference, phase angle difference and phase sequence relationship with the preset loop closing condition threshold. If the comparison results all meet the preset conditions, an indication signal that allows loop closing is generated.

2. The rural overhead power line loop-switching detection system according to claim 1, characterized in that: The data processing module is equipped with a phase sequence logic parsing unit, which is configured as follows: The two sets of acquisition units are controlled to establish potential reference systems for phase A, phase B, and phase C relative to the protective ground line PE and the neutral line N, respectively, so as to form a total of 12 signal channels to be tested covering the two power supply input sides. Based on the unified voltage threshold, the waveform crossing time of the 12 groups of signal channels under test is locked, and a phase sequence feature vector reflecting the potential timing characteristics of each phase is generated based on the crossing time. A statistical analysis algorithm is used to calculate the matching degree between the phase sequence characteristic vectors of the two power supply input lines, and the A, B, and C three-phase correspondence of the two power supply input lines is derived based on the combinational logic with the highest matching degree.

3. The rural overhead power line loop-switching detection system according to claim 2, characterized in that: The acquisition unit also includes a signal conditioning module, which has a built-in AC / DC converter configured to convert low-voltage analog signals with a frequency range of 0 to 460 kHz into DC voltage signals.

4. The rural overhead power line loop-switching detection system according to claim 3, characterized in that: The acquisition unit also includes a temperature and humidity acquisition module, which includes a capacitive humidity sensor and a thermocouple-to-digital converter with cold junction compensation function. The data processing module is configured to perform temperature drift compensation on the voltage amplitude signal based on the collected ambient temperature data.

5. The rural overhead power line loop-switching detection system according to claim 4, characterized in that: The acquisition unit is equipped with a dual-mode power supply interface, which includes a long-term monitoring power supply interface for connecting photovoltaic panels and rechargeable batteries, and a temporary maintenance power supply interface for connecting independent lithium battery packs.

6. The rural overhead power line loop-switching detection system according to claim 5, characterized in that: The voltage sensing module is equipped with a high-voltage isolation transformer and a signal conditioning circuit. The signal conditioning circuit integrates an AC / DC converter, which is configured to convert the AC analog signal stepped down by the high-voltage isolation transformer into a DC voltage signal within a frequency response range of 0 to 460 kHz, and control the overall measurement error within ±3%.

7. The rural overhead power line loop-switching detection system according to claim 6, characterized in that: The acquisition unit also integrates an environmental sensing module, which includes a capacitive humidity sensor and a thermocouple-to-digital converter with cold junction compensation. The main control terminal is configured to receive the temperature and humidity digital signals output by the environmental sensing module and perform environmental drift correction on the voltage amplitude signal based on the temperature and humidity digital signals.

8. The working method of the rural power grid overhead line loop-swapping detection system according to any one of claims 1 to 7, characterized in that: Includes the following steps: S1: The acquisition unit uses a voltage sensing module to sense the three-phase AC signal of the high-voltage line in real time, and after the high-voltage signal is stepped down by a voltage transformer, it is input to the signal conditioning circuit of the AC / DC converter. S2: The signal conditioning circuit processes the stepped-down analog signal within a frequency response range of 0 to 460 kHz, outputs the effective voltage value data corresponding to the three-phase line in real time, and controls the overall measurement error within a preset range. S3: A unified voltage threshold value is preset in the signal acquisition modules of the two sets of acquisition units, and the unified voltage threshold value is used as the reference level for waveform time-domain feature comparison of the dual power supplies; S4: The signal acquisition module monitors the three-phase voltage waveform in real time, locks the moment when the waveform amplitude crosses the unified voltage threshold, records the rising edge trigger moment and the falling edge end moment respectively, and generates time feature data containing timestamps. S5: The acquisition unit establishes potential reference systems for phases A, B, and C relative to the protective ground wire PE and the neutral wire N, respectively, forming 12 sets of signal channels to be measured, and statistically generates phase sequence feature vectors that reflect the potential timing characteristics of each phase based on the time feature data. S6: The acquisition unit uses a wireless transmission module to package the voltage RMS data, time characteristic data and phase sequence characteristic vector, and sends them to the main control terminal in real time through a wireless communication link; S7: After receiving the data, the data processing module of the main control terminal calculates the phase angle difference by comparing the waveform crossing time difference of the corresponding phases of the two power supplies based on the same time reference. Simultaneously, the voltage amplitude difference is calculated based on the aforementioned effective voltage value data; S8: The data processing module calls the phase sequence logic parsing unit, uses a statistical analysis algorithm to calculate the matching degree between the phase sequence feature vectors on both sides, and derives the A, B, and C three-phase correspondence of the two power supply input lines based on the matching degree to verify the phase sequence consistency. S9: The logic judgment module of the main control terminal will perform a multi-dimensional comparison between the calculated phase angle difference, voltage amplitude difference and phase sequence consistency results and the preset loop closing condition threshold. Only when all parameters meet the preset conditions will a loop closing indication signal be generated.

9. The working method of the rural power grid overhead line loop-switching detection system according to claim 8, characterized in that: The system also includes step S10: when the logic judgment module determines that any one of the phase angle difference, voltage amplitude difference, or phase sequence consistency does not meet the preset loop closing conditions, or when the system self-test detects a sensor failure or communication interruption device fault, an alarm trigger signal is immediately generated. The main control terminal responds to the alarm trigger signal by issuing an audible and visual warning and visually displays the specific parameter deviation value or device fault code that caused the loop closing to be prohibited on the display interface.

10. The working method of the rural power grid overhead line loop-switching detection system according to claim 9, characterized in that: The main control terminal's storage unit is pre-loaded with a fault handling strategy library. When the alarm trigger signal is generated, the main control terminal automatically retrieves the fault handling strategy library based on the current fault code or parameter deviation type, matches the corresponding fault location suggestions and solutions, and displays them synchronously with the alarm information on the display interface.

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