Transmission tower grounding resistance measurement method based on multi-loop high-frequency synchronous excitation

Abstract

This invention discloses a method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation, belonging to the field of power equipment testing and grounding resistance measurement technology. The method is implemented using a multi-circuit high-frequency signal excitation transmission device. First, a multi-circuit measurement calibration parameter library is established, a non-contact coupling unit is installed and the measurement parameters are initialized, then multiple synchronous high-frequency excitation signals are generated, amplified and dynamically impedance matched, and then non-contactly coupled to the grounding down conductor. Subsequently, multiple feedback signals are synchronously acquired and signal characteristics are extracted. Based on the feedback signals, multi-circuit synchronous closed-loop calibration is performed, the grounding impedance and grounding resistance measurements of each circuit are calculated, and anomalies are eliminated and weighted fusion is performed on the multiple measurement values ​​to obtain the final grounding resistance value. This invention eliminates the need to split the grounding down conductor, improving measurement efficiency, synchronization stability, and anti-interference capability.

Description

Technical Field

[0001] This invention relates to the field of power equipment testing and grounding resistance measurement technology, specifically to a method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation. Background Technology

[0002] The grounding system of transmission towers is a crucial component ensuring the safe operation of transmission lines. Its grounding resistance directly affects lightning current discharge capacity, equipment insulation safety, and the operational stability of the transmission line. If the grounding resistance of a transmission tower is too high, under the influence of lightning strikes, switching overvoltages, or fault currents, the tower potential can easily rise, leading to insulation flashover, equipment damage, or line tripping. Therefore, rapid and accurate detection of the grounding resistance of transmission towers is an important task in the operation and maintenance of transmission lines.

[0003] Existing methods for measuring the grounding resistance of transmission towers mainly include the potential drop method, clamp method, and high-frequency induction method. The potential drop method offers high accuracy, but typically requires the placement of current and voltage electrodes around the tower. The measurement process is significantly limited by site topography, line corridor, soil conditions, and available space, making the operation cumbersome and time-consuming for single-tower measurements, thus failing to meet the rapid inspection needs of a large number of transmission towers. While the clamp method can achieve non-contact measurement to some extent, it usually relies on a single measurement loop and is susceptible to stray currents, the surrounding electromagnetic environment, and the multi-branch parallel structure of the grounding system. Its stability and accuracy are insufficient in complex transmission line environments.

[0004] High-frequency induction methods apply high-frequency signals to the grounding down conductor and detect the response signal, allowing for measurements without completely dismantling the grounding system, thus offering good field adaptability. However, existing high-frequency induction measurement methods often employ single-loop excitation or single-channel acquisition structures, resulting in low signal redundancy and limited anti-interference capabilities. When multiple signals are required for parallel measurement or coordinated correction, existing devices struggle to ensure consistency in frequency, phase, and amplitude among the multiple high-frequency excitation signals, easily leading to issues such as signal asynchrony, phase shift, and inconsistent amplitude attenuation. This, in turn, affects the comparability of feedback signals and the accuracy of grounding impedance calculations.

[0005] Furthermore, under high-frequency excitation conditions, the measurement circuit formed by the transmission tower grounding down conductor, grounding electrode, soil medium, and measuring device exhibits significant complex impedance characteristics. Coupling differences, impedance mismatches, and signal reflections may exist between different excitation circuits, leading to distortion, attenuation, or phase drift in the feedback signal. If the grounding resistance is calculated directly based on a single feedback signal, significant measurement errors can easily occur due to abnormalities in the single signal or poor impedance matching.

[0006] Meanwhile, some traditional measurement methods require splitting or disconnecting the grounding down conductor during on-site testing. This not only increases the complexity of the operation and safety risks, but may also affect the grounding continuity of the transmission line in operation, making it unsuitable for on-site testing scenarios that require rapid, batch processing and minimal disturbance. Summary of the Invention

[0007] The purpose of this invention is to provide a method for measuring the grounding resistance of transmission towers that can achieve synchronous excitation of multiple high-frequency signals, non-contact coupling transmission, dynamic impedance matching, feedback closed-loop calibration, and fusion of multiple measurement results without splitting the grounding down conductor of the transmission tower, so as to improve measurement efficiency, measurement stability and measurement accuracy.

[0008] This invention is achieved through the following measures: a method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation, characterized in that the method is implemented based on a multi-circuit high-frequency signal excitation transmission device, which includes a synchronization signal generation module, a multi-channel excitation drive module, a multi-circuit signal coupling module, a multi-channel impedance matching module, a synchronization feedback adjustment module, a multi-channel power supply module, and an integrated protection module; the method for measuring the grounding resistance of transmission towers includes the following steps: S1, Establish a multi-loop measurement calibration parameter library; S2, Install the non-contact coupling unit and initialize the measurement parameters; S3 generates multiple synchronous high-frequency excitation signals; S4 performs power amplification and dynamic impedance matching on multiple synchronous high-frequency excitation signals; S5 non-contactly couples multiple synchronous high-frequency excitation signals to the grounding lead-down wire; S6, synchronously acquires multiple feedback signals and extracts signal features; S7 performs multi-channel synchronous closed-loop calibration based on feedback signals; S8, calculate the measured values ​​of grounding impedance and grounding resistance for each circuit; S9 performs anomaly removal and weighted fusion on multi-channel grounding resistance measurements; In this process, at the transmission tower under test, the connection between the transmission tower grounding down conductor and the grounding body is maintained, and the grounding down conductor is not disconnected. Through multiple non-contact coupling units, the multiple synchronous high-frequency excitation signals after power amplification and impedance matching are coupled to the transmission tower grounding down conductor, so that the grounding down conductor, grounding body, soil medium, non-contact coupling unit, impedance matching module and excitation drive module together form a multi-channel parallel excitation measurement circuit.

[0009] The establishment of the multi-loop measurement calibration parameter library includes: Before conducting on-site measurements on the transmission towers, the multi-circuit high-frequency signal excitation transmission device was connected to the standard grounding impedance simulation unit, and each excitation measurement circuit was calibrated to obtain the calibration parameters of each excitation measurement circuit under different excitation frequencies and different impedance matching states. The standard grounding impedance simulation unit includes multiple standard resistors with known resistance values, or multiple standard impedance components with known complex impedances; During calibration, different standard impedances are sequentially connected to the corresponding measurement circuits, the synchronization signal generation module is controlled to output a high-frequency excitation signal of a preset frequency, and the excitation terminal voltage, excitation terminal current and feedback signal of each excitation measurement circuit are collected through the synchronization feedback adjustment module. For each excitation measurement circuit and each standard impedance, the equivalent complex impedance of the excitation measurement circuit under calibration conditions is calculated based on the collected excitation terminal complex voltage and excitation terminal complex current. During the calibration process, the correspondence between the calibration equivalent complex impedance, standard impedance, background equivalent impedance, and complex coupling transfer coefficient of the excitation measurement circuit is established. The background equivalent impedance and complex coupling transfer coefficient of each excitation measurement circuit are determined by using calibration data from at least two different standard impedances. The calibration parameter library includes the background equivalent impedance, complex coupling transfer coefficient, amplitude compensation coefficient, phase compensation coefficient, impedance matching parameters, coupling unit number, and frequency response parameters corresponding to each excitation measurement circuit.

[0010] The installation of the non-contact coupling unit and the initialization of measurement parameters include: Multiple non-contact coupling units in the multi-loop signal coupling module are arranged outside the grounding lead; When the transmission tower under test has a grounding down conductor, multiple non-contact coupling units are arranged at intervals along the length of the grounding down conductor, and each non-contact coupling unit and the grounding down conductor maintain a consistent coupling posture. When the transmission tower under test has multiple grounding down conductors, multiple non-contact coupling units are respectively arranged on the outside of the corresponding grounding down conductors; The non-contact coupling unit is a hollow coil unit sleeved or clamped on the outside of the grounding lead, or a capacitive coupling unit set close to the grounding lead; Initialize the measurement parameters, which include the excitation frequency range, initial excitation frequency, excitation amplitude, excitation waveform, sampling frequency, phase synchronization threshold, amplitude attenuation rate threshold, impedance matching threshold, signal-to-noise ratio threshold, and measurement result dispersion threshold.

[0011] The generation of multiple synchronous high-frequency excitation signals includes: The synchronization signal generation module generates multiple synchronous high-frequency excitation signals based on the initialized measurement parameters. Each of the multiple synchronous high-frequency excitation signals has a corresponding amplitude, excitation frequency, and initial phase. The synchronization signal generation module uses a unified clock signal and a unified reference voltage to generate multiple synchronous high-frequency excitation signals, so that each synchronous high-frequency excitation signal has the same excitation frequency and the phase difference between each synchronous high-frequency excitation signal is less than or equal to the preset phase synchronization threshold. Within a measurement cycle, all synchronous high-frequency excitation signals are simultaneously at their peak or trough states.

[0012] The power amplification and dynamic impedance matching of the multi-channel synchronous high-frequency excitation signals include: The multi-channel excitation drive module receives multiple synchronous high-frequency excitation signals output by the synchronous signal generation module, and amplifies each synchronous high-frequency excitation signal to a preset power level through the corresponding power amplifier circuit. In each excitation measurement circuit, the multi-channel impedance matching module detects the input impedance of the corresponding circuit in real time, and adjusts the adjustable capacitor array and adjustable inductor in the corresponding circuit according to the detected input impedance, so that the input impedance of the excitation measurement circuit matches the output impedance of the corresponding excitation drive module. Based on the difference between the input impedance of each excitation measurement circuit and the output impedance of the corresponding excitation drive module, the reflection coefficient of the excitation measurement circuit is determined, and the impedance matching degree of the excitation measurement circuit is determined based on the reflection coefficient. When the impedance matching degree of the excitation measurement circuit is lower than the preset impedance matching threshold, continue to adjust the adjustable capacitor array and adjustable inductor in the excitation measurement circuit. When the impedance matching degree of the excitation measurement circuit reaches the preset impedance matching threshold, the current impedance matching parameters of the excitation measurement circuit are recorded.

[0013] The synchronous acquisition of multiple feedback signals and extraction of signal features includes: The synchronous feedback adjustment module synchronously samples each excitation measurement circuit, collecting the excitation terminal voltage, excitation terminal current, and feedback signal coupled back through the grounding lead in each excitation measurement circuit; For each excitation measurement loop, the synchronous feedback adjustment module acquires the excitation terminal voltage signal, excitation terminal current signal and feedback signal of that loop, and performs bandpass filtering, synchronous demodulation and phase analysis on the acquired signals to obtain the excitation terminal complex voltage, excitation terminal complex current and feedback complex voltage of that loop. Based on the excitation terminal complex voltage and the feedback complex voltage, determine the amplitude of the excitation terminal voltage, the amplitude of the feedback signal, the phase of the excitation terminal voltage, and the phase of the feedback signal for that path; The amplitude attenuation rate of the feedback signal relative to the excitation terminal voltage signal is determined based on the ratio of the difference between the amplitude of the excitation terminal voltage and the amplitude of the feedback signal to the amplitude of the excitation terminal voltage. Based on the difference between the phase of the feedback signal and the phase of the excitation voltage, the phase offset of the feedback signal relative to the excitation voltage signal is determined. The synchronous feedback adjustment module also calculates the signal-to-noise ratio, amplitude fluctuation, and phase fluctuation of the feedback signal.

[0014] The multi-channel synchronous closed-loop calibration based on feedback signals includes: The synchronous feedback adjustment module determines whether the multi-channel excitation measurement circuit meets the synchronous measurement conditions based on the amplitude attenuation rate and phase offset of each feedback signal. For any two excitation measurement loops, the inter-loop synchronization phase difference between them is determined based on the difference between the phase of one feedback signal and the phase of the other feedback signal. When the phase offset of any excitation measurement loop is greater than the preset phase offset threshold, or the inter-loop synchronization phase difference between any two excitation measurement loops is greater than the preset phase synchronization threshold, the synchronization feedback adjustment module sends a phase adjustment command to the synchronization signal generation module to compensate the output phase of the corresponding loop. When the amplitude attenuation rate of any excitation measurement loop exceeds the preset amplitude attenuation rate threshold, the synchronous feedback adjustment module sends an amplitude adjustment command to the synchronous signal generation module to compensate for the output amplitude of the corresponding loop. After amplitude and phase calibration are completed, the synchronous feedback adjustment module outputs a synchronous measurement enable signal; If the synchronous measurement conditions cannot be met within the preset number of adjustment cycles, the corresponding excitation measurement circuit will be marked as an abnormal circuit, and the integrated protection module will cut off the abnormal circuit or reduce the weight of the abnormal circuit in the subsequent fusion calculation.

[0015] The calculation of the measured values ​​of each grounding impedance and each grounding resistance includes: After each effective excitation measurement circuit meets the synchronous measurement conditions, the grounding impedance of each circuit is calculated based on the excitation terminal complex voltage, excitation terminal complex current, current impedance matching parameters, and calibration parameter library of each excitation measurement circuit. For each effective excitation measurement circuit, the measured equivalent complex impedance of the excitation measurement circuit under the actual measurement state is determined based on the complex voltage and complex current at the excitation terminal of that circuit. Retrieve the background equivalent impedance and complex coupling transfer coefficient corresponding to the current excitation frequency and current impedance matching parameters from the calibration parameter library; Based on the measured equivalent complex impedance, the background equivalent impedance, and the complex coupling transfer coefficient, the background influence of the excitation measurement circuit is subtracted and coupling compensation is performed to obtain the grounding impedance of the circuit. The real part of the grounding impedance is used as the grounding resistance measurement value corresponding to the excitation measurement circuit.

[0016] The process of anomaly removal and weighted fusion of multi-channel grounding resistance measurements includes: Obtain the signal quality parameters of each excitation measurement circuit, including impedance matching degree, signal-to-noise ratio, amplitude attenuation rate, phase offset, and feedback signal stability; If any excitation measurement circuit meets any of the following conditions, the grounding resistance measurement value of that excitation measurement circuit will be marked as abnormal data: The impedance matching degree of the excitation measurement circuit is lower than the preset impedance matching threshold. The signal-to-noise ratio of the feedback signal is lower than the preset signal-to-noise ratio threshold; The phase offset of the feedback signal is greater than the preset phase offset threshold; The amplitude attenuation rate of the feedback signal is greater than the preset amplitude attenuation rate threshold; The deviation of the measured grounding resistance value from the median of the multiple grounding resistance measurements is greater than the preset dispersion threshold. Excitation measurement loops that are not marked as abnormal data are considered as valid excitation measurement loops, and a set of valid excitation measurement loop numbers is formed. For each effective excitation measurement loop, the fusion weight is determined based on the signal quality parameters of that loop. The grounding resistance measurements of each circuit in the effective excitation measurement circuit number set are weighted and fused to obtain the final measured value of the grounding resistance of the transmission tower.

[0017] It also includes, when using a multi-frequency measurement method, performing the above steps S3 to S9 sequentially in a frequency range of 10 kHz to 1 MHz according to a preset frequency sequence to obtain candidate values ​​of grounding resistance at multiple frequency points.

[0018] The stability of candidate grounding resistance values ​​at multiple frequency points is judged. The effective frequency points are selected based on the frequency points with high signal-to-noise ratio, small phase fluctuation, high impedance matching degree and low dispersion of multi-channel measurement results. The final grounding resistance value is determined based on the candidate grounding resistance values ​​corresponding to the effective frequency points.

[0019] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows: While the grounding down conductor of the transmission tower under test remains connected to the grounding body, multiple non-contact coupling units are arranged outside the grounding down conductor, and multiple synchronous high-frequency excitation signals are coupled to the grounding down conductor through non-contact coupling. Therefore, grounding resistance measurement can be completed without splitting or disconnecting the grounding down conductor, reducing the complexity of on-site operations, minimizing disturbance to the operating state of the transmission line grounding system, and improving the safety of on-site testing.

[0020] This invention generates multiple synchronous high-frequency excitation signals through a synchronization signal generation module, ensuring that each synchronous high-frequency excitation signal has the same excitation frequency, while simultaneously ensuring that the phase difference between each synchronous high-frequency excitation signal is less than or equal to a preset phase synchronization threshold. This guarantees that the multiple excitation measurement circuits operate under a unified phase reference, reduces measurement deviations caused by asynchronous signals, and improves the comparability between multiple feedback signals.

[0021] This invention amplifies multiple synchronous high-frequency excitation signals using a multi-channel excitation drive module and monitors and adjusts the impedance matching of each excitation measurement circuit in real time using a multi-channel impedance matching module, ensuring that the input impedance of each excitation measurement circuit matches the output impedance of the corresponding excitation drive module. This reduces reflection, attenuation, and distortion during high-frequency signal transmission, improving excitation signal coupling efficiency and feedback signal stability.

[0022] This invention synchronously acquires the excitation terminal voltage, excitation terminal current, and feedback signals coupled back via the grounding lead in each excitation measurement circuit, and performs multi-channel synchronous closed-loop calibration based on the amplitude attenuation rate and phase offset of the feedback signals. Therefore, it can dynamically correct the amplitude and phase deviations of each excitation signal during the measurement process, ensuring that the multi-channel excitation measurement circuit continuously meets the synchronous measurement conditions and improving the stability of grounding impedance calculation.

[0023] This invention predetermines the background equivalent impedance and complex coupling transfer coefficient of each excitation measurement circuit using a multi-circuit measurement calibration parameter library. During actual measurement, based on the measured equivalent complex impedance, background equivalent impedance, and complex coupling transfer coefficient, it subtracts the background influence of the excitation measurement circuit and performs coupling compensation, thereby obtaining the grounding impedance of each circuit. This reduces the impact of the measurement device's own impedance, differences in coupling units, and differences in circuit transmission characteristics on the calculated grounding resistance, improving the accuracy of the measurement results.

[0024] This invention uses the real part of the grounding impedance of each path as the corresponding grounding resistance measurement value. Based on the impedance matching degree, signal-to-noise ratio, amplitude attenuation rate, phase offset, and feedback signal stability of each excitation measurement circuit, it performs anomaly removal and weighted fusion of the grounding resistance measurements. This avoids the adverse effects of a single path's abnormal signal on the final measurement result, improving the reliability and anti-interference capability of transmission tower grounding resistance measurement in complex electromagnetic environments.

[0025] This invention can perform multi-frequency measurements within a preset frequency range and assess the stability of candidate grounding resistance values ​​at multiple frequency points, selecting the effective frequency point as one that meets the requirements for signal-to-noise ratio, phase fluctuation, impedance matching, and dispersion of multi-channel measurement results. Therefore, it can select a more stable measurement frequency based on the on-site grounding system and electromagnetic environment conditions, improving adaptability under different operating conditions.

[0026] This invention can also integrate a protection module to monitor the current, voltage, and temperature of each excitation measurement circuit in real time. In the event of overcurrent, overvoltage, overheating, or surge anomalies, the abnormal circuit is cut off, causing the synchronous feedback adjustment module to stop using the feedback signal from the abnormal circuit for grounding resistance calculation. This improves the safety of the measurement process and the stability of the device operation, ensuring that measurements can continue based on the remaining effective excitation measurement circuits even when some circuits are abnormal. Attached Figure Description

[0027] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings listed below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a flowchart of a method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation in an embodiment of the present invention; Figure 2 This is a schematic diagram of multi-channel synchronous closed-loop calibration based on feedback signals in an embodiment of the present invention; Figure 3 This is a flowchart of the process for calculating grounding impedance based on measured equivalent complex impedance, fusing multiple grounding resistance measurements, and handling abnormal loops in an embodiment of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] See Figure 1 This embodiment provides a method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation. This method is suitable for non-contact measurement of the grounding resistance of transmission towers while the grounding down conductor of the transmission tower remains connected to the grounding body.

[0031] The measurement method in this embodiment is implemented based on a multi-loop high-frequency signal excitation transmission device. The multi-loop high-frequency signal excitation transmission device includes a synchronization signal generation module, a multi-channel excitation drive module, a multi-loop signal coupling module, a multi-channel impedance matching module, a synchronization feedback adjustment module, a multi-channel power supply module, and an integrated protection module.

[0032] The synchronization signal generation module generates multiple synchronous high-frequency excitation signals; the multi-channel excitation drive module amplifies the power of each synchronous high-frequency excitation signal; the multi-loop signal coupling module non-contactly couples the amplified multiple synchronous high-frequency excitation signals to the grounding down conductor of the transmission tower; the multi-channel impedance matching module performs dynamic impedance matching for each excitation measurement loop; the synchronization feedback adjustment module synchronously acquires each feedback signal and performs closed-loop adjustment of the output parameters of the synchronization signal generation module based on the amplitude attenuation rate and phase offset of each feedback signal; the multi-channel power supply module supplies power to each functional module and each excitation measurement loop; and the integrated protection module provides overcurrent, overvoltage, overheat, surge suppression, and fault location protection for each excitation measurement loop.

[0033] In this embodiment, the method for measuring the grounding resistance of transmission towers includes the following steps: S1. Establish a multi-loop measurement calibration parameter library.

[0034] Before conducting on-site measurements on the transmission towers, the multi-circuit high-frequency signal excitation transmission device was connected to the standard grounding impedance simulation unit, and each excitation measurement circuit was calibrated to obtain the calibration parameters of each excitation measurement circuit under different excitation frequencies and different impedance matching states.

[0035] The standard grounding impedance simulation unit includes multiple standard resistors with known resistance values, or multiple standard impedance components with known complex impedances. During calibration, different standard impedances are sequentially connected to the corresponding measurement circuits. The synchronization signal generation module is controlled to output a high-frequency excitation signal of a preset frequency, and the excitation terminal voltage, excitation terminal current, and feedback signal of each excitation measurement circuit are acquired through the synchronization feedback adjustment module.

[0036] For the The circuit excitation measurement circuit and the first Based on the acquired excitation terminal complex voltage and excitation terminal complex current, the first standard impedance is calculated. The equivalent complex impedance of the circuit excitation measurement loop under calibrated conditions.

[0037]

[0038] in, For the first The circuit excitation measurement circuit at frequency Impedance matching parameters and the The calibrated equivalent complex impedance under standard impedance connection conditions. For the first The excitation terminal complex voltage of the circuit excitation measurement loop under calibrated conditions; For the first The excitation terminal complex current of the circuit excitation measurement loop under calibrated conditions; For the first The impedance matching parameter set of the circuit impedance matching module includes the capacitor combination parameters of the adjustable capacitor array and the inductance value of the adjustable inductor.

[0039] During the calibration process, the first The relationship between the calibration equivalent complex impedance, standard impedance, background equivalent impedance, and complex coupling transfer coefficient of the circuit excitation measurement loop:

[0040] in, For the first The circuit excitation measurement circuit at frequency and impedance matching parameters The background equivalent impedance; For the first The circuit excitation measurement circuit at frequency and impedance matching parameters The complex coupling transfer coefficients under the given conditions, and Not zero; For the first A standard impedance.

[0041] Determine the first standard impedance by using calibration data from at least two different standard impedances. The background equivalent impedance of the circuit excitation measurement circuit and complex coupling transfer coefficient When using multiple standard impedances for calibration, the least squares fitting method is used to determine... and .

[0042] The calibration parameter library includes the background equivalent impedance, complex coupling transfer coefficient, amplitude compensation coefficient, phase compensation coefficient, impedance matching parameters, coupling unit number, and frequency response parameters corresponding to each excitation measurement circuit.

[0043] S2. Install the non-contact coupling unit and initialize the measurement parameters.

[0044] At the transmission tower under test, maintain the connection between the tower's grounding down conductor and the grounding electrode, without disconnecting the grounding down conductor. Arrange multiple non-contact coupling units from the multi-loop signal coupling module outside the grounding down conductor.

[0045] When the transmission tower under test has one grounding down conductor, multiple non-contact coupling units are arranged at intervals along the length of the grounding down conductor, and each non-contact coupling unit maintains a consistent coupling posture with the grounding down conductor; when the transmission tower under test has multiple grounding down conductors, multiple non-contact coupling units are arranged on the outside of the corresponding grounding down conductors.

[0046] The non-contact coupling unit is a hollow coil unit sleeved or clamped on the outside of the grounding lead, or a capacitive coupling unit located close to the grounding lead. When using a hollow coil unit, the number of coil turns, coil inductance, coil inner diameter, and shielding structure of each hollow coil unit remain consistent; when using a capacitive coupling unit, the coupling capacitance, isolation transformer, and withstand voltage parameters of each capacitive coupling unit remain consistent.

[0047] Initialize the measurement parameters, which include the excitation frequency range, initial excitation frequency, excitation amplitude, excitation waveform, sampling frequency, phase synchronization threshold, amplitude attenuation rate threshold, impedance matching threshold, signal-to-noise ratio threshold, and measurement result dispersion threshold.

[0048] Preferably, the excitation frequency range is 10kHz to 1MHz, and the excitation waveform is a sine wave. Optionally, the excitation waveform can also be a square wave or a triangular wave.

[0049] S3 generates multiple synchronous high-frequency excitation signals.

[0050] The synchronization signal generation module generates N synchronous high-frequency excitation signals based on the initialized measurement parameters, where N is an integer greater than or equal to 2.

[0051] For the The expression for the synchronous high-frequency excitation signal is:

[0052] in, For the first Synchronous high-frequency excitation signal, For the first The amplitude of the high-frequency excitation signal of the road synchronization, The excitation frequency, For the first The initial phase of the high-frequency excitation signal of the road synchronization.

[0053] The synchronization signal generation module uses a unified clock signal and a unified reference voltage to generate multiple synchronous high-frequency excitation signals, ensuring that each synchronous high-frequency excitation signal has the same excitation frequency and that the phase difference between each synchronous high-frequency excitation signal is less than or equal to a preset phase synchronization threshold. Preferably, the preset phase synchronization threshold is... .

[0054] Within a measurement cycle, all synchronous high-frequency excitation signals are simultaneously at their peak or trough states to ensure that multiple excitation measurement circuits are synchronously measured under the same phase reference.

[0055] S4. Perform power amplification and dynamic impedance matching on multiple synchronous high-frequency excitation signals.

[0056] The multi-channel excitation drive module receives multiple synchronous high-frequency excitation signals output by the synchronous signal generation module, and amplifies each synchronous high-frequency excitation signal to a preset power level through the corresponding power amplifier circuit.

[0057] In each excitation measurement circuit, the multi-channel impedance matching module detects the input impedance of the corresponding circuit in real time, and adjusts the adjustable capacitor array and adjustable inductor in the corresponding circuit according to the detected input impedance, so that the input impedance of the excitation measurement circuit matches the output impedance of the corresponding excitation drive module.

[0058] For the For each excitation measurement circuit, the input impedance of the circuit and the output impedance of the corresponding excitation drive module are used to determine the first... Reflection coefficient of the circuit excitation measurement loop:

[0059] in, For the first The reflection coefficient of the circuit excitation measurement loop. For the first The input impedance of the circuit excitation measurement circuit. For the first Output impedance of the excitation drive module.

[0060] Determine the first based on the reflection coefficient. Impedance matching of the circuit excitation measurement loop:

[0061] in, For the first Impedance matching of the circuit excitation measurement circuit.

[0062] When the Impedance matching of the circuit excitation measurement loop When the impedance is below the preset impedance matching threshold, continue adjusting the adjustable capacitor array and adjustable inductor in the excitation measurement circuit; when the impedance matching degree... When the preset impedance matching threshold is reached, record the current impedance matching parameters of the excitation measurement circuit. Then proceed to the subsequent excitation coupling step.

[0063] Preferably, the preset impedance matching threshold is 92%.

[0064] S5. Non-contactly couple multiple synchronous high-frequency excitation signals to the grounding lead.

[0065] The multi-loop signal coupling module uses multiple non-contact coupling units to couple multiple synchronous high-frequency excitation signals, after power amplification and impedance matching, to the grounding down conductor of the transmission tower. This allows the grounding down conductor, grounding body, soil medium, non-contact coupling unit, impedance matching module, and excitation drive module to jointly form a multi-channel parallel excitation measurement loop.

[0066] During non-contact coupling, the grounding down conductor does not need to be disconnected, and the grounding down conductor maintains its original electrical connection with the grounding body. Therefore, it is possible to obtain the electrical response characteristics of the grounding system under high-frequency excitation conditions without disrupting the operation of the transmission tower grounding system.

[0067] S6. Simultaneously acquire multiple feedback signals and extract signal features.

[0068] The synchronous feedback adjustment module synchronously samples each excitation measurement circuit, collecting the excitation terminal voltage, excitation terminal current, and feedback signal coupled back through the grounding lead in each excitation measurement circuit.

[0069] For the The circuit excitation measurement loop and the synchronous feedback adjustment module collect the first... Excitation terminal voltage signal Excitation terminal current signal and feedback signals The acquired signal is then subjected to bandpass filtering, synchronous demodulation, and phase analysis to obtain the first... Road excitation terminal complex voltage Excitation end current and feedback complex voltage .

[0070] According to the excitation terminal complex voltage and feedback complex voltage Determine the first Excitation terminal voltage amplitude, feedback signal amplitude, excitation terminal voltage phase, and feedback signal phase:

[0071]

[0072]

[0073]

[0074] in, For the first Excitation terminal voltage amplitude, For the first The amplitude of the feedback signal. For the first Phase of the excitation terminal voltage. For the first The phase of the feedback signal.

[0075] Further, calculate the first The amplitude attenuation rate of the feedback signal relative to the excitation terminal voltage signal:

[0076] in, For the first The amplitude attenuation rate of the feedback signal relative to the excitation terminal voltage signal.

[0077] Calculate the first Phase offset of the feedback signal relative to the excitation terminal voltage signal:

[0078] in, For the first The phase offset of the feedback signal relative to the excitation terminal voltage signal.

[0079] The synchronous feedback adjustment module also calculates the first Signal-to-noise ratio of the feedback signal Amplitude fluctuation and phase fluctuation are used for subsequent anomaly detection and multi-path result fusion.

[0080] S7. Perform multi-channel synchronous closed-loop calibration based on feedback signals.

[0081] The synchronous feedback adjustment module adjusts the amplitude attenuation rate of each feedback signal. and phase offset To determine whether the multi-channel excitation measurement circuit meets the synchronous measurement conditions.

[0082] For the The circuit excitation measurement circuit and the first The excitation measurement circuit is used to determine the inter-path synchronization phase difference between the two circuits.

[0083] in, For the first Path feedback signal and the first Inter-path synchronization phase difference between feedback signals.

[0084] When the phase offset of any excitation measurement circuit Greater than the preset phase offset threshold, or the inter-path synchronous phase difference between any two excitation measurement circuits. When the value exceeds the preset phase synchronization threshold, the synchronization feedback adjustment module sends a phase adjustment command to the synchronization signal generation module to compensate for the output phase of the corresponding circuit.

[0085] When the amplitude attenuation rate of any excitation measurement circuit When the preset amplitude attenuation rate threshold is exceeded, the synchronous feedback adjustment module sends an amplitude adjustment command to the synchronous signal generation module to compensate for the output amplitude of the corresponding loop.

[0086] Preferably, the amplitude attenuation rate of each feedback signal is less than or equal to 8%, and the phase offset is less than or equal to... And the inter-path synchronization phase difference between the multiple feedback signals is less than or equal to .

[0087] After amplitude and phase calibration is completed, the synchronous feedback adjustment module outputs a synchronous measurement enable signal. If the synchronous measurement conditions cannot be met within the preset number of adjustment cycles, the corresponding excitation measurement circuit is marked as an abnormal circuit, and the integrated protection module cuts off the abnormal circuit or reduces the weight of the abnormal circuit in the subsequent fusion calculation.

[0088] like Figure 2 As shown, during the multi-channel synchronous closed-loop calibration process, the synchronization signal generation module outputs multiple synchronous high-frequency excitation signals, and the multiple excitation measurement loops generate multiple feedback signals via grounding leads. The synchronization feedback adjustment module calculates the amplitude attenuation rate, phase offset, and inter-channel synchronization phase difference based on the multiple feedback signals, and determines whether the synchronization measurement conditions are met based on the calculation results. When the synchronization measurement conditions are not met, the synchronization feedback adjustment module outputs amplitude adjustment commands and phase adjustment commands to adjust the output amplitude and output phase of the synchronization signal generation module. When the synchronization measurement conditions are met, a synchronization measurement enable signal is output. If the synchronization measurement conditions still cannot be met within a preset number of adjustment cycles, the corresponding excitation measurement loop is marked as an abnormal loop.

[0089] S8. Calculate the measured values ​​of each grounding impedance and each grounding resistance.

[0090] After each effective excitation measurement circuit meets the synchronous measurement conditions, the grounding impedance of each circuit is calculated based on the excitation terminal complex voltage, excitation terminal complex current, current impedance matching parameters, and calibration parameter library of each excitation measurement circuit.

[0091] For the For the effective excitation measurement circuit, first calculate the equivalent complex impedance of the excitation measurement circuit under the measured condition:

[0092] in, For the first The circuit excitation measurement circuit at frequency and current impedance matching parameters The measured equivalent complex impedance is shown below.

[0093] Then, retrieve the parameter from the calibration parameter library that corresponds to the current excitation frequency. and current impedance matching parameters Corresponding background equivalent impedance and complex coupling transfer coefficient And calculate the first according to the following relationship Road grounding impedance:

[0094] in, For the first The grounding impedance is calculated from the excitation measurement circuit.

[0095] Because the grounding system exhibits complex impedance characteristics under high-frequency excitation conditions, the grounding impedance includes resistive and reactive components. In this embodiment, the real part of the grounding impedance is used as the measured grounding resistance value corresponding to this excitation measurement circuit:

[0096] in, For the first The measured value of the grounding resistance corresponding to the circuit excitation measurement circuit. This indicates taking the real part of a complex number.

[0097] like Figure 3As shown, during the grounding impedance calculation and multi-channel fusion process, the synchronous feedback adjustment module obtains the excitation terminal complex voltage, excitation terminal complex current, and current impedance matching parameters of each effective excitation measurement circuit to determine the measured equivalent complex impedance of each excitation measurement circuit under actual measurement conditions. Then, it retrieves the background equivalent impedance and complex coupling transfer coefficient corresponding to the current excitation frequency and current impedance matching parameters from the calibration parameter library, subtracts the background influence of the excitation measurement circuit, and performs coupling compensation to obtain the grounding impedance of each circuit. The real part of each grounding impedance is extracted to obtain the measured grounding resistance value of each circuit. Then, based on signal quality parameters such as impedance matching degree, signal-to-noise ratio, amplitude attenuation rate, phase offset, and feedback signal stability, anomalies are eliminated. The fusion weights are determined for the grounding resistance measured values ​​corresponding to the effective excitation measurement circuits, and weighted fusion is performed to obtain the final grounding resistance value. Data deemed abnormal is not included in the fusion process.

[0098] S9. Perform anomaly removal and weighted fusion on the multi-channel grounding resistance measurement values.

[0099] Obtain the signal quality parameters of each excitation measurement circuit, including impedance matching degree. Signal-to-noise ratio Amplitude attenuation rate Phase offset And the stability of the feedback signal.

[0100] When the When the circuit excitation measurement circuit meets any of the following conditions, the first... The grounding resistance measurement value of the circuit excitation measurement circuit is marked as abnormal data: No. Impedance matching of the circuit excitation measurement loop Below the preset impedance matching threshold; No. Signal-to-noise ratio of the feedback signal Below the preset signal-to-noise ratio threshold; No. Phase offset of the feedback signal Greater than the preset phase offset threshold; No. Amplitude attenuation rate of feedback signal The amplitude attenuation rate is greater than the preset threshold. No. Road grounding resistance measurement value The deviation from the median of the multi-path grounding resistance measurements is greater than the preset dispersion threshold.

[0101] Excitation measurement loops not marked as abnormal data are considered valid excitation measurement loops, forming a set M of valid excitation measurement loop numbers. The grounding resistance measurements of each loop in the valid excitation measurement loop number set M are weighted and fused to obtain the final measured value of the transmission tower grounding resistance.

[0102] For the The effective excitation measurement loop is used to determine the fusion weights based on the signal quality parameters of that loop. Preferably, the fusion weights impedance matching with this path and signal-to-noise ratio Positively correlated with the phase offset of that path Amplitude attenuation rate It is negatively correlated with the measured fluctuation.

[0103] The weights for each fusion path are satisfied:

[0104] Where M is the set of effective excitation measurement circuit numbers, For the first The fusion weight corresponding to the effective excitation measurement loop of the circuit.

[0105] The final grounding resistance value is determined as follows:

[0106] in, This is the final measured value of the grounding resistance of the transmission tower. For the first The measured value of the grounding resistance corresponding to the effective excitation measurement circuit of the circuit. For the first The fusion weight corresponding to the effective excitation measurement loop of the circuit.

[0107] When the number of circuits in the effective excitation measurement circuit number set M is less than the preset number, or when the dispersion between the measured values ​​of multiple grounding resistances is greater than the preset dispersion threshold, steps S3 to S9 are repeated, or the excitation frequency is changed and the measurement is repeated.

[0108] S10. Perform multi-frequency point verification and output the measurement results.

[0109] When using a multi-frequency measurement method, steps S3 to S9 are executed sequentially according to a preset frequency sequence within a frequency range of 10 kHz to 1 MHz to obtain candidate values ​​of grounding resistance at multiple frequency points.

[0110] The stability of candidate grounding resistance values ​​at multiple frequency points is judged. The effective frequency points are selected based on the frequency points with high signal-to-noise ratio, small phase fluctuation, high impedance matching degree and low dispersion of multi-channel measurement results. The final grounding resistance value is determined based on the candidate grounding resistance values ​​corresponding to the effective frequency points.

[0111] After the measurement is completed, the final measured value of the grounding resistance of the transmission tower is output. Effective excitation frequency, measurement status of each excitation measurement circuit, and measured grounding resistance of each circuit. fusion weight And the abnormal circuit number.

[0112] S11. Perform measurement process protection and fault handling.

[0113] During the measurement process from steps S3 to S10, the integrated protection module monitors the current, voltage, and temperature of each excitation measurement circuit in real time. When any excitation measurement circuit experiences overcurrent, overvoltage, overheating, or surge abnormalities, the integrated protection module disconnects the abnormal circuit and sends an abnormal status signal to the synchronous feedback adjustment module.

[0114] Upon receiving an abnormal status signal, the synchronous feedback adjustment module stops using the feedback signal from that abnormal loop to calculate the grounding resistance and continues the measurement based on the remaining effective excitation measurement loops. If the number of remaining effective excitation measurement loops is insufficient to complete multi-channel fusion, a remeasurement prompt is output.

[0115] Using the above method, this embodiment performs non-contact coupling measurement of the grounding down conductor using multiple synchronous high-frequency excitation signals without splitting the transmission tower grounding down conductor. The final measured value of the grounding resistance is obtained through impedance matching, feedback synchronous calibration, calibration parameter compensation, and multi-channel weighted fusion. Compared with single-loop high-frequency induction measurement, this embodiment improves on-site measurement efficiency, reduces measurement errors caused by single-channel signal attenuation, phase shift, and external electromagnetic interference, and maintains measurement stability by eliminating abnormal loops and fusing remaining loops when abnormal loops exist.

[0116] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. 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 method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation, characterized in that, The method is implemented based on a multi-loop high-frequency signal excitation transmission device, which includes a synchronization signal generation module, a multi-channel excitation drive module, a multi-loop signal coupling module, a multi-channel impedance matching module, a synchronization feedback adjustment module, a multi-channel power supply module, and an integrated protection module; the method for measuring the grounding resistance of transmission towers includes the following steps: S1, Establish a multi-loop measurement calibration parameter library; S2, Install the non-contact coupling unit and initialize the measurement parameters; S3 generates multiple synchronous high-frequency excitation signals; S4 performs power amplification and dynamic impedance matching on multiple synchronous high-frequency excitation signals; S5 non-contactly couples multiple synchronous high-frequency excitation signals to the grounding lead-down wire; S6 Simultaneously acquire multiple feedback signals and extract signal features; S7 performs multi-channel synchronous closed-loop calibration based on feedback signals; S8, calculate the measured values ​​of each grounding impedance and each grounding resistance; S9 performs anomaly removal and weighted fusion on multi-channel grounding resistance measurements; Among them, at the transmission tower to be tested, the connection between the grounding down conductor and the grounding body of the transmission tower is maintained, and the grounding down conductor is not disconnected; Multiple non-contact coupling units are used to couple the multi-channel synchronous high-frequency excitation signals, which have been amplified and impedance matched, to the grounding down conductor of the transmission tower. This allows the grounding down conductor, grounding body, soil medium, non-contact coupling units, impedance matching module, and excitation drive module to form a multi-channel parallel excitation measurement circuit.

2. The method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation according to claim 1, characterized in that, The establishment of the multi-loop measurement calibration parameter library includes: Before conducting on-site measurements on the transmission towers, the multi-circuit high-frequency signal excitation transmission device was connected to the standard grounding impedance simulation unit, and each excitation measurement circuit was calibrated to obtain the calibration parameters of each excitation measurement circuit under different excitation frequencies and different impedance matching states.

3. The method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation according to claim 1, characterized in that, The installation of the non-contact coupling unit and the initialization of measurement parameters include: Multiple non-contact coupling units in the multi-loop signal coupling module are arranged outside the grounding lead; When the transmission tower under test has a grounding down conductor, multiple non-contact coupling units are arranged at intervals along the length of the grounding down conductor, and each non-contact coupling unit and the grounding down conductor maintain a consistent coupling posture. When the transmission tower under test has multiple grounding down conductors, multiple non-contact coupling units are arranged on the outside of the corresponding grounding down conductors.

4. The method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation according to claim 1, characterized in that, The generation of multiple synchronous high-frequency excitation signals includes: The synchronization signal generation module generates multiple synchronous high-frequency excitation signals based on the initialized measurement parameters. The synchronization signal generation module uses a unified clock signal and a unified reference voltage to generate multiple synchronous high-frequency excitation signals, so that each synchronous high-frequency excitation signal has the same excitation frequency and the phase difference between each synchronous high-frequency excitation signal is less than or equal to the preset phase synchronization threshold. Within a measurement cycle, all synchronous high-frequency excitation signals are simultaneously at their peak or trough states.

5. The method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation according to claim 1, characterized in that, The power amplification and dynamic impedance matching of the multi-channel synchronous high-frequency excitation signals include: The multi-channel excitation drive module receives multiple synchronous high-frequency excitation signals output by the synchronous signal generation module, and amplifies each synchronous high-frequency excitation signal to a preset power level through the corresponding power amplifier circuit. In each excitation measurement circuit, the multi-channel impedance matching module detects the input impedance of the corresponding circuit in real time, and adjusts the adjustable capacitor array and adjustable inductor in the corresponding circuit according to the detected input impedance, so that the input impedance of the excitation measurement circuit matches the output impedance of the corresponding excitation drive module. Based on the difference between the input impedance of each excitation measurement circuit and the output impedance of the corresponding excitation drive module, the reflection coefficient of that excitation measurement circuit is determined, and the impedance matching degree of that excitation measurement circuit is determined based on the reflection coefficient.

6. The method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation according to claim 1, characterized in that, The synchronous acquisition of multiple feedback signals and extraction of signal features includes: The synchronous feedback adjustment module synchronously samples each excitation measurement circuit, collecting the excitation terminal voltage, excitation terminal current, and feedback signal coupled back through the grounding lead in each excitation measurement circuit; For each excitation measurement loop, the synchronous feedback adjustment module acquires the excitation terminal voltage signal, excitation terminal current signal and feedback signal of that loop, and performs bandpass filtering, synchronous demodulation and phase analysis on the acquired signals to obtain the excitation terminal complex voltage, excitation terminal complex current and feedback complex voltage of that loop. Based on the excitation terminal complex voltage and the feedback complex voltage, determine the amplitude of the excitation terminal voltage, the amplitude of the feedback signal, the phase of the excitation terminal voltage, and the phase of the feedback signal for that path; The amplitude attenuation rate of the feedback signal relative to the excitation terminal voltage signal is determined based on the ratio of the difference between the amplitude of the excitation terminal voltage and the amplitude of the feedback signal to the amplitude of the excitation terminal voltage. Based on the difference between the phase of the feedback signal and the phase of the excitation voltage, determine the phase offset of the feedback signal relative to the excitation voltage signal. The synchronous feedback adjustment module also calculates the signal-to-noise ratio, amplitude fluctuation, and phase fluctuation of the feedback signal.

7. The method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation according to claim 6, characterized in that, The multi-channel synchronous closed-loop calibration based on feedback signals includes: The synchronous feedback adjustment module determines whether the multi-channel excitation measurement circuit meets the synchronous measurement conditions based on the amplitude attenuation rate and phase offset of each feedback signal. For any two excitation measurement loops, the inter-loop synchronization phase difference between them is determined based on the difference between the phase of one feedback signal and the phase of the other feedback signal. When the phase offset of any excitation measurement loop is greater than the preset phase offset threshold, or the inter-loop synchronization phase difference between any two excitation measurement loops is greater than the preset phase synchronization threshold, the synchronization feedback adjustment module sends a phase adjustment command to the synchronization signal generation module to compensate the output phase of the corresponding loop. When the amplitude attenuation rate of any excitation measurement loop exceeds the preset amplitude attenuation rate threshold, the synchronous feedback adjustment module sends an amplitude adjustment command to the synchronous signal generation module to compensate for the output amplitude of the corresponding loop. After amplitude and phase calibration are completed, the synchronous feedback adjustment module outputs a synchronous measurement enable signal; If the synchronous measurement conditions cannot be met within the preset number of adjustment cycles, the corresponding excitation measurement circuit will be marked as an abnormal circuit, and the integrated protection module will cut off the abnormal circuit or reduce the weight of the abnormal circuit in the subsequent fusion calculation.

8. The method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation according to claim 1, characterized in that, The calculation of the measured values ​​of each grounding impedance and each grounding resistance includes: After each effective excitation measurement circuit meets the synchronous measurement conditions, the grounding impedance of each circuit is calculated based on the excitation terminal complex voltage, excitation terminal complex current, current impedance matching parameters, and calibration parameter library of each excitation measurement circuit. For each effective excitation measurement circuit, the measured equivalent complex impedance of the excitation measurement circuit under the actual measurement state is determined based on the complex voltage and complex current at the excitation terminal of that circuit. Retrieve the background equivalent impedance and complex coupling transfer coefficient corresponding to the current excitation frequency and current impedance matching parameters from the calibration parameter library; Based on the measured equivalent complex impedance, the background equivalent impedance, and the complex coupling transfer coefficient, the background influence of the excitation measurement circuit is subtracted and coupling compensation is performed to obtain the grounding impedance of the circuit. The real part of the grounding impedance is used as the grounding resistance measurement value corresponding to the excitation measurement circuit.

9. The method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation according to claim 8, characterized in that, The process of anomaly removal and weighted fusion of multi-channel grounding resistance measurements includes: Obtain the signal quality parameters of each excitation measurement circuit; If any excitation measurement circuit meets any of the following conditions, the grounding resistance measurement value of that excitation measurement circuit will be marked as abnormal data: The impedance matching degree of the excitation measurement circuit is lower than the preset impedance matching threshold. The signal-to-noise ratio of the feedback signal is lower than the preset signal-to-noise ratio threshold; The phase offset of the feedback signal is greater than the preset phase offset threshold; The amplitude attenuation rate of the feedback signal is greater than the preset amplitude attenuation rate threshold; The deviation of the measured grounding resistance value from the median of the multiple grounding resistance measurements is greater than the preset dispersion threshold. Excitation measurement loops that are not marked as abnormal data are considered as valid excitation measurement loops, and a set of valid excitation measurement loop numbers is formed. For each effective excitation measurement loop, the fusion weight is determined based on the signal quality parameters of that loop. The grounding resistance measurements of each circuit in the effective excitation measurement circuit number set are weighted and fused to obtain the final measured value of the grounding resistance of the transmission tower.

10. The method for measuring the grounding resistance of transmission towers based on multi-circuit high-frequency synchronous excitation according to claim 9, characterized in that, It also includes, when using a multi-frequency measurement method, executing steps S3 to S9 sequentially in a frequency range of 10 kHz to 1 MHz according to a preset frequency sequence to obtain candidate values ​​of grounding resistance at multiple frequency points; The stability of candidate grounding resistance values ​​at multiple frequency points is judged. The effective frequency points are selected based on the frequency points with high signal-to-noise ratio, small phase fluctuation, high impedance matching degree and low dispersion of multi-channel measurement results. The final grounding resistance value is determined based on the candidate grounding resistance values ​​corresponding to the effective frequency points.

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