Method, system and device for operating condition fault monitoring of heavy load overhead line

Abstract

The application discloses a method, system and device for operating state fault monitoring of heavy load overhead line, and relates to the technical field of electric fault detection of heavy load overhead line. The method comprises the following steps: performing predefined fault detection by injecting a high-frequency test signal into the heavy load overhead line to obtain a total harmonic distortion rate; performing first harmonic optimization adjustment according to comparison and analysis of the total harmonic distortion rate and a threshold value; performing second harmonic optimization adjustment according to monitoring and analysis results of external load fluctuation of the heavy load overhead line; and performing third harmonic optimization adjustment according to monitoring and analysis results of external environment fluctuation of the heavy load overhead line. The application achieves the effect of improving the dynamic regulation accuracy of the high-frequency test signal injection monitoring fault method of the heavy load overhead line under extreme weather through multi-stage distributed adjustment, and solves the problem of insufficient dynamic regulation accuracy of the high-frequency test signal injection monitoring fault method of the heavy load overhead line under extreme weather in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric fault detection of heavy load overhead lines, and in particular to a method, system and device for monitoring the operating state fault of heavy load overhead lines. BACKGROUND

[0002] With the development of society and the acceleration of urbanization, the demand for electricity is increasing. As an important part of power transmission, the safe and stable operation of heavy load overhead lines is crucial to ensuring power supply. Therefore, real-time monitoring and fault warning of heavy load overhead lines have become an important issue in the power industry, especially for monitoring the simultaneous occurrence of high resistance grounding anomalies and harmonic interference anomalies of heavy load overhead lines under extreme weather conditions.

[0003] The existing method for monitoring the operating state fault of heavy load overhead lines is achieved by the following method: automatically injecting high-frequency pulse signals in a specific frequency range, using efficient signal coupling technology, using anti-interference technologies such as pseudo-random coding, orthogonal coding, and spread spectrum technology, so that the impedance parameters and resonance parameters obtained through frequency spectrum analysis are used to analyze the fault location, and the electric fault monitoring of heavy load overhead lines is completed.

[0004] For example, the invention patent with publication number CN119165296A discloses a method and system for online monitoring and fault warning positioning of overhead lines, which includes: collecting traveling wave signals using sensors installed at each measurement point of the overhead line; identifying the traveling wave signals and fault types using a deep learning algorithm; using traveling wave ranging technology and GIS to obtain the distance of each fault point relative to the measurement point, matching the geographical information and topological structure of the overhead line, and obtaining the preliminary position of each fault point; using virtual simulation software, injecting faults and simulating the generation of traveling wave signals at the preliminary position of each fault point corresponding to each fault; comparing the similarity of each fault traveling wave signal with the corresponding simulated traveling wave signal, and determining the final fault position of the fault point according to the similarity result and generating a fault warning positioning prompt.

[0005] For example, the invention patent with publication number CN119375615A discloses a diagnostic device suitable for fault warning positioning of overhead cable of power transmission line, which relates to the technical field of cable fault detection, and includes a detection data acquisition unit, a partial discharge detection unit, and a fault detection processing unit. Through the optimization of sensors by the sensor optimization module and the assistance of signals by the signal auxiliary module, the electromagnetic interference during cable detection can be reduced after processing, thereby stabilizing the obtained traveling wave signals. Through signal amplification and signal filtering technology, the signal is enhanced and the signal-to-noise ratio is improved.

[0006] But in the process of implementing the technical scheme of the embodiments of the present application, the applicant finds that the above-mentioned technology at least has the following technical problems:

[0007] In the prior art, under extreme weather, the problem of high resistance grounding abnormality and large harmonic interference of the large load overhead line may occur simultaneously, high-frequency pulse signals of a specific frequency range are automatically injected, impedance parameters and resonance parameters obtained through frequency spectrum analysis are used to analyze the fault position, and the signal phase jitter caused by the external environmental influence and the external load influence makes it difficult to analyze the positioning and early warning of the problem, and the dynamic regulation accuracy of the high-frequency test signal injection monitoring fault method of the large load overhead line under extreme weather is insufficient. SUMMARY

[0008] The embodiments of the present application provide a running state fault monitoring method, system and device for a large load overhead line, solve the problem of insufficient dynamic regulation accuracy of the high-frequency test signal injection monitoring fault method of the large load overhead line under extreme weather in the prior art, and achieve the effect of improving the dynamic regulation accuracy of the high-frequency test signal injection monitoring fault method of the large load overhead line under extreme weather.

[0009] The embodiments of the present application provide a running state fault monitoring method for a large load overhead line, including the following steps: performing predefined fault detection on the large load overhead line by injecting a high-frequency test signal, obtaining a total harmonic distortion rate; performing harmonic first optimization adjustment according to the comparison analysis of the total harmonic distortion rate and a threshold value; performing external load fluctuation monitoring analysis of the large load overhead line after the harmonic first optimization adjustment, and performing harmonic second optimization adjustment according to the external load fluctuation monitoring analysis result of the large load overhead line; performing external environmental fluctuation monitoring analysis of the large load overhead line after the harmonic second optimization adjustment, and performing harmonic third optimization adjustment according to the external environmental fluctuation monitoring analysis result of the large load overhead line.

[0010] Further, the predefined fault detection on the large load overhead line by injecting a high-frequency test signal specifically includes: using a high-frequency test signal generator to generate a pulse signal of a specific frequency, coupling and injecting the high-frequency test signal into the large load overhead line through a capacitor coupler; installing a high-frequency sensor at a receiving monitoring point to capture reflected signals and transmitted signals; and positioning impedance abnormal points and resonance abnormal points through frequency spectrum analysis extraction and traveling wave positioning algorithm.

[0011] Further, the predefined fault detection by injecting a high-frequency test signal into the heavy-load overhead line further includes: sampling and collecting at a sampling rate built in a wide-band current transformer downstream of the injection point or at the end of the line to obtain a high-frequency time-domain signal; processing the high-frequency time-domain signal by fast Fourier transform to obtain a frequency-domain complex spectrum; extracting a fundamental wave amplitude of the frequency-domain complex spectrum from a heavy-load overhead line operation state fault database; if a frequency-domain amplitude value of the frequency-domain complex spectrum is greater than a predefined proportion value of the fundamental wave amplitude, no adjustment is made; if the frequency-domain amplitude value of the frequency-domain complex spectrum is less than or equal to the predefined proportion value of the fundamental wave amplitude, a frequency-domain complex spectrum part of the corresponding frequency-domain complex spectrum that is less than the predefined proportion value of the corresponding fundamental wave amplitude is filtered; and a total harmonic distortion rate of the heavy-load overhead line is obtained by extracting and analyzing the frequency-domain complex spectrum.

[0012] Further, the harmonic first optimization adjustment specifically includes: if the total harmonic distortion rate of the heavy-load overhead line is less than a total harmonic distortion rate threshold, no adjustment is made; and if the total harmonic distortion rate of the heavy-load overhead line is equal to or greater than the total harmonic distortion rate threshold, a passive filter is started for harmonic suppression by tuning the passive filter at a predefined position.

[0013] Further, the harmonic first optimization adjustment is performed outside the load fluctuation monitoring analysis of the heavy load overhead line, specifically comprising: directly extracting the heavy load overhead line load power historical average value, the heavy load overhead line leakage current historical average value, and the average discharge strength of partial discharge from the heavy load overhead line database; detecting the maximum and minimum values of the heavy load overhead line load power through the intelligent monitoring terminal of the heavy load overhead line; detecting the maximum value of the heavy load overhead line leakage current through the corresponding leakage current acquisition ring; detecting the maximum value of the discharge strength of the heavy load overhead line partial discharge through the corresponding high-frequency partial discharge detector; obtaining the first negative impact component of the external load fluctuation of the heavy load overhead line by analyzing the difference between the maximum and minimum values of the heavy load overhead line load power, the proportion of the heavy load overhead line load power historical average value, and the weight factor of humidity on the load power; obtaining the first proportional value by exponentially correcting the proportion of the maximum value of the heavy load overhead line leakage current and the historical average value of the heavy load overhead line leakage current, and obtaining the second proportional value by multiplying the proportion of the maximum value of the discharge strength of the heavy load overhead line partial discharge and the average discharge strength of the heavy load overhead line partial discharge, and analyzing the discharge times of the discharge strength of the heavy load overhead line partial discharge; superimposing the first proportional value and the second proportional value, and correcting the weight factor of humidity on the partial and leakage discharge to obtain the second negative impact component of the external load fluctuation of the heavy load overhead line; and comprehensively analyzing the first negative impact component and the second negative impact component to obtain the negative impact value of the external load fluctuation of the heavy load overhead line.

[0014] Further, the harmonic second optimization adjustment is performed according to the monitoring analysis result of the external load fluctuation of the heavy load overhead line, specifically comprising: if the negative impact value of the external load fluctuation of the heavy load overhead line is less than the negative threshold value of the external load fluctuation of the heavy load overhead line, no harmonic second optimization adjustment is performed; if the negative impact value of the external load fluctuation of the heavy load overhead line is equal to or greater than the negative threshold value of the external load fluctuation of the heavy load overhead line, the harmonic second optimization adjustment is performed, specifically: subtracting the negative threshold value of the external load fluctuation of the heavy load overhead line from the negative impact value of the external load fluctuation of the heavy load overhead line to obtain the negative difference value of the external load fluctuation of the heavy load overhead line; and reducing the period window of the fast Fourier transform and increasing the overlap rate of the fast Fourier transform according to the negative difference value of the external load fluctuation of the heavy load overhead line and the predefined negative difference value matching rule.

[0015] Further, the harmonic second optimization adjustment is further subjected to external environmental fluctuation monitoring analysis of the heavy load overhead line, specifically comprising: collecting the maximum mechanical stress of the conductor and the maximum swing amplitude of the conductor of the heavy load overhead line by the fiber grating sensor; if the maximum mechanical stress or the maximum swing amplitude of the conductor is greater than or equal to the corresponding threshold value, starting the hydraulic tension adjusting device; if the maximum mechanical stress or the maximum swing amplitude of the conductor is less than the corresponding threshold value, not adjusting, directly extracting the standard value of the mechanical stress of the conductor, the standard value of the swing amplitude of the conductor and the capacitance threshold value of the heavy load overhead line from the heavy load overhead line database, collecting the maximum capacitance value and the minimum capacitance value of the heavy load overhead line by the distributed capacitance sensor, correcting the ratio of the maximum mechanical stress of the conductor to the standard value of the mechanical stress of the conductor with the mechanical stress weight factor of the conductor to obtain the external environmental negative first component of the heavy load overhead line, correcting the ratio of the maximum swing amplitude of the conductor to the standard value of the swing amplitude of the conductor with the swing amplitude weight factor of the conductor to obtain the external environmental negative second component of the heavy load overhead line, analyzing the difference between the maximum capacitance value and the minimum capacitance value of the heavy load overhead line, analyzing the ratio of the difference to the capacitance threshold value of the heavy load overhead line, correcting the ratio with the capacitance weight factor of the heavy load overhead line to obtain the external environmental negative third component of the heavy load overhead line, combining the external load fluctuation negative influence value of the heavy load overhead line, the external environmental negative first component of the heavy load overhead line, the external environmental negative second component of the heavy load overhead line and the external environmental negative third component of the heavy load overhead line to obtain the external environmental negative influence value of the heavy load overhead line, which is used to represent the quantification level of the external load fluctuation negative influence value of the heavy load overhead line, the external environmental negative first component of the heavy load overhead line, the external environmental negative second component of the heavy load overhead line and the external environmental negative third component of the heavy load overhead line on the external load fluctuation influence degree of the heavy load overhead line.

[0016] Further, the harmonic third optimization adjustment is performed according to the monitoring analysis result of the external environmental fluctuation of the heavy load overhead line, specifically comprising: if the external environmental negative influence value of the heavy load overhead line is less than the external environmental negative influence threshold value of the heavy load overhead line, not adjusting; if the external environmental negative influence value of the heavy load overhead line is equal to or greater than the external environmental negative influence threshold value of the heavy load overhead line, performing spread spectrum gain on the heavy load overhead line of the corresponding injection point by the pre-defined wide frequency coupler and performing nonlinear notch filtering on the pre-defined frequency.

[0017] The embodiment of the application provides a kind of for the operating state fault monitoring system of heavy load overhead line, including pre-defined fault detection module, harmonic first optimization adjustment module, harmonic second optimization adjustment module and harmonic third optimization adjustment module;Pre-defined fault detection module, for by high frequency test signal injection heavy load overhead line carries out pre-defined fault detection, obtains total harmonic distortion;Harmonic first optimization adjustment module, for according to total harmonic distortion and threshold comparison analysis, carries out harmonic first optimization adjustment;Harmonic second optimization adjustment module, for after harmonic first optimization adjustment carries out heavy load overhead line external load fluctuation monitoring analysis, according to the harmonic second optimization adjustment of heavy load overhead line external load fluctuation monitoring analysis result;Harmonic third optimization adjustment module, for after harmonic second optimization adjustment carries out heavy load overhead line external environment fluctuation monitoring analysis, according to the harmonic third optimization adjustment of heavy load overhead line external environment fluctuation monitoring analysis result.

[0018] The embodiment of the application provides the device for applying the operating state fault monitoring method for heavy load overhead line, including hydraulic tension adjusting device hydraulic cylinder, hydraulic tension adjusting device hydraulic pump station, hydraulic tension adjusting device control valve group, hydraulic tension adjusting device sensing module, hydraulic tension adjusting device control module, hydraulic tension adjusting device communication module and hydraulic tension adjusting device protective shell: hydraulic tension adjusting device hydraulic cylinder: for by the effective length of lead wire change of piston rod's telescopic change;Hydraulic tension adjusting device hydraulic pump station: for providing high pressure oil source, drive hydraulic cylinder action;Hydraulic tension adjusting device control valve group: for controlling the flow and direction of hydraulic oil;Hydraulic tension adjusting device sensing module: for by fiber Bragg grating sensor detection feedback;Hydraulic tension adjusting device control module: for embedded controller to receive sensor signal, according to PID control output adjustment instruction;Hydraulic tension adjusting device communication module: for with the operating state fault monitoring system of heavy load overhead line linkage, support remote instruction and state back;Hydraulic tension adjusting device protective shell: for corrosion resistance, rain and dust proof, use IP67 protection level.

[0019] One or more technical solutions provided in the embodiment of the application have at least the following technical effects or advantages:

[0020] 1. By comparing the total harmonic distortion rate with the threshold value, the first optimization adjustment of harmonics is performed; according to the monitoring analysis result of the external load fluctuation of the heavy load overhead line, the second optimization adjustment of harmonics is performed; according to the monitoring analysis result of the external environmental fluctuation of the heavy load overhead line, the third optimization adjustment of harmonics is performed, which achieves the effect of improving the dynamic regulation accuracy of the high-frequency test signal injection monitoring fault method of the heavy load overhead line under extreme weather, and solves the problem of insufficient dynamic regulation accuracy of the high-frequency test signal injection monitoring fault method of the heavy load overhead line under extreme weather in the prior art.

[0021] 2. According to the monitoring analysis result of the external load fluctuation of the heavy load overhead line, the second optimization adjustment of harmonics is performed, and by dynamically adjusting the FFT window and the overlap rate, the real-time resolution balance, anti-interference enhancement and resource efficiency optimization are realized, and the fault monitoring reliability of the heavy load line under extreme weather is significantly improved.

[0022] 3. According to the monitoring analysis result of the external environmental fluctuation of the heavy load overhead line, the third optimization adjustment of harmonics is performed, and by high-precision sensing, dynamic weight correction, nonlinear interference suppression and spread spectrum gain optimization, accurate monitoring and active regulation of the heavy load overhead line under extreme weather are realized. The low-frequency modulation noise is suppressed by Volterra model, and the signal-to-noise ratio is obviously improved; the wire tension is adjusted by the hydraulic device in seconds, and the swing amplitude is greatly reduced; thereby providing key technical support for smart grid construction, especially in extreme scenarios such as typhoon and icing, which shows significant engineering value. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The flow chart of the operation state fault monitoring method for the heavy load overhead line provided by the embodiments of the present application is provided.

[0024] Figure 2 The structural schematic diagram of the operation state fault monitoring system for the heavy load overhead line provided by the embodiments of the present application is provided. DETAILED DESCRIPTION

[0025] The embodiments of the present application provide an operation state fault monitoring method, system and device for a heavy load overhead line, which solves the problem of insufficient dynamic regulation accuracy of the high-frequency test signal injection monitoring fault method of the heavy load overhead line under extreme weather in the prior art, and achieves the effect of improving the dynamic regulation accuracy of the high-frequency test signal injection monitoring fault method of the heavy load overhead line under extreme weather.

[0026] In order to better understand the above technical solutions, the above technical solutions will be described in detail in combination with the drawings of the specification and specific embodiments.

[0027] As Figure 1As shown, a flowchart of a method for monitoring the operating state fault of a heavy-load overhead line is provided in the embodiments of the present application. The method is applied to a system for monitoring the operating state fault of a heavy-load overhead line. The method comprises the following steps: performing predefined fault detection by injecting a high-frequency test signal into the heavy-load overhead line to obtain a total harmonic distortion rate; performing first harmonic optimization adjustment according to a comparison between the total harmonic distortion rate and a threshold value; performing external load fluctuation monitoring analysis of the heavy-load overhead line after the first harmonic optimization adjustment, and performing second harmonic optimization adjustment according to the external load fluctuation monitoring analysis result of the heavy-load overhead line; performing external environment fluctuation monitoring analysis of the heavy-load overhead line after the second harmonic optimization adjustment, and performing third harmonic optimization adjustment according to the external environment fluctuation monitoring analysis result of the heavy-load overhead line.

[0028] In the embodiments, under extreme weather such as typhoon, the strong wind of the typhoon causes tree branches to break and hang on the conductor, forming a high-resistance grounding conductor overload. The joule heat causes the tree branches to carbonize, the grounding resistance gradually decreases, and finally an arc discharge is triggered. The typhoon is accompanied by heavy rain, which causes the conductor to swing violently, resulting in periodic overload of the conductor and accelerating the sensor drift. The instantaneous reduction of the conductor spacing causes flashover, and the high-humidity environment aggravates the partial discharge. For the above scenarios, a specific high-frequency pulse signal is generally automatically injected using a capacitive coupler, and then the frequency spectrum generated by the influence of the high-frequency pulse signal on the heavy-load overhead line is analyzed to obtain corresponding impedance abnormal points and resonance abnormal points, thereby obtaining the operating state fault points of the heavy-load overhead line. However, because the heavy-load overhead line is affected by various external factors, the above method is prone to misjudgment, and the accuracy needs to be improved.

[0029] Further, the predefined fault detection by injecting a high-frequency test signal into the heavy-load overhead line specifically comprises: generating a pulse signal of a specific frequency using a high-frequency test signal generator, and coupling the high-frequency test signal into the heavy-load overhead line through a capacitive coupler; installing a high-frequency sensor at a receiving monitoring point to capture reflected signals and transmitted signals; and positioning impedance abnormal points and resonance abnormal points through frequency spectrum analysis and traveling wave positioning algorithms.

[0030] In this embodiment, a high-frequency test signal generator is used to generate a pulse signal at a specific frequency, typically 10 kHz to 1 MHz, which avoids the power frequency (50 / 60 Hz) and its harmonics and adapts to the line impedance characteristics. The signal waveform is usually a short pulse (such as a square wave or sine wave envelope) to enhance anti-interference ability and reflection characteristic identification. The coupler uses the principle of capacitive voltage division to couple the high-frequency test signal to the high-voltage conductor while isolating the power frequency high voltage, ensuring the safety of the equipment. The injected high-frequency test signal propagates along the conductor and produces reflected and transmitted waves when encountering impedance discontinuities (such as tree branch short circuits, conductor breaks, and flashover points). The reflected wave returns to the injection point, and the transmitted wave continues to propagate to the end of the line. By analyzing signal attenuation, phase change, and resonance characteristics through frequency spectrum analysis, time domain reflection (TDR), or traveling wave positioning algorithms, impedance abnormal points (such as carbonized tree branches) or resonance points (such as reduced conductor spacing leading to capacitance changes) can be located.

[0031] A high-voltage capacitor (i.e., a capacitive coupler) is connected to the line, and the low-voltage side is connected to the signal generator. Common parameters are 1000 pF to 0.1 μF, and the voltage rating needs to match the line voltage (such as 110 kV and above).

[0032] A wave choke can be installed at the substation side to prevent high-frequency test signals from entering the substation equipment, ensuring that the signal propagates along the line.

[0033] A high-frequency sensor can be used to receive the reflected signal, typically a wide-band current transformer or voltage transformer.

[0034] The injection location is usually chosen at the substation outlet or the end of the line tower, making it easy to cover the entire line.

[0035] The relative position of the receiving monitoring point to the injection point is the receiving position distance, typically ranging from 10 km to 50 km.

[0036] By frequency spectrum analysis and traveling wave positioning algorithms, impedance abnormal points and resonance abnormal points can be located, including: high-frequency sensors capture frequency domain data of reflected and transmitted signals, and in a typhoon environment, multiple samples can be superimposed and averaged to suppress rain noise (such as random pulses caused by raindrop impact).

[0037] Frequency feature extraction: convert time domain signals to frequency domain by fast Fourier transform to extract amplitude spectrum and phase spectrum.

[0038] For example, carbonized tree branches, reduced grounding resistance leading to resonance frequency shift. Reduced conductor spacing, increased capacitance, and decreased resonance frequency.

[0039] If an abnormal resonance peak is detected on a certain section of the line, the capacitance increase at that point is calculated based on the line parameters, and it is inferred that the conductor spacing has been reduced (e.g., due to strong winds causing the conductors to swing and collide). The determination of an abnormal resonance peak is made by setting a threshold value. There is a corresponding threshold value range at a specific frequency spectrum location. Both exceeding and not reaching the set threshold value range are considered abnormal resonance peaks.

[0040] The capacitance increase at that point is calculated based on the line parameters, and it is inferred that the conductor spacing has been reduced. The specific steps are shown as follows:

[0041] Establish an equivalent circuit model for the line: The transmission line can be simplified as a distributed parameter model, which includes inductance, capacitance, resistance, and conductance. The characteristic impedance and propagation constant of the line are key parameters that describe its electrical characteristics:

[0042] Characteristic impedance: determined by the ratio of inductance to capacitance, reflecting the impedance of the line to current.

[0043] Propagation constant: describes the attenuation and phase change of the signal when propagating on the line. In the case of ignoring loss, the propagation constant is mainly determined by inductance and capacitance.

[0044] Resonant frequency: the resonant frequency of the line is inversely proportional to the square root of the product of inductance and capacitance, and inversely proportional to the length of the line.

[0045] Assuming that the unit length inductance, capacitance and line length of the line are known, the fundamental resonant frequency of the line can be calculated. The fundamental resonant frequency is the lowest resonant frequency of the line under normal conditions, and is usually used to judge whether the line is in normal working state.

[0046] Threshold setting for abnormal resonance peak: In order to determine whether the resonant frequency is abnormal, a range of allowed frequency deviation needs to be set. This range is usually based on historical data or theoretical calculation. If the detected resonant frequency exceeds this range (whether too high or too low), it is determined to be abnormal.

[0047] Derivation of the relationship between capacitance change and resonant frequency: When the conductor spacing is reduced, the capacitance increases, which causes the resonant frequency to change. The resonant frequency is inversely proportional to the square root of the capacitance, so the change in capacitance can be inferred from the detected resonant frequency deviation. Specifically, if the detected resonant frequency is lower than the normal value, it means that the capacitance has increased; conversely, if the resonant frequency is higher than the normal value, it means that the capacitance has decreased.

[0048] Capacitance model backstepping of conductor spacing variation: the capacitance between conductors is inversely proportional to the conductor spacing. Through the change of capacitance, the change of conductor spacing can be backstepped. The specific steps include: according to the capacitance and conductor spacing under normal state, the relationship model of capacitance and spacing is established. The detected capacitance change is used to calculate the new conductor spacing. The new conductor spacing is compared with the safe spacing to determine whether there is an abnormality.

[0049] Traveling wave positioning algorithm

[0050] Principle: use the time difference of traveling wave generated by fault point reaching both ends of the line, combined with GPS synchronization to realize double-end positioning.

[0051] Specific steps:

[0052] The sensors at both ends of the line are synchronized by GPS clock (error ≤ 1 μs), and record the arrival time T1 (starting end) and T2 (end) of the traveling wave.

[0053] Positioning calculation:

[0054] S represents the fault location.

[0055] S Z represents the total length of the heavy load overhead line.

[0056] V represents the signal propagation speed, and the typical value of overhead line is 98% of the speed of light, i.e. about 294000 km / s.

[0057] T1 represents the time of traveling wave reaching the starting end. T2 represents the time of traveling wave reaching the end.

[0058] Waveform recognition and anti-interference:

[0059] Extract the singular points (such as sudden rising edge) of the traveling wave head through wavelet transform, and distinguish fault traveling wave from noise.

[0060] Example: the time difference T2-T1 of fault traveling wave detected by double-end is 0.4 ms, the total length of heavy load overhead line is 120 km, and the fault point is calculated to be 60.2 km away from the starting end, and the relevant personnel are notified to confirm that the flashover is caused by the reduction of conductor spacing.

[0061] Further, the predefined fault detection by injecting a high-frequency test signal into a large-load overhead line also includes: sampling and collecting at a sampling rate built in a wide-band current transformer downstream of the injection point or at the end of the line to obtain a high-frequency time-domain signal; processing the high-frequency time-domain signal by fast Fourier transform to obtain a frequency-domain complex spectrum; extracting a fundamental wave amplitude of the frequency-domain complex spectrum from a large-load overhead line operation state fault database; if a frequency-domain amplitude value of the frequency-domain complex spectrum is greater than a predefined proportion value of the fundamental wave amplitude, no adjustment is made; if the frequency-domain amplitude value of the frequency-domain complex spectrum is less than or equal to the predefined proportion value of the fundamental wave amplitude, a frequency-domain complex spectrum part corresponding to the frequency-domain complex spectrum less than the predefined proportion value of the corresponding fundamental wave amplitude is filtered; and the total harmonic distortion rate of the large-load overhead line is obtained by extracting and analyzing the frequency-domain complex spectrum.

[0062] In the embodiment, a wide-band current transformer (such as a Rogowski coil, with a bandwidth of DC-30 MHz) has a sampling rate ≥10 MS / s (assuming that the large-load overhead line has a fundamental wave of 1 MHz, the corresponding sampling rate is 100 MS / s, ensuring that at least 10 harmonics are captured), and the recording duration is at least 10 fundamental wave periods (such as 1 ms when the fundamental wave is 10 kHz). Trigger mode: a synchronous trigger signal of a signal transmitter is used to avoid random noise interference. Anti-aliasing filter: a low-pass filter (cutoff frequency = signal highest harmonic frequency × 1.5) is added before the ADC. DC offset removal: for example, if the injected signal is a 1 MHz sine wave, at least 10 μs (10 periods) of time-domain waveform needs to be collected, and the sampling rate is set to 100 MS / s, corresponding to 100 sampling points per period.

[0063] Performing FFT converts the time-domain signal into a frequency-domain complex spectrum, and the fundamental wave frequency is determined at the frequency point (such as 1 MHz) with the largest amplitude in the frequency-domain complex spectrum. For example, if the amplitude of the frequency-domain complex spectrum is 10 V (fundamental wave) at 1 MHz, 0.5 V (second harmonic) at 2 MHz, and 0.3 V (third harmonic) at 3 MHz after FFT, the harmonic below the threshold value is considered as noise if the amplitude threshold value (such as 1% of the fundamental wave amplitude) is lower than the threshold value. Amplitude threshold filtering sets the frequency point with an amplitude lower than 1% of the fundamental wave amplitude in the frequency-domain complex spectrum to zero (considered as noise) and retains the effective harmonic component.

[0064] The main steps of extracting and analyzing the total harmonic distortion rate according to the frequency-domain complex spectrum are as follows:

[0065] Identify the fundamental frequency (usually 50 / 60 Hz) from the frequency domain complex spectrum and extract the amplitude value corresponding to the fundamental frequency; extract the amplitude value at the integer multiple frequency points (such as 2nd, 3rd to Nth harmonic) of the fundamental frequency, and calculate the total harmonic distortion rate formula. Before calculation, filter through amplitude threshold filtering (such as 1%-5% of the fundamental amplitude) to avoid interference from invalid frequency points. Example process: if the fundamental amplitude of a certain signal is 100V, the 2nd harmonic is 30V, and the 3rd harmonic is 20V, then the THD is calculated as: The result indicates that the harmonic component accounts for 36.06% of the total signal.

[0066] Further, the first optimization adjustment of harmonics specifically includes: if the total harmonic distortion rate of the heavy load overhead line is less than the total harmonic distortion rate threshold, no adjustment is made; if the total harmonic distortion rate of the heavy load overhead line is equal to or greater than the total harmonic distortion rate threshold, a passive filter is started for harmonic suppression through passive filter tuning at a predefined location.

[0067] In this embodiment, the passive filter tuning adjusts the resonant frequency of the LC passive filter to match the current dominant harmonic (such as the 3rd or 5th harmonic). For example, if a resonance peak is detected at 150kHz (due to reduced conductor spacing leading to increased capacitance), the filter parameters are adjusted to 150kHz. The principle of passive filtering is to use the LC series resonance characteristic to present a low impedance path at a specific frequency (such as the 3rd or 5th harmonic), bypassing the harmonic current to ground.

[0068] After suppressing harmonics, the interference of noise on the positioning of impedance anomalies (such as carbonized branches) is reduced, avoiding misjudgment. For example, raindrop noise during a typhoon storm may cause THD to be artificially high, and after filtering, the positioning error can be reduced from ±500m to ±50m. Suppressing harmonics can reduce the risk of conductor overheating (Joule heat is positively correlated with harmonic loss), avoiding accelerated carbonization of branches and grounding faults. Avoiding resonance overvoltage causing flashover or insulation breakdown.

[0069] In terms of software and hardware, hardware includes LC filters, sensors, and tuning components; software involves harmonic analysis tools, parameter calculation software, and monitoring systems.

[0070] The predefined location is generally set to start the LC filter set near the dominant harmonic source (such as the low voltage side of the transformer or the point of concentration of non-linear loads) using star or delta connection. For example, for the 5th harmonic, a single-tuned filter in parallel structure is used.

[0071] Real-time monitoring of total harmonic distortion rate (THD) is achieved through power quality monitoring devices (such as Power Quality Analyzer) to ensure that THD is reduced below the threshold value (for example, from 15% to 5%).

[0072] LC passive filter bank (including adjustable reactor, capacitor, switching switch) is used to absorb specific harmonic frequency.

[0073] Harmonic analyzer (such as Fluke435II) and traveling wave positioning device (such as SEL-T400L) realize harmonic detection and fault location.

[0074] Further, the first optimized adjustment of the harmonic is carried out. The external load fluctuation monitoring analysis of the heavy load overhead line specifically includes: the heavy load overhead line load power historical average value, the heavy load overhead line leakage current historical average value, and the average value of the discharge intensity of partial discharge are directly extracted from the heavy load overhead line database; the maximum value and the minimum value of the heavy load overhead line load power are detected by the intelligent monitoring terminal of the heavy load overhead line; the maximum value of the heavy load overhead line leakage current is detected by the corresponding leakage current acquisition ring; the maximum value of the discharge intensity of the heavy load overhead line partial discharge is detected by the corresponding high-frequency partial discharge detector; the difference between the maximum value and the minimum value of the heavy load overhead line load power is analyzed by the proportion of the heavy load overhead line load power historical average value, and then the weight factor of the corresponding humidity on the load power is corrected to obtain the first influence component of the negative direction of the external load fluctuation of the heavy load overhead line; the first proportional value is obtained by the exponential correction of the proportion of the maximum value of the heavy load overhead line leakage current and the historical average value of the heavy load overhead line leakage current, and the proportion of the maximum value of the discharge intensity of the heavy load overhead line partial discharge and the average value of the discharge intensity of the heavy load overhead line partial discharge is multiplied by the discharge times of the discharge intensity of the heavy load overhead line partial discharge to obtain the second proportional value; the first proportional value and the second proportional value are superimposed, and then the weight factor of the humidity on the local and leakage discharge is corrected to obtain the second influence component of the negative direction of the external load fluctuation of the heavy load overhead line. The first influence component of the negative direction of the external load fluctuation of the heavy load overhead line and the second influence component of the negative direction of the external load fluctuation of the heavy load overhead line are comprehensively analyzed to obtain the negative influence value of the external load fluctuation of the heavy load overhead line.

[0075] In the embodiment, FZ0 represents the number of segments of the heavy load overhead line, FZ0=1, 2, 3..., FZ, FZ represents the total number of segments of the heavy load overhead line, JK0 represents the inspection monitoring point of the heavy load overhead line, JK0=1, 2, 3..., JK, JK represents the total number of inspection monitoring points of the heavy load overhead line, JS0 represents the detection time period of the heavy load overhead line, JS0=1, 2, 3..., JS, JS represents the total number of detection time periods of the heavy load overhead line.

[0076] The large-load overhead line external load fluctuation negative influence value of the JS0 section detection time period of the JK0th inspection monitoring point of the FZ0 section large-load overhead line, which is used to quantify the relative negative distortion degree value of the comprehensive influence of the large-load overhead line caused by external load fluctuation.

[0077]

[0078] The large-load overhead line load power maximum value of the JS0 section detection time period of the JK0th inspection monitoring point of the FZ0 section large-load overhead line. The intelligent monitoring terminal of the large-load overhead line can collect the line load current in real time through a high-precision current transformer and calculate the power parameter using an FFT algorithm. For example, minute-level data collection is supported, and the maximum load power can be monitored. The built-in wireless communication module (such as 4G / 5G) can upload data to the master station system to realize real-time tracking and collection of load peaks.

[0079] The large-load overhead line load power minimum value of the JS0 section detection time period of the JK0th inspection monitoring point of the FZ0 section large-load overhead line.

[0080] The large-load overhead line load power historical average value of the JS0 section detection time period of the JK0th inspection monitoring point of the FZ0 section large-load overhead line, which is directly extracted from the large-load overhead line database and used to represent the average level in the historical data of the large-load overhead line load power.

[0081] The large-load overhead line leakage current maximum value of the JS0 section detection time period of the JK0th inspection monitoring point of the FZ0 section large-load overhead line. In the corresponding leakage current collection ring of the corresponding inspection monitoring point of the large-load overhead line monitoring, a leakage current signal coupling device can be installed at the top of the insulator string to realize real-time collection of the maximum value of the large-load overhead line leakage current.

[0082] The large-load overhead line leakage current historical average value of the JS0 section detection time period of the JK0th inspection monitoring point of the FZ0 section large-load overhead line, which is directly extracted from the large-load overhead line database.

[0083] Discharge intensity maximum of partial discharge of the large load overhead line in the JSO period of detection of the JK0th inspection monitoring point of the FZ0 section large load overhead line, which is captured in real time by a high-frequency partial discharge detector (such as an OMICRON MPD600).

[0084] Discharge intensity average of partial discharge of the large load overhead line in the JSO period of detection of the JK0th inspection monitoring point of the FZ0 section large load overhead line, which is directly extracted from the large load overhead line database.

[0085] Discharge frequency of partial discharge of the large load overhead line in the JSO period of detection of the JK0th inspection monitoring point of the FZ0 section large load overhead line.

[0086] High humidity (>90%) reduces the surface resistance of the insulator, increases the leakage current (from 1 mA to 10 mA), and accelerates the generation of partial discharge broadband interference. The influence of humidity on the large load overhead line mainly manifests in two aspects: high humidity (>90%) leads to a decrease in the surface resistance of the insulator and an increase in the leakage current (from 1 mA to 10 mA), causing additional load power loss and increasing load power fluctuation. Humidity accelerates the enhancement of the conductivity of the contaminated layer, forming a conductive channel, which leads to an increase in the discharge pulse frequency and amplitude (such as more than 100 discharge pulses per minute).

[0087] Weight factor of humidity on load power in the JSO period of detection of the JK0th inspection monitoring point of the FZ0 section large load overhead line, reflecting the influence degree of the additional leakage current loss caused by humidity on the line load capacity.

[0088] Weight factor of humidity on partial and leakage discharge in the JSO period of detection of the JK0th inspection monitoring point of the FZ0 section large load overhead line, reflecting the enhancement effect of humidity on the discharge intensity (such as pulse number and amplitude).

[0089] Different humidity conditions are simulated in an artificial climate chamber, leakage current and discharge pulse characteristics are measured, and coefficients are fitted. Through nonlinear model calibration and actual measurement data, dynamic weight allocation can be realized, the mapping relationship between real-time humidity and the weight factor of humidity on load power and the weight factor of humidity on partial discharge is constructed, and the corresponding weight factor of humidity on load power and the weight factor of humidity on partial discharge are obtained by inputting the implementation humidity.

[0090] A specific weight factor construction process example is as follows: set a 20%-95% humidity gradient (interval 10%) in a phytotron, constant temperature 30℃ to simulate heavy load line environment. Use high-precision sensors to monitor leakage current, partial discharge pulse and load power under each humidity for 2 hours, and record environmental humidity data synchronously. Extract effective electrical parameters through wavelet denoising and pulse integration algorithm.

[0091] Fit 10 groups of experimental data into a continuous function to generate a humidity-weight mapping table of 512 discrete points, embedded in FPGA chip to realize μs-level query. When real-time humidity input, use cubic spline interpolation to dynamically calculate weight value.

[0092] Further, according to the harmonic second optimization adjustment of the external load fluctuation monitoring and analysis result of the heavy load overhead line, specifically: if the negative influence value of the external load fluctuation of the heavy load overhead line is less than the negative threshold value of the external load fluctuation of the heavy load overhead line, no harmonic second optimization adjustment is performed; if the negative influence value of the external load fluctuation of the heavy load overhead line is equal to or greater than the negative threshold value of the external load fluctuation of the heavy load overhead line, the harmonic second optimization adjustment is performed, specifically: subtracting the negative threshold value of the external load fluctuation of the heavy load overhead line from the negative influence value of the external load fluctuation of the heavy load overhead line to obtain the negative difference value of the external load fluctuation of the heavy load overhead line; according to the pre-defined load fluctuation negative difference value matching rule, the period window of the fast Fourier transform is reduced and the overlap rate of the fast Fourier transform is increased.

[0093] In this embodiment, the pre-defined load fluctuation negative difference value matching rule is the corresponding relationship between the negative difference value of the external load fluctuation of the heavy load overhead line and the adjustment of the period window reduction and overlap rate increase of the specific fast Fourier transform;

[0094] For example, when the negative difference value of the external load fluctuation of the heavy load overhead line is 0.5, the FFT analysis of 10 fundamental period (such as 50Hz corresponding to 200ms window) is adopted to improve the frequency resolution to 0.5Hz.

[0095] The Python code example is window_length=10 (1 / 50).

[0096] That is, 0.2 seconds (10 periods).

[0097] When the negative difference value of the external load fluctuation of the heavy load overhead line is 2, the fluctuation period (5 period window) is adopted: when the load mutates, the window is shortened to 5 periods (100ms), the resolution is sacrificed to improve the real-time performance and suppress the spectral tail effect.

[0098] When the external load fluctuation negative difference of the heavy load overhead line is 0.5, 30% overlap rate (such as window length 200 ms, each sliding 60 ms) is adopted, and the truncation error is reduced by Hanning weighting.

[0099] When the external load fluctuation negative difference of the heavy load overhead line is 2, 50% overlap rate (such as window length 200 ms, each sliding 10 ms) is adopted, and the truncation error is reduced by Hanning weighting.

[0100] Further, the harmonic second optimization adjustment is performed on the external environment fluctuation monitoring analysis of the heavy load overhead line, specifically including:

[0101] The corresponding conductor mechanical stress maximum value and conductor swing amplitude maximum value of the heavy load overhead line are collected by the fiber grating sensor;

[0102] If the mechanical stress maximum value or the conductor swing amplitude maximum value is greater than or equal to the corresponding threshold value, the hydraulic tension adjusting device is started;

[0103] If the mechanical stress maximum value or the conductor swing amplitude maximum value is less than the corresponding threshold value, the line mechanical stress standard value, the conductor swing amplitude standard value and the heavy load overhead line capacitance threshold value are directly extracted from the heavy load overhead line database without adjustment, the maximum value and the minimum value of the heavy load overhead line capacitance are collected by the distributed capacitance sensor, the proportion of the conductor mechanical stress maximum value and the conductor mechanical stress standard value is corrected with the conductor mechanical stress weight factor to obtain the first component of the external environment negative of the heavy load overhead line, the proportion of the conductor swing amplitude maximum value and the conductor swing amplitude standard value is corrected with the conductor swing amplitude weight factor to obtain the second component of the external environment negative of the heavy load overhead line, the difference analysis of the maximum value and the minimum value of the heavy load overhead line capacitance and the proportion analysis of the heavy load overhead line capacitance threshold value are corrected with the heavy load overhead line capacitance weight factor to obtain the third component of the external environment negative of the heavy load overhead line, the external load fluctuation negative influence value of the heavy load overhead line, the first component of the external environment negative of the heavy load overhead line, the second component of the external environment negative of the heavy load overhead line and the third component of the external environment negative of the heavy load overhead line are analyzed to obtain the external environment negative influence value of the heavy load overhead line, which is used to represent the quantization level of the influence degree of the external load fluctuation of the heavy load overhead line.

[0104] In this embodiment, the maximum mechanical stress and the maximum swing amplitude of the large-load overhead line are collected by the fiber grating sensor. The fiber grating sensor is a periodic refractive index modulation structure engraved in the optical fiber. When the optical fiber is subjected to strain or temperature change, the grating period changes, resulting in a shift in the center wavelength of the reflected light. By demodulating the wavelength shift, the conductor strain and vibration frequency can be deduced, and then the swing amplitude can be calculated.

[0105] When the fiber grating sensor detects that the mechanical stress or the swing amplitude of the large-load overhead line exceeds the set threshold, the following comprehensive measures can be taken to suppress the conductor swing and mechanical stress problem in typhoon weather: if the stress exceeds the threshold (such as 80% of the design value), start the hydraulic tension adjusting device to control the conductor tension within a safe range (such as ±5% of the design tension).

[0106] The working principle and process example of the hydraulic tension adjusting device are as follows:

[0107] If the mechanical stress or the swing amplitude is greater than the corresponding threshold, the adjustment instruction is triggered. The tension control target is to suppress the swing: by increasing the tension (shortening the equivalent length of the conductor), the rigidity of the conductor is increased, and the swing amplitude is reduced. Reduce stress: by reducing tension (lengthening the equivalent length of the conductor) to avoid material overload. Hydraulic action process: drive the hydraulic cylinder to extend or retract, change the position of the conductor suspension point (such as shortening 1cm can increase the tension by about 35%). Through the feedback of the tension sensor, the closed loop is verified until the actual tension enters the safe range (such as ±5% of the design value)

[0108] The large-load overhead line external environmental negative influence value of the JS0th detection time period of the JK0th inspection monitoring point of the FZ0th large-load overhead line represents the relative negative distortion degree value of the comprehensive influence of the large-load overhead line caused by the fluctuation of the external environment.

[0109]

[0110] The maximum mechanical stress of the conductor in the JS0th detection time period of the JK0th inspection monitoring point of the FZ0th large-load overhead line.

[0111] The mechanical stress standard value of the conductor in the JS0th detection time period of the JK0th inspection monitoring point of the FZ0th large-load overhead line, which is directly extracted from the large-load overhead line database, is used to represent the average level in the historical data of the mechanical stress of the conductor of the large-load overhead line.

[0112] The maximum conductor swing amplitude of the JS0 section detection time period of the JK0 inspection monitoring point of the FZ0 section heavy load overhead line represents. The inclination sensor is installed on the conductor to measure the inclination angle of the conductor. Combined with the length of the conductor and the inclination angle data, the maximum conductor swing amplitude is calculated.

[0113] The standard value of the conductor swing amplitude of the JS0 section detection time period of the JK0 inspection monitoring point of the FZ0 section heavy load overhead line represents. The standard value of the conductor swing amplitude is directly extracted from the heavy load overhead line database.

[0114] The maximum heavy load overhead line capacitance of the JS0 section detection time period of the JK0 inspection monitoring point of the FZ0 section heavy load overhead line represents. It is captured in real time by a distributed capacitance sensor.

[0115] The minimum heavy load overhead line capacitance of the JS0 section detection time period of the JK0 inspection monitoring point of the FZ0 section heavy load overhead line represents.

[0116] The threshold value of the heavy load overhead line capacitance of the JS0 section detection time period of the JK0 inspection monitoring point of the FZ0 section heavy load overhead line represents. The threshold value of the heavy load overhead line capacitance is directly extracted from the heavy load overhead line database.

[0117] The coupling effect of wind force on conductor mechanical stress, swing amplitude and line capacitance needs to be quantified by dynamic weight factor.

[0118] The conductor mechanical stress weight factor of the JS0 section detection time period of the JK0 inspection monitoring point of the FZ0 section heavy load overhead line represents. It reflects the direct influence of wind force on conductor tension and tower load, and is positively correlated with the square of wind speed.

[0119] The conductor swing amplitude weight factor of the JS0 section detection time period of the JK0 inspection monitoring point of the FZ0 section heavy load overhead line represents. It characterizes the wind-induced coupling effect of the conductor inertia, which is affected by wind speed, wind direction and conductor natural frequency.

[0120] The heavy load overhead line capacitance weight factor of the JS0 section detection time period of the JK0 inspection monitoring point of the FZ0 section heavy load overhead line represents. It quantifies the dynamic influence of wind-induced conductor spacing change on capacitance parameters, which is linearly related to the inverse of conductor spacing.

[0121] In the artificial climate chamber, different wind conditions are simulated, and through nonlinear model calibration and measured data, dynamic weight distribution can be realized, and the mapping relationship of real-time wind force value, conductor mechanical stress weight factor, conductor swing amplitude weight factor and large load overhead line capacitance weight factor is constructed. Input the implementation wind force value to get the corresponding conductor mechanical stress weight factor, conductor swing amplitude weight factor and large load overhead line capacitance weight factor.

[0122] The specific weight factor construction process is as follows: In the artificial climate chamber, set multiple wind speeds (3-20 m / s), different wind directions (0°, 45°, 90°) and turbulence intensities (10%-50%), simulate the dynamic response of the conductor under extreme wind conditions. Real-time monitoring of conductor dynamic tension fluctuation is realized by high-precision tension sensor. The three-dimensional swing trajectory of the conductor is collected by the inertial unit (IMU), and the maximum amplitude and main frequency are extracted.

[0123] Based on the aerodynamic load formula and turbulence correction term, the tension-wind speed-wind direction mapping relationship is established. Swing dynamics model: solve the amplitude and wind speed frequency domain response characteristics through the swing equation, and map the corresponding weight factor. Compile the trained model into FPGA executable code to realize microsecond-level weight query (resolution 0.5 m / s, 5° wind direction). Generate wind speed-weight mapping table to support dynamic correction by bilinear interpolation.

[0124] Further, according to the monitoring and analysis results of the external environmental fluctuation of the large load overhead line, the third optimization adjustment of the harmonic is carried out, which specifically includes: if the negative influence value of the external environment of the large load overhead line is less than the negative influence threshold of the external environment of the large load overhead line, no adjustment is made; if the negative influence value of the external environment of the large load overhead line is equal to or greater than the negative influence threshold of the external environment of the large load overhead line, the corresponding large load overhead line of the injection point is expanded by the spread spectrum gain through the pre-defined wideband coupler, and the nonlinear notch filter is performed on the pre-defined frequency.

[0125] In this embodiment, the coupling device: installs a wideband coupler (compatible with the installation position of the leakage current monitoring ring) on the top of the insulator string, and supports signal injection / extraction in the frequency band of 1 kHz-30 MHz.

[0126] The matching network can be pre-adjusted according to the actual conductor difference, so that the signal reflection loss is ≤20 dB.

[0127] For example, if the negative influence value of the external environment of the large load overhead line is equal to or greater than the negative influence threshold of the external environment of the large load overhead line, the spread spectrum bandwidth is expanded from baseband 10 kHz to 1 MHz, so that the interference power density is reduced by more than 20 dB. The coupling degree of signal frequency band and harmonic energy directly affects the signal-to-noise ratio. By frequency hopping to avoid interference area, combined with energy dispersion, the suppression effect of narrowband harmonic on specific frequency points can be suppressed.

[0128] Nonlinear notch filter implementation example steps:

[0129] Obtain the conductor swing acceleration signal through the fiber grating sensor, with a sampling rate ≥ 100 Hz (satisfying the Nyquist theorem for capturing 2 Hz interference). Modulation frequency estimation: perform fast Fourier analysis on the conductor swing acceleration signal to extract the dominant modulation frequency and its harmonics.

[0130] Band-pass filtering: use FIR filter (such as Hamming window design) to extract 0.52 Hz frequency band signal and suppress high frequency noise. Use the preprocessed conductor swing acceleration signal as input and the disturbed line signal as output to construct the training data set.

[0131] Model the nonlinear system through Volterra series to describe the coupling relationship between mechanical vibration and electrical signal interference. Volterra kernel identification: use the acceleration signal as input and adaptively identify high-order kernel parameters through LMS algorithm to optimize the nonlinear interference prediction model. LMS (Least Mean Squares) algorithm is an adaptive filtering algorithm, also known as mean square error minimization algorithm, widely used in signal processing, system identification, noise cancellation and other fields. Its core idea is to adjust the filter coefficients through iteration to minimize the mean square error (MSE) between the filter output and the expected signal. Dynamic notch design: construct a multi-stage notch filter bank, design transfer functions for modulation harmonics, and superimpose Volterra nonlinear correction terms to cancel interference. Use sliding window (such as 5 seconds data block) to update kernel parameters in real time, adapt to frequency drift caused by wind speed change. Adjust the nonlinear order dynamically according to the wind speed (such as enable 3-order kernel when wind speed ≥ 15 m / s), enhance the nonlinear interference suppression ability. Evaluate the filtering effect through signal-to-noise ratio (SNR) and fault location error, retrain the parameters when the error exceeds the threshold. Volterra series accurately captures the nonlinear interaction between conductor swing and electrical signal through high-order kernels (such as 2nd and 3rd order), which cannot be achieved by traditional linear filters.

[0132] As Figure 2As shown, a structure diagram of an operation state fault monitoring system for a heavy load overhead line is provided in the embodiment, and the operation state fault monitoring system for the heavy load overhead line comprises a predefined fault detection module, a harmonic first optimization adjustment module, a harmonic second optimization adjustment module and a harmonic third optimization adjustment module; the predefined fault detection module is configured to perform predefined fault detection by injecting a high-frequency test signal into the heavy load overhead line to obtain a total harmonic distortion rate; the harmonic first optimization adjustment module is configured to perform harmonic first optimization adjustment according to a comparison analysis of the total harmonic distortion rate and a threshold value; the harmonic second optimization adjustment module is configured to perform external load fluctuation monitoring analysis of the heavy load overhead line after the harmonic first optimization adjustment, and perform harmonic second optimization adjustment according to an external load fluctuation monitoring analysis result of the heavy load overhead line; and the harmonic third optimization adjustment module is configured to perform external environment fluctuation monitoring analysis of the heavy load overhead line after the harmonic second optimization adjustment, and perform harmonic third optimization adjustment according to an external environment fluctuation monitoring analysis result of the heavy load overhead line.

[0133] The operation state fault monitoring device for the heavy load overhead line comprises a hydraulic tension adjusting device, a hydraulic cylinder of the hydraulic tension adjusting device, a hydraulic pump station of the hydraulic tension adjusting device, a control valve group of the hydraulic tension adjusting device, a sensing module of the hydraulic tension adjusting device, a control module of the hydraulic tension adjusting device, a communication module of the hydraulic tension adjusting device and a protective shell of the hydraulic tension adjusting device.

[0134] In the embodiment, the hydraulic actuator, i.e., the hydraulic cylinder, is installed between a conductor and a suspension point of a tower, so as to adjust tension. The hydraulic pump station can be integrated with an electric or diesel driven pump. The control valve group comprises proportional valves and reversing valves, and precisely controls the flow and direction of the hydraulic oil. The sensing and feedback system comprises a displacement sensor, which monitors the stroke of the hydraulic cylinder and ensures the adjustment accuracy.

[0135] Those skilled in the art will appreciate that embodiments of the present application can be devised for a variety of applications. It is therefore intended that the present application cover all such modifications and variations of the application disclosed herein provided they come within the scope of the appended claims and their equivalents. It is intended to

[0136] The present application is described in reference to the drawings using a flowchart and / or a block diagram of the method, apparatus (system) and computer program product according to embodiments of the application. It will be understood that each block of the flowchart and / or block diagram, and combinations of blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processing device or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart and / or block diagram block or blocks. Figure 1 one or more functions specified by one or more blocks Figure 1 one or more functions specified by one or more blocks

[0137] These computer program instructions can also be stored in a computer- readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart and / or block diagram block or blocks. Figure 1 one or more functions specified by one or more blocks Figure 1 one or more functions specified by one or more blocks

[0138] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart and / or block diagram block or blocks. Figure 1 one or more functions specified by one or more blocks Figure 1 one or more functions specified by one or more blocks

[0139] While the preferred embodiments of the application have been described, additional variations and modifications can be employed by those skilled in the art. Therefore, the claimed application is intended to cover all such modifications and variations as fall within the scope of the appended claims and their equivalents.

[0140] Obviously, a person skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application belong to the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A method for operating condition fault monitoring of heavy load overhead lines, characterized in that, It comprises the following steps: Predefined fault detection is performed on the large-load overhead line by injecting a high-frequency test signal, and total harmonic distortion is obtained; According to the comparison between the total harmonic distortion and the threshold value, the first harmonic optimization adjustment is performed; After the first harmonic optimization adjustment, the external load fluctuation monitoring analysis of the large-load overhead line is performed, and the second harmonic optimization adjustment is performed according to the external load fluctuation monitoring analysis result of the large-load overhead line; The external load fluctuation monitoring analysis of the large-load overhead line after the first harmonic optimization adjustment specifically comprises: The average value of the load power of the large-load overhead line, the average value of the leakage current of the large-load overhead line, and the average value of the discharge intensity of the partial discharge are directly extracted from the large-load overhead line database; The maximum value and the minimum value of the load power of the large-load overhead line are detected by the intelligent monitoring terminal of the large-load overhead line; The maximum value of the leakage current of the large-load overhead line is detected by the corresponding leakage current acquisition ring; The maximum value of the discharge intensity of the partial discharge of the large-load overhead line is detected by the corresponding high-frequency partial discharge detector; The difference between the maximum value and the minimum value of the load power of the large-load overhead line is analyzed in proportion to the historical average value of the load power of the large-load overhead line, and then the weight factor of humidity on the load power is corrected to obtain the first negative impact component of the external load fluctuation of the large-load overhead line; The first proportional value is obtained by correcting the ratio of the maximum value of the leakage current of the large-load overhead line to the historical average value of the leakage current of the large-load overhead line by an exponential function, and the second proportional value is obtained by multiplying the ratio of the maximum value of the discharge intensity of the partial discharge of the large-load overhead line to the average value of the discharge intensity of the partial discharge of the large-load overhead line by the discharge frequency of the discharge intensity of the partial discharge of the large-load overhead line; the first proportional value and the second proportional value are superimposed, and then the weight factor of humidity on the partial and leakage discharge is corrected to obtain the second negative impact component of the external load fluctuation of the large-load overhead line; The first negative impact component and the second negative impact component of the external load fluctuation of the large-load overhead line are comprehensively analyzed to obtain the negative impact value of the external load fluctuation of the large-load overhead line; After the second harmonic optimization adjustment, the external environmental fluctuation monitoring analysis of the large-load overhead line is performed, and the third harmonic optimization adjustment is performed according to the external environmental fluctuation monitoring analysis result of the large-load overhead line; The external environmental fluctuation monitoring analysis of the large-load overhead line after the second harmonic optimization adjustment specifically comprises: The maximum value of the mechanical stress of the conductor and the maximum value of the conductor swing amplitude of the large-load overhead line are collected by the optical fiber grating sensor; If the maximum value of the mechanical stress or the maximum value of the conductor swing amplitude is greater than or equal to the corresponding threshold value, the hydraulic tension adjusting device is started; If the maximum mechanical stress or the maximum conductor swing amplitude is less than the corresponding threshold value, no adjustment is made, and the line mechanical stress standard value, the conductor swing amplitude standard value, and the heavy load overhead line capacitance threshold value are directly extracted from the heavy load overhead line database. The maximum mechanical stress of the conductor is corrected with the proportion of the maximum mechanical stress of the conductor and the standard value of the mechanical stress of the conductor and the mechanical stress weight factor of the conductor to obtain the negative first component of the external environment of the heavy load overhead line. The maximum swing amplitude of the conductor is corrected with the proportion of the maximum swing amplitude of the conductor and the standard value of the swing amplitude of the conductor and the swing amplitude weight factor of the conductor to obtain the negative second component of the external environment of the heavy load overhead line. The difference between the maximum capacitance of the heavy load overhead line and the minimum capacitance of the heavy load overhead line is analyzed, and the proportion of the difference and the heavy load overhead line capacitance threshold value is analyzed, and then the capacitance weight factor of the heavy load overhead line is corrected to obtain the negative third component of the external environment of the heavy load overhead line. The external load fluctuation negative influence value of the heavy load overhead line, the negative first component of the external environment of the heavy load overhead line, the negative second component of the external environment of the heavy load overhead line, and the negative third component of the external environment of the heavy load overhead line are analyzed to obtain the external environment negative influence value of the heavy load overhead line. The external environment negative influence value of the heavy load overhead line is used to represent the quantitative level of the external load fluctuation negative influence value of the heavy load overhead line, the negative first component of the external environment of the heavy load overhead line, the negative second component of the external environment of the heavy load overhead line, and the negative third component of the external environment of the heavy load overhead line.

2. The method for operating condition fault monitoring of heavy load overhead lines as claimed in claim 1 wherein, The predefined fault detection by injecting a high-frequency test signal into the heavy load overhead line specifically includes: Using a high-frequency test signal generator to generate a pulse signal of a specific frequency, and coupling the high-frequency test signal into the heavy load overhead line through a capacitive coupler; Installing a high-frequency sensor at the receiving monitoring point to capture reflected signals and transmitted signals; Extracting and locating impedance abnormal points and resonance abnormal points through spectrum analysis and traveling wave positioning algorithms.

3. The method for operating condition fault monitoring of heavy load overhead lines as claimed in claim 1 wherein, The predefined fault detection by injecting a high-frequency test signal into the heavy load overhead line also includes: Sampling and collecting high-frequency time domain signals downstream of the injection point or at the end of the line through the sampling rate built into the wideband current transformer; Processing the high-frequency time domain signals through fast Fourier transform to obtain frequency domain complex spectra; Extracting the fundamental amplitude of the frequency domain complex spectrum from the heavy load overhead line operating state fault database, and if the frequency domain amplitude value of the frequency domain complex spectrum is greater than the predefined proportion value of the fundamental amplitude, no adjustment is made. If the frequency domain amplitude value of the frequency domain complex spectrum is less than or equal to the predefined proportion value of the fundamental amplitude, the frequency domain complex spectrum part corresponding to the frequency domain complex spectrum less than the predefined proportion value of the fundamental amplitude is filtered. The total harmonic distortion rate of the heavy load overhead line is extracted and analyzed according to the frequency domain complex spectrum.

4. The method for operating condition fault monitoring of heavy load overhead lines as claimed in claim 1 wherein, The harmonic first optimization adjustment specifically includes: If the total harmonic distortion rate of the heavy load overhead line is less than the total harmonic distortion rate threshold value, no adjustment is made. If the total harmonic distortion rate of the heavy load overhead line is equal to or greater than the total harmonic distortion rate threshold, the passive filter is started for harmonic suppression by tuning the passive filter at the predefined position.

5. The method for operating condition fault monitoring of heavy load overhead lines as claimed in claim 1 wherein, The harmonic second optimization adjustment according to the external load fluctuation monitoring analysis result of the heavy load overhead line specifically includes: If the external load fluctuation negative influence value of the heavy load overhead line is less than the external load fluctuation negative threshold of the heavy load overhead line, no harmonic second optimization adjustment is performed. If the external load fluctuation negative influence value of the heavy load overhead line is equal to or greater than the external load fluctuation negative threshold of the heavy load overhead line, the external load fluctuation negative influence value of the heavy load overhead line is subtracted by the external load fluctuation negative threshold of the heavy load overhead line to obtain an external load fluctuation negative difference value of the heavy load overhead line. According to the external load fluctuation negative difference value of the heavy load overhead line, the period window of the fast Fourier transform is reduced and the overlap rate of the fast Fourier transform is increased according to a predefined load fluctuation negative difference value matching rule. The third component is the quantification level of the influence degree of the external load fluctuation on the heavy load overhead line.

6. The method for operating condition fault monitoring of heavy load overhead lines as claimed in claim 1 wherein, The harmonic third optimization adjustment according to the external environment fluctuation monitoring analysis result of the heavy load overhead line specifically includes: If the external environment negative influence value of the heavy load overhead line is less than the external environment negative influence threshold of the heavy load overhead line, no adjustment is performed. If the external environment negative influence value of the heavy load overhead line is equal to or greater than the external environment negative influence threshold of the heavy load overhead line, the spread spectrum gain is performed on the heavy load overhead line at the corresponding injection point through the predefined wideband coupler, and the nonlinear notch filtering is performed on the predefined frequency.

7. A system for operating state fault monitoring of a heavy load overhead line, which applies the method for operating state fault monitoring of a heavy load overhead line as claimed in any one of claims 1 to 6, characterized in that, The system includes a predefined fault detection module, a harmonic first optimization adjustment module, a harmonic second optimization adjustment module, and a harmonic third optimization adjustment module. The predefined fault detection module is configured to perform predefined fault detection on the heavy load overhead line by injecting a high-frequency test signal, and obtain a total harmonic distortion rate. The harmonic first optimization adjustment module is configured to perform harmonic first optimization adjustment according to a comparison analysis of the total harmonic distortion rate and a threshold. The harmonic second optimization adjustment module is configured to perform external load fluctuation monitoring analysis on the heavy load overhead line after the harmonic first optimization adjustment, and perform harmonic second optimization adjustment according to the external load fluctuation monitoring analysis result of the heavy load overhead line. The harmonic third optimization adjustment module is configured to perform external environment fluctuation monitoring analysis on the heavy load overhead line after the harmonic second optimization adjustment, and perform harmonic third optimization adjustment according to the external environment fluctuation monitoring analysis result of the heavy load overhead line.

8. The apparatus for operating condition fault monitoring of heavy load overhead lines according to any one of claims 1 to 6, characterized in that, The hydraulic tension adjusting device includes a hydraulic cylinder, a hydraulic pump station, a control valve group, a sensing module, a control module, a communication module, and a protective shell: The hydraulic cylinder is configured to change the effective length of the conductor by extending and retracting the piston rod. The hydraulic pump station is configured to provide a high-pressure oil source to drive the hydraulic cylinder to act. The control valve group is configured to control the flow and direction of the hydraulic oil. Hydraulic tension regulating device sensing module: for detecting feedback by fiber grating sensor; Hydraulic tension regulating device control module: for embedded controller to receive sensor signal and output adjustment instruction according to PID control; Hydraulic tension regulating device communication module: for linkage with operation state fault monitoring system of heavy load overhead line, supporting remote instruction and state feedback; Hydraulic tension regulating device protective shell: for corrosion resistance, rain and dust prevention, adopting IP67 protection level.

Images