Distribution network fault warning and location system based on distributed traveling wave online measurement

Abstract

The present invention discloses a distribution network fault warning and positioning system based on distributed traveling wave online measurement, which belongs to the technical field of distribution network, and includes: a traveling wave signal acquisition module, configured to acquire distribution network fault traveling wave signals; a traveling wave signal processing module, configured to process the acquired distribution network fault traveling wave signals, and determine the distribution network fault characteristic traveling wave signals; a fault identification and warning module, configured to quickly identify the distribution network fault type and perform fault warning according to the distribution network fault characteristic traveling wave signals; a fault location positioning module, configured to accurately locate the distribution network fault location according to the principle of double-end traveling wave ranging. The present invention solves the problem that the existing distribution network fault cannot be quickly identified, warned and accurately located based on distributed traveling wave online measurement, resulting in poor distribution network use effect. The present invention can quickly identify, warn and accurately locate distribution network faults based on distributed traveling wave online measurement, and can improve the use effect of the distribution network.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution networks, and in particular to a power distribution network fault early warning and positioning system based on distributed traveling wave online measurement. Background Art

[0002] The distribution network is composed of overhead lines, cables, poles, distribution transformers, disconnectors, reactive power compensators and some ancillary facilities. It plays an important role in distributing electric energy in the power grid. As the scale of the distribution network continues to expand and its structure becomes increasingly complex, fault identification and location in the distribution network becomes particularly important.

[0003] The Chinese patent application with publication number CN117630579B discloses a method for accurately locating distribution network faults based on distributed traveling wave detection, the method comprising the following steps: S1: configuring a traveling wave monitoring unit; S2: real-time monitoring of distribution network faults through the traveling wave monitoring unit; S3: filtering other types of interfering traveling waves except for fault traveling wave signals, identifying and selecting fault traveling waves; S4: calibrating the time point of the traveling wave head; S5: calculating the minimum propagation time of the traveling wave from each node to each endpoint, the endpoints being the ends of the main line and the ends of the branch line of the distribution network, and the nodes being all intermediate nodes except the endpoints; S6: presetting the fault point and calculating the Pearson coefficient r of the time array; S7: traversing the fault point, and judging the actual position of the fault point in turn based on the calculated Pearson coefficient r. Accurate fault location of the distribution network is achieved based on the traveling wave positioning method. However, the patent has the following defects:

[0004] Existing technologies cannot dynamically adjust the sampling rate of distributed traveling wave acquisition devices, making it impossible for distributed traveling wave acquisition devices to adapt to changes in the operating status of the distribution network, resulting in low accuracy and reliability of distribution network monitoring, and unable to fully guarantee the effectiveness of power grid operation analysis and fault diagnosis, resulting in poor rapid identification, early warning and precise positioning of distribution network faults. Summary of the invention

[0005] The purpose of the present invention is to provide a distribution network fault warning and positioning system based on distributed traveling wave online measurement, which can quickly identify, warn and accurately locate distribution network faults based on distributed traveling wave online measurement, improve the use effect of the distribution network, and solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The distribution network fault warning and positioning system based on distributed traveling wave online measurement includes:

[0008] A traveling wave signal acquisition module configured to collect distribution network fault traveling wave signals and transmit the data in real time through a high-speed communication network;

[0009] A traveling wave signal processing module is configured to process the collected distribution network fault traveling wave signal to determine a distribution network fault characteristic traveling wave signal;

[0010] A fault identification and early warning module is configured to quickly identify the type of distribution network fault and issue a fault early warning based on the distribution network fault characteristic traveling wave signal;

[0011] The fault location locating module is configured to accurately locate the fault location of the distribution network based on the principle of double-terminal traveling wave ranging.

[0012] Preferably, collecting the distribution network fault traveling wave signal includes:

[0013] Install the distributed traveling wave acquisition device at the key nodes of the distribution network;

[0014] Based on the distributed traveling wave acquisition device, the fault traveling wave signal is captured in real time, and the voltage and current traveling wave signals on the distribution network line are collected and recorded in real time to determine the distribution network fault traveling wave signal.

[0015] Preferably, collecting the distribution network fault traveling wave signal also includes:

[0016] After the distributed traveling wave acquisition device is installed on the key nodes of the distribution network, adaptive parameter initialization is performed, including:

[0017] After the distributed traveling wave acquisition device is installed on the key node of the distribution network, the node characteristic parameters of the corresponding position of the key node of the distribution network are collected within the preset trial operation time period, wherein the node characteristic parameters include impedance, grid frequency fluctuation range and voltage fluctuation;

[0018] Extract the voltage fluctuation amplitude corresponding to each voltage fluctuation;

[0019] The voltage fluctuation amplitude ratio corresponding to the voltage fluctuation amplitude of each voltage fluctuation is obtained by using the voltage fluctuation amplitude corresponding to each voltage fluctuation and the rated voltage;

[0020] When extracting the power grid frequency fluctuation range during the operation of key nodes of the distribution network, the specific frequency points at which the operation occurs and the corresponding operating time of each frequency point of the key nodes of the distribution network;

[0021] Obtaining a power grid frequency fluctuation coefficient according to each frequency point and the operating time corresponding to each frequency point;

[0022] The grid frequency fluctuation coefficient is used to determine the initial sampling rate of the distributed traveling wave acquisition device installed at the key node of the distribution network after the trial operation period ends, and the sampling rate of the distributed traveling wave acquisition device is dynamically adjusted according to the subsequent grid frequency fluctuation coefficient of the key node of the distribution network and the voltage fluctuation amplitude ratio corresponding to the voltage fluctuation amplitude of the voltage fluctuation.

[0023] Preferably, the grid frequency fluctuation coefficient is used to determine the initial sampling rate of the distributed traveling wave acquisition device after the trial operation period of the key node of the distribution network ends, and the sampling rate of the distributed traveling wave acquisition device is dynamically adjusted according to the subsequent grid frequency fluctuation coefficient of the key node of the distribution network and the voltage fluctuation amplitude ratio corresponding to the voltage fluctuation amplitude of the voltage fluctuation, including:

[0024] Extracting the grid frequency fluctuation coefficient corresponding to the preset trial operation time period after the distributed traveling wave acquisition device is installed on the key node of the distribution network;

[0025] The power grid frequency fluctuation coefficient is obtained by the following formula:

[0026] ;

[0027] Where S represents the grid frequency fluctuation coefficient; n represents the number of specific frequency points contained in the grid frequency fluctuation range of the key nodes of the distribution network; f i It indicates the grid frequency value corresponding to the operation state of the key node of the distribution network at the ith frequency point; f max Indicates the maximum grid frequency value corresponding to the grid frequency fluctuation range where the key node of the distribution network is located; T i represents the operating time of the key node of the distribution network corresponding to the operating state of the i-th frequency point; T max Indicates the operating time corresponding to the key nodes of the distribution network being in the maximum grid frequency operating state;

[0028] Obtaining a voltage fluctuation amplitude ratio intermediate value by using the voltage fluctuation amplitude ratio corresponding to the voltage fluctuation amplitude of each voltage fluctuation;

[0029] Determine the initial sampling rate of the distributed traveling wave acquisition device installed at the key node of the distribution network after the trial operation period ends by using the power grid frequency fluctuation coefficient combined with the intermediate value of the impedance and voltage fluctuation amplitude ratio;

[0030] The initial sampling rate of the distributed traveling wave acquisition device is obtained by the following formula:

[0031] ;

[0032] Where F represents the initial sampling rate of the distributed traveling wave acquisition device; f maxIndicates the maximum grid frequency value corresponding to the grid frequency fluctuation range where the key node of the distribution network is located; S represents the grid frequency fluctuation coefficient; B z Indicates the middle value of the voltage fluctuation ratio; Z indicates the impedance value; Z c Indicates the preset impedance reference value;

[0033] Real-time monitoring of the grid frequency fluctuation coefficient during the subsequent operation of key nodes in the distribution network;

[0034] Comparing the power grid frequency fluctuation coefficient during the subsequent operation of the key node of the distribution network with a preset power grid frequency fluctuation coefficient threshold;

[0035] When the grid frequency fluctuation coefficient during the subsequent operation of the key node of the distribution network reaches or exceeds the preset grid frequency fluctuation coefficient threshold, the voltage fluctuation amplitude ratio corresponding to the first voltage fluctuation closest to the moment when the grid frequency fluctuation coefficient reaches or exceeds the preset grid frequency fluctuation coefficient threshold is retrieved as the reference fluctuation amplitude ratio;

[0036] Comparing the reference fluctuation amplitude ratio with a preset fluctuation amplitude ratio threshold;

[0037] When the reference fluctuation amplitude ratio is not lower than the preset fluctuation amplitude ratio threshold, the sampling rate of the distributed traveling wave acquisition device assembly is adjusted using the current power grid frequency fluctuation coefficient and the reference fluctuation amplitude ratio;

[0038] Among them, the sampling rate of the adjusted distributed traveling wave acquisition device assembly is obtained by the following formula:

[0039] ;

[0040] Among them, F t represents the sampling rate of the distributed traveling wave acquisition device after adjustment; F represents the initial sampling rate of the distributed traveling wave acquisition device; S h It represents the power grid frequency fluctuation coefficient during the subsequent operation of the key nodes of the distribution network; S y represents the preset grid frequency fluctuation coefficient threshold; B represents the reference fluctuation amplitude ratio; B y Indicates the preset fluctuation amplitude ratio threshold.

[0041] Preferably, the collected distribution network fault traveling wave signal is processed, including:

[0042] A digital filter is used to filter the distribution network fault traveling wave signal to remove high-frequency noise and low-frequency interference in the distribution network fault traveling wave signal;

[0043] Wavelet denoising is used to denoise the distribution network fault traveling wave signal, remove the noise in the distribution network fault traveling wave signal, and retain the detailed characteristics of the distribution network fault traveling wave signal;

[0044] The maximum and minimum value normalization method is used to normalize the distribution network fault traveling wave signal, and the amplitude of the distribution network fault traveling wave signal is normalized to a unified range.

[0045] Preferably, processing the collected distribution network fault traveling wave signal also includes:

[0046] Extract features of the distribution network fault traveling wave signal, and extract features that can characterize the distribution network fault type from the distribution network fault traveling wave signal, including time domain features, frequency domain features, and time-frequency domain features;

[0047] Among them, time domain features include peak, mean, variance, kurtosis, and skewness; frequency domain features include spectrum energy, spectrum center of gravity, and spectrum bandwidth; time-frequency domain features include wavelet transform coefficients and Hilbert-Huang transform features;

[0048] The extracted features are selected based on the correlation coefficient method, and the features with high degree of distinguishing fault types are selected from the extracted features to determine the distribution network fault characteristic traveling wave signal.

[0049] Preferably, identifying the distribution network fault type and performing fault warning includes:

[0050] Collecting historical fault data of the distribution network, wherein the historical fault data of the distribution network includes a traveling wave signal of the historical fault of the distribution network and a corresponding distribution network fault type label;

[0051] Processing the traveling wave signals of the historical faults of the distribution network and dividing the historical fault data of the distribution network into a training set and a test set;

[0052] Based on deep learning technology, a training set is used to train the deep learning model, so that the deep learning model can autonomously learn the distribution network fault type prediction behavior, perform pattern recognition on the distribution network fault type, and determine the distribution network fault type prediction model;

[0053] Perform performance test on the distribution network fault type prediction model based on the test set to determine whether the distribution network fault type prediction model can achieve the expected effect;

[0054] According to the test results, the parameters of the distribution network fault type prediction model are adjusted, and the best distribution network fault type prediction model is determined through continuous iterative optimization.

[0055] Preferably, identifying the distribution network fault type and performing fault warning further includes:

[0056] Deploy the distribution network fault type prediction model in the actual distribution network fault type identification environment;

[0057] The distribution network fault characteristic traveling wave signal is input into the distribution network fault type prediction model. The distribution network fault characteristic traveling wave signal is analyzed and predicted through the distribution network fault type prediction model, the distribution network fault type is quickly identified, the distribution network fault warning is performed according to the distribution network fault type, the fault warning information is released in time, and the relevant personnel are notified to handle it.

[0058] Preferably, accurately locating the fault position of the distribution network according to the principle of double-terminal traveling wave ranging includes:

[0059] The peak detection method is used to detect the distribution network fault traveling wave signal, determine the first distribution network fault traveling wave signal that arrives, and use the first distribution network fault traveling wave signal that arrives as a reference signal;

[0060] Based on the correlation analysis method, the cross-correlation function between the reference signal and other distribution network fault traveling wave signals is calculated. According to the calculated cross-correlation function between the reference signal and other distribution network fault traveling wave signals, the position corresponding to the maximum value of the cross-correlation function is found, which is the time delay estimation value. According to the time delay estimation value, the arrival time of each distribution network fault traveling wave signal is determined.

[0061] Preferably, accurately locating the fault position of the distribution network according to the principle of double-terminal traveling wave ranging also includes:

[0062] Using the principle of double-end traveling wave ranging, according to the time difference between the traveling wave signal of the distribution network fault reaching the traveling wave collection devices at both ends, the traveling wave propagation speed and the line length, the precise location of the distribution network fault point is calculated by the following formula;

[0063] ;

[0064] Where x is the distance from the fault point of the distribution network to the traveling wave acquisition device at one end, L is the total length of the line, and are the time taken for the fault traveling wave of the distribution network to reach the traveling wave collection devices at both ends, and v is the propagation speed of the traveling wave.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] The present invention collects distribution network fault traveling wave signals and transmits them in real time through a high-speed communication network, processes the collected distribution network fault traveling wave signals, determines distribution network fault characteristic traveling wave signals, analyzes and predicts distribution network fault characteristic traveling wave signals through a distribution network fault type prediction model, quickly identifies distribution network fault types, performs distribution network fault warnings according to distribution network fault types, timely releases fault warning information, and notifies relevant personnel to handle them. Based on a relevant analysis method, the arrival time of each distribution network fault traveling wave signal is determined, and the principle of double-end traveling wave ranging is used to calculate the precise location of the distribution network fault point according to the time difference between the distribution network fault traveling wave signals arriving at traveling wave collection devices at both ends, the traveling wave propagation speed, and the line length. Based on distributed traveling wave online measurement, the distribution network fault can be quickly identified, warned, and accurately located, thereby improving the use effect of the distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is a module flow chart of the distribution network fault early warning and positioning system based on distributed traveling wave online measurement of the present invention. DETAILED DESCRIPTION

[0068] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0069] In order to solve the existing problem that the distribution network cannot be quickly identified, warned and accurately located based on distributed traveling wave online measurement, resulting in poor distribution network performance, please refer to Figure 1 , this embodiment provides the following technical solutions:

[0070] A distribution network fault warning and positioning system based on distributed traveling wave online measurement includes: a traveling wave signal acquisition module, a traveling wave signal processing module, a fault identification and warning module and a fault location positioning module.

[0071] Specifically, by utilizing the characteristics of traveling waves that are generated at the moment of fault and propagated along the line, distributed traveling wave acquisition devices are used to capture fault traveling wave signals in real time, achieve rapid warning and precise positioning of the fault, and improve the use effect of the distribution network.

[0072] Among them, the traveling wave signal acquisition module is used to collect the traveling wave signal of the distribution network fault and transmit the data in real time through the high-speed communication network;

[0073] In this embodiment, collecting the distribution network fault traveling wave signal includes:

[0074] Install the distributed traveling wave acquisition device at the key nodes of the distribution network;

[0075] Based on the distributed traveling wave acquisition device, the fault traveling wave signal is captured in real time, and the voltage and current traveling wave signals on the distribution network line are collected and recorded in real time to determine the distribution network fault traveling wave signal.

[0076] Specifically, collecting the distribution network fault traveling wave signal also includes:

[0077] After the distributed traveling wave acquisition device is installed on the key nodes of the distribution network, adaptive parameter initialization is performed, including:

[0078] After the distributed traveling wave acquisition device is installed on the key node of the distribution network, the node characteristic parameters of the corresponding position of the key node of the distribution network are collected within the preset trial operation time period, wherein the node characteristic parameters include impedance, grid frequency fluctuation range and voltage fluctuation;

[0079] Extract the voltage fluctuation amplitude corresponding to each voltage fluctuation;

[0080] The voltage fluctuation amplitude ratio corresponding to the voltage fluctuation amplitude of each voltage fluctuation is obtained by using the voltage fluctuation amplitude corresponding to each voltage fluctuation and the rated voltage;

[0081] When extracting the power grid frequency fluctuation range during the operation of key nodes of the distribution network, the specific frequency points at which the operation occurs and the corresponding operating time of each frequency point of the key nodes of the distribution network;

[0082] Obtaining a power grid frequency fluctuation coefficient according to each frequency point and the operating time corresponding to each frequency point;

[0083] The grid frequency fluctuation coefficient is used to determine the initial sampling rate of the distributed traveling wave acquisition device installed at the key node of the distribution network after the trial operation period ends, and the sampling rate of the distributed traveling wave acquisition device is dynamically adjusted according to the subsequent grid frequency fluctuation coefficient of the key node of the distribution network and the voltage fluctuation amplitude ratio corresponding to the voltage fluctuation amplitude of the voltage fluctuation.

[0084] The technical effect of the above technical scheme is: by collecting the impedance, grid frequency fluctuation range, voltage fluctuation and other parameters of the key nodes of the distribution network during the trial operation period, the node operation characteristics are fully grasped, and multi-dimensional data support is provided for subsequent analysis and sampling rate setting. The voltage fluctuation amplitude is extracted and its ratio to the rated voltage is calculated to quantify the degree of influence of voltage fluctuation on the distribution network, accurately evaluate the voltage stability, and provide a basis for the voltage dimension for sampling rate adjustment. The grid frequency fluctuation coefficient is calculated based on the frequency point and the corresponding operation time, the frequency fluctuation law is quantified, the influence characteristics of frequency change on the operation of the distribution network are clarified, and a reference for the frequency dimension is provided for sampling rate setting. The initial sampling rate is determined by using the grid frequency fluctuation coefficient in the trial operation phase, so that the sampling rate fits the actual operation characteristics of the key nodes of the distribution network, avoiding resource waste or incomplete data collection caused by too high or too low sampling rate. The sampling rate is dynamically adjusted according to the subsequent grid frequency fluctuation coefficient and voltage fluctuation amplitude ratio, so that the distributed traveling wave acquisition device can adapt to the changes in the operation status of the distribution network, ensuring that data can be efficiently collected in different voltage and frequency fluctuation scenarios, improving the accuracy and reliability of distribution network monitoring, and ensuring the effectiveness of grid operation analysis and fault diagnosis.

[0085] Specifically, the grid frequency fluctuation coefficient is used to determine the initial sampling rate of the distributed traveling wave acquisition device after the trial operation period of the key node of the distribution network ends, and the sampling rate of the distributed traveling wave acquisition device is dynamically adjusted according to the subsequent grid frequency fluctuation coefficient of the key node of the distribution network and the voltage fluctuation amplitude ratio corresponding to the voltage fluctuation amplitude of the voltage fluctuation, including:

[0086] Extracting the grid frequency fluctuation coefficient corresponding to the preset trial operation time period after the distributed traveling wave acquisition device is installed on the key node of the distribution network;

[0087] The power grid frequency fluctuation coefficient is obtained by the following formula:

[0088] ;

[0089] Where S represents the grid frequency fluctuation coefficient; n represents the number of specific frequency points contained in the grid frequency fluctuation range of the key nodes of the distribution network; f i It indicates the grid frequency value corresponding to the operation state of the key node of the distribution network at the ith frequency point; f max Indicates the maximum grid frequency value corresponding to the grid frequency fluctuation range where the key node of the distribution network is located; T i represents the operating time of the key node of the distribution network corresponding to the operating state of the i-th frequency point; T max Indicates the operating time corresponding to the key nodes of the distribution network being in the maximum grid frequency operating state;

[0090] Obtaining a voltage fluctuation amplitude ratio intermediate value by using the voltage fluctuation amplitude ratio corresponding to the voltage fluctuation amplitude of each voltage fluctuation;

[0091] Determine the initial sampling rate of the distributed traveling wave acquisition device installed at the key node of the distribution network after the trial operation period ends by using the power grid frequency fluctuation coefficient combined with the intermediate value of the impedance and voltage fluctuation amplitude ratio;

[0092] The initial sampling rate of the distributed traveling wave acquisition device is obtained by the following formula:

[0093] ;

[0094] Where F represents the initial sampling rate of the distributed traveling wave acquisition device; f max Indicates the maximum grid frequency value corresponding to the grid frequency fluctuation range where the key node of the distribution network is located; S represents the grid frequency fluctuation coefficient; B z Indicates the middle value of the voltage fluctuation ratio; Z indicates the impedance value; Z c Indicates the preset impedance reference value;

[0095] Real-time monitoring of the grid frequency fluctuation coefficient during the subsequent operation of key nodes in the distribution network;

[0096] Comparing the power grid frequency fluctuation coefficient during the subsequent operation of the key node of the distribution network with a preset power grid frequency fluctuation coefficient threshold;

[0097] When the grid frequency fluctuation coefficient during the subsequent operation of the key node of the distribution network reaches or exceeds the preset grid frequency fluctuation coefficient threshold, the voltage fluctuation amplitude ratio corresponding to the first voltage fluctuation closest to the moment when the grid frequency fluctuation coefficient reaches or exceeds the preset grid frequency fluctuation coefficient threshold is retrieved as the reference fluctuation amplitude ratio;

[0098] Comparing the reference fluctuation amplitude ratio with a preset fluctuation amplitude ratio threshold;

[0099] When the reference fluctuation amplitude ratio is not lower than the preset fluctuation amplitude ratio threshold, the sampling rate of the distributed traveling wave acquisition device assembly is adjusted using the current power grid frequency fluctuation coefficient and the reference fluctuation amplitude ratio;

[0100] Among them, the sampling rate of the adjusted distributed traveling wave acquisition device assembly is obtained by the following formula:

[0101] ;

[0102] Among them, F t represents the sampling rate of the distributed traveling wave acquisition device after adjustment; F represents the initial sampling rate of the distributed traveling wave acquisition device; Sh It represents the power grid frequency fluctuation coefficient during the subsequent operation of the key nodes of the distribution network; S y represents the preset grid frequency fluctuation coefficient threshold; B represents the reference fluctuation amplitude ratio; B y Indicates the preset fluctuation amplitude ratio threshold.

[0103] The technical effect of the above technical solution is: by combining the grid frequency fluctuation coefficient (reflecting the frequency distribution characteristics), the intermediate value of the voltage fluctuation amplitude ratio (quantifying voltage stability) and the impedance value (reflecting the grid load characteristics) to set the initial sampling rate, the adaptability between the initial sampling rate and the actual operating state of the distribution network can be effectively improved. The initial sampling rate is determined based on multiple parameters such as the grid frequency fluctuation coefficient, the intermediate value of the voltage fluctuation amplitude ratio and the impedance, so that the sampling rate of the distributed traveling wave acquisition device can accurately match the actual operating characteristics of the key nodes of the distribution network during the trial operation stage. For example, in the case of large grid frequency fluctuations, high voltage fluctuation amplitude ratio or special impedance values, the sampling rate can be reasonably set to ensure that sufficient and appropriate data is collected to avoid insufficient or oversampling. By real-time monitoring of the grid frequency fluctuation coefficient and the voltage fluctuation amplitude ratio and comparing them with the preset threshold, the sampling rate is dynamically adjusted according to the comparison results, so that the sampling rate can be adapted in real time as the operating state of the distribution network changes, further improving the fit between the sampling rate and the actual operating conditions. At the same time, through the logical judgment of the threshold values ​​corresponding to the expected ratio of the above-mentioned grid frequency fluctuation coefficient and voltage fluctuation amplitude, the judgment accuracy and timeliness of the sampling rate adjustment can be effectively improved, and unnecessary sampling rate adjustment can be prevented from causing reduced fault monitoring efficiency and excessive computing power resource occupation. At the same time, it can also prevent the problem of untimely capture of fault traveling wave signals due to untimely sampling rate adjustment; and it can effectively improve the adaptability and timeliness of real-time dynamic adjustment of the sampling rate and changes in the grid operation status.

[0104] Specifically, high-speed communication technologies such as optical fiber and 5G are used to realize real-time data transmission between the traveling wave acquisition device and the main station, so that the traveling wave signal propagates quickly, which can realize rapid warning and positioning of faults and shorten fault handling time.

[0105] Among them, the traveling wave signal processing module is used to process the collected distribution network fault traveling wave signal to determine the distribution network fault characteristic traveling wave signal;

[0106] In this embodiment, the collected distribution network fault traveling wave signal is processed, including:

[0107] A digital filter is used to filter the distribution network fault traveling wave signal to remove high-frequency noise and low-frequency interference in the distribution network fault traveling wave signal;

[0108] It should be noted that the digital filter is an algorithm or device composed of a digital multiplier, an adder and a delay unit. The function of the digital filter is to process the digital code of the input discrete signal to achieve the purpose of changing the signal spectrum, thereby removing the high-frequency noise and low-frequency interference in the fault wave signal of the distribution network.

[0109] Wavelet denoising is used to denoise the distribution network fault traveling wave signal, remove the noise in the distribution network fault traveling wave signal, and retain the detailed characteristics of the distribution network fault traveling wave signal;

[0110] It should be noted that wavelet denoising belongs to an audio processor, which achieves noise elimination through shortwave, thereby removing the noise in the distribution network fault traveling wave signal and retaining the detailed characteristics of the distribution network fault traveling wave signal.

[0111] The maximum and minimum value normalization method is used to normalize the distribution network fault traveling wave signal, and the amplitude of the distribution network fault traveling wave signal is normalized to a unified range.

[0112] It should be noted that the maximum and minimum normalization method is to linearly map the data to the interval [0, 1], eliminating the dimensional differences between data features and making the numerical ranges of different features consistent.

[0113] In this embodiment, the collected distribution network fault traveling wave signal is processed, and further includes:

[0114] Extract features of the distribution network fault traveling wave signal, and extract features that can characterize the distribution network fault type from the distribution network fault traveling wave signal, including time domain features, frequency domain features, and time-frequency domain features;

[0115] Among them, time domain features include peak, mean, variance, kurtosis, and skewness; frequency domain features include spectrum energy, spectrum center of gravity, and spectrum bandwidth; time-frequency domain features include wavelet transform coefficients and Hilbert-Huang transform features;

[0116] The extracted features are selected based on the correlation coefficient method, and the features with high degree of distinguishing fault types are selected from the extracted features to determine the distribution network fault characteristic traveling wave signal.

[0117] It should be noted that by extracting features from the distribution network fault traveling wave signal and selecting features with high fault type discrimination from the extracted features, the distribution network fault characteristic traveling wave signal is determined, which facilitates the subsequent analysis and prediction of the distribution network fault characteristic traveling wave signal through the distribution network fault type prediction model, quickly identifies the distribution network fault type, and issues distribution network fault warnings based on the distribution network fault type.

[0118] Among them, the fault identification and early warning module is used to quickly identify the type of distribution network fault and issue a fault early warning based on the distribution network fault characteristic traveling wave signal;

[0119] In this embodiment, identifying the type of distribution network fault and performing fault warning includes:

[0120] Collecting historical fault data of the distribution network, wherein the historical fault data of the distribution network includes a traveling wave signal of the historical fault of the distribution network and a corresponding distribution network fault type label;

[0121] Processing the traveling wave signals of the historical faults of the distribution network and dividing the historical fault data of the distribution network into a training set and a test set;

[0122] Based on deep learning technology, a training set is used to train the deep learning model, so that the deep learning model can autonomously learn the distribution network fault type prediction behavior, perform pattern recognition on the distribution network fault type, and determine the distribution network fault type prediction model;

[0123] Perform performance test on the distribution network fault type prediction model based on the test set to determine whether the distribution network fault type prediction model can achieve the expected effect;

[0124] According to the test results, the parameters of the distribution network fault type prediction model are adjusted, and the best distribution network fault type prediction model is determined through continuous iterative optimization.

[0125] In this embodiment, identifying the type of distribution network fault and performing fault warning also includes:

[0126] Deploy the distribution network fault type prediction model in the actual distribution network fault type identification environment;

[0127] The distribution network fault characteristic traveling wave signal is input into the distribution network fault type prediction model. The distribution network fault characteristic traveling wave signal is analyzed and predicted through the distribution network fault type prediction model, the distribution network fault type is quickly identified, the distribution network fault warning is performed according to the distribution network fault type, the fault warning information is released in time, and the relevant personnel are notified to handle it.

[0128] It should be noted that the distribution network fault type prediction model is used to analyze and predict the distribution network fault characteristic traveling wave signal, quickly identify the distribution network fault type, provide decision support for fault handling, and issue distribution network fault warnings according to the distribution network fault type. Fault warning information is released in a timely manner, and relevant personnel are notified to handle the situation, so that distribution network faults can be handled in a timely manner and quickly resolved.

[0129] Among them, the fault location positioning module is used to accurately locate the fault location of the distribution network based on the principle of double-terminal traveling wave ranging.

[0130] In this embodiment, the fault position of the distribution network is accurately located according to the principle of double-terminal traveling wave ranging, including:

[0131] The peak detection method is used to detect the distribution network fault traveling wave signal, determine the first distribution network fault traveling wave signal that arrives, and use the first distribution network fault traveling wave signal that arrives as a reference signal;

[0132] Based on the correlation analysis method, the cross-correlation function between the reference signal and other distribution network fault traveling wave signals is calculated. According to the calculated cross-correlation function between the reference signal and other distribution network fault traveling wave signals, the position corresponding to the maximum value of the cross-correlation function is found, which is the time delay estimation value. According to the time delay estimation value, the arrival time of each distribution network fault traveling wave signal is determined.

[0133] In this embodiment, the fault position of the distribution network is accurately located according to the principle of double-terminal traveling wave ranging, and further includes:

[0134] Using the principle of double-end traveling wave ranging, according to the time difference between the traveling wave signal of the distribution network fault reaching the traveling wave collection devices at both ends, the traveling wave propagation speed and the line length, the precise location of the distribution network fault point is calculated by the following formula;

[0135] ;

[0136] Where x is the distance from the fault point of the distribution network to the traveling wave acquisition device at one end, L is the total length of the line, and are the time taken for the fault traveling wave of the distribution network to reach the traveling wave collection devices at both ends, and v is the propagation speed of the traveling wave.

[0137] Specifically, the principle of double-end traveling wave ranging is to install traveling wave acquisition devices at both ends of the transmission line, and use the time difference of the traveling wave signal at both ends to calculate the location of the fault point. When a fault occurs at a certain point on the transmission line, the fault point will generate a high-frequency transient signal. This signal propagates along the line at a speed close to the speed of light. The traveling wave acquisition device records the time it takes for the traveling wave to arrive at both ends respectively. By calculating the time difference and the known line length and traveling wave propagation speed, the specific location of the fault point can be determined.

[0138] It should be noted that based on the correlation analysis method, the arrival time of each distribution network fault traveling wave signal is determined. By utilizing the double-end traveling wave ranging principle, the precise location of the distribution network fault point is calculated based on the time difference between the distribution network fault traveling wave signal arriving at the traveling wave collection devices at both ends, the traveling wave propagation speed and the line length, thereby improving the fault handling efficiency.

[0139] In summary, by collecting the distribution network fault traveling wave signal and transmitting it in real time through the high-speed communication network, the collected distribution network fault traveling wave signal is processed to determine the distribution network fault characteristic traveling wave signal, and the distribution network fault type prediction model is used to analyze and predict the distribution network fault characteristic traveling wave signal, quickly identify the distribution network fault type, and issue a distribution network fault warning according to the distribution network fault type. Fault warning information is released in time, and relevant personnel are notified to handle it. Based on the relevant analysis method, the arrival time of each distribution network fault traveling wave signal is determined. The principle of two-end traveling wave ranging is used. According to the time difference between the distribution network fault traveling wave signal reaching the traveling wave collection devices at both ends, the traveling wave propagation speed and the line length, the precise location of the distribution network fault point is calculated. Based on the distributed traveling wave online measurement, the distribution network fault can be quickly identified, warned and accurately located, which can improve the use effect of the distribution network.

[0140] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0141] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A distribution network fault warning and positioning system based on distributed traveling wave online measurement, characterized in that: include: A traveling wave signal acquisition module configured to collect distribution network fault traveling wave signals and transmit the data in real time through a high-speed communication network; A traveling wave signal processing module is configured to process the collected distribution network fault traveling wave signal to determine a distribution network fault characteristic traveling wave signal; A fault identification and early warning module is configured to quickly identify the type of distribution network fault and issue a fault early warning based on the distribution network fault characteristic traveling wave signal; A fault location locating module, configured to accurately locate the fault location of the distribution network based on the principle of double-terminal traveling wave ranging; The collecting of the distribution network fault traveling wave signal also includes: After the distributed traveling wave acquisition device is installed on the key nodes of the distribution network, adaptive parameter initialization is performed, including: After the distributed traveling wave acquisition device is installed on the key node of the distribution network, the node characteristic parameters of the corresponding position of the key node of the distribution network are collected within the preset trial operation time period, wherein the node characteristic parameters include impedance, grid frequency fluctuation range and voltage fluctuation; Extract the voltage fluctuation amplitude corresponding to each voltage fluctuation; The voltage fluctuation amplitude ratio corresponding to the voltage fluctuation amplitude of each voltage fluctuation is obtained by using the voltage fluctuation amplitude corresponding to each voltage fluctuation and the rated voltage; When extracting the power grid frequency fluctuation range during the operation of key nodes of the distribution network, the specific frequency points at which the operation occurs and the corresponding operating time of each frequency point of the key nodes of the distribution network; Obtaining a power grid frequency fluctuation coefficient according to each frequency point and the operating time corresponding to each frequency point; The grid frequency fluctuation coefficient is used to determine the initial sampling rate of the distributed traveling wave acquisition device after the trial operation period of the key node of the distribution network ends, and the sampling rate of the distributed traveling wave acquisition device is dynamically adjusted according to the subsequent grid frequency fluctuation coefficient of the key node of the distribution network and the voltage fluctuation amplitude ratio corresponding to the voltage fluctuation amplitude of the voltage fluctuation; Make dynamic adjustments, including: Extract the grid frequency fluctuation coefficient corresponding to the preset trial operation time period after the distributed traveling wave acquisition device is installed on the key node of the distribution network; the grid frequency fluctuation coefficient is obtained by the following formula: ； Where S represents the grid frequency fluctuation coefficient; n represents the number of specific frequency points contained in the grid frequency fluctuation range of the key nodes of the distribution network; f i It indicates the grid frequency value corresponding to the operation state of the key node of the distribution network at the ith frequency point; f max Indicates the maximum grid frequency value corresponding to the grid frequency fluctuation range where the key node of the distribution network is located; T i represents the operating time of the key node of the distribution network corresponding to the operating state of the i-th frequency point; T max Indicates the operating time corresponding to the key nodes of the distribution network being in the maximum grid frequency operating state; Obtaining a voltage fluctuation amplitude ratio intermediate value by using the voltage fluctuation amplitude ratio corresponding to the voltage fluctuation amplitude of each voltage fluctuation; The grid frequency fluctuation coefficient is combined with the intermediate value of the impedance and voltage fluctuation amplitude ratio to determine the initial sampling rate of the distributed traveling wave acquisition device after the trial operation period of the key node of the distribution network ends; the initial sampling rate of the distributed traveling wave acquisition device is obtained by the following formula: ； Where F represents the initial sampling rate of the distributed traveling wave acquisition device; f max Indicates the maximum grid frequency value corresponding to the grid frequency fluctuation range where the key node of the distribution network is located; S represents the grid frequency fluctuation coefficient; B z Indicates the middle value of the voltage fluctuation ratio; Z indicates the impedance value; Z c Indicates the preset impedance reference value; Real-time monitoring of the grid frequency fluctuation coefficient during the subsequent operation of key nodes in the distribution network; Comparing the power grid frequency fluctuation coefficient during the subsequent operation of the key node of the distribution network with a preset power grid frequency fluctuation coefficient threshold; When the grid frequency fluctuation coefficient during the subsequent operation of the key node of the distribution network reaches or exceeds the preset grid frequency fluctuation coefficient threshold, the voltage fluctuation amplitude ratio corresponding to the first voltage fluctuation closest to the moment when the grid frequency fluctuation coefficient reaches or exceeds the preset grid frequency fluctuation coefficient threshold is retrieved as the reference fluctuation amplitude ratio; Comparing the reference fluctuation amplitude ratio with a preset fluctuation amplitude ratio threshold; When the reference fluctuation amplitude ratio is not lower than the preset fluctuation amplitude ratio threshold, the sampling rate of the distributed traveling wave acquisition device assembly is adjusted using the current grid frequency fluctuation coefficient and the reference fluctuation amplitude ratio; the adjusted sampling rate of the distributed traveling wave acquisition device assembly is obtained by the following formula: ； Among them, F t represents the sampling rate of the distributed traveling wave acquisition device after adjustment; F represents the initial sampling rate of the distributed traveling wave acquisition device; S h It represents the power grid frequency fluctuation coefficient during the subsequent operation of the key nodes of the distribution network; S y represents the preset grid frequency fluctuation coefficient threshold; B represents the reference fluctuation amplitude ratio; B y Indicates the preset fluctuation amplitude ratio threshold.

2. The distribution network fault early warning and positioning system based on distributed traveling wave online measurement according to claim 1, characterized in that: Collecting distribution network fault traveling wave signals, including: Install the distributed traveling wave acquisition device at the key nodes of the distribution network; Based on the distributed traveling wave acquisition device, the fault traveling wave signal is captured in real time, and the voltage and current traveling wave signals on the distribution network line are collected and recorded in real time to determine the distribution network fault traveling wave signal.

3. The distribution network fault early warning and positioning system based on distributed traveling wave online measurement according to claim 1, characterized in that: Processing the collected distribution network fault traveling wave signal includes: A digital filter is used to filter the distribution network fault traveling wave signal to remove high-frequency noise and low-frequency interference in the distribution network fault traveling wave signal; Wavelet denoising is used to denoise the distribution network fault traveling wave signal, remove the noise in the distribution network fault traveling wave signal, and retain the detailed characteristics of the distribution network fault traveling wave signal; The maximum and minimum value normalization method is used to normalize the distribution network fault traveling wave signal, and the amplitude of the distribution network fault traveling wave signal is normalized to a unified range.

4. The distribution network fault early warning and positioning system based on distributed traveling wave online measurement according to claim 3 is characterized in that: Processing the collected distribution network fault traveling wave signal also includes: Extract features of the distribution network fault traveling wave signal, and extract features that can characterize the distribution network fault type from the distribution network fault traveling wave signal, including time domain features, frequency domain features, and time-frequency domain features; Among them, time domain features include peak, mean, variance, kurtosis, and skewness; frequency domain features include spectrum energy, spectrum center of gravity, and spectrum bandwidth; time-frequency domain features include wavelet transform coefficients and Hilbert-Huang transform features; The extracted features are selected based on the correlation coefficient method, and the features with high degree of distinguishing fault types are selected from the extracted features to determine the distribution network fault characteristic traveling wave signal.

5. The distribution network fault early warning and positioning system based on distributed traveling wave online measurement according to claim 1, characterized in that: Identify distribution network fault types and provide fault warnings, including: Collecting historical fault data of the distribution network, wherein the historical fault data of the distribution network includes a traveling wave signal of the historical fault of the distribution network and a corresponding distribution network fault type label; Processing the traveling wave signals of the historical faults of the distribution network and dividing the historical fault data of the distribution network into a training set and a test set; Based on deep learning technology, a training set is used to train the deep learning model, so that the deep learning model can autonomously learn the distribution network fault type prediction behavior, perform pattern recognition on the distribution network fault type, and determine the distribution network fault type prediction model; Perform performance test on the distribution network fault type prediction model based on the test set to determine whether the distribution network fault type prediction model can achieve the expected effect; According to the test results, the parameters of the distribution network fault type prediction model are adjusted, and the best distribution network fault type prediction model is determined through continuous iterative optimization.

6. The distribution network fault early warning and positioning system based on distributed traveling wave online measurement according to claim 5, characterized in that: Identify distribution network fault types and provide fault warnings, including: Deploy the distribution network fault type prediction model in the actual distribution network fault type identification environment; The distribution network fault characteristic traveling wave signal is input into the distribution network fault type prediction model. The distribution network fault characteristic traveling wave signal is analyzed and predicted through the distribution network fault type prediction model, the distribution network fault type is quickly identified, the distribution network fault warning is performed according to the distribution network fault type, the fault warning information is released in time, and the relevant personnel are notified to handle it.

7. The distribution network fault early warning and positioning system based on distributed traveling wave online measurement according to claim 1, characterized in that: Accurately locate the fault position of the distribution network based on the principle of double-terminal traveling wave ranging, including: The peak detection method is used to detect the distribution network fault traveling wave signal, determine the first distribution network fault traveling wave signal that arrives, and use the first distribution network fault traveling wave signal that arrives as a reference signal; Based on the correlation analysis method, the cross-correlation function between the reference signal and other distribution network fault traveling wave signals is calculated. According to the calculated cross-correlation function between the reference signal and other distribution network fault traveling wave signals, the position corresponding to the maximum value of the cross-correlation function is found, which is the time delay estimation value. According to the time delay estimation value, the arrival time of each distribution network fault traveling wave signal is determined.

8. The distribution network fault early warning and positioning system based on distributed traveling wave online measurement according to claim 7, characterized in that: Accurately locate the fault position of the distribution network based on the principle of double-terminal traveling wave ranging, and also include: Using the principle of double-end traveling wave ranging, according to the time difference between the traveling wave signal of the distribution network fault reaching the traveling wave collection devices at both ends, the traveling wave propagation speed and the line length, the precise location of the distribution network fault point is calculated by the following formula; ； Where x is the distance from the fault point of the distribution network to the traveling wave acquisition device at one end, L is the total length of the line, and are the time taken for the fault traveling wave of the distribution network to reach the traveling wave collection devices at both ends, and v is the propagation speed of the traveling wave.

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