168results about "Fault location by pulse reflection methods" patented technology

The invention discloses a self-adaptive fault reflection method and device based on adjustable excitation frequency, and belongs to the technical field of cable fault detection and positioning. The method comprises the following steps: injecting an excitation signal which can be adjusted in a range of 1kHz-10MHz through an adjustable impedance matching network; collecting a reflected signal and calculating an SNR (f) curve; optimizing by adopting a particle swarm optimization algorithm and taking maximization of a signal-to-noise ratio as a target, and determining an optimal excitation frequency; and finally, calculating the fault position and type based on the optimal frequency. The particle swarm optimization algorithm is adopted to perform adaptive optimization on the excitation frequency, and the adjustable impedance matching network is combined to form a closed-loop adaptive detection framework of excitation-acquisition-analysis-optimization-re-excitation, so that the excitation frequency can be automatically adjusted according to a real-time detection result, and the detection accuracy is improved. And the fault detection sensitivity, the positioning precision and the energy efficiency are obviously improved.

The invention provides a line loss reason analysis and positioning method and system based on artificial intelligence and a medium, and relates to the technical field of power system management.The method comprises the steps that when the bus loss rate of a target station area exceeds a preset line loss threshold value, an excitation sequence is issued to a general meter, a circuit breaker and a user electricity meter of the target station area, respectively obtaining corresponding transient response data, and further constructing a dynamic topological graph of the target transformer area; and a topological structure is optimized by combining a graph neural network and an attention mechanism, and abnormal connection points are detected. And determining downstream associated user electric meters, and calculating the power utilization abnormity score based on the load data. And injecting a steep front traveling wave signal into the electric meter with the highest score to obtain a reflection characteristic parameter. And performing iterative analysis by using a Double DQN reinforcement learning algorithm, determining a fault point, a line loss reason type and confidence, and realizing efficient and accurate line loss reason positioning and analysis. According to the invention, efficient and accurate troubleshooting of line loss reasons is realized.

The invention discloses a photovoltaic cable health state assessment method and system, and the system comprises a signal collection module which is disposed at a key node of a cable, and comprises an ultra-wideband pulse sensor, an infrared thermometer, and an illumination sensor; the edge processing module is used for constructing a state characteristic curve and identifying a target sample time interval; the cloud analysis engine is used for executing defect contribution simulation value extraction and thermal-electric coupling model iterative optimization; according to the scheme, multi-dimensional signals such as current, voltage, partial discharge pulse, temperature and illumination intensity are synchronously collected through a distributed sensor network, a multi-parameter evaluation system including amplitude, phase and temperature is constructed, and the health state level, the defect position distribution and the simulation value change trend are displayed through multi-dimensional signal fusion and multi-parameter analysis. And the detection accuracy and comprehensiveness are improved.

The invention relates to the technical field of power system relay protection, in particular to a power transmission line single-end fault positioning method and system. The method comprises the following steps: taking an envelope zero crossing point of an initial transient traveling wave signal as an attenuation ending moment; taking the moment from the occurrence moment of the initial transient traveling wave signal to the attenuation ending moment as an analysis time window; taking the duration of the analysis time window as the attenuation duration of the initial transient traveling wave signal; taking the maximum energy peak value as a resonant frequency identification reference threshold value, searching whether the energy of other frequency peak values greater than the resonant frequency identification threshold value exists or not, and if so, judging whether the initial transient traveling wave signal has resonant interference or not based on the attenuation duration of the initial transient traveling wave signal; if yes, designing a filter for the frequency component, and filtering the initial transient traveling wave signal; and obtaining a fault positioning result of the power transmission line based on the filtered transient traveling wave signal. According to the invention, the single-end fault positioning precision is effectively improved.

The invention relates to a power distribution network fault positioning method combined with multi-terminal traveling wave sampling and a terminal. The method comprises the following steps: synchronously acquiring a transient interference spectrum excited by a network disturbance singular point; normalizing the transient interference spectrum, and extracting a high-dimensional spectrum feature vector from the transient interference spectrum; for each candidate singular point, predicting a theoretical spectrum feature vector of the candidate singular point through a forward propagation operator, and calculating a holographic coherence index between the theoretical spectrum feature vector and an actually observed spectrum feature vector, thereby iteratively reconstructing a singular point holographic data volume representing global fault probability distribution; and carrying out image decoding analysis on the singular point holographic data body, and determining the accurate position of the network disturbance singular point by searching a global maximum value point. According to the method, the fault positioning problem is converted into an image reconstruction and understanding problem, and the positioning precision and robustness are remarkably improved by using the complete information of the traveling wave signal instead of single time information.

The invention relates to the technical field of power grid faults, in particular to a coal mine power grid fault positioning method, which comprises the following steps: collecting transient current traveling wave signals generated when a fault occurs; executing a first layer of PSO to adaptively find an optimal parameter combination for the VMD, and processing a transient current traveling wave signal based on MRSVD to obtain an input signal of the VMD; inputting an input signal into VMD based on the optimal parameter combination, decomposing to obtain intrinsic mode function components, calculating a kurtosis-permutation entropy index of the intrinsic mode function components, selecting the intrinsic mode function component with the highest value as an optimal mode component, extracting initial traveling wave arrival time by combining a symmetric differential energy operator, executing a second-layer PSO, and obtaining a second-layer PSO; correcting the initial traveling wave arrival time through a physical constraint optimization model, and adjusting the traveling wave velocity by adopting a self-adaptive wave velocity estimation strategy to obtain the corrected traveling wave head time and traveling wave velocity; and calculating the position of the fault point based on the corrected traveling wave head time and traveling wave velocity. According to the invention, rapid and accurate positioning of fault points is realized, and the robustness is high.

The invention discloses an ant colony optimization energy focusing cable insulation damage positioning method and device, and relates to the technical field of cable detection engineering, and the method comprises the steps: generating a Gaussian envelope linear frequency modulation chirp detection signal, injecting the detection signal into a to-be-detected cable, and collecting an incident signal and an echo signal containing a reflection component; constructing a parameterized time-frequency analysis kernel function family under a Cohen type time-frequency distribution framework, and searching and optimizing kernel parameters by using an ant colony optimization algorithm; and calculating the time frequency distribution and energy-time curve of the signal based on the energy focusing time frequency analysis kernel function obtained through optimization, extracting the arrival time corresponding to an energy peak value, and realizing cable insulation damage positioning according to the reflection time delay and the propagation wave velocity. According to the method, energy peak focusing and peak position stability are enhanced while cross terms are restrained, defect positioning precision and robustness are remarkably improved, and the method is suitable for engineering online detection and automatic implementation of cable insulation damage.

The invention relates to the technical field of photovoltaic cable fault positioning, in particular to a photovoltaic cable fault positioning method based on multi-source data fusion, which comprises the following steps of: deploying fault recording units at two ends of a combiner box and an inverter side of a photovoltaic string, acquiring a voltage waveform and a current waveform when a fault occurs, and performing band-pass filtering processing to obtain a fault recording unit; and a double-end synchronous transient traveling wave signal is obtained. In the photovoltaic cable fault positioning process, the purity and synchronism of input signals are guaranteed by collecting voltage waveforms and current traveling waveforms at the two ends and conducting filtering processing, wavelet decomposition is conducted on the basis of synchronous transient traveling wave signals, time points corresponding to modulus maximum points are extracted, energy values are calculated, and the fault positioning accuracy is improved. Double characterization of the time domain and the energy domain is achieved, and the time characteristic and the energy characteristic of traveling wave propagation can be synchronously analyzed.

The invention provides a medium-voltage grounding fault positioning method and device, a medium and terminal equipment, and relates to the technical field of power grid fault positioning, and the positioning method comprises the steps: obtaining a time sequence traveling wave interference signal based on a historical original voltage signal, and forming a sample data set; based on the sample data set, constructing an interference signal prediction model through an evolutionary algorithm; determining a real-time line mode voltage traveling wave signal, and determining a traveling wave interference prediction signal by using an interference signal prediction model; determining a real-time pure traveling wave signal based on a difference value between the real-time line mode voltage traveling wave signal and the traveling wave interference prediction signal; determining whether a medium-voltage grounding fault occurs or not; and under the condition that the occurrence of the medium-voltage grounding fault is determined, determining the occurrence position of the medium-voltage grounding fault by using the real-time pure traveling wave signal. Through the method provided by the invention, fault traveling waves can be accurately restored, fault detection and positioning are carried out according to the fault traveling waves, the anti-interference capability of medium-voltage grounding fault detection and positioning is improved, and the accuracy of detection and positioning is improved.

The invention relates to the technical field of electric power, in particular to a cable nondestructive testing method which comprises the following steps: acquiring corresponding calibration parameters from a database according to the model of a to-be-tested cable, and calculating the total length and fault position of the to-be-tested cable at the near end of the to-be-tested cable by adopting a time domain reflection method; at the tail end of the cable to be detected, at the tail end, at least two core wires are short-circuited, a four-wire detection method is adopted to measure the direct-current resistance of a core wire loop at the near end, and standard temperature correction is conducted on the direct-current resistance of a single core wire; the resistivity to be measured is calculated by using the total length of the cable to be measured, the actual cross sectional area of the core wire and the direct current resistance of the single core wire at the standard temperature, and whether the actual core wire material of the cable to be measured is qualified is analyzed according to the resistivity to be measured and a resistivity threshold value set based on the calibrated core wire material. And early warning is carried out based on a core wire material analysis result and a fault position. According to the method, the cable length, the fault position and the core wire material qualification can be quickly, nondestructively and accurately detected on site.

The invention relates to the technical field of line power distribution, and provides a transient fault isolation method and system for a flexible direct current power transmission overhead line, and the method comprises the steps: collecting real-time monitoring data in the operation process of the flexible direct current power transmission overhead line, extracting a dynamic characteristic coefficient according to the original voltage waveform data and the original current waveform data, and calculating a line transient energy distortion rate; the method comprises the following steps: acquiring line transient energy operation power in a preset time period, extracting a disturbance signal in combination with a line transient energy distortion rate to generate a disturbance level to identify a transient fault type, and determining an isolation area according to a total line topological parameter and waveform data corresponding to each monitoring point, and matching a corresponding isolation mode according to the transient fault type and the isolation region. According to the invention, the transient fault can be accurately identified, the fault identification precision and isolation efficiency are improved, and the transient fault protection requirement of the flexible DC power transmission system during operation is met.

The invention belongs to the field of power distribution network fault diagnosis, and particularly discloses a power distribution line fault intelligent section positioning method, which does not depend on real-time waveform information in a traditional power supply state, does not adopt an accurate distance measurement method depending on a traveling wave propagation path, and does not depend on a high-frequency injection signal in combination with synchronous multi-point response. A fault feature matrix is constructed, and the AI classification model obtained through training is utilized to realize rapid and accurate identification of a fault section; and meanwhile, a cloud model continuous learning mechanism is designed, so that the system has the intelligent characteristics of self-evolution and self-adaption, and the technical bottleneck of insufficient consideration of intelligence, practicability and robustness in a power-off working condition of a traditional method is broken through.

A system comprises a digitally programmable frequency chirp generator configured to generate a frequency chirp, an attenuator coupled to the digitally programmable frequency chirp generator and a directional device integrated into a cryogenic circuit configured to control superconducting qubits and coupled to the digitally programmable frequency chirp generator. The directional device comprises a main arbitrary waveform generator and an on-chip programmable self-interference canceller.

The application discloses a kind of digital primary-secondary fusion pole-mounted circuit breaker and its travelling wave ranging time method. The circuit breaker includes feeder terminal and transformer digitizing unit, the feeder terminal is connected with satellite synchronous clock, and the feeder terminal and transformer digitizing unit are connected by cable to realize the uplink communication connection from the feeder terminal to the transformer digitizing unit. In the application, the feeder terminal periodically and uniformly sends data frame to the transformer digitizing unit based on second pulse signal, the transformer digitizing unit obtains time stamp synchronized with second pulse signal based on the received data frame, and obtains travelling wave data with time stamp, thereby improving the accuracy of ranging.

The present application relates to a kind of broadband impedance spectrum cable fault identification method, system and storage medium, comprising: according to any preset cable fault type, establish cable equivalent model;Frequency-sweep signal is input to model, obtain the parameter of cable core, sheath and steel armor under different frequency-sweep signals, and the input impedance of cable head under different frequency-sweep signals is calculated based on cable modulus matrix and input impedance formula, draw fault broadband impedance amplitude spectrum and phase spectrum;Repeat the above steps, obtain cable fault broadband impedance amplitude spectrum and phase spectrum;Real-time acquisition actual cable input impedance and draw real-time broadband impedance amplitude spectrum and phase spectrum, compare with cable fault broadband impedance amplitude spectrum and phase spectrum, identify cable fault type and fault point distance from head end.Compared with prior art, the present application realizes the quick cable fault identification and fault point determination.

A method for detection and localisation of a broken conductor within a Single Wire Earth Return (SWER) power distribution network is provided. The method includes: injecting, from one or more transmitters, a unique and continuous Zadoff-Chu Orthogonal frequency-division multiplexing (OFDM) signal for each transmitter into the network via a coupling circuit. A receiver continuously samples and demodulates the signals to detect the presence of transmitters, wherein detection of a signal is asserted by comparing the averaged cross-correlation signal peak for a particular transmitter and one or more channels in the OFDM scheme designated for estimating noise, as the loss of such signal indicating a broken conductor occurrence. Upon detecting a broken conductor occurrence, the method sends a trip signal to a switching device associated with the receiver to remove power from the system. The method further uses time or frequency reflectometry to estimate the broken conductor location in the network.

The invention specifically relates to a cable defect identification and positioning method based on a broadband impedance spectrum, and belongs to the technical field of power distribution network equipment fault detection. According to the method, the advantages of the frequency domain reflection method and the reflection method are comprehensively considered, whether the parameters of the frequency domain reflection method and the time domain reflection method need to be corrected or not is judged by using the positioning deviation degree, the positioning deviation degree, the fluctuation width and the combined positioning ratio are used as indexes in the correction process, the respective defects of the frequency domain reflection method and the time domain reflection method are eliminated, and the correction accuracy is improved. The advantages are fused, and the corrected parameters are adopted for positioning, so that the accuracy of cable defect positioning and identification is greatly improved.

Systems, methods, and apparatus, including computer programs encoded on computer-readable media, for downhole fault detection in a well system are disclosed. A spread spectrum time domain reflectometry (SSTDR) apparatus of the well system may transmit an SSTDR signal downhole via a well electrical cable of the well system and receive a reflected SSTDR signal. The SSTDR apparatus may determine whether a downhole fault exists in the well electrical cable or in a well device based on a signal analysis of the reflected SSTDR signal and the transmitted SSTDR signal. The SSTDR apparatus may also use historical SSTDR data and a machine learning algorithm for downhole fault detection and analysis. When a downhole fault is detected, the SSTDR apparatus also may determine a type of the downhole fault and a location of the downhole fault, such as the depth downhole of the downhole fault.

A control device is configured to be connected to an electronic device via a signal line and to transmit an abnormal site determination signal to the electronic device via the signal line. In response to detection of a reflected signal of the abnormal site determination signal, a reflection time from transmission of the abnormal site determination signal to reception of the reflected signal is calculated, and an abnormal site of the signal line is determined based on the reflection time.

Systems and techniques are provided for distance estimation. A first pulse signal injected into a first end of a transmission line can reflect off a first short caused across the transmission line by a first device. A peak voltage of a first difference signal corresponding to the reflection can be measured. A second pulse signal injected into the transmission line by the first device can reflect off a second short caused across the transmission line by a second device farther from the first end than the first device. A peak voltage of a second difference signal corresponding to the reflection of the second pulse signal can be measured. The location of the first device along the transmission line can be determined based on a first distance estimate using the peak voltage of the first difference signal and a second distance estimate using the peak voltage of the second difference signal.

The present invention relates to a method for probing a circuit breaker electrically connected between a first line section and a second line section of an electric line. The method comprises the following steps: - a first step of injecting one or more first signals at a first point of said electric line, wherein said one or more first signals have frequency content at least partially included in a predefined frequency range; - a second step of detecting one or more second signals at a second point of said electric line, wherein said one or more second signals are detected with a detection frequency band calculated based on said frequency range; - a third step of calculating a frequency response function of said electric line in said frequency range based on the detected one or more second signals.

The invention discloses an electric power line fault positioning and early warning system, relates to the technical field of electric power, and solves the problem of insufficient early warning capability of existing processing methods. The signal acquisition unit captures a plurality of broadband transient signals and full-waveform backscattering signals on a power line, and the broadband transient signals and the full-waveform backscattering signals are converted into a digital signal sequence through the data acquisition and processing unit. The chaos fingerprint database module stores reference known boundary features; the threatening early warning module detects a weak threatening signal from the digital signal sequence in a normal monitoring state, and outputs a threatening early warning signal when the weak threatening signal is detected; when the self-adaptive positioning module monitors that a hard fault occurs, chaos features are extracted from the full-waveform backscattering signals, a dynamic transformation operator is solved based on reference known boundary features, the dynamic transformation operator is used for correcting the off-line chaos fingerprint reference library to generate a corrected fingerprint library, and the corrected fingerprint library is used for positioning the full-waveform backscattering signals. And the chaos features are matched in the corrected fingerprint database, so that the fault position can be solved. The method is used for fault positioning and early warning.

The invention discloses a fault positioning method and device for a power supply line of a coal mining machine, a medium and equipment, and relates to the technical field of coal mine intelligent power grid information. The method comprises the following steps: carrying out adaptive decomposition on an actual current traveling wave through a variational mode decomposition algorithm after parameters are optimized through a pigeon inspired algorithm; selecting a head end IMF component and a tail end IMF component from the plurality of IMF components at the head end of the actual current traveling wave and the plurality of IMF components at the tail end of the actual current traveling wave; respectively extracting instantaneous energy distribution diagrams of the head end IMF component and the tail end IMF component; capturing moments corresponding to energy abrupt change points from the instantaneous energy distribution diagrams of the head end IMF component and the tail end IMF component; according to the moment when the actual current traveling wave reaches the head end and the moment when the actual current traveling wave reaches the tail end, the distance between the single-phase earth fault point and the head end of the coal cutter power supply line is determined. The method can improve the accuracy of coal mine circuit fault positioning.

A method for detecting a fault in a power system is provided. The method comprises: obtaining current change at a first position of a power line in the power system and voltage change at a second position of the power line, the second position being located on a side of the first position opposite to a power source (1001); determining, based on the obtained current change and the obtained voltage change, transient energy indicating a fault direction of the fault relative to the first position (1002); determining energy thresholds based on line parameters of the power line and the obtained current change (1003); and identifying the fault direction based on comparison of the determined transient energy and the determined energy thresholds (1004). In the method, the thresholds for identifying the fault direction can be accurately determined in real time, thereby improving accuracy and response speed of the fault detection and protection.

The invention relates to a cable fault identification method based on a frequency domain reflection method, and belongs to the technical field of detecting faults in a cable by adopting a pulse reflection method in electrical variable measurement. The method comprises the following steps: setting interval time for increasing sine wave signal frequency to divide moments; calculating an initial frequency f0, and transmitting a sine wave signal with the frequency f0 and the phase of 0 degree into the cable; and then calculating the phase offset at each moment, taking four times of the sine wave signal frequency as the lower limit frequency of the frequency domain reflection method at the moment when the phase offset is equal to 180 degrees for the first time, and further carrying out cable fault identification. According to the method, the lower limit frequency of the frequency domain reflection method is accurately set according to the actual characteristics of the to-be-detected cable, so that omission of cable fault key characteristics is avoided, and the identification accuracy is greatly improved.

The invention relates to a fault positioning method and device for a low-voltage distribution line, computer equipment, a readable storage medium and a program product, and relates to the technical field of power fault detection. According to the invention, the fault positioning precision of the low-voltage distribution line can be improved. The method comprises the following steps: generating a fusion transmitting signal according to PN sequences of a TDR pulse signal and an SSTDR step signal; acquiring a fusion echo signal corresponding to the fusion emission signal, and performing multi-stage noise reduction processing and signal enhancement processing on the fusion echo signal to obtain a preprocessed target fusion echo signal; performing correlation operation on each sampling branch according to the candidate return band of each sampling branch to obtain a correlation peak value corresponding to each sampling branch, and identifying a fault branch in each sampling branch according to the correlation peak value; and determining a net echo on the fault branch according to the turn-back template and the optimal amplification coefficient corresponding to the turn-back template, determining a target rising edge according to the net echo, and mapping the target rising edge as a fault distance on the fault branch.

A computer-implemented method for performing an enhanced resolution time domain reflectometry is provided. Aspects include obtaining a plurality of waveforms by transmitting a first pulse on a transmission line, transmitting a second pulse on the transmission line, where the second pulse is transmitted after the first pulse by a delay, and capturing and measuring reflections of the transmitted pulses, where the delays corresponding to each of the plurality of waveforms are different. Aspects also include identifying a discontinuity of the transmission line based at least in part on the plurality of waveforms. Based on determining that the transmission line includes a discontinuity, the aspects include calculating a third derivative curve for each of the plurality of waveforms, and calculating a length of the discontinuity of the transmission line based on the third derivative curves. Aspects also include creating a notification indicative of the location and length of the discontinuity of the transmission line.

The invention relates to the technical field of cable fault positioning, in particular to a cable fault accurate positioning method and system for cable health monitoring, and the method comprises the steps: obtaining a collection reflection section and an experiment reflection section; obtaining the matching degree of the experimental reflection section; other parameters except the noise intensity in the experiment parameter group are constant, and the noise intensity is quantitatively analyzed to obtain the comprehensive matching degree of the collection reflection section and the experiment reflection section; screening the parameter groups to obtain a plurality of matching parameter groups and a reflection initial search range; comprehensively analyzing the probability that the correlation degree of the reflected pulse signal and the matching parameter group reflects each moment as the starting moment, and selecting the starting moment of the reflected pulse signal; and obtaining the distance of the fault point by using the starting time of the reflected pulse signal. The invention aims to solve the interference of noise on the starting moment of the reflected pulse signal and improve the accuracy of the time domain reflection method.

The invention relates to the field of power cable fault monitoring, and discloses an intelligent chip-assisted cable fault accurate positioning system and a cable. The system comprises a test host and micro-control nodes distributed along the cable; the system is provided with a pulse receiving and transmitting module, a reference acquisition module, a centroid extraction module, a wave velocity calibration module, a dynamic windowing module and a positioning calculation module, and a micro-control node is pre-implanted in the cable. The system constructs a local physical baseline to obtain a centroid timestamp and calculate a real-time local wave velocity, intercepts reflected wave characteristics in combination with a dynamic integral time window, and synthesizes absolute position coordinates of a target. Absolute time synchronization errors among distributed nodes are eliminated by constructing a local physical baseline, and a dynamic windowing mechanism is utilized to adapt to wave velocity change and waveform dispersion caused by aging of a cable medium, so that the problem of feature extraction instability caused by a fixed window is solved, and the absolute precision of fault positioning is improved.