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35results about How to "Obvious fault features" patented technology
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Power distribution network single-phase earth fault zone positioning method and positioning device
ActiveCN103454559AThe amplitude and phase characteristics are obviousObvious fault featuresFault locationPhase currentsOptical communication
The invention provides an online low-current earth fault positioning method and positioning device based on a BP neural network and by means of a multi-source data fusion algorithm. Due to the fact that terminals arranged on different positions on a circuit accurately catch zero-sequence current transient signals of zero-sequence currents which exceed a starting value before a previous period of a starting value and after four periods of the starting value, signal characteristics of a fault transient signals are extracted by means of a Prony algorithm, a wavelet packet algorithm, an HHT algorithm and a fractal algorithm, the characteristics extracted by the algorithms are analyzed by means of the BP neural network, and a zone where a fault occurs is determined. The positioning device comprises a terminal and a main station, wherein the terminal is arranged on an overhead line tower or in a cable ring main unit, the input end of the terminal receives a zero-sequence current signal synthetized by a phase current signal of a CT secondary side of a power distribution circuit including an overhead line and a cable, the terminal is connected with the main station through optical cable communication or mobile communication, and the main station is arranged in a transformer substation or a dispatch center, comprises an optical cable communication module and a mobile communication module and receives a signal sent by the terminal. The method and the device are mature in technology and high in reliability.
Owner:STATE GRID CORP OF CHINA +2
Method and system for detecting winding deformation faults of power transformer
ActiveCN102721464AObvious fault featuresDistinctive featuresSubsonic/sonic/ultrasonic wave measurementFrequency spectrumTransformer
The invention discloses a method for detecting winding deformation faults of a power transformer. The method includes that different vibration characteristics of the transformer in a normal state and a fault state are combined according to running characteristics of the transformer, vibration signals are monitored by a vibration sensor mounted on the surface of the transformer, frequency spectrums of the vibration signals are analyzed, and the transformer is judged to have winding deformation faults if the ratio of 50Hz energy sum and 150Hz energy sum to (50+150Hz) energy sum to (100+200Hz) energy sum which are actually measured is obvious increased as compared with that of the transformer in the normal state and an actually measured 100Hz energy value is hardly changed or even reduced as compared with that of the transformer in the normal state. The invention further discloses a system for detecting the winding deformation faults of the power transformer. The method and the system have the advantages of obvious fault characteristics and good repeatability, and are universal for power transformers of the same type, engineering implementation is simple, and diagnosis is intuitive.
Owner:JIANGSU ELECTRIC POWER CO +2
Method and device for positioning single-phase ground fault section of power distribution network based on transient signal prony algorithm
ActiveCN102967800AThe amplitude and phase characteristics are obviousObvious fault featuresFault locationComputed tomographyAlgorithm
The application provides a positioning method and a positioning device for a single-phase ground fault section of a power distribution network based on a transient signal prony algorithm. The positioning method comprises the following steps in sequence: accurately capturing zero-sequence current transient signals of the zero-sequence current in one cycle before exceeding the starting value and in four cycles after exceeding the starting value through terminals in different positions on a circuit; extracting the transient high-frequency component signal which plays a lead role in the fault transient signals through the prony algorithm; and analyzing the section of the fault point according to the transient high-frequency component signals. The positioning device comprises terminals and a master station, wherein the terminals are arranged on overhead line poles and towers or cable ring main units; the input ends of the terminals are used for receiving phase current signals from the CT (Computed Tomography) secondary sides of power distribution lines (including overhead lines and cables) and combining the phase current signals into the zero-sequence current signals; the input ends of the terminals are connected with the master station in an optical fiber communication way or a mobile communication way; the master station is built in a transformer substation or a control center and comprises an optical fiber communication module and a mobile communication module; and the master station is used for receiving the signals transmitted by the terminals. The method and device provided by the application are mature in technology and high in reliability.
Owner:SHENYANG POWER SUPPLY LIAONING POWER +2
Locating method and device for one-phase earth fault of power distribution network based on transient state signal wavelet transformation
ActiveCN102944817AThe amplitude and phase characteristics are obviousObvious fault featuresFault location by conductor typesShort-circuit testingPhase currentsEngineering
The invention discloses a locating method and device for a one-phase earth fault region of a power distribution network. The locating method comprises the following steps of: accurately acquiring zero sequence current transient state signals within two periods before and after a zero sequence current exceeds a starting value through terminals arranged in different positions on a line; carrying out wavelet transformation and reconstruction on the zero sequence current transient state signals by the terminals; and analyzing a fault point region according to an approximation coefficient integral value of a detail component after the reconstruction. The locating device disclosed by the invention consists of a terminal and a master station, wherein the terminal is arranged on an overhead line tower or in a cable ring network cabinet, the input end of the terminal is used for receiving a phase current signal at the secondary side of a distribution line CT, the phase current signal is synthesized to obtain a zero sequence current signal, and the terminal is connected with the master station through optical fiber communication or mobile communication; and the master station is arranged in a converting station or dispatching center, composed of an optical fiber communication module and a mobile communication module and used for receiving a signal sent by the terminal. The locating method and device are matured in technique and high in reliability.
Owner:STATE GRID CORP OF CHINA +2
Multi-message fusion section locating method based on extreme learning machine
ActiveCN103941156AObvious fault featuresImprove segment positioning robustnessFault locationFeature vectorLearning machine
Disclosed is a multi-message fusion section locating method based on an extreme learning machine. After a fault happens, terminals extract feature vectors from zero-sequence transient current measured in real time according to a transient energy method, a wavelet method and a first half-wave method, upload the feature vectors to a master station and input the feature vectors into the extreme learning machine network where weight parameters are obtained after being trained, and the main station starts the multi-message fusion locating algorithm and outputs a section locating result. As the terminals installed at the multiple positions of a circuit can detect the transient zero-sequence current signals in real time, so that the section locating method based on the transient messages can be applied to the actual engineering. The influence on the method by factors like the grounding position, the grounding time and the grounding transition resistance is small, the extreme learning machine is intelligently fused and comprehensively analyzes the zero-sequence current transient information after the fault, and various algorithms are fused to achieve the complementary effect. The inherent defects of a single locating method are overcome, the transient zero-sequence current characteristic can be fully utilized, the fault section can be determined accurately, and the smaller the space between the terminals is, the more accurate the locating is.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING) +1
Gear system multi-fault diagnosis method based on COM assemblies
InactiveCN104316317AObvious fault featuresHigh precisionMachine gearing/transmission testingDecompositionEngineering
The invention discloses a gear system multi-fault diagnosis method based on COM assemblies, which integratedly utilizes empirical mode decomposition, wavelet threshold noise reduction, a higher-order cumulant theory and a COM assembly technology. The wavelet threshold noise reduction directly acts on a high-frequency intrinsic mode function component obtained through the empirical mode decomposition rather than acting on a reconstruction signal obtained through a whole signal. Empirical mode decomposition-higher order cumulant processing are performed on the reconstruction signal after the noise reduction, and according to a spectrum analysis result, a diagnosis about a fault mode and a damage degree is made, such that the diagnosis precision and efficiency can be enhanced, and diagnosis functions are enriched. During an implementation process, the COM assembly technology is taken as a software realization means of a diagnosis system, and each part is developed to a COM assembly and can be combined to form an application system which can carry out fault mode and damage degree diagnosis; and by using the method provided by the invention, typical single-fault diagnosis can be carried out, composite multi-fault diagnosis can also be carried out, and the development and online upgrading of the diagnosis system are facilitated.
Owner:NORTHWESTERN POLYTECHNICAL UNIV
Rolling bearing fault diagnosis method based on EEMD and distribution fitting testing
InactiveCN103900815AMitigating the problem of modal aliasingObvious fault featuresMachine bearings testingRegular distributionDiagnosis methods
The invention discloses a rolling bearing fault diagnosis method based on EEMD and distribution fitting testing, and relates to the field of rotary machine fault diagnosis. The method includes the steps that original signals are decomposed into a series of IMF components by means of EEMD; then each IMF component is sampled to obtain a sampling point; testing is carried out through a normal probability plot and a Jarque-Bera test, and whether data accord with normal distribution or not is judged; the IMF components according with white noise characteristics are removed, and signals after other components are added and noise reduction is carried out are reserved; finally, fault diagnosis is carried out on rolling bearings by means of an envelope spectrum. According to the method, the aim of signal noise reduction can be well achieved, signal fault features can be more obvious, ultimately fault frequency is identified by means of the envelope spectrum, and fault types of the rolling bearings can be well diagnosed.
Owner:LANZHOU JIAOTONG UNIV
Power distribution networksingle-phase grounding fault handling method based on dual-mode function
ActiveCN110456230AAvoid issues that affect power supply reliabilitySuppress transient failuresEmergency protective circuit arrangementsFault location by conductor typesTransient stateTransformer
The invention provides a power distribution networksingle-phase grounding fault handling method based on a dual-mode function, and belongs to the technical field of powerdistribution automation. The technical scheme is mainly suitable for a delaylow-resistanceinputgrounding mode of a neutral point, and can be compatible with grounding modessuch as non-grounding of the neutral point, grounding of the neutral point through an arc suppression coil and grounding of the neutral point through low resistance. According to the scheme, a transientpower direction protection / grounding overcurrent protection dual-mode function is deployed for a first-stage section switch of a 10kV outgoing line of a transformer substation, thetransientpower direction protection / grounding overcurrent protection dual-mode function or a voltage-time type feeder automation function is deployed for a later-stage section switch, and when grounding faults occur, rapid handling of single-phase grounding faults is realizedby logic cooperation of all stages of switches.
Owner:STATE GRID CORP OF CHINA +1
Line selection method based on FastICA for low current grounding system in single-phase grounding fault
The invention relates to the technical field of grounding fault identification, in particular to a line selection method based on a FastICA for a low current grounding system in a single-phase grounding fault. According to the method, the FastICA method is utilized to process zero-sequence current of the grounding fault, three observation channels are arranged to separate fault steady-state components, transient-state components and noise signals from observation signals, the line fault characteristics are obvious after processing, and accurate line selection can be conducted on a fault line according to the energy of line separation variables. Because the noise signals are separated at the same time, the method is reliable, high in anti-interference capability and capable of not being affected by interference signals; meanwhile, for different initial phase angles of the fault, satisfactory line selection results can all be obtained by means of the method. By using the method to decompose and analyze the zero-sequence current of the fault, the cancellation or compensation among the components of the signals can be avoided, so that the fault characteristics are obvious to achieve the accurate line selection, and the method is widely applicable to the low current grounding system.
Owner:GUANGXI UNIV
Multi-domain semi-supervised fault diagnosis method and device for axial plunger pump bearing
ActiveCN112729835ATroubleshoot Cross-Domain Issues in TroubleshootingEasy to identifyMachine part testingSustainable transportationControl engineeringLearning network
The invention provides a multi-domain semi-supervised fault diagnosis method for an axial plunger pump bearing, and the method comprises the steps: obtaining a source domain signal and a target domain signal, and carrying out the conversion of the source domain signal and the target domain signal, and obtaining a source domain sample and a target domain sample; wherein the source domain signal is a vibration signal of known partial fault information under a certain working condition; the target domain signal is a vibration signal of fault information of an unknown part under another working condition; performing source domain semi-supervised fault diagnosis on the source domain samples after the time-frequency transformation processing by adopting the trained semi-supervised fault diagnosis model to obtain all marked fault samples of the source domain; importing all the marked fault samples of the source domain and the target domain samples subjected to time-frequency transformation processing into a trained multi-target domain transfer learning network at the same time for fault diagnosis of each domain to obtain diagnosis results of all the samples; wherein the diagnosis result comprises normality, an inner ring fault, an outer ring fault and a rolling body fault. By implementing the invention, the problem of cross-domain fault diagnosis of the existing axial plunger pump bearing can be solved.
Owner:WENZHOU UNIVERSITY
Series arc detection method for low-voltage power distribution network
ActiveCN113176479ALittle influence on load powerObvious fault featuresTesting dielectric strengthEffective value measurementsTerminal voltageDistribution networks
The invention discloses a series arc detection method for a low-voltage power distribution network, and belongs to the field of electrical engineering measurement. The method is characterized by comprising the following steps: step a, setting monitoring nodes in a to-be-monitored line; step b, synchronously viewing the to-be-detected line and acquiring the voltage at the two ends; step c, performing filtering processing on the Uo; step d, obtaining a Us-Uo waveform; step e, executing the next step if the series arc fault occurs, and returning to the step b if the series arc fault does not occur; step f, counting the number of faults; and if a preset threshold value is exceeded, cutting off the circuit or sending an alarm signal; if not, returning to the step f. According to the series arc detection method for the low-voltage power distribution network, the series fault arc is detected by measuring the voltage difference between the head end and the tail end of the line, the method for judging the existence of the series fault arc by using the voltage information has the advantages that the influence of the load type and the load power is small, and the fault characteristics are more obvious, so that the judgment accuracy is higher.
Owner:SHANDONG KEHUI POWER AUTOMATION +1
Grounding fault identification and grounding line selection method based on zero-sequence current resistive component
InactiveCN111141990AEasy to identifyEasy to handleFault location by conductor typesShort-circuit testingElectrical resistance and conductanceFeeder line
In order to solve the problem of high-resistance grounding identification and processing of an asymmetric power grid, the invention provides a grounding fault identification and grounding line selection method based on a zero-sequence current resistive component. The resistive current is generated in a fault loop through the compensation damping resistor. According to the method for detecting andcalculating the zero-sequence current resistive component and increment of each feeder line when the power distribution network breaks down, the influence of asymmetric current in the power distribution network in the feeder lines on recognition and line selection of a grounding fault is eliminated, so that the high-resistance recognition and processing capacity of the asymmetric power grid is improved. Particularly, the grounding line selection accuracy of the asymmetric power distribution network is improved.
Owner:李景禄
Micro-grid protection method based on zero-sequence characteristic signal injection
ActiveCN112636312AWide applicabilityNot affected by control strategyEmergency protective circuit arrangementsSingle network parallel feeding arrangementsSignal onPower grid
The invention relates to a micro-grid protection method based on zero-sequence characteristic signal injection. The method comprises the following steps: selecting an inversion type micro-power supply in a micro-grid as an injection source, selecting one inversion type micro-power supply in the micro-grid as an injection source when the micro-grid works normally, and continuously injecting a small-amplitude characteristic signal while the injection source outputs the power frequency current, wherein the characteristic signal is a zero-sequence characteristic signal; continuously monitoring the characteristic signal amplitude at the outlet of the injection source by the injection source, and starting microgrid protection if the characteristic signal amplitude is reduced to be less than a first multiple of a first rated value; and after protection is started, increasing characteristic signal injection of an injection source, and measuring characteristic signals on all sections of lines of the microgrid to serve as the basis of fault positioning and phase selection. Compared with the prior art, the method has the advantages that the applicability is wide; the fault response characteristic is simple, the fault characteristic is obvious, and maloperation or refusal operation is not easy to occur; and the method has the advantages of high reliability, high sensitivity, high selectivity and the like for protecting the microgrid.
Owner:TONGJI UNIV
A positioning method and positioning device for a single-phase ground fault section in a distribution network
ActiveCN103454559BThe amplitude and phase characteristics are obviousObvious fault featuresFault locationPhase currentsEngineering
The invention provides an online low-current earth fault positioning method and positioning device based on a BP neural network and by means of a multi-source data fusion algorithm. Due to the fact that terminals arranged on different positions on a circuit accurately catch zero-sequence current transient signals of zero-sequence currents which exceed a starting value before a previous period of a starting value and after four periods of the starting value, signal characteristics of a fault transient signals are extracted by means of a Prony algorithm, a wavelet packet algorithm, an HHT algorithm and a fractal algorithm, the characteristics extracted by the algorithms are analyzed by means of the BP neural network, and a zone where a fault occurs is determined. The positioning device comprises a terminal and a main station, wherein the terminal is arranged on an overhead line tower or in a cable ring main unit, the input end of the terminal receives a zero-sequence current signal synthetized by a phase current signal of a CT secondary side of a power distribution circuit including an overhead line and a cable, the terminal is connected with the main station through optical cable communication or mobile communication, and the main station is arranged in a transformer substation or a dispatch center, comprises an optical cable communication module and a mobile communication module and receives a signal sent by the terminal. The method and the device are mature in technology and high in reliability.
Owner:STATE GRID CORP OF CHINA +2
Series arc fault online detection method and device
ActiveCN112415350AAccurate identificationCheck as soon as possibleTesting dielectric strengthCharacter and pattern recognitionElectric machineryReal time acquisition
The invention discloses a series arc fault on-line detection method and device, and the method employs loop current and power voltage signals of a three-phase motor, carries out the grouping of collected signals to determine the number of phases where an arc fault happens, and facilitates the quick troubleshooting of the arc fault. Then power supply harmonic waves and load noise in the current andvoltage signals can be separated by using a kernel principal component analysis method, a fifth principal component and a sixth principal component with obvious fault characteristics are selected tocarry out characteristic analysis, and the kurtosis and skewness of the fifth principal component and the kurtosis and skewness of the sixth principal component are taken as four-dimensional fault characteristic vectors; a firefly algorithm is adopted to optimize penalty coefficients and kernel function parameters of a support vector machine, a feature vector set is used for training the optimizedsupport vector machine to obtain a series fault recognition model, loop current and power supply voltage signals are collected in real time and input into the series fault recognition model to achieve real-time detection of series faults. The method has a fault positioning function and is high in fault identification accuracy.
Owner:LIAONING TECHNICAL UNIVERSITY +1
Gearbox fault feature extraction method based on scale space and improved sparse representation
ActiveCN113310684AEliminate modal aliasingAccurate extractionMachine part testingCharacter and pattern recognitionSingular value decompositionFeature extraction
The invention relates to a gearbox fault feature extraction method based on a scale space and improved sparse representation. The method comprises the following steps: dividing an original signal into a plurality of frequency band component signals by using a scale space according to a frequency band, wherein the frequency band component signals take the meshing frequency of each order of a gear as a center; constructing a noiseless DCT dictionary for the frequency band component signals; constructing an observation dictionary used for performing sparse decomposition on the frequency band component signals, including adding noise signals into atoms of a noiseless DCT dictionary in an orthogonal matching pursuit algorithm iteration process based on a singular value decomposition algorithm to obtain a noisy DCT dictionary; selecting an optimal atom in the observation dictionary by taking a fusion index of the minimum variance and the inner product as a criterion; based on an orthogonal matching pursuit algorithm, using the observation dictionary to carry out sparse reconstruction on the frequency band component signals; and analyzing the demodulation spectrum and then extracting the fault characteristic frequency of the gearbox. The method is used for extracting the fault features of the gearbox, and has higher time-frequency resolution and reconstruction precision compared with other methods.
Owner:SOUTHEAST UNIV
Fault section binary positioning method based on self-checking learning
PendingCN114720819AImprove search efficiencyImprove analysis efficiencyFault location by conductor typesShort-circuit testingAdaptive learningInterference (communication)
The invention belongs to the technical field of automation of a power system, and particularly discloses a fault section binary positioning method based on self-checking learning, which comprises the following steps: after a fault occurs, an acquisition terminal uploads an actual measurement signal to a master station, firstly, wavelet transform is utilized to complete time sequence synchronization of a waveform and polarity checking of a detection device; and a twin neural network is introduced to complete similarity judgment of upstream and downstream transient zero-sequence currents of a fault point, fault section positioning is realized, and finally, on the basis of a system network topology, a binary search method is used to quickly determine a minimum fault section. The method can effectively eliminate interference caused by operation errors of transmission time delay of communication equipment and reverse connection of a current transformer, adaptive learning of the twin neural network can reveal potential relations of data, the fault detection capability under the conditions of different grounding positions, grounding moments, transition resistances and the like is improved, a fast search algorithm is combined, and the fault detection efficiency is improved. The generalization of the neural network can be fully reflected, the calculation amount of the master station can be reduced, and the positioning efficiency is improved.
Owner:CHONGQING UNIV OF POSTS & TELECOMM
Gearbox fault diagnosis method based on PSOOBP-CS algorithm
ActiveCN113567117AImprove computing efficiencyObvious fault featuresMachine part testingNeural learning methodsLocal optimumFeature extraction
The invention provides a gear box fault diagnosis method based on a PSOOBP-CS algorithm, which is characterized in that gear box fault feature data is extracted based on ICEEMDSN and MPE algorithms, existence of intermittent components is judged firstly, and a corresponding decomposition algorithm is adopted accordingly, so the operation efficiency is improved, and the residue of white noise added in the signal decomposition process by only adopting the ICEEMDAN algorithm in the traditional feature extraction method is reduced. According to the invention, test data is collected through a gear case working condition data collection device and transmitted to a fault diagnosis unit in a computer, an Elman-TCL neural network stored in the fault diagnosis unit is optimized by using a PSOOBP-CS algorithm, the search capability of PSO and the global search capability of CS are superposed, the particle speed and position in the PSO algorithm are optimized, and the particle global optimal position of the PSO algorithm is optimized, so the defects of premature convergence and easy falling into local optimum are overcome, and the fault diagnosis effect is good.
Owner:NANJING AGRICULTURAL UNIVERSITY
Gearbox Fault Diagnosis Method Based on psoobp-cs Algorithm
ActiveCN113567117BImprove computing efficiencyObvious fault featuresMachine part testingNeural learning methodsLocal optimumFeature extraction
The invention provides a gearbox fault diagnosis method based on the PSOOBP-CS algorithm, extracts the fault characteristic data of the gearbox based on the ICEEMDSN and MPE algorithms, first judges the existence of the intermittent component, and adopts the corresponding decomposition algorithm accordingly, which improves the computing efficiency and reduces In the traditional feature extraction method, only the ICEEMDAN algorithm is used to remove the white noise residue added in the signal decomposition process. The present invention collects test data through the gear box working condition data acquisition device, and transmits to the fault diagnosis unit in the computer, utilizes the PSOOBP-CS algorithm to optimize the Elman-TCL neural network stored in the fault diagnosis unit, and combines the search ability of PSO with the CS The superposition of the global search ability of the PSO algorithm optimizes the particle velocity and position in the PSO algorithm, and optimizes the global optimal position of the particle in the PSO algorithm, so that it can get rid of the shortcomings of premature convergence and easy to fall into local optimum, and the fault diagnosis effect is good.
Owner:NANJING AGRICULTURAL UNIVERSITY
Method and system for detecting winding deformation faults of power transformer
ActiveCN102721464BObvious fault featuresDistinctive featuresSubsonic/sonic/ultrasonic wave measurementFrequency spectrumTransformer
The invention discloses a method for detecting winding deformation faults of a power transformer. The method includes that different vibration characteristics of the transformer in a normal state and a fault state are combined according to running characteristics of the transformer, vibration signals are monitored by a vibration sensor mounted on the surface of the transformer, frequency spectrums of the vibration signals are analyzed, and the transformer is judged to have winding deformation faults if the ratio of 50Hz energy sum and 150Hz energy sum to (50+150Hz) energy sum to (100+200Hz) energy sum which are actually measured is obvious increased as compared with that of the transformer in the normal state and an actually measured 100Hz energy value is hardly changed or even reduced as compared with that of the transformer in the normal state. The invention further discloses a system for detecting the winding deformation faults of the power transformer. The method and the system have the advantages of obvious fault characteristics and good repeatability, and are universal for power transformers of the same type, engineering implementation is simple, and diagnosis is intuitive.
Owner:JIANGSU ELECTRIC POWER CO +2
Locating method and device for one-phase earth fault of power distribution network based on transient state signal wavelet transformation
ActiveCN102944817BThe amplitude and phase characteristics are obviousObvious fault featuresFault location by conductor typesShort-circuit testingPrimary stationStation
A distribution network phase-to-earth fault section location method and location device. By terminals mounted in different positions on a line, zero sequence current transient signals of 2 periods before a zero sequence current exceeds a startup value and of 2 periods after exceeding the startup value are accurately caught, and the terminals perform wavelet transformation and reconstruction on the zero sequence current transient signals, and analyse a section where a fault point is located according to the approximation coefficient integral value of a reconstructed precise component.The location device is composed of two parts; terminals and a main station. The terminals are mounted on an aerial line pole or in a cable ring main unit, the input ends of which receive phase current signals of a distribution line CT secondary side which are combined to obtain a zero sequence current signal, and are connected to the main station by optical fibre communication or mobile communication. The main station is mounted in a transformer station or at a scheduling centre, includes an optical fibre communication module and a mobile communication module, and receives signals transmitted from the terminals.
Owner:STATE GRID CORP OF CHINA +2
Multi-information fusion segment location method based on extreme learning machine
ActiveCN103941156BObvious fault featuresImprove segment positioning robustnessFault locationElectrical resistance and conductanceLearning machine
Disclosed is a multi-message fusion section locating method based on an extreme learning machine. After a fault happens, terminals extract feature vectors from zero-sequence transient current measured in real time according to a transient energy method, a wavelet method and a first half-wave method, upload the feature vectors to a master station and input the feature vectors into the extreme learning machine network where weight parameters are obtained after being trained, and the main station starts the multi-message fusion locating algorithm and outputs a section locating result. As the terminals installed at the multiple positions of a circuit can detect the transient zero-sequence current signals in real time, so that the section locating method based on the transient messages can be applied to the actual engineering. The influence on the method by factors like the grounding position, the grounding time and the grounding transition resistance is small, the extreme learning machine is intelligently fused and comprehensively analyzes the zero-sequence current transient information after the fault, and various algorithms are fused to achieve the complementary effect. The inherent defects of a single locating method are overcome, the transient zero-sequence current characteristic can be fully utilized, the fault section can be determined accurately, and the smaller the space between the terminals is, the more accurate the locating is.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING) +1
A line selection method for single-phase ground fault in small current grounding system based on fastica
The invention relates to the technical field of grounding fault identification, in particular to a line selection method based on a FastICA for a low current grounding system in a single-phase grounding fault. According to the method, the FastICA method is utilized to process zero-sequence current of the grounding fault, three observation channels are arranged to separate fault steady-state components, transient-state components and noise signals from observation signals, the line fault characteristics are obvious after processing, and accurate line selection can be conducted on a fault line according to the energy of line separation variables. Because the noise signals are separated at the same time, the method is reliable, high in anti-interference capability and capable of not being affected by interference signals; meanwhile, for different initial phase angles of the fault, satisfactory line selection results can all be obtained by means of the method. By using the method to decompose and analyze the zero-sequence current of the fault, the cancellation or compensation among the components of the signals can be avoided, so that the fault characteristics are obvious to achieve the accurate line selection, and the method is widely applicable to the low current grounding system.
Owner:GUANGXI UNIV
A series arc detection method for low-voltage distribution network
ActiveCN113176479BLittle influence on load powerObvious fault featuresTesting dielectric strengthEffective value measurementsTerminal voltageComputer science
The invention relates to a series arc detection method for a low-voltage distribution network, which belongs to the field of electrical engineering measurement. It is characterized in that it includes the following steps: step a, setting a monitoring node in the line to be tested; step b, synchronously looking at the line to be tested and collecting the voltage at both ends; step c, performing filtering processing on Uo; step d, obtaining Us- The waveform of Uo; step e, if a series arc fault occurs, go to the next step, if no series arc fault occurs, return to step b; step f, count the number of faults; if it exceeds the preset threshold, cut off the line or send an alarm signal. If the preset threshold value is not exceeded, return to step f; in the series arc detection method for low-voltage distribution network, the detection of series fault arc is realized by measuring the voltage difference between the head end and the end of the line, and the voltage information is used to judge the series fault The existence of arc has the advantage of being less affected by load type and load power, and its fault characteristics are more obvious, so its judgment accuracy is higher.
Owner:SHANDONG KEHUI POWER AUTOMATION +1
Protection method for turn-to-turn short circuit fault of controllable reactor
InactiveCN113013856AProtection sensitivity is lowImprove accuracyEmergency protective circuit arrangementsFault location by conductor typesPhase currentsShort circuit protection
The invention discloses a protection method for a turn-to-turn short-circuit fault of a controllable reactor. The protection method comprises the following steps of 1, acquiring the electrical quantity of the controllable reactor, namely the grid-side three-phase voltage, three-phase current and the control-side three-phase current; 2, calculating the control side zero-sequence current, the network side negative-sequence voltage and the negative-sequence current according to the electrical quantity; 3, taking the control side zero-sequence current as a protection starting threshold to carry out protection starting judgment; 4, calculating a negative sequence power direction angle by using the grid-side negative sequence voltage and the negative sequence current, and taking the negative sequence power direction angle as a judgment basis of a fault position; and 5, when a small turn-to-turn fault occurs, processing the negative sequence power direction angle by using a dynamic mean value method, and then judging the fault occurrence position in the system. According to the protection method, the control side zero sequence current and the grid side negative sequence power direction principle are combined, so that the sensitivity of the control side turn-to-turn short circuit protection of the controllable reactor can be improved; the problem of negative sequence power direction angle fluctuation during small turn-to-turn short circuit is solved by adopting a dynamic mean value method, and the protection reliability is improved.
Owner:江苏益邦电力科技有限公司
Method for detecting early failure of generator by enhancing transformations by electrical current characteristic
InactiveCN101363901BEarly fault extractionObvious fault featuresDynamo-electric machine testingElectric machineFourier transform on finite groups
The invention provides a method for the early failure detection of a motor using current characteristic enhancement transformation, which comprises (1) real-time collecting three-phase current of an induction machine ia, ib, and ic, and calculating a transformation matrix K based on a current power frequency fe; (2) demodulating via the following formula to obtain a torque current iq and a magnetizing current id, wherein iqd0 is equal to Kiabc; (3) performing fast Fourier transformation of torque current iq and the magnetizing current to obtain a subtle current characteristic spectrum; and (4) comparing with the failure characteristic frequency of the induction machine, and determining the failure types of the induction machine. The method has the advantages of simple principle, simple operation, and high measuring accuracy, and can extract failure characteristic component in severe power frequency background using the current characteristic enhancement transformation to detect the early failure of the induction machine.
Owner:NAT UNIV OF DEFENSE TECH
A single-phase-to-ground fault handling method for distribution network based on dual-mode function
ActiveCN110456230BAvoid issues that affect power supply reliabilitySuppress transient failuresEmergency protective circuit arrangementsFault location by conductor typesTransient stateDual mode
A method for handling single-phase grounding faults in distribution networks based on dual-mode functions, which belongs to the field of distribution automation technology. , The neutral point is grounded through the arc suppressing coil, the neutral point is grounded through a small resistance and other grounding methods. In this scheme, the transient power directional protection / ground overcurrent protection dual-mode function is deployed in the substation 10kV outlet first-level section switch, and the transient power directional protection / ground overcurrent protection dual-mode function or voltage-time type is deployed in the subsequent section switch The feeder automation function, when a ground fault occurs, uses the logic coordination of switches at all levels to realize the rapid disposal of single-phase ground faults.
Owner:STATE GRID CORP OF CHINA +1
Method and device for positioning single-phase ground fault section of power distribution network based on transient signal prony algorithm
ActiveCN102967800BThe amplitude and phase characteristics are obviousObvious fault featuresFault locationPhase currentsOverhead line
The application provides a positioning method and a positioning device for a single-phase ground fault section of a power distribution network based on a transient signal prony algorithm. The positioning method comprises the following steps in sequence: accurately capturing zero-sequence current transient signals of the zero-sequence current in one cycle before exceeding the starting value and in four cycles after exceeding the starting value through terminals in different positions on a circuit; extracting the transient high-frequency component signal which plays a lead role in the fault transient signals through the prony algorithm; and analyzing the section of the fault point according to the transient high-frequency component signals. The positioning device comprises terminals and a master station, wherein the terminals are arranged on overhead line poles and towers or cable ring main units; the input ends of the terminals are used for receiving phase current signals from the CT (Computed Tomography) secondary sides of power distribution lines (including overhead lines and cables) and combining the phase current signals into the zero-sequence current signals; the input ends of the terminals are connected with the master station in an optical fiber communication way or a mobile communication way; the master station is built in a transformer substation or a control center and comprises an optical fiber communication module and a mobile communication module; and the master station is used for receiving the signals transmitted by the terminals. The method and device provided by the application are mature in technology and high in reliability.
Owner:SHENYANG POWER SUPPLY LIAONING POWER +2
Fault Diagnosis Method of Rolling Bearing Based on Enhanced Mel's Linear Frequency Cepstral Coefficient
ActiveCN113776835BReduce the difficulty of feature learningImproved fault characteristicsMachine part testingNeural architecturesTime domainFeature extraction
The invention provides a fault diagnosis method for a rolling bearing based on an enhanced Mel linear frequency cepstral coefficient, belonging to the technical field of rolling bearing fault diagnosis. The method includes: acquiring a time domain vibration signal of the rolling bearing; using a preset Mel linear frequency filter The feature extraction is performed on the time-domain vibration signal to obtain a two-dimensional feature map of the enhanced Mel linear frequency cepstral coefficients; the final diagnosis result is obtained according to the two-dimensional feature map of the enhanced Mel linear frequency cepstral coefficients and a preset Transformer model; the present invention Accurate and rapid diagnosis of rolling bearing faults can be achieved under the condition of data distribution offset.
Owner:SHANDONG UNIV
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