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A Deep Generative Model with Multiscale Features Enabled Industrial Internet of Things for Intelligent fault Diagnosis of Bearings

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Research 2023年第3期6卷 57-68页

作者： He-xuan Hu Yicheng Cai Qiang Hu Ye Zhang Key Laboratory of Water Big Data Technology of Ministry of Water Resources Hohai UniversityNanjing 211100P.R.China College of Computer and Information Hohai UniversityNanjing 211100P.R.China

Effective condition monitoring and fault diagnosis of bearings can not only maximize the life of rolling bearings and prevent unexpected shutdowns caused by equipment failures but also eliminate unnecessary costs and waste caused by excessive maintenance.However,the existing deep-learning-based bearing fault diagnosis models have the following defects.First of all,these models have a large demand for fault data.Second,the previous models only consider that single-scale features are generally less effective in diagnosing bearing faults.Therefore,we designed a bearing fault data collection platform based on the Industrial Internet of Things,which is used to collect bearing status data from sensors in real time and feed it back into the diagnostic model.On the basis of this platform,we propose a bearing fault diagnosis model based on deep generative models with multiscale features(DGMMFs)to solve the above problems.The DGMMF model is a multiclassification model,which can directly output the abnormal type of the bearing.Specifically,the DGMMF model uses 4 different variational autoencoder models to augment the bearing data and integrates features of different scales.Compared with single-scale features,these multiscale features contain more information and can perform better.Finally,we conducted a large number of related experiments on the real bearing fault datasets and verified the effectiveness of the DGMMF model using multiple evaluation metrics.The DGMMF model has achieved the highest value under all metrics,among which the value of precision is 0.926,the value of recall is 0.924,the value of accuracy is 0.926,and the value of F1 score is 0.925.

关键词： fault bearings diagnosis

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A new technique for fault diagnosis in transformer insulating oil based on infrared spectroscopy measurements

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High Voltage 2024年第2期9卷 319-335页

作者： Mohamed M.F.Darwish Mohamed H.A.Hassan Nagat M.K.Abdel-Gawad Matti Lehtonen Diaa-Eldin A.Mansour Department of Electrical Engineering Faculty of Engineering at ShoubraBenha UniversityCairoEgypt Department of Electrical Engineering and Automation School of Electrical EngineeringAalto UniversityEspooFinland Department of Electrical Power Engineering Egypt-Japan University of Science and Technology(E-JUST)New Borg El-Arab CityEgypt Department of Electrical Power and Machines Engineering Faculty of EngineeringTanta UniversityTantaEgypt

Condition monitoring of the insulating system within power transformers has a massive importance according to the electrical utilities.Dissolved gas analysis(DGA)is frequently used for this purpose.However,DGA lacks the necessary level of accuracy to identify all equipment faults,particularly in their initial stages of degradation.Also,it does not have the capability for real-time monitoring and relies on manual sampling and laboratory testing,causing potential delays in fault identification.Additionally,the interpretation of DGA data necessitates specialised expertise,which may pose difficulties for smaller entities that have limited access to resources.Therefore,the contribution of this research is to use infrared spectroscopy measurements as a new effective technique substituting the DGA method for fault diagnosis in insulating oil.The inception faults that were considered in this study were the electrical fault(discharges of high energy)and the thermal fault(300°Cfaults.Subsequently,six samples of pure paraffinic mineral oil were taken to be degraded in the laboratory.Following that,all of them besides another sample that were not subjected to any kind of faults were taken to be examined by Fourier transform infrared(FTIR)spectroscopy to obtain an overview of the oil's behaviour in each fault case.After that,the FTIR analysis was initially verified utilising the DGA method.Then,for further affirmation,the dielectric dissipation factor(DDF)for all samples was measured.In the final analysis,the verification tests provide experimental evidence about the outperformance of this new optical technique in detecting the transformer's inception faults in addition to proving its potential for being a superior alternative to the well-known traditional diagnostic techniques.

关键词： fault diagnosis spectroscopy

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Reliability analysis of large-diameter high-grade-steel natural gas pipelines under fault action

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Petroleum Science 2022年第5期19卷 2387-2398页

作者： Xiao-Ting Gu Xue-Rui Zang Zhen-Yong Zhang Peng Yang Wen-Zhen Miao Ping Cao Bin Zhao School of Petroleum Engineering Yangtze UniversityWuhan430100HubeiChina Key Laboratory of Drilling and Production Engineering for Oil and Gas Wuhan430100HubeiChina College of Pipeline and Civil Engineering China University of Petroleum(East China)Qingdao266580ShandongChina China Petroleum Pipeline Engineering Corporation Langfang065000HebeiChina China Petroleum Pipeline Engineering Co. Ltd.Langfang065000HebeiChina Sinopec Zhongyuan Petroleum Engineering Design Co. Ltd.Zhengzhou450000HenanChina Sinopec Jianghan Petroleum Engineering Design Co. Ltd.Wuhan430223HubeiChina College of Geophysics and Oil Resources Yangtze UniversityWuhan430100HubeiChina

There are a lot of researches on qualitative aseismatic measures for buried gas pipeline crossing movable faults.But a few of them are quantitative,especially in the size and shape of the trench.The paper first established the finite element model of the strain of buried pipeline crossing a fault which effected by the size and shape of the trench.And it obtained new soil spring stiffness which considered different buried depth,bottom width of trench,trench slope and elastic modulus of soil.The mechanical analysis model of pipeline is established,and the limit state equation of pipeline is fitted.The reliability and sensitivity of the natural gas pipeline under fault action are analysed by a Monte Carlo method,and the error and accuracy are verified.When the pipeline is under tension,the sensitivity from large to small is buried depth,sand friction angle,pipe diameter,pipeline displacement,trench bottom width,trench depth,clay cohesion,trench slope and clay friction angle;when the pipeline is under pressure,the trench depth and clay cohesion have great influence.The findings of this study provide a reference for pipeline design and safety evaluation under fault action.

关键词： Trench parameters Natural gas pipeline fault Soil-pipeline interaction Soil spring stiffness

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Investigation on micro-mechanism of palm oil as natural ester insulating oil for overheating thermal fault analysis of transformers

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High Voltage 2022年第4期7卷 812-824页

作者： Hanbo Zheng Xufan Li Yongji Feng Hang Yang Weijie Lv Guangxi Key Laboratory of Intelligent Control and Maintenance of Power Equipment Guangxi UniversityNanningChina

In order to explore the pyrolysis mechanism of palm oil as the natural ester insulating liquid from the molecular aspect,the ReaxFF reactive force field was used to simulate the pyrolysis process of palm oil.Firstly,the molecular models of the four main molecules of palm oil-tripalmitin,trilinolein,triolein,and tristearin-are constructed via density functional theory(DFT).Secondly,the vibrational frequencies of the four molecules are calculated,so as to calculate the infrared(IR)spectra.Thirdly,molecular dynamics(MD)simulations employing the ReaxFF method are performed to simulate the pyrolysis reaction of the palm oil system under different temperatures,so as to observe the generation pathways of major products used in the dissolved gas analysis(DGA)in the transformer thermal fault analysis.Finally,hydrogen bonds in the pyrolysis process are counted.It is found that the number of hydrogen bonds gradually increased with the increase of pyrolysis time and pyrolysis temperature.It reveals why the life of the insulating paper immersed with natural esters is prolonged,and why the breakdown voltage is reduced slowly in the actual experiment from another perspective.This study can provide theoretical guidance and effective reference for the thermal fault analysis of an insulating liquid using palm oil as raw material.

关键词： fault pyrolysis mechanism

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Intelligent overheating fault diagnosis for overhead transmission line using semantic segmentation

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High Voltage 2024年第2期9卷 309-318页

作者： Xiangyu Yang Youping Tu Zhikang Yuan Zhong Zheng Geng Chen Cong Wang Yan Xu Beijing Key Laboratory of High Voltage and EMC North China Electric Power UniversityBeijingChina College of Electronic and Information Engineering Tongji UniversityShanghaiChina

The strain clamps and leading wires are important components that connect conductors on overhead transmission lines and conduct current.During operation,poor contact between these components can cause abnormal overheating,leading to electric failures and threatening power system reliability.Recently,the use of unmanned aerial vehicles equipped with infrared thermal imagers for strain clamp and leading wire maintenance has become increasingly popular.Deep learning-based image recognition shows promising prospects for intelligent fault diagnosis of overheating faults.A pre-treatment method is proposed based on dynamic histogram equalisation to enhance the contrast of infrared images.The DeepLab v3+network,loss function,and existing networks with different backbones are compared.The DeepLab v3+network with ResNet101 and convolutional block attention module added,and the Focal Loss function achieved the highest performance with an average pixel accuracy of 0.614,an average intersection over union(AIoU)of 0.567,an F1 score of 0.644,and a frequency weighted intersection over union of 0.594 on the test set.The optimised Atrous rates has increased the AIoU by 12.91%.Moreover,an intelligent diagnosis scheme for evaluating the defect state of the strain clamps and leading wires is proposed and which achieves a diagnostic accuracy of 91.0%.

关键词： union fault diagnosis

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Molecular pyrolysis process and gas production characteristics of 3-element mixed insulation oil under thermal fault

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High Voltage 2022年第6期7卷 1130-1140页

作者： Dawei Feng Ge Chen Xiaoyu Yan Jian Hao Ruijin Liao State Key Lab of Reliability and Intelligence of Electrical Equipment School of Electrical EngineeringHebei University of TechnologyTianjinChina Hebei International Joint Research Center for Reliability and Intelligence of Modern Electrical Equipment TianjinChina State Key Laboratory of Power Transmission Equipment&System Security and New Technology School of Electrical EngineeringChongqing UniversityChongqingChina

Mixed insulation oil is considered as a desired substitute for traditional mineral oil.A novel 3-element mixed insulation oil has been developed in our previous works,whose parameters satisfy the mineral oil standard(IEC 60296:2012).In the application of transformer oil,dissolved gas analysis is an effective method for insulation fault diagnosis.Thermal fault is a common and typical fault in transformers;however,the pyrolysis process and gas production characteristics of mixed insulation oil under thermal fault remain unknown.In this study,the pyrolysis process and gas production characteristics of 3-element mixed insulation oil have been studied through simulation and experiments,and mineral oil is equally treated for comparison.Results show that the gas production characteristics of mixed oil are closely related to its base oils,and 3-element mixed insulation oil generates more H_(2)and C_(2)H_(6)under thermal fault,in which the percentage of H_(2)in the mixed oil is always three times that in the mineral oil.More CO_(2)is produced in mixed oil under thermal fault because of ester bonds;C_(2)H_(4)is also a main characteristic gas for mixed insulation oil under thermal fault,and its proportion increases continuously with the increase of temperature.For mineral oil,the weight loss temperature in thermogravimetric(TG)curve corresponds to evaporation rather than decomposition.Natural esters have poor thermal stability according to simulation results,but they possess high flash point and weight loss temperature in the TG curve primarily because of their large average molecular weight.

关键词： insulation fault pyrolysis

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New correlation features for dissolved gas analysis based transformer fault diagnosis based on the maximal information coefficient

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High Voltage 2022年第2期7卷 302-313页

作者： Yongliang Liang Zhongyi Zhang Ke‐Jun Li Yu‐Chuan Li School of Electrical Engineering Shandong UniversityJinanChina Department of Electrical&Electronic Engineering Imperial College LondonSouth Kensington CampusLondonUK

Online monitoring of gases dissolved in transformer oil is widely applied.Improving the performance of dissolved gas analysis(DGA)‐based fault diagnosis methods by exploring new features of time‐series data has become an appealing topic.In this study,a new type of correlation features between characteristic gases was extracted from time‐series data based on the maximal information coefficient(MIC),and a fuzzy inference system was established.After the introduction of the principle of the MIC and a method for calculating the MIC‐based correlation features,the dominant symptom features that can be used to classify fault types were extracted through the receiver operating characteristic curve.Then,fuzzy rules were learnt,and a fuzzy inference system was designed.In addition,to improve the feasibility of the method,the Newton interpolation method was used for adaptation to the existing sampling cycle.The diagnostic results of the test data show that the proposed method has excellent per-formance and outperforms some prevailing traditional rule‐based methods as well as some artificial intelligent methods.The results also show that by exploring new cor-relation features from time‐series data based on the MIC,the performance of DGA‐based methods can be improved.

关键词： fault diagnosis coefficient

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Modelling and analysis of half-/full-bridge hybrid MMC when riding through DC-side pole-to-ground fault

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High Voltage 2022年第3期7卷 496-509页

作者： Zhen He Jiabing Hu Lei Lin Pingliang Zeng School of Automation Hangzhou Dianzi UniversityHangzhouChina State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhanChina

In a modular multilevel converter-based high-voltage direct current(MMC-HVDC)system,the dc fault ride through(FRT)control is an effective way to deal with a dc-side pole-to-ground(PTG)fault.However,the setting of FRT duration brings potential hazards:1)MMC will face the risk of“secondary short circuit”if FRT duration is short;2)ac grid may have power angle stability issue if FRT duration is long.To avoid these hazards and provide theoretical guidance for the FRT duration setting,transient behaviour of dc fault current during the PTG FRT stage is explored in this work.Firstly,challenges of the transient analysis are summarised as non-linearity and high-order issues.In light of this,numerical and Hilbert-Huang Transformation methods are introduced to evaluate the non-linearity issue.It is found that the path of MMC from dc current to dc internal voltage is weakly non-linear.Hence,a linear transient model is built to analyse the dc fault current.By participation factor analysis,the order of the proposed model is further reduced,so that an analytical expression of the dc fault current is approximately derived.Based on the analytical expression,regularities and mechanism of dc fault current are fully revealed.Application of the transient analysis to the setting of FRT duration is elaborated in detail.Finally,the PSCAD/EMTDC simulation verifies the validity of the proposed model and analytical expression.

关键词： fault ground setting

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fault-sand combination modes and hydrocarbon accumulation in Binhai fault nose of Qikou Sag, Bohai Bay Basin, East China

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Petroleum Exploration and Development 2019年第5期46卷 919-934页

作者： ZHOU Lihong HAN Guomeng DONG Yueqi SHI Qianru MA Jianying HU Jinnan REN Shichao ZHOU Kejia WANG Jincheng SI Weiliu Dagang Oilfield Company PetroChinaTianjin 300280China

Based on seismic and logging data,taking the downthrow fault nose of Binhai fault in Qikou Sag as the object of study,we analyzed fault characteristics,sand body distribution,fault-sand combinations and hydrocarbon accumulation to reveal the hydrocarbon enrichment law in the fault-rich area of fault depression lake basin.The results show that the Binhai Cenozoic fault nose is characterized by east-west zoning,the main part of the western fault segment is simple in structure,whereas the broom-shaped faults in the eastern segment are complex in structure,including several groups of faults.The difference of fault evolution controls the spatial distribution of sand bodies.The sand bodies are in continuous large pieces in the downthrow fault trough belt along the Gangdong fault in the middle segment of the fault nose,forming consequent fault-sand combination;whereas the fault activity period of the eastern part of the fault nose was later,and the sand bodies controlled by paleogeomorphology are distributed in multi-phase north-south finger-shaped pattern,forming vertical fault-sand combination pattern matching with the fault.The configuration between faults and sand bodies,and oil sources and caprocks determine the vertical conductivity,plane distribution and vertical distribution of oil and gas.Two oil and gas accumulation modes,i.***.single main fault hydrocarbon supply-fault sand consequent matching-oil accumulation in multi-layers stereoscopically and fault system transportation-fault sand vertical matching-oil accumulation in banded overlapping layers occur in the middle and eastern segments of the fault nose respectively,and they control the difference of oil and gas distribution and enrichment degree in the Binhai fault nose.

关键词： Bohai Bay Basin Qikou Sag Binhai fault nose sandstone development mechanism fault-sand combination oil and gas accumulation reservoir control mechanism

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fault diagnosis based on measurement reconstruction of HPT exit pressure for turbofan engine

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Chinese Journal of Aeronautics 2019年第5期32卷 1156-1170页

作者： Xin ZHOU Feng LU Jinquan HUANG College of Energy and Power Engineering Jiangsu Province Key Laboratory of Aerospace Power System Nanjing University of Aeronautics and Astronautics

Aero-engine gas path health monitoring plays a critical role in Engine Health Management(EHM). To achieve unbiased estimation, traditional filtering methods have strict requirements on measurement parameters which sometimes cannot be measured in engineering. The most typical one is the High-Pressure Turbine(HPT) exit pressure, which is vital to distinguishing failure modes between different turbines. For the case of an abrupt failure occurring in a single turbine component, a model-based sensor measurement reconstruction method is proposed in this paper. First,to estimate the missing measurements, the forward algorithm and the backward algorithm are developed based on corresponding component models according to the failure hypotheses. Then,a new fault diagnosis logic is designed and the traditional nonlinear filter is improved by adding the measurement estimation module and the health parameter correction module, which uses the reconstructed measurement to complete the health parameters estimation. Simulation results show that the proposed method can well restore the desired measurement and the estimated measurement can be used in the turbofan engine gas path diagnosis. Compared with the diagnosis under the condition of missing sensors, this method can distinguish between different failure modes, quantify the variations of health parameters, and achieve good performance at multiple operating points in the flight envelope.

关键词： Component-level model Condition monitoring fault diagnosis Measurement reconstruction Turbofan engines Unscented Kalman filter

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