2018 Condition Monitoring and Diagnosis (CMD)最新文献

{"title":"Detection of Single Line-to-Ground Fault Using Convolutional Neural Network and Task Decomposition Framework in Distribution Systems","authors":"Ying Du, Qingzhu Shao, Yadong Liu, G. Sheng, X. Jiang","doi":"10.1109/CMD.2018.8535600","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535600","url":null,"abstract":"Fault feature extraction is critical for fault line detection, but difficult to be effective and robust. Unbalanced characteristics of the fault signal sample will make feature extraction more difficult. A novel method using Choi- Williams time-frequency distribution based convolutional neural network and task decomposition framework was proposed. Choi- Williams time-frequency analysis was applied to generate time-frequency distribution image of fault signal. Then, convolutional neural network (CNN) was trained by a lot of time-frequency distribution images generated under different fault conditions. CNN can extract features of the time-frequency distribution image adaptively and select the fault line. The task decomposition framework was first proposed to solve the problem of unbalanced fault signal sample for better feature extraction. A resonant grounding distribution system is simulated to verify this method under different fault conditions and the results showed the detection of the single line-to-ground fault is more accurate.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"22 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91545141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dielectric Loss Factor and Circuit Impedance Under Partial Discharge Via Excess Current Detection","authors":"Tianxin Zhuang, Shujing Yang, M. Ren, B. Song","doi":"10.1109/CMD.2018.8535607","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535607","url":null,"abstract":"Partial discharge measurement plays an important role in the assessment of insulation status and fault diagnosis of power equipment. Presently, the most commonly used industrial applications of PD detections are based on the broadband measurement systems that count amplified PD pulses. The limitations of these traditional measurements are that the system requires a relatively high sampling rate and calculation capability, and is very sensitive to the ambient noise. To eliminate noise interference and save the cost of PD detection system, a technique measurement of excess currents, which measures the dielectric response currents through test object before and after PD activities to capture the activities of PD, has been reported in some recent studies. This work aims to explore the parameters that characterize the PD activities via excess current technology and to seek new ideas for PD detection. In this work, a measurement setup for measurement of PD excess currents averaged from 300 periods is applied and three typical insulation defect models were tested under 50Hz voltages. Excess currents for each case are measured. Then the corresponding dielectric loss factors and circuit impedances are obtained by comparing them to the synchronous voltages. The results show that the loss factors increase after PD while the circuit impedances decrease. Meanwhile, the loss factors continue to increase and the circuit impedances continue to decrease as the voltages turn up where the rate of the change shows more rapid in the needle-plate model. Moreover, the loss factors and circuit impedances in the dielectric barrier model and air void model are respectively higher and lower than the values before PD when the voltages drop below the PD extinction voltages, which does not appear in the needle-plate model. These characteristics provide a new idea for PD detection by monitoring the loss factors or circuit impedances via excess current detection.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"54 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87018054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Statistical Approach for Effectively Analyzing the Grain Size Distribution Along the Thickness Direction in Commercial ZnO-Based Varistor Ceramics","authors":"Lei Zhang, Chuan Yu, Le Zhang, Wenfeng Liu, Kangning Wu, Shengtao Li, Jianying Li","doi":"10.1109/CMD.2018.8535707","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535707","url":null,"abstract":"Grain size and its spatial distribution are the crucial issues in the study of advanced materials with a grain-grain boundary structure. It not only implies the grain growth mechanism of those materials, but also determines most of their macroscopic properties, such as mechanical strength, current conduction, ageing and so on. Therefore, it is of importance to clarify the grain size distribution (GSD) in ZnO-based varistor ceramics, a key protection element against overvoltage. In the present paper, a new approach based on the log-normal distribution was proposed to analyze the variation of GSD along the thickness direction of two commercial ZnO varistors. It is found that GSD follows log-normal distribution rather than commonly used normal distribution. In addition, with the proposed grain size, i.e., averaged log-normal grain size (dLN) and most probable grain size ($d_{max}$), the variation of GSD along the thickness direction was clearly revealed, which exhibited quite different behavior depending on the samples. With the probability plot, the microscopic uniformity is carefully analyzed and discussed. It is proposed that probability plots can be divided into three regions, representing large grains, grains whose sizes follow the lognormal rule and small grains, respectively. With the proposed method, it is possible to obtain more quantitative information, which is of significance for the further development of ZnO-based varistor ceramics and other advanced materials.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"29 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91231906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Voltage Harmonics on Condition Assessment of Polluted Insulator through a Simulation Model","authors":"A. Banik, S. Nielsen, G. Nourbakhsh","doi":"10.1109/CMD.2018.8535674","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535674","url":null,"abstract":"The condition assessment of outdoor high voltage insulators is of prime importance to power utilities. There are numerous indicators used for inferring the surface condition of an insulator based on an analysis of measured leakage current. To date, the assumption by most researchers has been that the supply voltage subject on insulators is sinusoidal with little or no harmonic induced distortion. However, in real-life due to ever increasing trend of using power electronics devices in power network, significant amount of harmonic distortion is common and insulators in the power system are directly subjected to this distortion. Therefore, the effectiveness of all those present indices under purely sinusoidal voltage will become questionable in presence of distorted supply voltage. This work aims to investigate the effect of voltage harmonic contents on the measured leakage current of polluted insulators via a developed simulation model. In this paper, by considering the practical supply voltage distortion, authors have shown the major drawback of present indices based condition assessment techniques. Authors have also tried to provide an optimal solution by proposing a Crest Factor (CF) based distinctive index to overcome the problem, based on simulation results.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"234 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73507684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying a Mathematical Model to Optimize Pump Maintenance Planning Decisions - A Case of Irrigation Asset Management in K.S.A","authors":"M. Anis","doi":"10.1109/CMD.2018.8535792","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535792","url":null,"abstract":"With increasing investments being made by the Provincial Government in KSA's Eastern Province on irrigation water distribution projects, more focus is being placed on finding ways to reduce expenditure and restore the lost performance of irrigation assets due to planned or un-planned overhauls. This article presents a modeling approach to improve the repair schedule at the local water pump stations with an aim of minimizing total life-cycle cost of the pumps while maintaining eco-friendly standards. The case study used focuses on a Sanitary Wastewater Treatment Plant (SWTP) having centrifugal pumps running in parallel configuration to pump water from tanks to service reservoir. The opted methodology considers a realistic set of assumptions with the type of data available to identify four main parameters for maintenance decisions- the Hydraulic Model, Operation Model, Deterioration Model and Optimization Model. A hydraulic mode for the pumping system has been defined with performance measures like head-flow, power-flow and system curves and is used to compliment the deterioration model, which predicts the drop in pump performance with continuous use. Operational inputs such as the production schedules, pump schedules, duty specification, hydraulic output etc. are combined with deterioration mechanisms, namely the wear ring and internal surface deterioration, to identify an optimization model- an optimal pump overhaul schedule. While the hydraulic model is explained numerically using equations to approximate solutions, the optimization model is discussed as a linear integer programming problem using heuristics. Mathematically computed solutions to the models are finally applied to a system of three pump stations to forecast an appropriate number of overhauls for each pump station over the next four years with the subsequent costing involved. Thus, the described approach serves as a model-based decision support system tool (DSS) to assist planning engineers and asset maintenance managers in crucial pump overhaul planning and budgeting decisions.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"61 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88493866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Methodology of Searching the Best AE Sensor Array to localize PD sources in Power Transformer","authors":"Shao-Rui Qin, Yan-Bo Wang, G. Ding, Taiyun Zhu, Jianlin Li, Guanjun Zhang","doi":"10.1109/CMD.2018.8535845","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535845","url":null,"abstract":"The partial discharge (PD) is the main cause of the insulation failure in power transformers. Localization of the partial discharge source in the transformer effectively and precisely has a very important meaning in the insulation maintenance. The acoustic emission(AE) method has attracted researchers' attention because AE sensors have excellent ability to resist electromagnetic interference and they are convenient to be installed. Many researchers use an array of multiple AE sensors to collect PD signals and use the time difference between the signals to localize the PD source. However, if the sensor arrangement is unreasonable, it will inevitably introduce a huge error in time difference estimation. In this paper, the propagation characteristics of AE signals and the basic principles of time-difference-of-arrival (TDOA) methods are briefly introduced. After that, this paper describes how to set up a transformer physical model proposes a method of optimizing the arrangement of ultrasonic sensor arrays to better localize the partial discharge power in transformers. The algorithm is used to optimize the sensor array on two planes of a 35kV transformer.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"254 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80711576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Characteristics and Detection of the Partial Discharge Induced by the Micro Cracks in GIS Insulators","authors":"Xiao Li, Yang Xu, Jiangrong Cheng, Weidong Liu, Wensheng Gao","doi":"10.1109/CMD.2018.8535818","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535818","url":null,"abstract":"The micro cracks resulted from the defective manufacturing technology are common to see in GIS insulators, and many researches have already been done on it. However, most of these studies are based on the simulative defects made in laboratories, rather than on the defects on real made insulators, and thus the equivalence between the experimental condition and the practical situation in real substations cannot been guaranteed. In this paper, partial discharge (PD) experiments are carried out on a real made GIS post insulator with micro crack inside. It is found that the ultra-high frequency (UHF) method is not sensitive to the PD of this type based on the investigation on the PD characteristics, and the mechanism of the PD process is analyzed to explain why it cannot be detected by the UHF method. According to the special PD characteristics the defect displayed, suggestions on the adjustment of the PD frequency band is made in order to find the micro cracks in GIS insulators on-site.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"58 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78406554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frequency Response Analysis of the Transformer Subjected to Twice Short-circuit Impulse Tests Under Two Different Connection Schemes","authors":"Song Wang, Shuang Wang, H. Qiu, Hanke Feng, Shuhong Wang, Ahmed Abu-Siuda","doi":"10.1109/CMD.2018.8535767","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535767","url":null,"abstract":"Power transformer is a key equipment in power system. Ensuring the safety operation of transformer is beneficial to decrease the economic loss and casualties. In this paper, twice short-circuit impulse tests are performed on a 10kV transformer. After each test, frequency response analysis (FRA) measurements based on two different terminal connection schemes, namely end to end voltage ratio (EE) and transfer voltage ratio (TF) ways, are conducted to record the FRA results. The impacts of short-circuit on transformer will be investigated by the change of FRA curves. In addition, a numerical index will be utilized to find out the more sensitive measurement connection way to the variation of the traces. The contributions of this paper can give a complement for the current interpretation of the FRA signatures.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"148 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77363552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on Radial Stability and Its Influence Factors of Transformer Windings under Short Circuit Fault","authors":"Shuang Wang, Song Wang, Shuhong Wang, H. Qiu, Hanke Feng, Ting Zhu","doi":"10.1109/CMD.2018.8535883","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535883","url":null,"abstract":"The safe operation of power transformers is of great significance to the stability of the power system. Radial stability of windings is an important issue for transformer design and maintenance. This paper presents an effective method to analyze the radial stability of windings. The electromagnetic characteristics of a 110 kV two-winding power transformer is calculated and analyzed by finite element method. The mathematical model of radial stability of the power transformer windings under short circuit condition is established. The radial stability analysis of the low winding is performed. The relationship between critical buckling load and its influence factors, including winding material characteristics and winding structure parameters, are obtained based on the buckling analysis. The research results can provide reference for the transformer design, manufacture, operation and maintenance.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"27 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79156687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polarization and Depolarization Current Measurement of Underground Cable with Different Cable lengths, Temperatures and Test Voltages","authors":"K. Thungsook, P. Nimsanong, N. Marukatut, N. Pattanadech","doi":"10.1109/CMD.2018.8535789","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535789","url":null,"abstract":"This paper represents the polarization and depolarization current (PDC) measurement of 12/20(24) kV XLPE power cable with different cable lengths, cable dimensions, temperatures and test voltages. In experiment 1, the XLPE cable with 5 m long and cross section of 240 mm2 was prepared for (Case V1) investigation. Moreover, two of 2.5 m cables connected by the pre-molded joint (Case V2) was also prepared. In the experiment 1, the PDC experiment was investigated with different step DC test voltages i.e., 500V, 750V and 1,000V respectively. Besides, the dielectric response of underground cables with the length of 15 cm with cross section of 185 mm2 and the lengths of 2.5 m and 5 m with cross section of 240 mm2 including the length of 100 m with cross section of 70 mm2 were prepared for experiment 2. To investigate the effect of temperatures on dielectric response, the cable specimen with the length of 15 cm with cross section of 185 mm2 was set up under ambient temperatures of 30, 50, 70 and 90 degree Celsius for PDC measurement in experiment 3. PDC test results obtained from the experiments were compared. Then the dielectric parameters for PDC experiment such as charge difference analysis, capacitance ratio analysis, and polarization loss factor were analyzed and reported in this paper.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"13 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74375798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}