Xin Zhao, Siyi Zhang, Cheng-lu Lin, Zhi Yang, Zhonglei Li, T. Han
{"title":"Characterization of Electrical Treeing in XLPE versus Temperature Gradients","authors":"Xin Zhao, Siyi Zhang, Cheng-lu Lin, Zhi Yang, Zhonglei Li, T. Han","doi":"10.1109/ICD46958.2020.9341977","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341977","url":null,"abstract":"Cross-linked polyethylene (XLPE) plays a significant role in AC power cables. In the cables, the difference in temperatures of conductor and surrounding environment produces a temperature gradient in XLPE, and the electrical and thermal aging accelerate the degradation. When defects exist in the dielectric, an electrical tree may be initiated. Hence, it is necessary to research the electrical tree in XLPE under the temperature gradient. In this paper, XLPE samples were tested under 50 Hz AC voltage with multiple temperature gradients, and the electrical tree was recorded by a digital microscope. To simulate an electrical stress concentration, a pair of needle-plate electrodes was utilized in this experiment. There are two types of temperature gradients in this experiment, one is to set the needle electrode temperature to 100 °C and increase the ground electrode temperature from 30 to 70 °C, and the other is the opposite. The tree structure, growth process, fractal dimension, accumulated damage and tree length were recorded and analyzed. The experiment results indicate that the temperature gradient affects the growth rate and the structure of trees. When the ground electrode temperature is higher than the needle tip, the tree grows faster. The fractal dimension and the accumulated damage increase as the temperature gradient increases.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"23 1","pages":"25-28"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78032953","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}
Jinjing Peng, Yu Gao, Jing Li, Xuri Xu, Zheng Song, B. Du
{"title":"Partial Discharge Erosion of Polypropylene/Elastomer Blends Characterized with Multi-Sensors under AC Voltage","authors":"Jinjing Peng, Yu Gao, Jing Li, Xuri Xu, Zheng Song, B. Du","doi":"10.1109/ICD46958.2020.9341807","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341807","url":null,"abstract":"Polypropylene (PP) has been considered as a promising insulation material for power cable in both AC and DC systems because of its excellent insulation performance and recyclability. The exposure to partial discharge gives rise to the deterioration of the material that threatens the safe operation of cable. Therefore, it is of great significance to understand the mechanism of partial discharge of PP and its blends subjected to AC voltage. In this work, PP/elastomer blends with thickness of $150 mu mathrm{m}$ were prepared as samples. A needle-plane electrode system was employed to introduce partial discharge by applying an AC voltage with 5 kVrms for 2 hours. The erosion behavior was characterized through multi-sensors system, including high frequency current transformer (HFCT), optical recorder and gas sensor. To better understand the erosion mechanism, isothermal surface potential decay (ISPD) method was used to analyze trap characteristics. The results showed that the trap center became shallower with the increase of elastomer content for both ethylene-octene copolymer elastomer (EOC) and polypropylene based elastomer (PBE). Compared with pure PP, the addition of elastomer improved the resistance of partial discharge and PP with 20 wt% loading percent of EOC presented better resistance to partial discharge compared with PP with 20 wt% loading percent of PBE.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"95 1","pages":"890-893"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85723348","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":"Volatile Acid and Polymer Formation in Various Insulation Liquids Upon Accelerated Thermal Ageing","authors":"E. Matić, M. Meissner, S. Schober, M. Mittelbach","doi":"10.1109/ICD46958.2020.9342021","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9342021","url":null,"abstract":"Insulation liquids perform a vital role in protecting power equipment, such as transformers, from thermal, electrical and environmental stress. Considering the poor fire-safety properties and low biodegradability of mineral oil as the leading kind of insulation liquid, alternative insulation liquids are of high interest for their implementation in power equipment. In this experiment we aimed to simulate the processes occurring in faulty power equipment by ageing four different kinds of insulation liquids (mineral oil, GTL-insulation liquid, synthetic ester and natural ester) under laboratory conditions. The use of optimized analytical routine methods has allowed us to monitor as well as quantify volatile acid and polymer formations upon ageing of insulation liquids. The ageing process under aerated conditions has led to the formation of formic, acetic and propionic acid, especially in natural ester, alongside notable polymerization effects. All other types of insulation liquids showed significantly lower amounts of volatile acids. Per contra, the experiments conducted under oxygen-free conditions resulted in minimal volatile acid and polymer build-ups in all four insulation liquids.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"49 1","pages":"317-320"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80719830","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":"Effect of sPP Content on Dielectric Relaxation and Trap Level Characteristics of PP blend insulation","authors":"M. Fan, Zhonglei Li, B. Du, S. Zhou","doi":"10.1109/ICD46958.2020.9341925","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341925","url":null,"abstract":"Polypropylene (PP) is regarded as a recyclable alternative to XLPE for cable insulation on account of its higher heat resistance and higher electrical resistivity. The dielectric relaxation and trap level characteristics of isotactic PP (iPP), syndiotactic PP (sPP) as well as atactic PP (aPP) blends are investigated. The associations between polymer polarization response and traps level characteristics of PP blends are discussed. Frequency-domain dielectric spectroscopy (FDS) methods are used to analyze the polarization response of five PP blends at 50, 70 and 90 0C. Isothermal surface potential decay (ISPD) tests are performed to acquire the traps level distribution and the influences of traps level characteristics on the dielectric response are discussed. The polymer polarization behaviours a and $delta$ of five samples is closely related to segmental movements and carriers hopping behaviours, separately. The intensity of a relaxation strength ($Deltavarepsilon_{a}$) declines with the increase of sPP content, because the related coefficient (g) between PP molecular chains is reduced. The calculated energy $E_{tau}$ for $delta$ process is in proportion to the shallow traps level, because the shallow traps with a higher level increase the potential barriers of carriers hopping behaviors. The increase in temperature causes the dipole to undergo intense Brownian motion in the electric field, resulting in a decrease in $Deltavarepsilon_{a}$ with increasing temperature. The thermal motion of the charge increases the mobility of carriers in the PP and causes $Deltavarepsilon_{delta}$ to increasewith increasingtemperature.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"43 1","pages":"431-434"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86911218","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":"Effect of Insulating Oil on Space Charge Characteristics of Oil-impregnated Paper Under DC Voltage","authors":"Ganlin Mao, Shengtao Li, Shijun Li, Zhao Ge, Liuqing Yang, Liuhao Jiang","doi":"10.1109/ICD46958.2020.9341880","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341880","url":null,"abstract":"At present, the oil-paper insulation structure is mainly composed of traditional mineral oil and cellulose insulation paper. The hots pot of future research is to select better insulation oil to improve the overall insulation life of the system. Compared with traditional mineral insulation oil, gas to liquid(GTL) oil made from base oil refined by natural gas liquefaction technology by Fischer-Tropsch(FT) method are characterized by high oxidative stability and low sulfur content. In this paper, the space charge accumulation, distribution and attenuation characteristics of oil-impregnated paper composed of GTL oil and traditional mineral oil were studied. The space trap energy level and trap density distribution of two oil-impregnated papers were obtained according to isothermal decay current(IDC) method. The experimental results show that in the voltage-on stage, traditional mineral oil-impregnated paper is more prone to charge injection and the injection speed is faster. In the voltage-off stage, the traditional mineral oil-impregnated paper attenuates the charge faster, and the GTL oil-impregnated paper has more residual charge. Moreover, the trap level of GTL oil-impregnated paper is deeper than that of traditional mineral oil-impregnated paper.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"51 1","pages":"443-446"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75709243","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}
Amirhossein Mahtabani, I. Rytöluoto, R. Anyszka, Eetta Saarimäki, Xiaozhen He, K. Lahti, M. Paajanen, W. Dierkes, A. Blume
{"title":"Silica Functionalization: How Does it Affect Space Charge Accumulation in Nanodielectrics Under DC?","authors":"Amirhossein Mahtabani, I. Rytöluoto, R. Anyszka, Eetta Saarimäki, Xiaozhen He, K. Lahti, M. Paajanen, W. Dierkes, A. Blume","doi":"10.1109/ICD46958.2020.9341818","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341818","url":null,"abstract":"Functionalization of silica nanoparticles with polar aminosilane and its effect on space charge accumulation under high voltage direct current (DC) was studied in polypropylene (PP)/ Ethylene-Octene Copolymer (EOC) /silica nanodielectrics. The modification reaction conditions were varied in order to alter the deposited layer grafting density and morphology, and hence, the filler-polymer interfacial properties. The effect of this alteration was then studied on the space charge accumulation under a high DC field as one of the most important properties to tune for HVDC cable insulation systems. The chemical modification of the silica surface was first confirmed via Thermogravimetric Analysis (TGA) and Fourier Transform IR Spectroscopy (FTIR). Differential Scanning Calorimetry (DSC) was performed on the nanocomposites to study the effect of the nano-engineered interfacial areas on nucleation and crystal formation. The effect of the amine functional groups on the charge carrier trapping and transport in this insulation system was studied via Thermally Stimulated Depolarization Current (TSDC) method.It was argued that the amine functionality on the silica surface can induce deep trap states at the filler-polymer interfaces, and hinder further injection of the space charge. Under certain modification conditions, the aminosilane can form “island-like” structures on the silica surface. These islands can both facilitate nucleation, inducing transcrystallization at the filler-polymer interface, and further contribute to the induction of deep traps which result in reduction of space charge accumulation in the nanodielectric.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"11 1","pages":"281-284"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91148357","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":"Interface charge effect measurement in 2-μm-thick polypropylene sample under voltage with thermal method","authors":"Céline Corbrion, S. Holé","doi":"10.1109/ICD46958.2020.9342009","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9342009","url":null,"abstract":"A 2-$mu$m-thick polypropylene sample has been subjected to 10 kV/mm for 4 weeks. Thanks to surface temperature measurement along with heat pulse measurement, it is possible to detect the position at which the electric field varies inside the sample even without inverse convolution calculation.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"8 10 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89673281","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}
I. Rytöluoto, Eetta Saarimäki, J. Pelto, M. Paajanen, Xiaozhen He, R. Anyszka, Amirhossein Mahtabani, W. Dierkes, P. Seri, H. Naderiallaf, K. Lahti, Minna Niittymäki
{"title":"Feasibility of Mini-Scale Injection Molding for Resource-Efficient Screening of PP-Based Cable Insulation Nanocomposites","authors":"I. Rytöluoto, Eetta Saarimäki, J. Pelto, M. Paajanen, Xiaozhen He, R. Anyszka, Amirhossein Mahtabani, W. Dierkes, P. Seri, H. Naderiallaf, K. Lahti, Minna Niittymäki","doi":"10.1109/ICD46958.2020.9341820","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341820","url":null,"abstract":"This study presents a critical evaluation of the effect of two different sample manufacturing techniques on the morphological and dielectric properties of polypropylene (PP)-based nanocomposites, namely mini-scale injection molding (IM) vs. pilot-scale cast film extrusion. Polarized light microscopy revealed that the IM specimen morphology exhibited a layered “skin-core” type morphology, largely differing from the spherulitic morphology of the corresponding extruded cast films. Higher degree of crystallinity in the IM specimens was evidenced by calorimetric and X-ray diffraction methods. The processing-dependent morphological differences were found to affect the isothermal charging current (ICC) and thermally stimulated depolarization current (TSDC) characteristics due to differences in charge mobility and trapping, thus making direct comparison of IM and cast film specimens non-straightforward. Nevertheless, mini-scale injection molding can be seen as a resource-efficient sample manufacturing method for facilitating early-stage screening of the best-performing material candidates, given that the morphological features are carefully taken into account.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"13 1","pages":"209-212"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83358180","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}
M. Meissner, E. Matić, S. Schober, Martin Darmann, M. Mittelbach
{"title":"Monitored Migration of Additives from Thermally Upgraded Paper into Various Insulation Liquids","authors":"M. Meissner, E. Matić, S. Schober, Martin Darmann, M. Mittelbach","doi":"10.1109/ICD46958.2020.9341830","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341830","url":null,"abstract":"To determine the long-term persistence of stabilizing additives in thermally upgraded Kraft paper insulation material under operation conditions, the nitrogen migration from the solid material into the encircling insulation material was monitored as part of a large-scale ageing study. Therefore, thermally upgraded as well as normal Kraft paper, combined with pressboard, copper and sheet metal in representative amounts and ratios, was immersed in different types of insulation liquids (mineral oil, G-t-L oil, synthetic as well as natural ester). A continuous 56-day ageing experiment under oxygen-free conditions at elevated temperatures (130 and 150°C) was conducted, with a continuous sampling interval of 2 weeks. The nitrogen concentration of the embedding insulation liquids stayed constant for every insulation liquid aged with natural Kraft paper material, whereas a clear increase of nitrogen levels could be observed over time as soon as thermally upgraded Kraft paper was immersed into the insulation liquids. For prolonged ageing periods at 150°C the measured nitrogen levels in the insulation liquid could rise by as much as 120 ppm, corresponding to nearly 0.3% of dry insulation paper mass, indicating a significant loss of nitrogen-rich stabilizing agents into the corresponding insulation liquid just within weeks of ageing.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"144 1","pages":"649-652"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76806181","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":"Preliminary Development and Application of a Stress-Strength Model for Reliability Estimation of Aged LV Cables for Nuclear Power Plants","authors":"D. Fabiani, G. Mazzanti, S. V. Suraci, B. Diban","doi":"10.1109/ICD46958.2020.9341856","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341856","url":null,"abstract":"As a part of the H2020 EU Project called “TeaM Cables” - which has, among its aims, modelling reliability of Nuclear Power Plant (NPP) cables - the goal of this paper is to develop a model for the prediction of the residual reliability of Low Voltage (LV) cables for NPPs subjected to gamma radiation stress. The model estimates the probability that such cables withstand random stress overshoot in-service.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"122 1","pages":"37-40"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88688594","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}