2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena最新文献

{"title":"Electrochemical capacitances of carbon powder treated with dielectric barrier discharge","authors":"D. Tashima, R. Hirakawa, T. Sakoda, M. Otsubo","doi":"10.1109/CEIDP.2011.6232608","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232608","url":null,"abstract":"Powdery activated carbons were treated using dielectric barrier discharge. In comparison with low pressure plasma, dielectric barrier discharge operated at atmospheric pressure can dramatically reduce the processing time and does not need vacuum equipment. In this study, electrochemical properties of Electric Double Layer Capacitors (EDLCs) made of oxygen plasma-treated powdery activated carbons were examined through Cyclic Voltammetry (CV), cole-cole plots and X-ray Photoelectron Spectroscopy (XPS). It was found that the specific capacitance of EDLCs could be improved by using oxygen plasma-treated activated carbon powder. A comparison of EDLCs using carbon powder treated for 15 S versus untreated EDLCs shows a 20% increase in specific capacitance, which indicates that the plasma treatment for EDLC's carbon powder are suitable for high-energy applications. The enhancement of capacitance was mainly attributed to an increase in the BET surface area of the carbon powder and the creation of phenolic hydroxyl groups on the surface of the carbon. The phenolic hydroxyl groups caused oxidation-reduction reactions, because oxygen was included in the operation gas. In addition, the phenolic hydroxyl groups improved the penetration of the electrolyte solution.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"157 1","pages":"109-112"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80481722","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":"DC breakdown characteristic on LDPE/MgO nanocomposite influenced by DC prestress","authors":"Y. Murakami, S. Imazawa, M. Kurimoto, M. Nagao, Y. Inoue, C. Reddy, Y. Murata","doi":"10.1109/CEIDP.2011.6232664","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232664","url":null,"abstract":"To understand the space charge formation of low-density polyethylene (LDPE)/nano-sized magnesium oxide (MgO) nanocomposite materials, the breakdown strength and the space charge formation influenced by DC prestress were investigated. DC breakdown strength (Fb) of LDPE decreased with increase of DC prestress. A packet-like charge was observed under DC pre-stress. When the applied field turned to a ramp field from a constant field, the space charge decreased with incase of applied field. A packet-like charge, enhancing the local filed in bulk, might bring to many dissociated carrier. Therefore, it was considered that DC-Fb of LDPE decreased with increase of DC pre-stress field because bulk of LDPE became more conductive condition by generation of a packet like charge. On the other hand, DC-Fb of LDPE/MgO nanocomoposite increased with increase of DC pre-stress field. In case of MgO content of 1 phr, a packet-like charge was not observed under DC pre-stress field and a little positive space charge was formed in the bulk The positive charge decrease gradually with increase of ramp filed. When the MgO content was 5 phr, little space charge was observed under DC constant or ramp fields. The MgO nanofiller may trap the space charge, and the homo space charge in the vicinity of electrodes suppressed the carrier injection.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"2 1","pages":"334-337"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84209247","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 properties of colossal permittivity materials: An update","authors":"C. Cheballah, Z. Valdez-Nava, L. Laudebat, T. Lebey, P. Bidan, S. Diaham, S. Guillemet-Fritsch","doi":"10.1109/CEIDP.2011.6232754","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232754","url":null,"abstract":"During the last ten years, a lot of interest has been devoted to the so-called colossal dielectric constant (CDC) material. The first materials exhibiting this behavior were the perovskyte-based ceramics based on the CaCu3Ti4O12 composition (CCTO). Relative dielectric permittivity can attain values up to (or even larger than) 105. Nevertheless, their losses are still high, the lower values ranging 10%, in a narrow frequency range, thus limiting their applications. Most work on this type of materials aims to reduce these losses and widen their useful frequency range. On the other hand, the underlying physical mechanisms responsible of the CDC are still under study. While the analysis of broadband impedance spectroscopy measurements leads most of the authors to propose an interfacial polarization mechanisms (at the electrodes or at internal barriers), there is a limited number of complementary electrical characterization techniques, for the moment, they comfort the proposed interfacial polarization mechanisms. In the present work, several characterization techniques like I-V, Sawyer-Tower (ST) measurements, and time-domain polarization are used to characterize these materials. One of our main results is the observation of a non-symmetrical response of these materials related to the direction of the polarization. These results are observed for both macroscopic level on bulk polycrystalline material and within individual grains of the same samples. These results do not fit current accepted models for polarization for CDC materials.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"44 1","pages":"706-709"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85423788","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":"Experienced gained from 132 kV EPDM composite insulators in a coastal environment","authors":"S. Rowland, A. Tzimas, M. Queen","doi":"10.1109/CEIDP.2011.6232668","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232668","url":null,"abstract":"A number of EPDM insulators have been taken from service on a 132 kV system after eight years in a harsh environment and have been examined. Fortuitously three different insulator designs are available and compared. Two of the insulators were installed in a vertical orientation and one in the horizontal. The insulators are characterized visually, electrically and for hydrophobicity. They have been found to be fit for purpose, but show extensive superficial ageing, in particular blackening, of the polymer surfaces. No severe degradation has been identified. In particular there is evidence of discharge activity around the prominent longitudinal mould lines on all the insulators.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"47 1","pages":"353-356"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84145468","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 epoxy coating on particle movement in SF6/N2 gas insulated Busduct","authors":"M. Rao, J. Amarnath","doi":"10.1109/CEIDP.2011.6232634","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232634","url":null,"abstract":"Due to an exceptional combination of physical and chemical properties, SF6 has become the only insulating gas used in gas insulated electric power transmission and distribution equipment. However, the fact that SF6 is one of the strongest man made greenhouse gases has promised a search for substitute gases with lower or no environmental impact. Thus, it is needed to develop the alternative dielectric gas or gas mixtures having better insulating characteristics and no greenhouse effect. The main issue concerning the practical use of such mixtures is their behavior in the presence of metallic particle contamination. In this paper particle movement is determined in epoxy coated gas insulated Busduct with SF6 and N2 gas mixtures as insulating medium. In the gas mixture, conducting particle material considered for study are Aluminium, Copper and Silver. The results have been analyzed and presented.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"15 1","pages":"211-214"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73278888","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 spacers regarding endwinding design of large rotating electrical machines","authors":"M. Lerchbacher, D. Imamović, G. Lemesch, F. Ramsauer, M. Muhr","doi":"10.1109/CEIDP.2011.6232713","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232713","url":null,"abstract":"Today large rotating electrical machines are supposed to operate at optimised conditions and the highest degree of efficiency. Often the overall size of a generator has a significant impact on transport restrictions as well as cost efficiency. A key market requirement is a combination of high efficiency, very compact design and cost efficiency of acquisition and operation. One of the main elements to meet these demands is an optimised endwinding design of high voltage stator windings. A compact design requires among other things minimised distances between adjacent insulated bars or coils in the endwinding which consequently leads to a continuously increasing stress (thermal, electric) on spacers located in the endwinding area. Therefore the influence of spacers on the corona behaviour of air and hydrogen is the main focus for high voltage insulation stator winding design, especially in relation to the endwinding. The end winding area has to be designed in such a way that no corona activity can occur during the operation of the generator. On the one hand the distances between adjacent bars or coils should be as small as possible while on the other hand any corona activity should be avoided. In this paper the results of experimental investigations in air and hydrogen for electrode-spacer configurations are presented. Metallic electrodes were covered with standard insulation material which is used in generators. The test arrangement allowed changing the gas pressure whereas the gap distance between the electrodes was defined by the used spacer. To determine the corona inception and extinction voltage we used a conventional PD measurement system according to the IEC 60270 standard. Additionally for verification of our results we used acoustical (ultrasonic microphone) and optical (UV camera) PD detection systems. The purpose of this study was to determine the influence of spacers on partial discharge behaviour (corona inception and extinction voltage) of insulating systems used in endwinding areas. On the basis of gas physics and our previous studies we expected a decreasing corona inception and extinction voltage by increasing pressure and gap distance for spacer configurations. This is in comparison with configurations without spacers. In our experiments we were able to corroborate this. However, to formulate a conclusive relationship between the influences of spacers on PD inception level, further work needs to be done.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"20 1","pages":"538-541"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81255677","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":"UHF detection of PD in power transformers: The influence of disturbances","authors":"A. Cavallini, C. G. A. Ramos, G. Montanari, H. Saad, M. Tozzi","doi":"10.1109/CEIDP.2011.6232688","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232688","url":null,"abstract":"Ultra-high frequency partial discharge sensors are often deemed to be immune to disturbance, i.e., signals generated by partial discharge sources outside the transformer itself. In this paper, the above claim is investigated resorting to both computer simulations and experimental tests. The results indicate that corona from power lines in proximity of a transformer, or surface discharges on the surface of bushings can provide signals that are comparable with those generated by PD sources. These findings suggest that care must be taken when evaluating data coming from this type of sensors, as false alarms can be obtained.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"35 1","pages":"436-439"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82965133","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":"Mechanical properties of polypropylene nano-composites: An investigation about the correlation with space charge measurements","authors":"F. Guastavino, E. Torello, G. Coletti, Z. Vuluga, D. Panaitescu, S. Iancu","doi":"10.1109/CEIDP.2011.6232748","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232748","url":null,"abstract":"Sets of nanostructured PP films have been prepared using various techniques and procedures. They have been subjected to mechanical tests (stress-strain curves and to impact strength tests) and have been subjected to electrical space charge tests by means of Pulse ElectroAcoustic techniques. Suitable analysis about the relevant correlations were performed and did produce results useful from the quality control point of view and interesting as regards the production process tuning.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"253 1","pages":"680-683"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86711523","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":"Three-dimensional tree simulation considering interfaces with various angles of inclination to electric force line","authors":"Y. Ju, H. Uehara, K. Kudo","doi":"10.1109/CEIDP.2011.6232772","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232772","url":null,"abstract":"We previously carried out a three-dimensional (3D) tree simulation of a composite system with an interface perpendicular or parallel to the electric force line based on a dielectric breakdown model considering the growth probability. It was found that an interface perpendicular to the electric force line exhibits a positive barrier effect and that an interface parallel to the electric force line exhibits a negative barrier effect. In this study, we carried out a 3D tree simulation that considers interfaces having various angles of inclination to the electric force line, for which different barrier effects were observed. Furthermore, the simulated tree with interfaces having various angles of inclination either creeps on the barrier, penetrates the barrier or develops along the edge of the barrier.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"2 1","pages":"780-783"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90914797","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":"Comparison between RF and electrical signals from the partial discharge activity of twisted pair cables at reduced pressures","authors":"M. Given, R. Mason, M. Judd, P. McGlone, I. Timoshkin, M. Wilson","doi":"10.1109/CEIDP.2011.6232707","DOIUrl":"https://doi.org/10.1109/CEIDP.2011.6232707","url":null,"abstract":"A pressure-controlled test facility has been set up that allows the PD behaviour of polymer insulated twisted pair samples exposed to 50 Hz AC voltages in the range of 0 to 10 kV to be characterised. Resulting PD activity is quantified using the methods defined in IEC standard 60270 and by using a simple monopole antenna to detect the RF signals excited inside the pressure vessel by the discharges. This paper gives the results of preliminary tests performed on samples of wire insulated with Ethylenetetraflourethylene, Silicon Rubber and Polyvinylchloride in the pressure range between 103 and 105 Pa in atmospheric air. The dependence of PD inception voltage on the environmental pressure is reported. Changes in the behaviour of the PD activity; the correlations between the RF and electrical measurements and the frequency components of the RF signals as the applied voltage and pressure are varied are characterised and discussed.","PeriodicalId":6317,"journal":{"name":"2011 Annual Report Conference on Electrical Insulation and Dielectric Phenomena","volume":"33 1","pages":"514-517"},"PeriodicalIF":0.0,"publicationDate":"2011-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90970264","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}