IPMHVC June 2012, San Diego, CA, US
Jouya Jadidian is a Ph.D. student at the Massachusetts Institute of Technology (MIT), Cambridge, MA. Before joining the Electrical Engineering and Computer Science Department of MIT, he worked on magnetic flux compression generators, vacuum arcs and resonance inductors at the High Voltage and Pulsed Power Research Institute, University of Tehran where he received the B.Sc. and M.Sc. degrees in 2006 and 2008, respectively. His current research interests include breakdown phenomena in vacuum, gases and liquids, plasma processing, pulsed power technology, electrohydrodynamics and magnetohydrodynamics. He received 2010 IEEE NPSS scholarship award for his work on helical FCGs. He has also received the 2011-2012 IEEE DEIS Fellowship award for his PhD thesis project, “Streamer-Surface Flashover Breakdown in Liquid Immersed Dielectric Systems.” This thesis project has developed a multicarrier charge transport physical model of streamer initiation, propagation and branching in transformer oil based insulation systems.
In the paper presented at IPMHVC 2012, surface flashover formation and expansion mechanisms on the surfaces of different solid dielectrics immersed in transformer oil have been numerically analysed. Streamers emanating from a positive or negative needle electrode tend to initiate surface flashovers, if an immersed solid dielectric permittivity is higher than the transformer oil permittivity and/or the solid dielectric interfacial surface cuts the path of the streamer. Perpendicular interface of the solid immersed dielectric impedes the breakdown by deflecting the streamer along the solid interface as shown in the figure. The parallel dielectric interface, however, assists the breakdown by regulating the surface flashover velocity to an approximately constant value (~ 10 km/s).
Mr. Jadidian and his advisor, Prof. Markus Zahn, hope that this research helps engineers develop new and more reliable insulating systems with higher breakdown strengths.
CEIDP October 2012, Montreal, Canada
Markus Krause was born in 1978 in Naumburg, Germany. From the University of Applied Sciences Jena, Germany, he received his Diploma in Physics Engineering in 2007. Currently he is a Ph.D. student at the Johannes Kepler University in Linz, Austria. He is working in the Department of Soft Matter Physics (http://www.somap.jku.at/ ). For his Ph.D. research he is working with ferroelectric materials and polymers to build new sensor applications for industry.
Awarded Proposal: Large Area Piezoelectric Impact Sensors
Printed electronics is an active area of research in academia and industry, with many potential applications in diverse markets. The use of highly insulating materials and the employment of dielectric phenomena based on the piezo- and pyroelectric effect in polar insulators promise large area sensors useful in human machine interfaces, biomedical sensing, but also
in impact sensing, for example as protection sensor to save pedestrians or humans working in sensitive areas. In my PhD project I have worked within an interdisciplinary team of researchers on the development of printed piezoelectric sensors (http://www.3plast-sensor.eu/ ). I have developed the electrical poling process of these printed sensors, and showed their potential application in a Toy-Car-Demonstrator. The fully flexible, large-area ferroelectric (PVDF-TrFE) sensors were printed by a screen-printing process. They are mounted on the bumper of a car to avoid crashes by the detection of human body radiation. In the case the crash is no more avoidable, we are able to measure the impact strength and the position of the collision, to activate safety systems. The evaluated data are stored and can be transferred to a computer for further investigation. A presentation of this project is given in a short video sequence demonstrating the function of the application and is located here: http://www.youtube.com/watch?v=_wcaYDxi5_8 .
Roger Schurch was born in Temuco, Chile. He received his electrical engineering degree in 2006 from the Santa Maria Technical University, Valparaiso, Chile. He was a high voltage equipment analyst at Transelec Transmission Company in Santiago, Chile, from 2006 to 2008. He joined the Department of Electrical Engineering, Santa Maria Technical University, as a Junior Lecturer in 2008, where he also carried out dielectric tests for mining and utility companies. Since 2011, he has been a Ph.D. student at the School of Electrical and Electronic Engineering, The University of Manchester, UK. His research project involves the study of electrical trees and partial discharges in polymeric insulation.
Awarded proposal: A Novel Approach for Imaging of Electrical Trees
Electrical treeing is a long term electrical breakdown process in polymers, and therefore, can be a precursor of power equipment failure. In order to get a better understanding of the phenomenon a considerable effort has been put in imaging and morphological characterisation of electrical trees. However, most of the imaging research has been carried out from a two dimensional perspective. This work is focused on the three dimensional (3-D) imaging of electrical trees using X-ray computed tomography, a non-destructive imaging technique. Electrical trees in polymeric materials were scanned using X-ray tomography with phase contrast enhancement. A 3-D virtual replica of the electrical tree can be created, with a spatial resolution of a few microns, through which the electrical tree can be sliced and internally inspected (http://youtu.be/dviPFw2C1wE ). Electrical treeing characteristics such as length, area, volume and number of branches can be extracted from the model. The future research considers more advanced tomography techniques in the nano-scale dimensions.
Zepu Wang (S’09) was born in Chengdu, China in 1986. He received the B.Sc. degree from Shanghai Jiao Tong University (SJTU), Shanghai, China in 2008. He is currently a graduate student pursuing his Ph.D. degree at the Rensselaer Polytechnic Institute, Troy, New York. His research interests include studying the effect of filler geometry on various dielectric properties of polymer nanocomposites and developing new composite materials with value of industrial applications. He is a member of IEEE Dielectrics and Electrical Insulation Society (DEIS) and Materials Research Society (MRS).
Awarded Proposal: Graphene Oxide Filled Nanocomposite – A New Field Grading Material
Graphene oxide filled silicone rubber nanocomposites were found to possess a large nonlinear coefficient of electrical conductivity, smaller low field conductivity than that of the neat polymer and an increase in the dielectric constant over that of the polymer matrix with a very small increase in the dielectric loss. These electrical and dielectric properties make graphene oxide/silicone nanocomposites an excellent candidate for a field grading material. Possible mechanisms that lead to the observed dielectric behavior are discussed in this work. The effect of sample size and processing on the material properties is also discussed.
Edited by Antonios Tzimas
IEEE DEIS GOLD members Chair