In this seminar I will introduce the basics of the electrical discharges (plasma) in non-polar liquids and liquid/solid interfaces and their importance in specific applications such as high-powered transformers, capacitors, cables etc. The precursor mechanism of breakdown in these liquid and liquid/solid insulating systems are usually call streamers and their characteristics vary significantly with the nature of the liquid, voltage, pressure, electrode configuration, etc. In the first part of this seminar I will introduce the state of the art and classification of the streamers and their main physical characteristics. The second part of the seminar is dedicated to the theoretical understanding of the streamers and the importance of the gas/liquid interface formation during their inception and propagation. The last and fourth part of the seminar is dedicated to the measurement techniques and detection and the future work for the analysis of the phenomena. Note that the future analysis and study of the streamers involves several side research areas such as signal processing, fluid and electro-fluid dynamics methods, etc. thus further effort and research need to be performed in these areas to improve the understanding of the phenomena.
Dr. David Ariza in currently (2019) working as EMC specialist at ABB AB – FACTS in Västerås, Sweden. He is responsible for the analysis of the EMC performance of the ABB FACTS systems in the connected grid. As ABB FACTS are built using advanced power electronics based upon the latest thyristor and IGBT technology, new EMC procedures and recommendations need to be developed in order to guarantee the good EMC performance of the systems under high power switching emissions. Thus, the work is in relation to high frequency designs, high power radio interference and electromagnetic compatibility.
In 2018 Dr. David Ariza joined Inmotion Technology in Stockholm, Sweden, to contribute to the design of the electronics of the future generation of vehicle motor controllers ACH inverters for electric busses and trucks. Dr. David Ariza was responsible for the characterization and testing of the product (ACH Controller) under critical conditions of temperature and humidity.
Dr. David Ariza received his Ph.D. in 2017 at the Royal Institute of Technology KTH at the School of Electrical Engineering in Stockholm, Sweden. His Ph.D research project was funded by ABB AB Corporate Research Västerås, Sweden, through the Swedish Centre for Smart Grids and Energy Storage SweGRIDS and the EIT InnoEnergy Materials Platform. His research was intended to improve the insulating systems of high voltage transformers based on cellulose and non-polar dielectric liquids. Dr. David Ariza was responsible for the design and construction of a reactor to research the initiation and propagation of plasma (electrical discharges) in liquids under controlled conditions, do experiments and the scientific analysis. In 2016 Dr. David Ariza did a visiting research at the Leibniz Institute for Plasma Science and Technology INP Greifswald, Germany, in order to carry out specific experiments with the reactor, in cooperation with the experts at the institute, to improve the understanding of the electrical discharges at liquids/solid interfaces. Dr. David Arizas research was awarded for best poster at the KTH Energy Platform at the Energy dialogue 2016 in Stockholm Sweden.
During the early time of his career Dr. David Ariza received his B.Sc. and M.Sc. degrees from the National University of Colombia, Bogotá in 2010 and 2012. As part of the Electromagnetic Research Group of the National University of Colombia Dr. David Ariza was leading a research project that designed and constructed a system to generate power from atmospheric electricity using atmospheric discharges during thunderstorm activity. Due to his outstanding research, Dr. David Ariza was granted a master thesis with honours. Additionally, the international community of the respective topic awarded Dr. David Ariza with a Diploma for young scientists for a high-quality presentation of a paper and notable contributions to the field of lightning research and lightning protection at the International Conference on Lightning Protection ICLP 2012. As part of the EMC – UNC research group Dr. David Ariza was also involved in three other projects: the design and construction of a high-power generator for high voltage and EMC testing, the design and assembling of high power impulse and microwave radiating parabolic antenna and the design and constructions of a switching oscillator (jammer) for high voltage pulsed radiation.