|dc.contributor.author||Meyer, Hans Kristian Hygen||
|dc.description.abstract||Dielectric-air insulation systems can reduce the carbon footprint of medium voltage switchgear, as they can replace SF6-insulated systems. Such replacement is, however, not easy, as the devices are typically compact and complex, with strongly inhomogeneous electric fields. Withstand voltages are typically estimated with empirical models for discharge formation and propagation. Any dielectric surface can change the conditions for such evaluations, especially as the surfaces accumulate charge.
The aim of this work was to study the influence of dielectric surfaces on breakdown in non-uniform atmospheric air gaps. Short (≤ 120 mm) rod-plane gaps with a polycarbonate barrier were used throughout. The development of pre-breakdown and breakdown processes were clarified with high-speed imaging, photomultipliers and fast current measurements. It was shown that breakdown around the 50% level is governed by leader-like discharges rather than streamers.
Surface potential measurements demonstrated that streamers charge dielectric barriers in a way that is predictable with variations of saturation charge boundary conditions (zero or constant normal electric field at the air side of the interface). Such predictions allow utilization of beneficial surface charging effects in switchgear design.
Moreover, it was shown that drift-diffusion models can be used to simulate important discharge behaviour in dielectric-air insulation systems. Such models are computationally heavy, but can become useful for dielectric design of high voltage components as computer capabilities are improving. It was shown that 2D planar streamers charge dielectric surfaces to saturation within tens of ns. The streamer-exposed surface is charged mainly by drifting ions from the streamer channel, but also by electron emission processes from the dielectric surface.
The thesis is presented as a collection of seven peer-reviewed articles published in journals and conference proceedings, together with an overview document. The results presented in this thesis contribute to a better understanding on how dielectric barriers influence electrical breakdown in air.||
|dc.relation.ispartofseries||Doctoral theses at NTNU;2019:106||
Hygen Meyer, Hans Kristian; Mauseth, Frank; Pedersen, Per Atle; Ekeberg, Jonas.
Streamer Propagation in Rod-Plane Air Gaps with a Dielectric Barrier. I: 2016 Annual Conference on Electric Insulation and Dielectric Phenomena - CEIDP 2016. IEEE conference proceedings 2016 ISBN 978-1-5090-4654-6. s. 1037-1040
Hygen Meyer, Hans Kristian; Mauseth, Frank; Pedersen, Per Atle; Husøy, Martine; Ekeberg, Jonas.
Breakdown in short rod-plane air gaps under positive lightning impulse stress. Proceedings of the Nordic Insulation Symposium 2017 ;Volum 25. (CC-BY)
Hygen Meyer, Hans Kristian; Mauseth, Frank; Husøy, Martine; Pedersen, Per Atle.
Surface charging of dielectric barriers under positive lightning impulse stress. I: 2017 Annual Conference on Electric Insulation and Dielectric Phenomena - CEIDP 2017. IEEE 2017 ISBN 978-1-5386-1194-4. s. 802-806
Meyer, Hans Kristian Hygen; Mauseth, Frank; Pedersen, Per Atle; Ekeberg, Jonas.
Breakdown mechanisms of rod-plane air gaps with a dielectric barrier subject to lightning impulse stress. IEEE transactions on dielectrics and electrical insulation 2018 ;Volum 25.(3) s. 1121-1127
Meyer, Hans Kristian Hygen; Blaszczyk, Andreas; Schueller, Michael; Mauseth, Frank; Pedersen, Per Atle.
Surface charging of dielectric barriers in short rod-plane air gaps – experiments and simulations. I: 2018 IEEE International Conference on High Voltage Engineering and Application - ICHVE 2018. IEEE conference proceedings 2018 ISBN 978-1-5386-5086-8.
Blaszczyk, Andreas; Christen, Thomas; Meyer, Hans Kristian; Schueller, Michael.
Surface Charging Formulations for Engineering
Applications. Validation by Experiments and
Scientific Computing in Electrical Engineering : SCEE 2018,
Meyer, Hans Kristian Hygen; Mauseth, Frank; Marskar, Robert; Pedersen, Per Atle; Blaszczyk, Andreas.
Streamer and surface charge dynamics in non-uniform air gaps with a dielectric barrier. IEEE transactions on dielectrics and electrical insulation 2019 ;Volum 26.(4) s. 1163-1171
|dc.title||Dielectric barriers under lightning impulse stress: Breakdown and discharge-dielectric interaction in short non-uniform air gaps||nb_NO
|dc.subject.nsi||VDP::Technology: 500::Electrotechnical disciplines: 540::Electrical power engineering: 542||nb_NO