MI
M.A. Imhof
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High- and medium-voltage systems operating in extreme industrial environments require optimized dielectric insulation to ensure safety and equipment reliability. While traditional research focuses on room-temperature standards or pressurized gases like SF6, establishing guidelines for unsealed equipment demands a deeper understanding of atmospheric air under severe thermal stress.
To address this gap, this thesis evaluates the dielectric breakdown strength of air at elevated temperatures using a dedicated high-temperature test setup. Designed to simulate open, unsealed operational environments, the setup reaches temperatures up to 800 degrees Celsius and measures precise breakdown voltages up to 70 kV peak for inter-electrode gap distances up to 8 cm. Experimental results showed that across the tested temperature ranges, dielectric breakdown was predominantly density-related. Furthermore, combining elevated temperatures with variations in electrode shape and gap distance mostly did not produce any distinctive additional effects, proving that geometric field stress profiles remain largely invariant under thermal scaling. Finally, a finite element modelling methodology in COMSOL Multiphysics has been described that evaluates localized electric field and thermal distributions. Based on the electrode geometries and empirical breakdown measurements, estimations are made on localized peak electric field strengths at discharge initiation. Simulations show that COMSOL accurately calculates electric field strengths, proving that combining numerical modelling with high-temperature experimental findings provides a highly useful and reliable approach for determining the breakdown strength of high-voltage configurations in extreme-temperature environments. ...
To address this gap, this thesis evaluates the dielectric breakdown strength of air at elevated temperatures using a dedicated high-temperature test setup. Designed to simulate open, unsealed operational environments, the setup reaches temperatures up to 800 degrees Celsius and measures precise breakdown voltages up to 70 kV peak for inter-electrode gap distances up to 8 cm. Experimental results showed that across the tested temperature ranges, dielectric breakdown was predominantly density-related. Furthermore, combining elevated temperatures with variations in electrode shape and gap distance mostly did not produce any distinctive additional effects, proving that geometric field stress profiles remain largely invariant under thermal scaling. Finally, a finite element modelling methodology in COMSOL Multiphysics has been described that evaluates localized electric field and thermal distributions. Based on the electrode geometries and empirical breakdown measurements, estimations are made on localized peak electric field strengths at discharge initiation. Simulations show that COMSOL accurately calculates electric field strengths, proving that combining numerical modelling with high-temperature experimental findings provides a highly useful and reliable approach for determining the breakdown strength of high-voltage configurations in extreme-temperature environments. ...
High- and medium-voltage systems operating in extreme industrial environments require optimized dielectric insulation to ensure safety and equipment reliability. While traditional research focuses on room-temperature standards or pressurized gases like SF6, establishing guidelines for unsealed equipment demands a deeper understanding of atmospheric air under severe thermal stress.
To address this gap, this thesis evaluates the dielectric breakdown strength of air at elevated temperatures using a dedicated high-temperature test setup. Designed to simulate open, unsealed operational environments, the setup reaches temperatures up to 800 degrees Celsius and measures precise breakdown voltages up to 70 kV peak for inter-electrode gap distances up to 8 cm. Experimental results showed that across the tested temperature ranges, dielectric breakdown was predominantly density-related. Furthermore, combining elevated temperatures with variations in electrode shape and gap distance mostly did not produce any distinctive additional effects, proving that geometric field stress profiles remain largely invariant under thermal scaling. Finally, a finite element modelling methodology in COMSOL Multiphysics has been described that evaluates localized electric field and thermal distributions. Based on the electrode geometries and empirical breakdown measurements, estimations are made on localized peak electric field strengths at discharge initiation. Simulations show that COMSOL accurately calculates electric field strengths, proving that combining numerical modelling with high-temperature experimental findings provides a highly useful and reliable approach for determining the breakdown strength of high-voltage configurations in extreme-temperature environments.
To address this gap, this thesis evaluates the dielectric breakdown strength of air at elevated temperatures using a dedicated high-temperature test setup. Designed to simulate open, unsealed operational environments, the setup reaches temperatures up to 800 degrees Celsius and measures precise breakdown voltages up to 70 kV peak for inter-electrode gap distances up to 8 cm. Experimental results showed that across the tested temperature ranges, dielectric breakdown was predominantly density-related. Furthermore, combining elevated temperatures with variations in electrode shape and gap distance mostly did not produce any distinctive additional effects, proving that geometric field stress profiles remain largely invariant under thermal scaling. Finally, a finite element modelling methodology in COMSOL Multiphysics has been described that evaluates localized electric field and thermal distributions. Based on the electrode geometries and empirical breakdown measurements, estimations are made on localized peak electric field strengths at discharge initiation. Simulations show that COMSOL accurately calculates electric field strengths, proving that combining numerical modelling with high-temperature experimental findings provides a highly useful and reliable approach for determining the breakdown strength of high-voltage configurations in extreme-temperature environments.
Bachelor thesis
(2024)
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M.A. Imhof, T.A. ter Horst, F.L. Walterbos, M. Ghaffarian Niasar, J. Dong, M. Popov, Amir Heidary
In this thesis, "Design & Reliability Assessment of AEA Propulsion Grid", the development of a reliable and efficient propulsion grid for All-Electric Aircraft (AEA) is investigated to reduce aviation emissions. Our primary objective is to design a lightweight Power Management and Distribution (PMAD) system that meets stringent reliability standards. By analyzing materials, heat transfer, and grid design, we propose optimized grid topologies that balance weight and reliability. The findings emphasize the importance of redundancy and suggest further research into subcomponent failure rates, control aspects, and real-world testing to enhance system reliability and performance. This thesis provides valuable insights into the future of electric aviation, highlighting the necessity for continued investigation and practical application to ensure ultra-reliable electric propulsion systems and make zero-emission flight a reality.
...
In this thesis, "Design & Reliability Assessment of AEA Propulsion Grid", the development of a reliable and efficient propulsion grid for All-Electric Aircraft (AEA) is investigated to reduce aviation emissions. Our primary objective is to design a lightweight Power Management and Distribution (PMAD) system that meets stringent reliability standards. By analyzing materials, heat transfer, and grid design, we propose optimized grid topologies that balance weight and reliability. The findings emphasize the importance of redundancy and suggest further research into subcomponent failure rates, control aspects, and real-world testing to enhance system reliability and performance. This thesis provides valuable insights into the future of electric aviation, highlighting the necessity for continued investigation and practical application to ensure ultra-reliable electric propulsion systems and make zero-emission flight a reality.