Thesis
On transient electric field and ionisation phenomena in gas and at dielectric interfaces under impulsive energisation
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2024
- Thesis identifier
- T17088
- Person Identifier (Local)
- 202057098
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- Ever since the first creation of pulsed energy sources during the mid-to-late 20th century, the principles of pulsed power have been successfully applied to a multitude of applications. The realisation of pulsed power spans multiple scales and across multiple domains: from state-of-theart facilities for high-energy-density research, aimed at probing the fundamental constituents of matter; to innovative techniques for tumour treatment and drug delivery through plasma medicine; or for the improvement of crop yields in plasma-assisted agriculture. From the extent of its impact alone, pulsed power technology should be considered nothing short of a technological marvel. However, ever-increasing requirements have introduced unprecedented levels of transient electrical stress on insulating system components. Progress in both fundamental and applied principles of dielectric and breakdown phenomena under fast-rising impulse action is, therefore, instrumental to ensure the continued success of pulsed power science and technology. The present work addresses several poorly-understood aspects of impulsive breakdown phenomena in gas and within composite solid-solid and solid-gas insulator topologies. The application of a diverse set of methodologies has progressed towards a greater understanding of impulsive breakdown processes across its various stages: from the initial development of transient electric fields in composite materials, to complete impulsive flashover. Key issues addressed from extensive modelling work pertain to the time-dependency of electric field and ionisation processes, which focused on their effects on the overall breakdown evolution and on the properties of generated plasmas. Novel analytical descriptions of transient field behaviour, avalanche development, and streamer propagation—under impulse and overstressed conditions—have lent insight into: the coupling between dielectric relaxation and impulse waveshape in composite materials; provided new scaling relationships relating to streamer breakdown modes; and have introduced closedform expressions for estimating overstressed breakdown strength and time. The experimental characterisation of impulsive flashover behaviour across five polymeric materials: PVC, Delrin, Ultem, Torlon, and Perspex, in solid-solid arrangements, has provided critical knowledge relating to the role of sharp surface features on the reduction of interfacial breakdown strength. Impulsive flashover tests across solid-gas configurations indicated that short-wavelength surface features provide a greater contribution to the enhancement of the flashover strength compared to longwavelength undulations. Altogether, results and conclusions of this work have provided a solid foundation on which composite insulating technology for pulsed applications can be built.
- Advisor / supervisor
- Timoshkin, Igor
- Resource Type
- Note
- Previously held under moratorium 20th May 2024 from until 22nd May 2025.
- DOI
关系
项目
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PDF of Thesis T17088 | 2024-10-10 | 公开 | 下载 |