Master of Dental Surgery / This work was digitised and made available on open access by the University of Sydney, Faculty of Dentistry and Sydney eScholarship . It may only be used for the purposes of research and study. Where possible, the Faculty will try to notify the author of this work. If you have any inquiries or issues regarding this work being made available please contact the Sydney eScholarship Repository Coordinator - ses@library.usyd.edu.au

This thesis deals with the online measurement of partial discharge (PD) in a high-voltage direct current (HVDC) converter station. The HVDC station is a particularly challenging environment for PD measurement due to elevated interference levels caused from the switching of the thyristor-controlled converters. Online PD measurements are performed on two specimens, one is an HVDC converter transformer and the other an HVDC converter wall bushing. The measurements are performed in the high-frequency range between 400-kHz to 30-MHz with a modern PD measurement instrument that employs a signal processing technique known as feature extraction. The results demonstrate that online measurement of PD in an HVDC station environment is possible. Input filtering and feature extraction methods can mitigate the converter interference. The feature extraction methods can also isolate individual PD phenomena, and allow for the trending and monitoring of insulation degradation. Furthermore, specific strategies for PD measurement and analysis are developed.

This thesis deals with the online measurement of partial discharge (PD) in a high-voltage direct current (HVDC) converter station. The HVDC station is a particularly challenging environment for PD measurement due to elevated interference levels caused from the switching of the thyristor-controlled converters. Online PD measurements are performed on two specimens, one is an HVDC converter transformer and the other an HVDC converter wall bushing. The measurements are performed in the high-frequency range between 400-kHz to 30-MHz with a modern PD measurement instrument that employs a signal processing technique known as feature extraction. The results demonstrate that online measurement of PD in an HVDC station environment is possible. Input filtering and feature extraction methods can mitigate the converter interference. The feature extraction methods can also isolate individual PD phenomena, and allow for the trending and monitoring of insulation degradation. Furthermore, specific strategies for PD measurement and analysis are developed.

Master of Dental Surgery / This work was digitised and made available on open access by the University of Sydney, Faculty of Dentistry and Sydney eScholarship . It may only be used for the purposes of research and study. Where possible, the Faculty will try to notify the author of this work. If you have any inquiries or issues regarding this work being made available please contact the Sydney eScholarship Repository Coordinator - ses@library.usyd.edu.au

Thesis.

Thesis (M.S.)--University of Michigan, 1983.

Thesis (M.S.)--University of Michigan, 1983.

We introduce geometrically partial comodules over coalgebras in monoidal categories, as an alternative notion to the notion of partial action and coaction of Hopf algebras introduced by Caenepeel and Janssen. We show that our new notion suits better if one wants to describe phenomena of partial actions in algebraic geometry. We show that under mild conditions, the category of geometric partial comodules is complete and cocomplete and the category of partial comodules over a Hopf algebra is lax monoidal. We develop a Hopf-Galois theory for geometric partial coactions to illustrate that our new notion might be a useful additional tool in Hopf algebra theory. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

published_or_final_version / Dentistry / Master / Master of Dental Surgery

published_or_final_version / Dentistry / Master / Master of Dental Surgery