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Corona ions emitted from overhead AC high voltage powerlines have been investigated and their effect on atmospheric aerosol charge assessed for potential health effects evaluation. To quantify the influence of the powerlines on the environment, ground-level measurements have been made upwind and downwind of ten lines in South West England.

This thesis describes the investigation into the use of visual servoing to keep an unmanned aerial vehicle (UA V) aligned with overhead electricity distribution lines, in order to use it to inspect them. The UAV would carry cameras in order to capture video footage showing the line's condition. Firstly, the current methods of inspecting overhead electricity distribution lines, line-walking and manned helicopters, are described. A review of visual servoing and the relevant tracking methods is presented. Then a mathematical model of a ducted-fan UAV is developed. Analysis of the image geometry is performed to show how movements of the UAV affect the positions that the overhead lines appear in the images from the UAV's camera. This analysis shows that it should be possible to estimate the UAV's position relative to the lines if two cameras, one pointing forward and one pointing backwards, are used. The design and construction of a laboratory test rig to perform experiments is described. Then the image processing method, based on the Hough transform, used to extract the overhead lines from the image is described followed by the development of a tracker, which makes use of fuzzy logic and a Kalman filter, to track the overhead lines from frame to frame. Experiments are performed to see how well the UAV is able to follow the lines using the laboratory test rig. Finally, conclusions are drawn as to how well the system works as well as suggestions for the future direction of the project.

Thesis (D. Tech. Electrical engineering) --Vaal University of Technology / A comprehensive study upon "Non-conventional methods for energy extraction from the high voltage transmission lines" was addressed in this thesis. As defined in this study, a non-conventional method to extract energy is one that does not touch the conductors of the line. The theoretical framework which originated in the Maxwell's equations was presented as a base for discussion of all the methods and the conditions for the extraction to be possible. This study presents various methods such as capacitive and inductive to extract energy from high voltage alternating current transmission lines (HVAC). Although in theory, for high voltage direct current transmission lines (HVDC), the conditions for extraction are not matched, there remain some methods that could still attract interest. The centre point of this thesis is the new power application of the Rogowski coil. This method is analysed in full extent starting from theoretical modelling, computer simulations, design of the actual Rogowski coil and power electronics associated with it, and experimental results on a reduced scale model. In doing this, strong mathematical tools and computer software such as Matlab 6, Quick Field and MathCAD were used. At the end of this thesis, some conclusions are presented together with new ideas for further research in the field.