Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Electrical Power and Machines

In this thesis, a systematic semi-heuristic method (genetic algorithm) is employed to produce optimal reduction in overhead power lines{u2019} magnetic field. Passive shielding is applied on different power lines with two different phase arrangements and different configurations. The research also explores the effectiveness of the series capacitive compensation on the mitigation performance. Studying the mitigation effectiveness is not only at a certain point such as ROW edge, but everywhere around the line. For this purpose, zone-based mitigation is presented by modifying the objective function to be based on a specific geographic domain, at which magnetic field is desired to be minimal. To obtain the feasibility of magnetic field mitigation for a power line, the cost of passive shielding is modeled. The cost model contains four basic elements, namely, cost of shield conductors, cost of power losses, cost of support structures, and cost of capacitive compensation. Genetic algorithm is used to handle passive shielding with its cost as a multi-objective problem. The problem is made up of two main objective functions: maximization of the magnetic field reduction and minimization of the cost of mitigation. Pareto optimal set which gives the relation between optimal cost and reduction in magnetic field is presented. A new index which measures the feasibility and effectiveness of mitigation of a line is defined and formulated. This index is called 2Feasibility Index3

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