الفهرس 
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Abstract
Over the past three decades great interest has developed around the world in the environmental and biological aspects of electromagnetic fields produced by overhead transmission lines (OHTL). During the last few years the interest has shifted from electric to magnetic fields, which cause potential hazards to any metal part parallel or in close proximity to power lines: such as, railways, communication cables, and Pipelines which cause deeply pitting corrosion for the metal, shock for any worker, and economical problems for government The objective of this thesis is to compute the ground level magnetic field under normal and abnormal conditions of the Egyptian 500-kV single circuit transmission line between Cairo and El-kourimate, in three dimension (3-D) coordinates by using 3-D integration technique. Abnormal conditions include symmetric fault, un-symmetric faults, direct stroke, and indirect stroke on the OHTL as illustrated. Where, ATP software is used to simulate the OHTL under all faulty and lightning conditions. Varying time magnetic fields under normal and abnormal conditions, at certain points that located at mid-span, tower height and right-of-way (ROW), are also computed to indicate the worst case The induced voltages in the buried gas pipeline due to inductive and conductive coupling in normal and abnormal conditions are calculated. The effects of homogeneous and non-homogeneous soil resistivities on the calculated values of the induced voltage in the buried gas pipeline under normal operation conditions of the OHTL is investigated. Where, the non-homogeneous soil resistivities are simulated with a three layers with different thicknesses and different soil resistivities. The effects of the parameters of the three layers soil (soil resistivity and depth of the first soil layer) as well as the effect of the power line current and the pipeline leakage resistance on the induced voltages along the pipeline and under normal conditions are illustrated. Also, the actual soil resistivities are measured in the four different seasons and are used in the calculation of the induced voltage to investigate the effect of the four different seasons Mitigation system to minimize impact of power line on pipeline at normal and abnormal conditions is implemented. Also, under normal conditions, the pipeline inductive induced voltages after applying an earthing system are measured and compared with the calculated values. A case study of the inductive and conductive interference between the pipeline and the power line is illustrated.