الفهرس 
INDUCED VOLTAGES MITIGATION TECHNIQUES AND CATHODIC PROTECTION SYSTEM
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Abstract
Electromagnetic fields produced by high voltage overhead transmission lines are still
considered an important subject in several research areas due to their harmful effects
on human health and environment. These Electromagnetic fields produces high level
of induced voltages at nearly steel pipelines. This problem appeared obviously at the
Natural Gas Transmission Network at the last 10 years where the pipelines share the
same routes with high voltage transmission lines. The induced voltages at Gerga /
Aswan pipeline and Taba / sharm pipeline reached to very dangerous levels and some
technicians have been strongly shocked and exposed to death. Environmental Impact
Assessment studies (EIA) are very important to be carried out before establishing of
power line projects to evaluate the electromagnetic effects on the project environment
especially on nearby pipelines as well as its social and health impacts. This thesis
presents a comprehensive study to the induced voltages along a section of Taba /
sharm Gas pipeline, 500 mm2 cross section area and 208 km length which lies in the
same right of way with an actual sophisticated overhead transmission line tower
carrying four circuits (two 220 kV circuits and two 66 kV circuits) under different
loading conditions. Three different mitigation methods were applied along the
pipeline under normal and abnormal conditions (balanced, severe unbalanced loading
and during different short circuit conditions). Mitigation techniques using cancellation
wire, gradient control wires and using polarization cells were investigated. Results
obtained showed that polarization cells give more efficient values for reduction of
induced voltages using the suggested technique. A model was developed using the
Alternative Transients Program (ATP) to simulate the whole system with the different
mitigation methods. The effect of transmission lines maintenance scenarios on the
induced voltage levels on the gas pipeline was also investigated. An economic impact
assessment technique was developed to determine the appropriate and economic
method.