Optimum Configuration for Higher Transmission Ratings for Proposed Hybrid Overhead Power Lines in Egypt Electric Utility

Because of the growth of residential areas and the power industry, the needs for electrical energy, and voltage levels have increased in Egypt's Electric Utility. Converting the existing alternating current lines to direct current for higher transmission ratings is one of the optimum solutions. One way of averting new power lines construction caused by a deficiency of appropriate right-of-way is to change overhead power lines from AC to DC. Four hybrid line configurations are suggested. The first configuration is double-circuit working with AC voltage of 500 kV with a bipolar circuit of DC voltage of ±500 kV without modifications with the transmission system, while the second, third, and fourth configurations are double-circuit working with 500 kV AC with a bipolar circuit of a voltage of ±500 kV with required conductor and/or tower modification. Therefore, the power frequency electric field calculations under the high voltage overhead transmission line have caused wide public concern. In this paper, the charge simulation method is utilized to explain the two-dimensional (2-D) electric fields underneath the high voltage overhead transmission lines.