Electric Field Mitigation Near Over Head Power Lines Using Voltage Unbalance

Abstract

A lot of people have to live near power lines, and there is strong evidence that electric fields around power lines may cause cancer as well as many other symptoms that humans can directly observe, such as poor short-term memory, chronic fatigue, depression, nausea, and rashes. Hence, it is necessary to mitigate these fields to acceptable values to protect such groups. There are already many conventional compensation techniques in electric field mitigation may be useful in areas where the space is available however in residence with high civil density other techniques should be introduced. In the present paper, the self-compensation using voltage unbalance will be introduced. The main concept of the research is that the electric field resulting from three-phase voltages is negligible as the separations among phases are too small. However, in Overhead Transmission Lines the separations among conductors are determined based on the breakdown strength of air and cannot be changed widely. On the other hand, this concept could be applied electrically not mechanically in overhead power lines by controlling the three-phase voltages to make it as if it were located as near as possible to each other, resulting in a lower electric field. Genetic Algorithm (GA) is used to find the desired voltage unbalance achieving the electric field as minimum as possible in the residence area. The proposed algorithm is applied to 11 kV line and the results show that the electric field is reduced to about 82% under the safe limit, which is considered a very good percentage compared to other techniques.