Transmission lines magnetic field management feasibility under cost constraints

The scientific issues concerning the relationship between electromagnetic fields and adverse health effects are very complex and difficult to interpret. Epidemiologic data are limited and many results to date are based on small studies with methodological limitations. As a result, there are large differences in the way that these studies are evaluated and interpreted, both within the scientific community in general, and among scientists and Agencies within the federal governments and utilities bodies. This paper contains studies of electromagnetic fields around 138 kV and 230-kV transmission lines and the practical solutions to the field reduction predicted by computer simulation. Chosen were transmission lines 1 and 2 of 138 kV and 230 kV where the data was collected near areas that may be of concern to human occupants. Line 1 consists of two transmission lines of three phase lines. Data was collected with EMDEX II gauss meter approved by EPRI. Analysis of initial measurements was done and compared with simulated data using Southern California Edison's FIELDS program. Feasibility of three new rephasing configurations are evaluated based on the magnitude of magnetic field reduction, the economics, and the practicality. At the edge of the right-of-way, simulation shows a 40 to 80% reduction in magnetic fields. This study demonstrates that rephasing, where applicable, is an effective method to manage magnetic field distribution within, at the edge of, and outside of the transmission line right-of-way. Advantages of each method are presented in this paper with a detail configuration of each simulation, including cost analysis of implementation of such designs.