Impact of electromagnetic field management on the design of 500 kV transmission lines

The electric and magnetic field (EMF) issue has become an area of increasing public concern. There is a heightened sensitivity among the public to the siting and construction of new, and the upgrading of existing electric facilities. There is substantial scientific uncertainty and no widespread agreement among scientists as to how the presently available information regarding the possible health effects of electric and magnetic fields should be interpreted. Animal and epidemiological studies are inconclusive on whether exposure to EMF can cause human health effects. Minimizing electric and magnetic field strength is one of the many factors to consider in the planning and design of a transmission system. It must be considered along with other issues such as safety, environmental concerns, reliability, insulation and electrical clearance requirements, aesthetics, cost, operations and maintenance. The field reduction techniques described in this paper are proven methods, and the new techniques are explained thoroughly and incorporated taking into consideration the percentage field reduction, maintenance, and operational reliability. The constraints for electric and magnetic field reduction by line compaction and optimization of bundles configuration are studied taking into consideration the international accepted minimum clearances. The importance of the phase configuration and sequence is also demonstrated. Novel-field cancellation methods are presented. Systematic comparisons of the effectiveness of different line designs in reducing the EMF are included.