Thestrengthofthepowerfrequencyelectricintensityandmagneticfieldofthe500-kVdoublecircuittransmissionlineswascalculatedbyusingtheequivalentchargemethodandtheAmpere'sLaw,andtheenvironmentalimpactfactorsofthefieldswereevaluated.Byoptimizingthephasesequence,thefrequencyelectricintensityandmagneticfieldstrengthcanbereduced.Withinadistanceof25mfromthecenterofthetransmissionline,thepowerfrequencyelectricintensityandmagneticfieldstrengthfalloffsharplywiththedistanceincrease.Finally,thebestphasesequenceandtheminimumgroundclearanceofthetransmissionlineswereobtainedtomeettherequirementsoftheleastimpactonenvionment.
