A Mitigation Model For The Influence Of Power Frequency Electromagnetic Field On Sensitive Environmental Points Of Transmission Lines

Cross high tension line has obtained strong growth momentum in recent decades.and their efficient power transmission has been accompanied by the power frequency electromagnetic field(EMF).The EMF has gathered increased public attention because scientists have identified it as an indoor environmental pollutant or toxin.In recent years,much progress has been made in the area of EMF;research has been started to find effective unconventional solutions to these problems.Because simulation of a non-uniform electric field plays an important role in the understanding of EMF,numerical methods such as the charge simulation method(CSM),the charge density method,the Monte-Carlo method(MCM),the finite difference method(FDM)?and integral equation methods have been used to simulate non-uniform EMF.Several concepts for field reduction have been proposed;general classification of the different approaches to magnetic field exposure reduction is as follows:modification of public activity patterns,design of electrical facilities and equipment for lower electric and magnetic fields,and shielding.Methods for reducing electromagnetic fields involve the following:distance,conductor configuration,phase arrangement,split-phase,current reduction,shielding or active cancellation,and undergrounding.The power frequency electromagnetic field intensity in an environmentally sensitive site is calculated through vertically space crossed AC transmission lines model.Then,the distributions of power frequency electromagnetic field intensity are analyzed along three directions across the sensitive plot.The heights of a 1000 kV and 110 kV high-voltage transmission lines and the phase sequence are selected as factors,and different levels are applied on them,generating the final full factor experimental design table which obtained the significant factors on the power frequency electromagnetic field intensity.Finally,the best high-voltage transmission line arrangements is found based on vibrant effective values calculated from the intensity at different phase sequences.The height of the 1000 kV high-voltage transmission line plays a decisive role in the power frequency electromagnetic field intensity in the environmentally sensitive site(the increasing height significantly decreased the intensity),while the height of the 110 kV has less effect.When the intensities in different phase sequences are superposed on the vector,the optimal high-voltage transmission line arrangements are 41m(1000 kV)-8m(110 kV)and 41(1000kV)-15m(110kV),causing the weakest environmental electromagnetic influence in selected sensitive site.