Research On Influence Of Shielding Line On The Electromagnetic Environment Of Transmission Lines And Power Extraction

With the increasing voltage level of power grid,the influence of electromagnetic environment of transmission lines have been one of the main restricted factors to line construction.Along the extra-high voltage(EHV)AC transmission lines,there are a lot of remote rural areas with low power consuming.It means expensive equipment investment,such as EHV transformer with conventional power supplements method.In this paper,the influence on the power frequency electric field and radio interference of EHV transmission lines are discussed.The schema to improve the electromagnetic environment and extract energy using shielding line is proposed to improve the stability and economy of power system.The main research contents are as follows:(1)According to the theory of multi-conductor transmission lines,the parameter matrix of EHV transmission lines is calculated.According to the theory of uniform transmission line,voltage distribution along the transmission line is analyzed.(2)Equivalent charge method is used to analyze the power frequency electric field of EHV transmission lines above ground 1.5m.The influence of the vertical and horizontal position、the radius、the numbers and the bundled forms of shielding lines on the power frequency electric field is discussed.The using of bundled shielding lines is proposed to reduce the power frequency electric field strength.(3)The effect of monitoring spot’s position on the radio interference strength of EHV transmission lines with terminal transformer station is analyzed based on excitation function method.And the influence of different bundled forms of shielding lines on radio interference strength is analyzed.(4)In this paper,the power extraction system using shielding lines is proposed and designed.The induced voltage of shielding line is simulated.The influence of the length、the height、the radius and the bundled forms of shielding lines on the power extraction system is analyzed.The influence on efficiency of the extracting energy with different bundled forms of shielding lines and the length of shielding lines is studied.