Research On Electromagnetic Environment Of Transmission Lines

With the development of electric power industry, the voltage rank of transmission lines is continuously raised. People are paying increasing attention to the influence of electromagnetic environment of transmission lines accordingly.The electromagnetic parameter of power transmission include:electrical field, magnetic field, radio inference (RI) and audible noise (AN). This paper makes detail research on the four electromagnetic parameter. This paper introduces theoretical calculation method and their standards for each electromagnetic environment parameter.For the normal electric field, including surface electric field and the field distribution under the transmission lines, two different methods: Markt-Megele and successive images are induced to calculate the electric field and the differerce of the two methods is presented. This paper analyzes the influence of sub-conductor radius, number of sub-conductors, line height to ground and conductor inter-spacing on surface electric field and the electric field under transmission lines and emphasizes on the mitigation method of the electric field. The calculation of power frequency magnetic field under transmission lines is also introduced.The total electric field and ion current density under transmission lines is detailed introduced. This paper discusses the impacts of double-circuit DC experimental line with different pole arrangements on the total electric field on ground level and does some calculations and anaysis.This paper introduces two different methods of experiential formula and generation function for calculating RI of transmission lines. Also, it presentes the method of AN.Based on the anaylsis of theoretical calculation method, calculation software of electromagnetic environment of transmission lines is developed with VC++ which can calculation transmission lines of different circuits, different configuration of tower and different conductor disposal.