Study On Prediction And Calculation Of Electromagnetic Environment Of UHV Transmission Lines

In order to meet the needs of national economic development, China State Grid Corp proposed the strategic target of constructing ultra high voltage (UHV) power grid. In recent years, many institutions have done a lot of research on relevant technology of UHV power grid, including research on the aspect of electromagnetic environment of UHV transmission lines. So far our country has no industry standards or national standards associated with the limit or calculation method of the UHV transmission lines’electromagnetic radiation. With the planning, construction or operation of China’s several UHV AC and DC transmission lines, related research work must be pressed on. In this context, this paper studies the calculation method of three electromagnetic environment parameters of UHV AC transmission line and builds the corresponding prediction models, which include power frequency electric field, power frequency magnetic field and radio interference. This paper also introduces the design of corresponding prediction software.On the aspect of power frequency electric field, this paper introduces the basic method of calculating the power frequency electric field of AC transmission lines using the charge simulation method (CSM). The key content of this part are influence of corona discharge on ground level power frequency electric field underneath UHV AC transmission lines and the establishment of3-D power frequency electric field calculation model of HV transmission line near buildings with an improvement of simulation charge setting on the surface of building. Finally this part analyzes some influencing factors on power frequency electric field, such as the wire height, phase space, wire arrangement and so on.On the aspect of power frequency magnetic field, this paper introduces the basic method of calculating the power frequency magnetic field of AC transmission lines using Ampere’s circulation theorem and then analyzes several main influencing factors.On the aspect of radio interference, this paper mainly studies on the calculation process of excitation function method. Based on the analysis of the happening mechanism of corona, this part explains how to work out the phase current of each wire using phase-mode transformation, and then work out the radio interference field strength at field point.Based on the above study, this paper works out the simulating procedures of the above three electromagnetic environment parameters of AC transmission lines of different loops using MATLAB. UHV AC transmission line electromagnetic environment prediction software is made using the mixed programming of VC and MATLAB.