Research Of Simulation And Analogy In The Environmental Impact Assessment Of Transmission Line

Along with the development of China's economy and sociality, the electricity requirement of every industry rises increasely. The government is building a lot of hydropower station, thermal power station and wind power station in whole country, including the three Gorges project which draws worldwide attention. Along with the construction of power projects, new construction and optimization of electricity net is building at the same time. Because of the technical improvement of electricity transmission and distribution, the capacity of electricity net is growing gradually, the length of transmission lines are lengthening, and the grade of voltage is advancing. It is advantage to electric power resource allocation, but the denser electrical network is brought more and more attention by citizen, especially in littoral developed region of east China, it is inevitable to Adjacent to adjoin, even stride over houses and schools when a transmission line builds, thereby a new way of contamination borns, it calls "Electromagnetism pollution".State Environmental Protection Administration of China issued HJ/T24-1998( for short) in November 1998, to reinforce the environmental supervise management to the project of electromagnetism radiation. According to , the environmental impact forecast and assessment of transmission line engineering is mainly used by simulating and analogizing to other circulated transmission line. There is no standard about simulation and analogy of transmission line to stipulate how to select analogy lines in China, thereby the phenomenon of selecting analogy line unstandardly has been appearing in the process of transmission line EIA. It finally leads to the result that the measurement values in Check and accept of transmission lines are very different from the forecast value in EIA reports (explain that with the example).Based on the theoretical calculation of the power-frequency electromagnetic field and radio interference intensity, this article integrates electromagnetic focast software which is programmed by Wuhan High voltage Research Institute, and analyzes the factor which influence the value and distribution of electromagnetic field, radio interference under transmission line, aiming to bring forward a more reasonable and unitive foundation to select analogy line, and frame measure to prevent electromagnetic pollution of transmission line efficiently. The research of this article is as follow:1. This article explain that the regulation of analogy line selection in < technical regulation> is not enough canonical and comprehensive.2. This article not only analyzes intrinsic factors which influence the value and distribution of electric field, magnetic induction and radio interference under transmission line, such as grade of voltage, current, height of lines, location order of line and distance of phases, number of circuit and its location order, section area of line and number of bundle conductors, shielding lines and so on. but also analyzes extrinsic factors such as another transmission lines, buildings and vegetation under or nearby the analogy line, and terren, geology and weather condition at lines' locus.3. This article pays more attention to research two aspects: on the one hand is the reinforcement and weakening effect of electromagnetism when multiline span parallelly, on other hand is the shield and aberrance effect of buildings to power frequence electric field under transmission line.According to repeating fieldwork measurement and theoretical forecast, the author summarizes eleven tips of experience about selection of analogy lines in EIA of transmission lines, and hopes those can bring references for other EIA of electromagnetism.