Study On Measurement Method Of Electromagnetic Environment Caused By High Voltage Power Lines And Substations

With the development of electric power industry and the expanding of many towns,220kV transmission lines have been becoming the main grid of most cities. Inevitably,500kV transmission lines which located in the suburbs enter the towns, and the highvoltage electric substations along with the high voltage transmission lines emerged inthe residential area. The electromagnetic pollution to the neighborhood residents, whichare generated by the transmission and transform equipments, has brought the attentionof many departments. At the same time, the residents with horror emotion to theelectromagnetic pollution reject the construction of electric power. It brings muchtrouble for our country's economic construction. In order to research the transmissionand transform equipments'electromagnetic pollution, large amount field measure isnecessary.The issue concentrated on the measuring method of high voltage transmission linesand substation's electromagnetic environment and combined the mathematic methodand field measure. First, the charge simulation method was discussed and its basic ideasand application steps were concluded. Then, the two-dimension mathematic models oftransmission lines with one circuit, double circuits and multiple circuits on one towerand three-dimension mathematic models of single bus, double buses, double buses withbypass bus and crossing buses in the substation were established respectively. All of themodels are implemented on matlab with charge simulation method. The distribution ofeach-type transmission lines on matlab was simulated and the correction of theprograms was checked. The distribution of the field density was calculated with the realproject models datum. According to the results, the field measuring spot was arranged.The fro-disposal software designed with excel was used to compare the measurementresults and the theoretical results, analyze the errors and process data. Simultaneous themeasured electromagnetic environment was evaluated according to the present nationalstandard on the electromagnetic environment.Combined with large amount measurement results, the issue analyzed theelectromagnetic fields of each-frequency of 500kV transmission line with one circuit,220kV transmission line with double circuits, proposed the width of safe-aisle. Andanalyzed the electromagnetic fields of each-frequency of 220kV and 550kV electricsubstations, generalized the source of the radiation. Concluded the electromagneticfields distribution of each-type transmission lines and electric substations, proposed theguard method, which provided the reference for the design of power systems and theenvironmentalists. The author measured the electromagnetic fields distribution of the transmissionlines, which have trees and buildings under the lines. The results showed that the treesand building have the ability of shield, especially for the power frequency electric fields,100k~3GHz RF electric fields, 100k~30MHz and 30MHz~1GHz RF magnetic fields,degrade 1~2 orders. But the influence on power frequency magnetic fields is limited.The issue also analyzed this phenomenon. The issue compared the high voltage AC overhead transmission lines'RF interferelimit value of home and abroad and present the modify recommendations on deficiencyof our national standards.