The Simulation And Calculation Of The Electromagnetic Environment For UHV AC Transmission Lines

As the rapid development of China’s economy and the continuous improvementof people’s living standards, the development of UHV transmission systems becomethe priority of our country electric power industry. When the voltage level isdeveloped to UHV stage, the electromagnetic field strength around transmissionlines will increase, causing electromagnetic compatibility or electrical safety issues,the animals, plants and humans may also be affected. In order to meet therequirements of electromagnetic environmental control and optimization of griddesign, it is necessary to study the electromagnetic environment problems of UHVtransmission lines. At present, the research of the UHV transmission lineelectromagnetic environment problems is still in its infancy, needing the methodsbased on the electromagnetic field calculation model and research results to assessthe electromagnetic environment of China’s UHV transmission lines. In this context,the charge simulation method is used in this paper to research the electromagneticenvironment and the distribution of the frequency electromagnetic field aroundUHV AC transmission lines and the influencing factors, aimed at providing areference for our country’s future optimization design of the UHV transmissionlines.Firstly, we take the three-phase AC to1000Kv horizontally aligned single-loopUHV transmission lines for example, to introduce the calculation steps of thefrequency electric field around UHV AC transmission lines in detail, and then we setup a simulation modelling on the two-dimensional space. Analysising the simulationresults, we can get the transverse distribution of the UHV AC transmission lines at1.5meters minimum sag from the ground. Secondly, we use the frequency electricfield calculation model to analysis and summary the influencing factors on thefrequency electric field. The result shows that the main factors include the distancebetween the phase conductors, the number of split wires and the wires height fromthe ground, but influence cause by the impact of the radius of the sub-wires is small.Therefore we can consider the four influencing factors in the future design of UHVtransmission lines, thereby reducing the frequency electric field under the transmission lines. Thirdy, on the basis of simplification of UHV transmission lines,the calculation steps and model building of frequency magnetic field around thethree-phase1000Kv UHV AC transmission line of the two-dimensional space isintroduced, simulating to get the lateral distribution of power frequency magneticfields at1.5meters from the ground of1000Kv UHV transmission lines. Studyingthe factors affecting frequency magnetic field by the model. The simulation resultsshow that reducing the distance between each phase transmission lines or the currentin power lines, increasing the distance between wire and the ground can make thefrequency magnetic field at the bottom of the transmission lines decreases.