Analysis Of3-Dimension Electromagnetic Field For Quadruple-circuit Transmission Line With110kV/220kV Dual Voltage On The Same Tower And Optimization Of Phase Sequence Arrangement

Since the21st century, China’s rapid economic growth, the urban scaleexpands unceasingly, the electricity load has increased dramatically, the originaltransmission line is not able to meet the needs of the people production andliving. To solve this contradiction, the rapid development of electric powerconstruction has become an important factor to promote the growth of oureconomy. As urban scale expansion has led to the transmission corridor resourcestense increasingly. In order to save the resources of the corridor and electricpower’s construction costs, the erection of transmission lines on the same towergets the favour of power grid gradually. The quadruple-circuit transmission linewith220/110kV on the same tower, which is widely used in the economicdeveloped area and built in residential area, but the electromagnetic environmentis complex relatively under the quadruple-circuit transmission line with dualvoltage on the same tower, in order to ensure the surrounding of security, anaccurate evaluation of the electromagnetic field is of great importance under thetransmissin line.In this paper, based on the charge simulation method, establishing themathematical model of electric field for high voltage transmission line,considering the effects of sag, which for the electric field calculation of thesmaller span transmission line is accurate on the open field. Combining withMatlab, we simulate to the engineering example and obtaine the distributionregularity of electric field for power frequency near the ground, and theestablished mathematical model considering the ground wire to the influence of electromagnetic field, greatly improve the accuracy of the electromagnetic fieldanalysis. Actual situation of overhead transmission lines is larger sag, to improvethe precision of the calculation. thus catenary model is used, based on whichestablish the mathematical model the electric field for power frequency, andcombined with the moment method is used to solve the programming. Throughthe simulation of the example, summarizes the distribution of the electric fieldfor power frequency near the ground under the model, with three dimensionaldistribution of the electric field for power frequency and the distribution of theelectric field along the length of transmission line direction is different. The samefactory frequency magnetic field on the simulation analysis of transmission linemodel for three dimensional distribution of magnetic field.Through numerical simulation analysis of the quadruple-circuit transmissionline with220/110kV on the same tower, three dimensional distribution and lawsof electromagnetic field and laws with in a span, three dimensional distributioncan reflect the electric field, at the same time the change rule of the horizontaland vertical within a span;Analyzed the design conditions, including the radius ofchild’s wire, the number of split conductor, the horizontal spacingof the phaseconductors, the minimum height with overhead transmission line to the groundand the influence of the distribution of electromagnetic field, puts forwardcorresponding measures and conclusions, combined with the design conditionsfactors and studied meteorological conditions factors to the impact of the level ofthe electromagnetic field, and the solutions are discussed. For different phasesequence arrange, use simulation calculation to electromagnetic field ofquadruple-circuit transmission line with220/110kV dual voltage on the sametower, through the simulation analysis, to determine a better phase sequence.According to the circuit caused by the phase sequence is arranged to producezero sequence impedance of three-phase unbalanced theory study, thusoptimizing the phase sequence, improve the electromagnetic environment underthe line.