Study On Electromagnetic Environment Of Ultra-High Voltage AC Transmission Lines

It is estimated that power requirement in our country tends to increase in the following15-20 years.To satisfy the electricity supply, hydropower and thermal power will be built as well as ultra-high voltage transmission lines used for power supply channel. In this paper, electromagnetic environment characteristics models of UHV power transmission project are elaborated depended on construction methods. Calcultion model of parallel transmission lines and cross transmission lines are established to analyze factors that can influence electromagnetic environment of transmission lines. Mesanwhile, conclusions of corona cage test of radio interference and audible noise are introduced. Main works are as follows:1. Demonstration on electromagnetic environment of UHV AC transmission lines. Four electromagnetic environment parameters - power frequency electric field, power frequency magnetic field, radio interference and audible noise models of UHV AC transmission project are constructed. Calculation results which are deduced by these models are compared with test results. Factors which can influence the electromagnetic environment of UHV AC transmission lines are presened and methods which can relieve the electromagnetic environment problems are illustrated.2. Models of parallel UHV AC transmission lines are set up in this paper. To fulfill the UHV project design, various factors which could affect the distribution of electromagnetic environment parameters are discussed. Methods which can relieve the electromagnetic environment problems of parallel UHV AC transmission lines are illustrated.3. To evaluate the electromagnetic environment level of cross UHV AC transmission lines, three-dimensional transmission line models are set up in this paper which are uesd to execute the cross region of UHV transmission line and EHV transmission lines.Various factors which could affect the distribution of electromagnetic environment parameters are discussed. Methods which can relieve the electromagnetic environment problems of cross UHV AC transmission lines are illustrated.4. Corona cages test of radio interference and audible noise is carried on according to different structures, different structures bunbles. Comparison test on stranded wires and patten wires on basis of UHV corona cage are completed, conclusion on radio interference and audible noise experiment are summarized. Radio interference test are completed in climate laboratory with modible corona cage to summarize altitude calibration from 0m to 4000m.