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

In recent years, the development of UHV is determined by the facts including the increasing demand for power supply, the imbalanced distribution of energy resources and the current situation of electricity industry. However, the electromagnetic environment problems caused by power transmission lines have become one of key restraint factors for UHV development with its increasingly importance for selection of line parameter and enhanced awareness of public environmental protection. Therefore, it is of great significance to stimulate the UHV construction by research on electromagnetic environment problems caused by UHV AC transmission lines.The electromagnetic parameter of power transmission lines include electrical field, magnetic field, radio interference and audible noise. The power frequency electromagnetic fields are analyzed in this paper by finite element method with auxiliary of Ansoft Maxwell, some discussion for radio interference(RI) and audible noise(AN) is added, the main work can be summerized as followed.Firstly, the simulation analysis was carried out to investigate the influencial factors of frequency electromagnetic field, according to which the measures to reduce electromagnetic field by changing line parameters are summarized. A measurement method of human body induction under lines is also recommended and the feasibility of the proposed method is validated by the experimental results.In this dissertation, Shielding effect is studied from four aspects of shield wire, including its horizontal position, vertical height, number and radius, so as to hunt for the optimal position of the shield wire. With different shielding targets, analysis of shielding effects exerted by different erection positions of shield wire on electric field is conducted, which paves way for rational position selection of shield wires.Finally, as to corona, the generation mechanism, the calculation of electric field intensity on wire surface and the corona inception field are introduced. In addition, RI and AN are expounded from three aspects of calculation, limit value and corresponding restrain measures.