Radio Interference Due To Corona Discharge On UHV AC Transmission Lines

With the rapid development of our country's economy, our demands for electric power grow continuously, and the grid of our country can not meet the increasing needs of the electric power for the situation of the energy resources and loading distribution. The best way of resolving the contradiction is to build UHV projects. The probability of corona discharge is extremely high because the voltage of UHV transmission lines is higher than EHV lines. At the same time, as the voltage turn into UHV level, radio interference (RI) has become the critical factor which determines the power transmission line's structure and parameters. Therefore, it is very important to settle the radio interference problems. This paper focuses mainly on the radio interference problems of UHV AC transmission lines.This paper starts with the analysis of pulsed corona discharge, holds that excitation function method gives the best answer, then compares the five commonly used excitation function, showing that the one of High Voltage Transmission Research Center (HVTRC) on wet conditions (WETC) gives the smallest error. For the computation of the radio interference caused by the corona of AC UHV transmission line, a simplified model and a list of partly and completely decoupled ones have been presented and proved brief, fast and of low error. Also, it can meet the engineering requirements. At last, this paper compares the relationship between the radio interference and the parameters such as the number of the bundled conductor, the radius of the subconductor, the conductor height and phase sequence and presents that increasing the number of the bundled conductor, the radius of the subconductor and the conductor height can reduce the radio interference. In addition, same phase sequence transmission lines give lower radio interference than different phase sequence ones.