特高压输电线分裂导线表面电场及起晕分析

Analysis on Electric Field Intensity and Onset Corona Zone on the Split Conductor Surface of UHV Transmission Line

输电导线起晕的重要判别条件是导线表面电场强度是否达到临界值。为研究分裂导线表面电晕分布情况,根据单相八分裂导线起晕电压试验值,先运用模拟电荷法计算了1 000 kV特高压八分裂子导线表面每个匹配点的电场强度值,然后与用经验公式计算出的临界场强对比,找出子导线表面的电晕分布区域,并计算出了该域内的起晕点个数、起晕角度、占导线表面比等数据以及子导线半径、导线高度对起晕分布的影响。分析计算表明:每根子导线在表面有限范围内起晕,且占整个导线表面积的30%～40%;对地高度越高子导线表面起晕范围越大,子导线半径对起晕范围也有一定影响。通过研究工作,期望对分析导线的电晕损耗等问题提供有力的帮助。

The onset corona criterion of transmission line is that the electric field intensity on conductor surface exceeds a certain critical value. In this paper, in order to study distribution of corona zones on split conductor surface, the charge simulation method is employed to calculate the electric field intensity of each matching point on the surface of a 1 000 kV UHV single-phase 8-split conductor according to the relative experimental value of onset corona voltage. The onset corona zone distribution on the conductor surface is obtained by comparing the calculated electric field intensity values with the ones from empirical formula. Furthermore, the number of onset corona points, the angle of onset corona zone, as well as the influences of conductor＇s radius and height on the distribution of onset corona zones, are achieved. The results show that onset corona zones account for 30%-40% of whole conductor surface; the higher the conductor height, the larger the onset corona zone; the radius of split conductor also influences the area of onset corona zone. This study may facilitate the analysis of corona loss in transmission line.