Comparison of Corona Performance under Foul Weather Conditions

摘要

With the construction of extra-high voltage and ultra-high voltage overhead transmission lines in China,the studies of corona problems of stranded conductor are significant when considering environmental standards and economic efficiency.This paper presents laboratory experiments results carried out on an ac energized stranded conductor subjected to foul weather conditions,including simulated glaze icing,rime icing and corresponding rain conditions,and the experiments were conducted in a corona cage located in an artificial climate chamber.We adopt ultraviolet imager,oscilloscope and digital sound level meter to measure corona inception voltage,corona loss and audible noise separately.The presented work analysis the ice morphology of different ice category formed on the conductor.Through the recorded ultraviolet photon video,the ultraviolet photon number varied with applied voltage under foul weather conditions was extracted to obtain the corona inception voltage.From the biggest to the lowest,the sequence of corona inception voltage is rain condition,rime ice covered conductor and glaze ice covered conductor under same precipitation rate.With regard to corona loss,the order is upside down.Curve fitting found that a power function relation exist between corona loss and the stranded conductor surface gradient under foul weather conditions.A linear relationship exist between the A-weighted audible noise and applied electric field intensity of rime ice covered conductor and rain condition,and the audible noise of rime ice covered conductor is bigger.In terms of glaze ice covered conductor,the audible noise grow exponentially at the corona inception period,and changed to linearly then.The presented results could provide references to the design of ac overhead transmission lines under foul weather conditions.