Electrical characteristics of an energised conductor under various weather conditions

When a transmission line is subjected to adverse weather conditions,rain drops or ice can be formed on its surface,leading to discharge phenomena known as corona.The corona discharge increases corona loss,leakage conductance,and capacitance,the latter two effects facilitating harmonic conditions and power quality degradation.This study investigates the electrical characteristics of an energised conductor under rain,rime,and glaze ice conditions.The experiments were carried out in a climate room using a corona cage.It was found that the leakage conductance of a corona-cage configuration was at its highest under glaze ice condition and at its lowest under rime condition for the same background surface electric field.With the presence of icicles,the change in capacitance under glaze ice accretion was complex.From the experimental results,it can be concluded that the corona-cage configuration is mainly characterised by its capacitive nature before the corona onset.When the corona discharge occurs,the corona cage exhibits a resistive–capacitive nature.With the increase of applied voltage,the configuration becomes more resistive.