Melting process of multi-icicles and its flashover performance

Typical icing morphology, including bridged and non-bridged icicles, affects the electrical strength of energized transmission line insulators under melting conditions. This paper is concerned with melting process of multi-icicles and its flashover performance. Two different models with the same gap length was tested and compared. It was found that partial discharge in bridged icicle occurred from the air gap inside to cut off the icicle and elongated forward to penetrate through the whole icicle. This penetration required more energy, leading to increased flashover voltage compared to partially bridged icicles. Experiments and modeling show that non-bridged multi-icicles are more vulnerable to flashover.