Withstand voltage performance of outer-rib type suspension insulators subjected to ice accretion under DC voltage application

Artificial icicle was built up on the outer-rib and DC-Fog type suspension insulator strings, and withstand voltage tests were carried out. In case of the outer-rib type insulator, some air gaps were found remaining among the accreted icicles and it takes more time for icicles to completely bridge between the insulators, comparing to DC-Fog type. Therefore, excellent withstand voltage performance of the outer-rib type suspension insulator was observed under ice accretion condition.