Insulator icing test methods, selection criteria and mitigation alternatives

IEEE-PES Task Forces on insulator icing have been active since 1999 in developing icing test methods and recommending insulator selection criteria. Progress towards this goal included methods for obtaining reproducible results and also modeling of important factors. This paper reports on the progress and work accomplished by the PES Task Forces, serving as input data to the joint DEIS/PES task force work initiated recently to expand the technical basis of the existing knowledge. In selecting adequate insulators for substations and lines at distribution and transmission voltage levels, special measures may be needed in locations exposed to freezing conditions. The environmental and insulator parameters that influence the risk of flashover are noted. The selection process and mitigation options, based on these environmental parameters, are then described. The selection criteria include insulator size, shape, surface material, surface quality, electric field improvement, and orientation.