Phenomenon of an anomalous discharge on an AC

In two last publications, the model of flashover of HV insulation on unusually low voltages was developed. It was shown that the investigated mechanism of the anomalous discharge determines reliability of work of insulation under lightning and switching impulse overvoltages. New criteria and ways of insulation optimization are offered. Questions of application of this model for improvement of a design of insulators on Overhead Lines and Substations were considered. However for number of cases there is significant flashover probability for special insulation (with clean and dry surface!) under rate voltage. All kinds of insulators without sheds being used in EHV Power Energetic concern to these cases. For example, different special internal insulators without sheds as well as operational sticks intended for work on Overhead Lines and Substations without removal voltage. In the present work the developed model proves existence of a real flashover probability for such insulation, considers stage by stage the mechanism of anomalous flashover and the ways of preventing anomalous discharges.