Volcanic ash contamination of high voltage insulators: Revising insulator design to aid the electrostatic repulsion of volcanic ash

Abstract

Ashfalls from volcanic eruptions can pose a considerable risk to electric transmission and distribution networks. Dry ash is non-conductive [1] and unlikely to cause an insulator flashover; but it is of concern when the ash becomes damp/wet through light rain, dew, and fog. Volcanic ash is the signature of a volcano; all volcanoes have slightly different volcanic ash. During an eruption the ash absorbs charged halogens and molecules into its surface which dry to become soluble salts [1]. When the ash becomes wet, these trapped soluble salts dissolve in the water to form a conductive channel. This can result in insulator flashover. Current insulator cleaning methods are exceedingly labour intensive and can only occur once a volcanic eruption has finished. Linemen are required to manually clean each and every insulator. This is a very time consuming task and may result in a lengthy downtime for the affected transmission line [2]. A self-cleaning insulator would vastly improve the current situation. Not only would the insulators be less susceptible to the build-up of ash, the effort and money required to manually clean the insulators would be substantially reduced. Only transmission lines potentially susceptible to volcanic ash contamination would need to be retrofitted, with either new insulators, or to modify existing insulators to improve their self-cleaning abilities and assist the natural cleaning of heavy rain.