Impact of Biological Growths on Application of Composite Insulators by Mikko Jalonen

The TSO in Finland has been using composite insulators at substations and on transmission lines for 20 years without serious issues. But in recent years biological growths have begun to be observed on some of these insulators. Although the growths have been washed according to supplier instructions, there has not been a clear understanding of their impact. An R&D project was therefore conducted in cooperation with two other TSOs whose aim was to provide guidelines on how to treat this issue from the risk of flashover and ageing points of view as well as to determine whether periodic cleaning is needed and, if so, the most practical methods. This presentation reviews results of this research and explains the value gained from the asset management perspective.