How environmental factors impact line performance, field results from Southwest Europe

Long series of field data obtained from exploitation and maintenance of electricity grids from 10kV to 400kV have shown the prevalence of environmental factors as the primary influence on the performance of over-head lines in Southwest Europe. Vegetation and clearance, lightning and birds come at the top of concerns; forest fires, fog and pollution follow and broad similarities were observed across territories and voltage levels. The main environmental factors affecting grids are introduced and a strategy to establish the nexus of cause that binds environmental factors, effects on power lines observed during inspections and grid events is proposed. Field data for distribution and transmission grids are presented to illustrate some of the hypotheses for causal links.