Short interruptions caused by lightning in overhead line medium voltage networks

Lightning strokes represent a considerable cause of short interruptions in overhead line medium voltage networks. The overvoltages caused by lightning can not be avoided but their influence can be limited by appropriate overvoltage protection. This paper presents the results of theoretical studies about the number of short interruptions caused by lightning in various environmental circumstances. The results will be compared to the fault statistics collected from Kainuun Energia. In the calculations, the environmental conditions, ground flash densities and various overvoltage protection types of power distribution transformers are taken into account. At the end, further research is discussed.