Modelling and Analysis of Switching Overvoltages Caused by Short Circuits in MV Cables Connected with Overhead Lines

摘要

In rural power distribution networks, the cause of disturbances is typically weather related, like thunder, snow and ice, and trees fallen by snow, wind and storms [1]. In areas supplied by overhead lines, an auto-reclosure sequence is commonly used to clear temporary faults. In these areas, the share of permanent faults is typically less than 10% [1,2]. In Finland, on average, about 70% of permanent faults in rural MV networks are caused by weather conditions such as thunder, snow, icing, storm, hard wind and fallen trees [1]. However, the cause of the majority of faults remains unknown when they are cleared automatically. Typically, no statistics of the causes of temporary faults is available in literature [3].