Operation of the weatherproof electricity distribution network

During the last decade, Finland has faced so many weather-related disturbances such as strong wind, storms, and snow load conditions that caused power outages for a longer time. The new Electricity market act came into action in 2013, which set a target that weather-related disturbances cannot knock out the power for more than 6 hours in urban areas and 36 hours in rural areas. By 2028, these limits should be reached by ensuring the uninterrupted electricity supply to 100% of customers. The tightening security of supply has prompted the Finnish DSOs to renovate and improve their networks to achieve the target. The Finnish DSOs took many initiatives by managing the forests that pose a risk to the distribution line, moving the overhead lines from forest to roadsides, using covered conductor or aerial cables, implementing simplified primary substation, and increasing the network automation. However, these initiatives have been proved as traditional reliability improvement methods. In the recent few years, the importance of building the weatherproof electricity distribution network has been highlighted. This Master´s thesis includes literature related study, interview, and case studies to find out the weatherproof network solutions which are capable of withstanding without any loss of function, even in major disturbance situation. Underground cabling and wide power line corridor have been so far considered as the weatherproof network solution. Privately owned DSOs have many investors, and their investment could be funded by increasing the distribution fee paid by the consumers. Thus, Underground cabling is the most prominent techniques among the top DSOs in Finland to meet the supply security requirements due to its less operational and outage cost. However, the higher investment cost makes it less popular among the few DSOs who have their networks in the forests and fewer customers. Therefore, the wide power line corridor could be the appropriate weatherproof network solution for those DSOs belonging to the public or municipalities. Nevertheless, it only applies to those networks that have 20-30 years of technical lifetime left to take this approach into account. Periodical inspection of the traditional OHL, partial discharge measurements for monitoring the condition of underground cable, advanced FLIR system, and back-up power arrangements during the outage ensures the smooth operation of weatherproof electricity distribution network