Influence of supply security requirements on underground cabling rates in Finland

This paper provides a view to assess effects of supply security requirements in Finnish electricity distribution networks on network renovation demands. In the beginning of September in 2013 a new Electricity Market Act came into effect in Finland. It sets limits for duration of allowed interruptions. As a background of the act are long interruptions caused by several major disturbances within the past years. Thus, the legislation demands distribution system operators (DSOs) that do not fulfil the criteria of the maximum allowed interruption duration, to develop supply security. Improvement of supply security requires significant actions in distribution networks, which often means replacing of existing lines with underground cables or other line structures that are major-disturbance-proof (MDP) or resilient to major disturbances.