Quality of supply in the deregulated Norwegian power system

Since 1995 the Norwegian regulator has required annual reporting of interruption data by the network companies. Main results from the reported data in 1995-1999 are presented in the paper. The statistics shows that the annual number of interruptions per delivery point has been relatively constant during this five-year period. The annual energy not supplied (ENS) shows a decreasing tendency due to a quite evident reduction in ENS for notified interruptions. The interruption statistics are utilized for many purposes by the regulator, the network companies and as a basis for research. Some examples of utilization of the statistics are presented in the paper