Methods for Advanced Compilation of Interruption Statistics to Cater the Renewing Regulation

Deregulation of electricity market in the middle 90’s changed power distribution in Finland to more business oriented direction although the network business remained as regulated natural monopoly. According to the Electricity Market Act, the distribution companies have general obligations, e.g., to develop their electricity distribution networks and to have moderate distribution pricing. When assessing the reasonableness of the pricing Finnish Energy Market Authority (the market regulator) takes into account also the efficiency of network companies. For some time now the efficiency has been evaluated with DEA-model, in which power quality in the form of interruption time is at present one of the input parameters. In the future, power quality will be determined more accurately and diversified based on more accurate interruption statistics and interruption cost parameters. Tampere University of Technology (TUT) and Lappeenranta University of Technology (LUT) have had joint projects for developing methods to compose interruption statistics with a reliable way to cater the needs of network planning and operation, and also the needs of the regulation and efficiency determination of network companies. The research has been carried out partly also with the Finnish Energy Market Authority. The use of interruption statistics and interruption cost parameters was studied also with reliability calculation tool to determine the structure of interruption costs (i.e. what percentage of interruption costs is caused by certain customer group and certain interruption type) and average interruption cost parameters using the data of two Finnish distribution companies. To collect diversified interruption figures distribution companies have to know, e.g., the number of different kind of interruptions and the interruption durations, and also the number of customers and their annual energy consumption for each secondary substation. This settles new needs for the compilation of interruption statistics and the data systems, because interruptions have to be saved at the secondary substation level, when previously it was enough to only count the number of secondary substations attached to the interruption. While most progressive companies already at present have modern data systems, which handle automatically a great deal of the work associated with interruption statistics, some companies still handle this with primitive Excel-applications or even with pencil and paper. In the future, the distribution companies have to assure that their data systems meet the requirements of the renewing regulation and interruption statistics. Depending on the automation level and the data systems of the distribution company, it will have some alternative methods for the compilation of interruption statistics.