This project was started within the Market-Design programme of Elforsk, with the aim of developing representative test systems of Swedish distribution networks. Using such test systems as a basis for reliability and customer interruption cost calculations makes it feasible to analyse the network tariff regulation of Swedish power distribution companies. In particular, it enables studies of the incentives for companies to invest in system reliability. Until now, the available test systems are either not representative of Swedish conditions, or too small in scale and limited in function.
Within this project we have created two test systems. In order to represent the diversity of actual Swedish distribution networks, we have created one test system for urban environments and another for rural environments. The test systems contain information about structure, customer composition, load data, component failure statistics and cost of power interruptions. To enable reliability and customer interruption cost calculations, the test systems have been implemented in Matlab. In this project power distribution company representatives and responsible authorities have been valuable as primary information sources.
The resemblance of actual systems to the test systems has been confirmed for several individual aspects, including their overall performance. Reliability in terms of frequency and duration of power interruptions is consistent with data found in annual reports submitted to the Swedish Energy Markets Inspectorate.
Improvements of the test systems can be made through in depth studies of both the total system-load distribution among the different customer categories, and the cost incurred by customers from power interruptions. Data for failure statistics and time-dependent load-profiles will be more accurate in the near future, and can be used for updating the test systems.