New methods and applications for distribution system reliability analysis

In Germany, planning tasks in the field of distribution systems are especially characterized by changing conditions. To these belong the emerging area of distributed utility, the growing number of dispersed generation units, the altering of cost awareness in the utilities, as well as the new potential due to advanced secondary technology in the fields of protection and switchgear equipment including the overall control system. Considering that distribution system failures are the major cause of customer interruptions in Europe, effective and reasonable planning tools and criteria are important for covering the needs of a competitive utility environment in the future. This paper gives examples for new developments and applications in the field of distribution system reliability. The two studies discussed underline that significant savings can be obtained during the network design process when using these tools for decision making. The first application uses the modelling for automatic switching when calculating the reliability of supply of an industrial customer with electrical pumps. The second task deals with the reinforcement of a given grid when considering a slow load increase.