Practical Application of

Liberalization of the energy markets has increased the cost pressure on network operators significantly. Corresponding cost saving measures in general will have negative effects on quality of supply, especially on supply reliability. On the other hand, a decrease of supply reliability is not acceptable for customers and politicians - and the public awareness was focused by several blackouts in the European and American transmission systems. In order to handle this delicate question of balancing network costs and supply reliability, detailed and above all quantitative information is required in the network planning process. A suitable tool for this task is probabilistic reliability analysis, which has already been in use for several years successfully. The method and possible applications are briefly described here and application is demonstrated with various examples from practical studies focusing on distribution systems. The results prove that reliability analyses are becoming an indispensable component of customer-oriented network planning.