Liberalization has increased economic pressure on network operators, urging them to compromise between cost savings and supply reliability. In this context, the detailed and quantitative evaluation of supply reliability is gaining ever more importance—especially its application in comprehensive asset management methods. However, the large number of components especially in medium voltage distribution networks leads to high computation times for such probabilistic reliability analyses. A recent research project deals with investigations into a forecast of system supply reliability performance following a simplified methodology. Developing different forecasting methods, also several aspects of significant importance for the calculation of supply reliability in MV distribution systems in general were identified. Especially for electrical networks of a certain size, the overlapping of independent single failures, as well as complex failures play an important role. This paper presents the background of the reliability centered asset management approach as well as the general idea and different approaches to the forecasting methods in theory briefly. Following, the application on two different example networks demonstrates the approaches and the achieved results, and reveals also the relevance of overlapping and complex failures in these results.