Medium voltage distribution system reliability calculation with the consider of high voltage distribution system and substation

According to the operational features of distribution network, the paper presents a method to calculate the distribution system reliability that also considers multi-layers failure. Based on the regular reliability calculation, the results are promoted. Firstly, the distribution system is divided into different parts by different voltage level. Secondly, based on the characteristics of the distribution system, a comprehensive evaluation method, which combines the high and medium voltage distribution system and the substation´s influence, is taken into account. Through integration of the boundary condition, using the series and parallel formula, the promoted results are calculated. An example demonstrates the effectiveness and the accuracy of the method. It is a method which can be utilized in the cases of general index, and also satisfies with the various needs of the reliability calculation.