Use of fuzzy techniques in reliability assessment of electric distribution systems

The basic function of a power system is to provide an adequate electrical supply to its customers as economically as possible with reasonable level of reliability. Evaluating the reliability of a power system is a complex process and the work with the actual methods is difficult. Reliability studies require information about the history of the network components´ behaviour, about the economic consequences of outages etc. The input data for analysis methods are the reliability coefficients in the perspective of the long time behaviour of the system. This general framework is now known as one that can use the uncertainties in reliability indices (failure and repair rates) and can find the System Average Interruption Duration Index (SAIDI) as fuzzy variable. In this paper we propose to use fuzzy techniques instead of the statistical methods in determination of the reliability indices. The length of the distribution feeders is also another variable included in the fuzzy model. Test results on real distribution networks show that the proposed method can be used as a powerful tool for estimation of SAIDI.