Reliability Assessment in Active MV Distribution Networks with Possibility of Automonous Microgrids

Among the innovative management philosophies currently investigated by researchers in order to improve the distribution systems reliability in presence of dispersed generation (DG), an interesting solution is represented by “intentional islanding” of portions of a public distribution network containing DG (often referred to as “Microgrids”), realized thanks to appropriate control and management systems. Considering the need for the distribution network operators to evaluate different viable solutions in terms of network structures and management criteria in order to optimize their investments, the present paper proposes a comparison between different scenarios that can be applied to active MV distribution networks to define the procedures required by fault location and service restoration based on network reliability analyses. The considered scenarios are characterized by the use of traditional networks with automated and telecontrolled protection devices, the use of manual and automated emergency tie-lines and the implementation of intentionally islanded Microgrids. The calculation of system and load point reliability indexes is performed by means of DIgSILENT PowerFactory software, by using a by using a Failure Effect Analysis based on probabilistic approach with component fault models represented by Weibull-Markov distribution functions.