Reliability evaluation for meshed distribution networks based on minimal cut sets method

Abstract

The paper proposes a reliability evaluation for meshed distribution networks based on minimal cut sets method. Distribution networks with meshed layout but radially operated have been commonly used in urban environments since they give some advantages in terms of lines thermal limit and voltage drop. The evaluation procedure is divided into three steps: firstly, it determines the minimal cut sets from each source node to each load nodes of the DN; secondly, it calculates the failure rate and the outage time for each minimal cut sets identified; lastly, it calculates the system average interruption frequency index and the system average interruption duration index. A sensitivity analysis of two specific system layouts, which we refer to as 1-step ladder and 2-steps ladder, has been carried out varying the maximum power flow allowed during normal operation. The method shows that, to improve reliability, as more as the distribution network is loaded as more as it should be meshed.