Composite reliability evaluation model for different types of distribution systems

The paper develops a set of composite distribution system reliability evaluation models that can be applied to a nonradial type system. The developed models reflect the effect of distribution substations, primary distribution systems, and the interaction between them. First, reliability assessments for five configurations of distribution substation are performed using minimal cut-set technique. Next, the interaction between distribution substation and primary distribution system is modeled according to the tripping behavior of feeder circuit breakers. Last, the contribution of reliability indices evaluated from the primary distribution system is added to the previous two effects, and then the composite load point reliability evaluation models are developed. The developed models are demonstrated on five types of distribution system modified from a reliability test system. Comparisons of reliability indices are made and discussed.