Modeling the impact of substations on distribution reliability

A distribution substation is where a power system transitions from a networked topology to a radial topology. As such, it can have a significant influence on distribution system reliability and, ultimately, customer satisfaction. This paper examines three aspects of substation reliability modeling. It first compares substation reliability models of varying complexity. It then performs a sensitivity analysis of substation reliability to component reliability parameters. Last, it develops an equivalent distribution substation model that can be used with feeder reliability models to compute overall distribution system reliability. This method results in accurate composite system reliability results, but allows substation reliability analysis and feeder reliability analysis to be decoupled.