Weather-based distribution system reliability evaluation

The weather environment can severely impact the performance of an overhead distribution system and an electric utility's operational ability. The likelihood of system failure increases due to enhanced line failure rates during bad weather periods. Reliability appraisals without incorporating weather conditions can be quite optimistic and affect planning and design decisions. Recognition of various weather contributions to the total system performance indices help to pinpoint situations where investment may provide maximum reliability improvement. An approach is presented to assess distribution system reliability in different weather conditions such as normal, adverse and extreme and illustrated using a practical distribution system. Reliability indices are evaluated in three different weather states and a series of sensitivity studies are presented. The effects of repair time and the frequency of major storm occurrences are illustrated.