The economic aspect of reliability in distribution system planning

A distribution system planning procedure to handle reliability not only as an important type of analysis but as an integrated part of the cost minimization problem is described. The reliability is described as an operating cost by evaluating the cost of nondelivered power (NDP) and nondelivered energy (NDE). Reported case studies show that the economic assessment of reliability is of great importance in distribution system automation and design. The case studies show that the cost of outages tends to dominate the total costs even when the specific costs of outages (NDP/NDE) are quite low. Distribution planning studies also reveal that uncertain outage cost premises may be investigated and compensated by sensitivity analyses, helping the planner to achieve a safer design strategy. In case of costs of outages, the planning approach described makes it possible to establish a level of distribution system reliability that balances private and socio-economic cost/benefit criteria