Reliability worth assessments of electrical distribution networks

Reliability evaluation techniques have reached a stage at which they can be applied to real systems in a very effective and efficient manner. However, the economic impact of system reliability, or more specifically system unreliability, on users and customers is not so readily available. In order to achieve this, there is a need to know customer and user outage costs and their evaluation of reliability worth. During the past 5 years, major surveys of domestic, commercial and industrial customers have taken place in the UK in order to provide this information. These outage costs can then be used as input data to cost implications and worth assessments of system planning and operational decisions. This paper first reviews these outage cost data and secondly describes how this information can be used in system planning considerations. Although this paper deals with the electricity supply industry, the concepts are equally applicable to all types of systems.