Risk assessment as an integrated part of distribution system reinvestment project analysis

Abstract

In the ageing infrastructure of electricity distribution, the emphasis on maintenance and reinvestment decisions is ever increasing – focusing on doing the right thing at the right time. Maintenance and reinvestment decisions are important parts of distribution system asset management, as means to control risk. Distribution companies are increasingly recognizing risk assessment as an important tool in distribution system asset management [1, 2, 3]. This paper describes a concept of risk assessment applied to projects regarding potential replacement or refurbishment of existing installations or sub-systems. Such projects are referred to as reinvestment projects. A project is an individual job, limited in time and costs, as opposite to a continuous process, e.g. reoccurring maintenance activities. The handling of reinvestment projects relates to specific nonroutine reinvestment decisions, that cannot be directly covered by the rules of the distribution company maintenance and reinvestment strategies, and hence need to be dealt with individually. The paper focuses on risk assessment as basis for reinvestment project decisions, proposing a framework for including risk assessment as a part of the work process of a reinvestment analysis. Further the paper describes the use of this framework and how this can support the distribution company work flow. Practical use is illustrated through a case study performed in cooperation with a Norwegian DSO, dealing with reinvestment analysis of MV/ LV substations.