Aspects of Risk Assessment in Distribution System Asset Management: Case Studies

The reliability of power systems is a major concern for network designers and operators. For several reasons, the level of electricity distribution network risk, in the UK as elsewhere, is perceived to be increasing in the short term, and further sources of increased risk can be anticipated in the longer term. An asset management approach seeks to optimise the balance between capital expenditure and the risk to customer supplies. To do this effectively, network risk must first be defined and measured. This chapter describes ways of modelling, evaluating and comparing the levels of risk in different parts of the network and under various operating assumptions. It also enables different strategies for mitigating that risk to be quantified, including maintenance policies, replacement and reinforcement construction projects, network reconfiguration and changes to operating practices. In the longer term, it allows evaluation of the impact on network risk of initiatives such as widespread distributed generation, demand side management and smart grids.