A framework for asset replacement and investment planning in power distribution networks

Within the UK power distribution sector the DNOs (Distribution Network Operators) are responsible for a large quantity of assets of various types. The expansion of the network in the 1960´s led to a number of assets now reaching the end of their design lives. DNOs work within a limited budget for non-load related asset replacement, as agreed during price control reviews with Ofgem (currently DPCR5 and moving towards RIIO). This paper focuses on developing a framework for targeting asset replacement, centred on risk assessment and optimising the risk profile across the asset base. A framework for investment planning is proposed, which consists of the following stages 1) asset data collection, 2) risk quantification, 3) asset condition prediction using Semi-Markov modelling for asset degradation modelling, 4) compile and aggregate risk profiles, 5) optimisation of asset risk and investment to identify which assets should be replaced for the greatest impact on the risk profile. This is in order to produce a practical investment strategy to minimise risk.