Variability evalution of distribution networks quality of supply performance indices

Distribution networks reliability performance indices present a stochastic behaviour characterised by intrinsic variability which cannot be eliminated. This behaviour may be attributed to weather conditions or to the combined effects of the condition of assets throughout their lifecycle. The ability to quantify the probability of networks performing within certain boundaries or not beyond certain thresholds is therefore very important in assessing the reliability performance of distribution systems. Also, considering the growing impact of performance based regulation there is a need to compare, understand and quantify differences in the reliability performance across networks. This issue is addressed in this paper, in the context of the current regulation regime in the UK, as new network planning tools and methods are being employed.