Quantification of low voltage network reinforcement costs: A statistical approach

Long-term investment for large-scale low voltage (LV) (0.4 kV in the U.K.) networks is one of the key issues concerned by distribution network operators (DNOs). The major difficulties in carrying out long-term LV distribution network investment at the system level are the extensiveness of these networks and the very limited network information, such as utilizations of transformers and circuits. To overcome these difficulties, this paper proposes a novel statistical method for quantifying the reinforcement costs in LV distribution networks driven by demand growth. The triangular probability distribution is used to represent the distribution of utilization levels of circuits and transformers in LV networks, allowing the assessment of the scale of network assets to be reinforced based on probabilities. The demand driven reinforcement for a given period is evaluated in terms of thermal violation and voltage violation. Total reinforcement costs are determined based on the evaluated proportions of assets to be reinforced, their unit costs and total amount. The proposed statistical method is implemented into a practical distribution system in Great Britain (GB).