Economic benefit of preventive cable replacement in distribution networks based on the alignment with reinforcement measures

Abstract

This article investigates the economic benefit of aligning asset maintenance actions with actions resulting from necessary distribution network development. For this, an existing optimisation approach to strategic network planning at low-voltage level based on a genetic algorithm is expanded to include the opportunistic preventive renewal of assets. The renewal of power cables that is expected due to degradation is brought forward in time and carried out at the same time as actions that are necessary to increase the network capacity to host increasing distributed generation. It is shown in theory and with exemplary case studies that overall costs can be reduced, depending on opportunity costs and the relation of direct costs to costs which the maintenance and reinforcement actions share, such as certain parts of construction work. In the two case studies with real low-voltage, networks the cost reduction amounts to 39% at maximum when cable replacement and the laying of new cables are aligned, compared to the separate execution of the necessary construction work. The case studies also reveal that the decision on the technical option for reinforcing a network may change due to the joint optimisation of renewal and reinforcement. In some cases, now traditional network reinforcement is advised, where sole strategic planning would recommend voltage control devices as the optimal choice.