Economic operation of distribution networks with distributed generation and quality of service

Uncertainties in distributed generation with renewable sources, and load fluctuations due to demand response, require the Distribution System Operator to have tools to coordinate supply and demand with an adequate quality of service. A cost optimization method is proposed for this purpose, based on two time-scales: a slow scale were topology changes and transformer taps are varied with their operation costs, and a fast time-scale based on an optimal power flow, in which costs of power supply and quality of service are incorporated. To solve the latter we rely on convex relaxations to the DistFlow model, which allow an efficient solution in radial topologies. We also develop a detailed model in DistFlow of wind and photovoltaic generators operating as subnets of the Distribution network. The method is demonstrated with data from a real network in Uruguay.