Minimizing the Reactive Support for Distributed Generation: Enhanced Passive Operation and Smart Distribution Networks

Renewable distributed generation (DG), primarily wind power, will represent the lion's share of the new generation capacity that will be connected to distribution systems. However, while both firm and variable generation present our traditionally passive distribution networks with well-established technical challenges, the requirements and practices related to the power factor operation of these generation plants might lead to undesirable effects at the transmission level with the reactive power support needed by high penetrations of DG capacity potentially impacting on weak areas of the transmission grid. In this work, this problem is formulated as the minimization of the reactive support for DG and is investigated using two different operational perspectives: adopting passive but enhanced power factor and substation settings, and implementing Smart Grid control schemes. These two approaches are modeled using a tailored multi-period AC optimal power flow technique that caters for the variability of demand and generation, and considers N-1 contingencies. The results demonstrate that the enhanced passive approach is able to achieve a performance almost as good as Smart Grid control without the need for any additional investment.