Centralized Optimal Management of Distribution Resources Considering the Effects of Local Controllers of Generators

In order to foster increasing shares of renewable generation at distribution level, it is necessary to introduce control strategies to avoid voltage and loading congestions. Control strategies are also needed to facilitate the provision of ancillary services to the transmission grid by distributed resources. Centralized control solutions are often the best choice for an optimal management of distribution networks, but they usually require monitoring vast network areas and many grid nodes, which is frequently unaffordable. For this reason, some portions of the network (i.e. LV nodes) can be operated in an unsupervised way, and the fundamental control functions are operated by generators local controllers. Of course, these controllers also impact on the supervised network portions, therefore centralized architectures should take their (side) effects into account in order to compensate them. This paper analyses the behavior of a real distribution grid with a hybrid control strategy (i.e. where automatic local controllers are implemented in some portions, while some generators and distribution transformers are controlled by the network operator) and compares it to situations in which either central control only or local controllers only are activated.