Supervised control of hybrid AC-DC grids for power balance restoration

Abstract

In this paper, the flexibility of hybrid AC-DC distribution networks is exploited to coordinate multiple Distributed Energy Resources (DERs) with the aim of promptly restoring unexpected power imbalances caused by intermittent Renewable Energy Sources (RESs) and loads. Given the potential large-scale nature of the problem, the AC distribution network is decomposed into non-overlapping areas named clusters, equipped with MicroGrids (MGs) and non-dispatchable units, and interconnected also by the DC network. Each cluster is endowed with a Model Predictive Controller designed to compensate the local active power variability by requesting balancing services to the local MGs. A supervisory layer is designed and activated to optimally transfer power through the controllable DC links guaranteeing enough operative margins to each cluster. The designed architecture is tested on a benchmark grid composed of the IEEE 37-bus and 13-bus systems, connected by a multi-terminal DC network. The reported numerical results witness the effectiveness of the proposed approach.