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

• Published in: Electric power systems research Vol. 196; p. 107107
• Main Authors: Bonassi, Fabio, La Bella, Alessio, Lazzari, Riccardo, Sandroni, Carlo, Scattolini, Riccardo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2021
• Subjects: Ancillary services; Hybrid AC-DC grid; Microgrids; Power balance; Predictive control; Power balance; Hybrid AC-DC grid; Ancillary services; Microgrids; Predictive control
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2021.107107

•We propose a multi-layer scheme for the power balancing of hybrid AC-DC distribution grids.•The grid is assumed to be divided in areas, named clusters, controlled by decentralized MPC controllers, to locally and promptly compensate active power imbalances.•A supervisory layer manages the power exchanges among clusters to ensure that they have enough power margins to operate independently.•An Optimal Reactive Power Flow is periodically performed to keep voltages and currents within regulatory limits, and to minimize power losses.•The proposed approach has been tested on a benchmark system consisting of the IEEE 37- bus and IEEE 13-bus networks interconnected by a multi-terminal DC grid, witnessing promising results. 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.