On the hierarchical control framework for distributed energy storage management in large-scale distribution networks

In recent years, the medium voltage (MV) distribution networks have undergone a continuity of modifications as a massive number of renewable energy generation resources in the form of small-scale DGs (e.g., wind turbines, Combined Heat and Power (CHP) and solar energy) and energy storage systems (ESSs) penetrate into the utility grid. This trend has mainly been driven by advances in Distributed Energy Resources (DER) technology and the pursuit of low-carbon energy provision in many nations. As the DGs and the energy storage units are often deployed locally to the demands and the surplus energy could also be flexibly stored or absorbed by the grid which brings the obvious benefits for managing the power loads in peak times. At present many power utilities are being faced with the reality of conventional centralized control systems limitations, as they can greatly degrade due to the complexity of dealing with the network events that would require enormous amount of data to be properly managed, or even not pragmatic in realistic deployment. To meet this emerging challenge, this paper presents a hierarchical control framework that enables the distribution network operators (DNOs) to implement an approximately optimal energy dispatch based on the distributed energy storage systems distributed across a large-scale distribution networks, and further promote t.he demand response performance in terms of reliable power supply to the critical power loads whilst improve the global energy utilization efficiency of the renewable DGs. In such a way, the proportion of power supply from the renewable sources can be significantly promoted and the cost-effective network management can be achieved.