Hierarchical control framework for integrated coordination between distributed energy resources and demand response

Demand response represents a significant but largely untapped resource that can greatly enhance the flexibility and reliability of power systems. This paper proposes a hierarchical control framework to facilitate the integrated coordination between distributed energy resources and demand response. The proposed framework consists of coordination and device layers. In the coordination layer, prior to each scheduling period, each coordinator receives the aggregated utility or cost functions as well as the power operating ranges from aggregators or device controllers. Then, various resources or their aggregations are optimally coordinated in a distributed manner to achieve the system-level objectives. The obtained regulation signals are sent back to aggregators or device controllers for real-time control. In the device layer, at the scheduling stage, the controller at each device reports to coordinators (directly or through aggregators) the required information for optimal coordination, and receives the regulation signals from its commander once the coordination is completed. During the real-time operation, individual resources are controlled to follow the optimal power dispatch signals. For practical applications, a method is presented to determine the utility functions of controllable loads by accounting for the real-time load dynamics and the preferences of individual customers. The effectiveness of the proposed framework is validated by detailed simulation studies.