The Hierarchical Modeling Approach for Centralized Control Microgrid Cyber Physical System

To clearly show the operation state of each unit of the microgrid and its state transfer process, a three-layer cyber-physical integration modeling framework containing physical device layer, control decision layer and system optimization layer was proposed. Based on the design of the functions of the three layers, the model of each layer was established respectively. The state machine was used to describe the transition process between different operating states of each unit in the physical device layer, and the continuous change characteristics of each unit in each state were characterized by differential equations. The formal mathematical expressions of multi-element tuple were used to describe the control functions of the control decision layer. The optimization objectives of the microgrid system layer were established based on the actual requirements of the system, and can be used to determine the optimal operation strategy of the microgrid system. The combination of the three layers of models can form an overall model of the microgrid system with cyber-physical integration, for the purpose of presenting the state transition process of each unit in the operation and control process of the microgrid system under a certain optimization objective. Finally, a typical hybrid AC/DC microgrid system was taken as an example to verify the proposed modeling approach, and the results show that the proposed modeling approach effectively improves the observability of the microgrid system. © 2022 Chinese Society for Electrical Engineering. All rights reserved.