Research On Coordinated Control And Energy Optimization Of Multi-microgrid Based On Distributed Hybrid Control

With the development of distributed generation and micro-grid technology, more and more microgrids will be connected into the distribution network through the low or medium voltage nodes. Consequently, a novel distribution network which includes multi-microgrid is formed. Due to the diversity of the components, multi-microgrid can provide abundant optimizable freedoms for the coordinated control of active distribution network. However, the complexity of the control structure makes how to efficiently realize the coordinated operation between multiple sub-microgrids and multi-microgrid and distributed network become one of the key technologies. This paper focuses on the coordinated control strategies of distributed network with multi-microgrid and the main contents are as follows:1. A hierarchical coordination control structure based on the different control objectives and control time scale demands of multi-microgrid system is designed and the multi-agent system(MAS) technology is used to achieve the proposed hierarchical structure. In the hierarchical coordination control structure, the control strategy for the power interaction of multi-microgrid within the multi-microgrids and distribution network, within the microgrids in different operational modes is proposed for the demands of energy optimization in each hierarchy.2. The optimization models corresponding to the different operational modes of multi-microgrid are established. A optimized two levels model which consisted of a distribution network model and a multi-microgrid level is used in the grid-connected mode, hi the optimization of distribution network model, the multi-microgrid can participate in the distribution network dispatching, and assist the distribution network to achieve peak load shifting; while to make full use of the distributed generation and improve the economy in the multi-microgrid is the optimal objective of multi-microgrid level. A single level optimized model is used in the stand-alone mode, and the optimal objective is the same as that of grid-connected mode except the voltage and frequency of bus in the multi-microgrid are supported by the main sources. Furthermore, the established models are solved by using the particle swarm algorithm.3. A platform is constructed to verify the proposed hierarchical coordination control structure and the established energy optimal models. According to the simulation results, The object can be achieved, no matter what the operation states multi-microgrid in and what the control strategies use, by the proposed coordinated control strategies, and the pluralistic demand of users can be met under the preconditions to meet the economic requirements.