Research And Application Of The Coordinated Control Strategy For Microgrid Mode Switching

As an effective way of consumptive distributed power, micro-grid has been developed rapidly in recent years. As one of the key technology of micro-grid, on one hand, micro-grid mode switching control technology can improve the reliability of the power supply of micro-grid, on the other hand, this technology not only subtractive the passive effect of DG on distribution network, but also improve the absorptive capacity of the distributed power system.Based on the research of micro-grid mode switching control strategy of micro-grid and mode switching control system, this paper studies the key technology of the micro-grid mode switching process, then a micro-grid mode controller is developed on the basis of above. So far, this method has been successfully used and proved a certain practical value in national 863 Plan projects-Luxi island micro-grid demonstration projects. Full text as follows:(1) This paper summarizes the current situation of micro-grid mode switching control strategy and its switching control system both domestic and overseas. The present situation of the mode switching control system in the domestic and international micro-grid is summarized. On the basis of this, several control strategy has been proposed such as master slave control and the peer control of the micro-grid operation, the P/Q and V/F control strategy of the energy storage converter.(2) According to the structure of the micro-grid, the operation mode is summarized. We did theoretical research such as micro-grid operation mode adaptive identification method based on ternary expression; fast detection technology of unplanned DG islanding; emergency control technologies of the exchange power at grid connection point; synchronization control of micro-grid; Finally, the modeling and implementation of the micro-grid mode switching control strategy based on XML is proposed.(3) A micro-grid mode controller is developed. According to the scale of micro-grid, the simple model of micro-grid control system structure and extend the configuration of micro grid mode control system structure are proposed. A hardware framework of the micro-grid mode controller is designed to meet the mode switching control requirements, the software structure of the micro-grid mode controller is designed in detail, include:input and output, components, strategies database, strategies parser and strategies actuator.(4) Finally, the micro-grid model controller was used in the national 863 project of Wenzhou Zhejiang Luxi island micro-grid demonstration project. At the engineering scene, we experimented active control, passive control and synchronization control. The experimental results verified the correctness and robustness of the micro-grid model controller and its control strategy.