Simulation Analysis Of Light Storage Micro - Grid Operation Control

As the problem of the environment is more and more serious, the distributed power generation technology has been paid widely attention and lots of researches are conducted. But large penetration of DGs will certainly reduce the stability of the utility when accessing to the network and other bad influences will also be brought out. In order to coordinate the contradictions between DGs and utility and fully excavate value and benefits brought by DGs to users and grid, the researchers propose the concept ofMicrogrid. Microgrid gets the distributed generators, loads, distributed energy storages, and control devices together, it can operate with utility acting as a controllable unit and apart from utility operating with itself when fault occurs within the network as well. Microgrid is regarded as the most effective way to use distributed energy. Aiming at the typical microgrid, a basic research is conducted to support the theoretical gist for the demonstration projects, corresponding research work as following:1) The PV generator system and energy storage system are analyzed particularly, and the practical mathematical models of PV modular and battery cell are built. Then, the dynamical external characteristics are studied, and compared with the paragraph supported by manufacturer.2) The DC converter and AC converter’s structure and control tech are introduced particularly, and the constant power control, constant voltage/frequency control, droop control are analyzed, and control strategies are built correspondingly. More emphases are paid on PV control of PV system and PQ& U/F control of energy storage system, and they are modeled and simulated laying the foundation for the whole microgrid simulation.3) The microgrid’s operation modes and coordination control methods are summarized, and the advantages and disadvantages of C-S mode, P2P mode, hierarchical mode and the problems need to be solved at different operation mode are analyzed. As a result, a practical microgrid model based on C-S mode is developed including PV generator and battery system.4) The microgrid including PV and battery are modeled based on PSCAD, which is an electromagnetic transient software used in power system simulation. The PQ and U/f control strategy of DG are studied and some operation conditions are designed such as grid-connected mode, islanded mode and the switch process. The effectiveness of control strategy at different scenes are simulated and analyzed for supporting the demonstration projects.