Research On Microgrid Modeling And Its Transient Simulation

With the growing demand of electricity, the energy crisis intensifies, large power grids revealed some drawbacks. Distributed generation technologies receive more and more attention. As a new energy, distributed generation technologies are friendly to the environment but unstable. In order to solve the problem of the connection-grid of distributed power generations and make full use of new energy, this paper proposed the concept of micro-grid. The micro-grid combines all kinds of distributed energy, energy storage devices, control devices and load and has flexible operation mode and high reliability. It is the main trend of the future development of the electric power system. However, the instability of distributed energy has a great influence on the grid; therefore, the research on the control of distributed generation will be of great importance. Power sharing for distributed power control method was researched on the basis of the traditional control methods of micro-grid in his paper. The main contents are:On the basis of the topic background, the significance of research on micro-grid and the research of micro-grid home and abroad, the structure of the three-phrase inverter in microgrid was introduced and the main method of controlling the micro-grid inverter was summarized, including droop control, constant power control and constant voltage constant frequency control. The principle of each method, characteristics and scope of application was analyzed.The condition of power even distribute between parallel inverters was discussed on the basis of the mathematical model of inverter in micro-grid and then got the relationship of power even distribute among source voltage, line impedance and the number of parallel inverters. The method to achieve power even distribute between parallel inverters was designed and achieved by simulation.Finally, micro-grid model was set up in PSCAD/EMTDC, the method proposed in this paper is effective comparing with the traditional, the effectiveness of the proposed control method was verified.