| With the development of new power industry towards "energy conservation and environmental protection",the research on microgrid technology focusing on renewable energy power generation has attracted more and more attention.In the islanded microgrid system,in addition to continuous power supply,ensuring its good power quality is a vital condition for the normal operation of the power grid system.In this paper,islanded microgrid based on different voltage levels is taken as the research object.Aiming at the traditional islanded microgrid power quality control methods,it is difficult to meet the requirements of output dynamic response and stability of power quality under the fluctuation and intermittence of distributed energy in islanded microgrid,The power quality closed-loop control method based on situation awareness and situation orientation is adopted to improve the performance of the system.In addition,based on the simulation model of islanded microgrid with different voltage levels,two different power quality control methods are proposed according to the resistance and inductance characteristics of islanded microgrid with different voltage levels.The main research contents of this paper is as follows:(1)Research status and difficulties of power quality of islanded microgrid.On the basis of reading the literature at home and abroad,understand the research status at home and abroad and the difficulties of power quality control of islanded microgrid,and put forward the key research content of this paper.(2)Characteristic analysis and modeling of islanded microgrid with different voltage levels.The resistance and inductance characteristics of islanded microgrid with different voltage levels are analyzed,the islanded microgrid with different voltage levels is modeled,the distributed energy control method is analyzed,and the influencing factors of power quality are simulated.(3)Design of power quality closed-loop control strategy based on situation awareness and situation orientation.A closed-loop power quality control strategy based on situation awareness and orientation is designed to improve the power quality of islanded microgrid.Firstly,through the collection of power quality indicators and influencing factors of islanded microgrid,the situation is predicted through prediction algorithm,and then each part of islanded microgrid is reasonably mobilized for power quality regulation through situation orientation.(4)Power quality control method of islanded microgrid with different voltage levels based on situation awareness and orientation.Based on the understanding and analysis of situation awareness and orientation,the closed-loop control strategy of power quality is designed.Firstly,through historical data collection and data preprocessing,it is classified into training data and test data,model training and model prediction are carried out,transmitted to situation orientation for scheme formulation and task implementation,fed back to the power grid system,and the closed-loop control of power quality is completed.(5)Establishment of evaluation index of power quality.According to the power quality object studied in this paper,the evaluation index of power quality is formulated,which can better reflect the regulation of power quality.Finally,the accuracy of the evaluation index is explained in the simulation verification. |
