Design And Implementation Of Micro-Grid Power Quality Monitoring System

In order to better analyze and study the monitoring technology of power quality of micro grid,this paper focuses on the design and implementation of power quality monitoring system of grid-connected micro grid.The interference source analysis,power quality monitoring system design,disturbance detection and classification identification algorithm,construction of monitoring platform and experimental verification are studied in depth.The research work in this paper can provide hardware platform and method reference for power quality monitoring and control of grid-connected micro grid.The main work of the paper includes:1.Main interference sources and their characteristics of power quality in micro grid are analyzed and discussed,and the conclusions of interference sources of power quality in micro grid are summarized.2.The detection algorithm based on improved S transform is designed for the extraction of perturbation characteristic of the power quality of micro grid,and the power quality recognition algorithm based on integrated neural network is designed for the power quality recognition of micro grid.A comprehensive evaluation method for power quality of micro grid is proposed.3.Designed the power quality monitoring system of the low-voltage grid-connected micro grid,which can monitor and evaluate the power quality of the micro grid from the four links of the disturbance characteristic value extraction,disturbance identification and power quality evaluation.4.Set up a grid-connected low-voltage micro grid experimental platform,and designed two experimental devices for power quality disturbance experiment of micro grid.One is the load tank simulation and the other is the short-circuit simulation device.The simulated load tank is mainly used to simulate various load-related disturbance sources in micro grid and the short-circuit simulator is mainly used to simulate various short-circuit faults in micro grid.The establishment of the experimental platform provides a research and test environment for the power quality monitoring and control of micro grid.5.Based on this experimental platform,a series of experiments of power quality disturbance of micro grid are designed,including the perturbation experiment of grid-connected state micro grid,the perturbation experiment of off-grid state and the perturbation experiment of operating switch of micro grid.The experiment of harmonic injection in grid-connected state,the experiment of harmonic injection in off-grid state and the experiment of harmonic &sudden disloading(simulating mixed disturbance)in off-grid state were completed,and the experimental data were analyzed.