Research On Islanding Detection Of Grid Connected Photovoltaic Grid Connected Inverter

The problem of energy crisis and environmental pollution is becoming more and more serious,so it is a powerful method to solve the problem.Solar power generation is an important part of renewable energy power generation system.With the rapid development of solar energy technology,in the end of 2014,the global installed capacity of photo-voltaic power generation has reached28.1GW.A large number of photo-voltaic grid connected power generation system will be put into the traditional power system,which will bring new technical challenges to the safe operation of power system.In this paper,the photo-voltaic grid connected inverter as the background.First of all,this paper introduces the background and significance of photo-voltaic power generation,and summarizes the topology and control method of grid connected inverter.Secondly,this paper introduces the islanding detection technology of photo-voltaic grid connected inverter,which includes remote detection and local detection.The local detection is divided into two categories: passive and active islanding detection.This paper mainly analyzes the single-phase islanding detection method of active frequency shift method,with positive feedback active shift principle of positive feedback active frequency shift method and frequency method after optimization,and the corresponding blind analysis and simulation analysis.Then,with the development of economy and technology,multi-inverter DG systems will be used more extensively,and the researchers have paid more attention to the islanding detection methods of multi-inverter systems.Therefore,the researches of this paper focus on the islanding detection technologies of mulit grid connected inverter based DG systems,the specific contents is divided into five parts.1.The principle of passive islanding detection method is analyzed in the part of photo-voltaic grid connected inverter.2.Analyze the principle of the active frequency shift method(AFD)and the positive feedback active frequency shift(AFDPF)method and the blind area analysis of the two grid connected inverters.3.analysis of the two grid connected inverter using the principle of AFDPF method.4.Analyze the principle of the active frequency shift method(AFD)and the positive feedback active frequency shift(AFDPF-new)method and the blind area analysis of the two grid connected inverters.5.the analysis of the two grid connected inverter using positive feedback active frequency shift method(AFDPF)and the optimization of the positive feedback active frequency shift method(AFDPF-new)principle and blind area analysis.Finally,the simulation model of two parallel grid connected photo-voltaic inverter is built by Matlab/Simulink simulation software,the two inverter operation were carried out simulation analysis on traditional AFDPF and improved AFDPF islanding detection method.