The Research Of Distributed Generation Island Detection Technology

As the world’s growing energy consumption and the environment worsening in the world,the development of new energy and use by governments on the agenda, includingphotovoltaic received more attention for its advantages. The problem of islanding detectionand protection is the most important in the Photovoltaic power generation systemsFirst of all, through the analysis of the I-V characteristic curve of solar battery, P-Vcharacteristic curve to construct a general model of solar cell and solar cell technology ofmaximum power point tracking (MPPT) was improved, Newton method is put forward tocombine with climbing method to find the most power advantages, complete the inverter sideof the system structure. The simulation results show that the method can fast track and findthe output of the current environment and fluctuation of maximum power point of tiny.Through the analysis of the advantages and disadvantages of active and passive islanddetection method, the active frequency shift method based on frequency change, and based onthe harmonic is proposed on the basis of change of positive feedback active frequency shiftassay, its advantage lies in the detection speed, high precision, and the impact on the powergrid close to passive detection can almost had no effect. It is verified by simulation insingle-phase and three-phase system can be a very good job, complete set in advance.About the normal frequency and harmonic wave will affect the test results of problem,put forward using wavelet transform to analyze public point voltage waveform disturbancestart to automatically adjust the threshold, further reduce the impact on the grid and improvethe detection efficiency.