Research On Characteristics And Detection Methods Of Photovoltaic Grid-connected Inverter Islanding

Photovoltaic power generation is one of the main forms of renewable energy generation.Grid-connected inverter is the core component of PV systems.To ensure the safety, it is essential for the grid-connected inverter to obtain islanding detection.The current inverter mainly through the processs of adding disturbance in the way to complete the island effect detection. Practically, the active islanding detection method such as active frequency drift has a blind as a result of various types of load condition.The passage carries out a detailed study and analysis about the effect on the islanding.Firstly,the passage describes the operating princeple and control strategy of the photovoltaic inverter.There are two kinds of control strategies based on deadbeat current.A solid foundation for the simulink model with the active frequency drift method has been established.Secondly,the passage makes a depth research on the island effect.And it concludes the theoretical relationship of the load condition and voltage, current when the islanding happens.lt selects the active frequency shift method and the sliding-mode phase-shift method analyzed in detail.Thirdly.it includes the various verisions of islanding detection test standard from different countries.And it finished a set of complete test program which has been widely used photovoltaic grid-connected inverter islanding protection test in domestic.Finally, the article make a blind analysis on the active frequency drift method.Based on the blind spot of the active frequency shif method, it introduce a new detection way which is based on the frequency variation.We develop a new device applied with the way mentioned above. And it test the new detection way after a series of experiments.