Design and operation of grid-connected photovoltaic system with power-factor control and active islanding detection

An approach to power-factor control and islanding detection of a grid-conne cted photovoltaic system is proposed. With the designated control circuit, deviation at the output of the inverter can be observed. Coupled with the a lgorithm developed, this deviation serves as a useful aid to detect islandi ng more effectively. The proposed method has been tested through different scenarios, including the loss of grid and operation in parallel. Simulation studies and hardware circuits were both made to validate the effectiveness of the method. With the test results they help consolidate the feasibility and practicality of the approach for the applications considered.