Methodology for islanding operation of distributed synchronous generators

There is an increase interest for islanding operation of distributed generators (DG) due to economical and technical reasons. However, the control strategy applied to the DG is different for grid connected and islanding conditions, which demands identifying the DG connection status. This paper presents a methodology for detecting the DG connection status. The methodology is able to detect the occurrence of an islanding event or the reconnection of the DG to the utility grid. The developed method is based on a disturbance in the torque applied to the generator and it does not depend on communication systems. According to the response of this disturbance, it will be possible to identify whether the DG is connected to the utility grid or not.