Distributed generation can potentially support unintentional system islands, isolated from the remainder of system. The islands pose a significant risk to safety and equipment, and need to be quickly detected eliminated. Islands are detected by sensitive unde and over voltage and frequency functions, sometimes aided by active island destabilization techniques.
This project presents a new method for islanding detection of distributed generation (DG) inverter that relies on analyzing reactive power versus frequency characteristic of the DG and islanded load. The proposed method on equipping DG-interface with Q-F droop curve that forces the DG to lose its stable operation once an islanding condition occurs. A simple passive islanding scheme that relies on frequency can then be used to detect the moment of islanding. The performance of proposed method can then be evaluated under the anti islanding test configuration. The studies reported in this project are based on simulations using MATLAB.
The results show that the proposed method has negligible non detection zone and is capable of accurately detecting islanding within the standard permissible detection times. In addition, the technique proves to be robust under multiple DG operation.