Synchronized Reactive Power Variation Method for Islanding Detection Using High-Frequency Signal Injection

This paper proposes a synchronized reactive power variation (RPV) method for islanding detection in multi-inverter based distributed generation (DG) systems. The proposed method utilizes a high-frequency signal injection for synchronization, and therefore, additional communication components are not needed. The reactive power varies periodically under the condition that the high frequency signal is detected as expected. Once the detection time of the high frequency voltage is out of predesigned range, the RPV activation time will be changed to guarantee the synchronization. As RPVs of parallel-connected inverters are synchronized, the proposed method can work effectively in multi-inverter DGs. Simulation studies are carried out to verify the effectiveness of the proposed islanding detection method in multi-inverter based system.