A Hybrid Unintentional Islanding Identification Methodology for IIDGs

The identification of unintentionally islanded microgrids (UIM) is one of the major challenges in microgrid. A hybrid unintentional islanding identification methodology (HUIIM) is proposed in this work. It is based on average absolute d-axis voltage deviation (AADVD), circuit breaker status, and disturbance injection through d-axis current controller. The disturbance is injected only by the disturbance injection module (DIM). The disturbance is injected by the DIM only after the microgrid is islanded, it makes the d-axis voltage to vary on post islanding condition. Consequently it becomes an indication of the islanding formation for the distributed generators, upon analysing the d-axis voltage islanding formation is detected. The status of the circuit breaker is transferred to the DGs without using the communication. Since, the DIM injects disturbance only after the microgrid is islanded the proposed methodology does not degrade the power quality during the grid-connected mode of operation (GMO) and it does not destabilize the microgrid on post islanding condition. Also, it identifies the islanding condition within 140 milli sec and also clearly distinguishes the non-islanding from the islanding conditions. The proposed methodology is validated in MATLAB/SIMULINK 2024a version.