Two-stage active power curtailment-based islanding detection technique for photovoltaic-based microgrids with zero non-detection zone

• Two-stage active power curtailment-based islanding detection technique is proposed. • Accurate detection with zero NDZ in less than 1.2 s. • Cost-effective integration into the existing solar inverters due to its simple structure. • Simple implementation into all PV module and inverter technologies. Effective islanding detection is mandatory for distributed generations (DGs) to avoid equipment damage and ensure the safety of network personnel. This paper proposes a fast, accurate, power quality-friendly, and practical two-stage active power curtailment (APC)-based islanding detection technique (IDT) for photovoltaic (PV)-rich microgrids. In the first stage, a periodic small disturbance is injected into the maximum power point tracking (MPPT) algorithm to slightly curtail the DG’s active power, causing a small mismatch even on a balanced island. During islanding, the introduced active power mismatch shifts output voltage, triggering the second stage disturbance to the MPPT algorithm. Hence, the output voltage drops further, resulting in islanding detection. A real-time digital simulation (RTDS) using the modified IEEE 13-node system corroborates the successful detection of all stringent cases in less than 1.2 s with no false tripping for non-islanding disturbances. This zero non-detection zone (NDZ) is achieved by curtailing less than 1 % of the DG’s available output. This technique is a practical solution for microgrids with high penetration of photovoltaic generators (PVGs) due to its simple structure and straightforward threshold determination, irrespective of the microgrid structure. The fast detection time allows the DG to seamlessly transition to the standalone microgrid.