Islanding Detection in a Grid-Connected Photovoltaic System Using Zero-Sequence Impedance

Grid-connected photovoltaic (PV) power systems have the benefit of being rapid and dependable sources of electricity. The power industry has been obliged to transition over to more PV-penetrated distributed generation as a result of solar energy’s favourable environmental effects in order to keep up with rising load demand. In grid-connected, PV systems, the problem of unintentional islanding in grid connectivity still presents a barrier. Therefore, quick islanding detection is required for effective and trustworthy operation of system. This paper proposes a passive islanding detection technique based on zero-sequence impedance computation at the Point of Common Coupling (PCC) for a PV interconnected grid system. The approach is simulated and tested under several Islanding test scenarios. By measuring the zero-sequence impedance at the PCC, which is calculated from the zero-sequence voltage and zero-sequence current, the islanding mode is identified. By identifying the Non-Detection Zone (NDZ), which fulfils the IEEE requirements of 2 s execution time, the results of this technique have been achieved and confirmed. A PV integrated grid system is used in the study, and many islanding situations were created using MATLAB/Simulink (version 2018b).