• Boina Ramya
• Dr. A. Jaya Laxmi
• T. Venkatesh

In natural disaster conditions, the disconnection between grid and load centres is the most probable condition. To maintain continuous power supply, it requires that loads should be connected to the locally available DERS which is known as islanding condition. In DGs that are directly connected to a grid, the islanding phenomenon can occur during unplanned disconnections from the grid. Specifically, islanding occurs when the grid-connected inverter of the DG and part of the local load are disconnected from the rest of the grid. If this phenomenon is not detected and the generation from a Photo Voltaic (PV) or other energy source remains operative, the islanded DG system remains energized by the inverter. The islanding phenomenon in PV systems is one of the most important problems in this area because it poses a safety hazard to repair and maintenance personnel. Grid connected photovoltaic systems have been paid more attention by people. The problem of anti-islanding is a key problem that threatens the secure operation of distributed generation (DG) system, so the system must have the function of timely detecting islanding. The traditional active frequency drift (AFD) method is not fast enough, and the total harmonic distortion (THD) is large, which greatly affect the output current quality. Hence, an improved active frequency drift detection method based on changing chopping factor (cf) is proposed in view of the above shortcomings of the traditional AFD method. In this method, the detection time is shortened, THD is reduced. The effectiveness and superiority of the proposed method are verified by Matlab/Simulink simulation.

Islanding detection, Active Frequency drift, Non-Detection Zone, Total Harmonic Distortion.

"An Islanding Detection Method For A Grid-Connected Distribution System Using Fuzzy Controller", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.12, Issue 11, page no.a167-a174, November-2025, Available :http://www.jetir.org/papers/JETIR2511021.pdf

"An Islanding Detection Method For A Grid-Connected Distribution System Using Fuzzy Controller", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.12, Issue 11, page no. ppa167-a174, November-2025, Available at : http://www.jetir.org/papers/JETIR2511021.pdf