2025. COMPARISON AND EFFECTIVENESS OF SLIP MODE FREQUENCY SHIFT AND SANDIA FREQUENCY SHIFT ACTIVE METHODS FOR ISLANDING DETECTION IN SINGLE-PHASE GRID-CONNECTED PHOTOVOLTAIC SYSTEMS. Journal of Engineering Studies and Research. 30, 4 (Jul. 2025), 7–18. DOI:https://doi.org/10.29081/jesr.v30i4.001.