Sandia Frequency Shift (SFS) is one of the active islanding detection methods that rely on frequency drift to detect an islanding condition. Recently, SFS has been widely applied to inverter-based distributed generations due to its small Non-Detection Zone (NDZ). The NDZ in SFS method highly depends on its design parameters. Improper tuning of these parameters may result in failure of the method. In the proposed method in this paper, the load parameters are estimated online and the SFS parameter is adaptively tuned to eliminate NDZ using fuzzy load parameter estimation (FLPE) method. Simulation results verify the excellent performance of the proposed method.