Background The islanding condition may appear in power grid lines to which additional energy sources with power electronic converters have been connected, such as solar panels or wind turbines. It is a hazardous operating state for grid workers and devices connected to the islanded part of the grid. The state results from the inability to control amplitude and frequency of basic harmonic of the grid voltage. Material and methods simulations, laboratory tests Results The results show that frequency based anti-islanding detection algorithms, can be tuned in a narrow range of input parameters to adjust the detection time in wide range. By tuning these parameters, there is a possibility to influence THD in power converter output current, especially in the case when the converter cooperates with the utility. An introduction of a modified reference current waveform an approximate 30% reduction of THD in output current can be achieved in a real electric circuit. Moreover, injected distortion in comparison to the basic version of the AFD method amplifies higher harmonic orders that can be easily filtered out. Conclusions The knowledge about results, may be used in the designing process of high effective, reliable anti-islanding protection systems characterized by reduced total harmonic distortions injected into converter output current.