This study presents a new frequency estimation unit developed for three-phase systems. The algorithm relies on equidistant sampling and demonstrates better accuracy in determining the fundamental frequency, even in distorted three-phase systems. The method involves independently acquiring five equidistant samples in αβ frames and subsequently combining them to estimate the fundamental frequency. Further, a discrete orthogonal signal generator (D-OSG) prefiltering method is integrated with the proposed frequency estimator to deal with problems caused by high distortion grid conditions. It is worth noting that the proposed frequency estimation algorithm stands out for its inherent ability to successfully mitigate the impact of harmonics. The effectiveness of the proposed scheme is comprehensively assessed in the MATLAB/Simulink environment.