A novel frequency estimator for adversely distorted grid signals

Abstract

This paper presents a novel technique for frequency estimation of grid signal under adverse distorted condition. The proposed method is a combination of Zero Crossing Detection (ZCD), and Goertzel Transform (GT) based ZCD (GZCD) for the accumulation of their desirable features and eradication of their drawbacks. ZCD gives a low computational solution of frequency estimator, but it is always suffered by harmonics, noise and other power quality disturbances. To get the low complexity benefits of ZCD it is used after the GT. Thus, the power quality degradation in the signal can be minimised by the GT. However, GT is found to have a slow dynamic response. The MATLAB and PSCAD results verify the robustness of the proposed method against various grid conditions and the hardware experimental results show that proposed method is easy to implement in real-time digital signal processor and provide a fast and accurate estimation of the grid frequency.