An Advanced Full Cycle DFT Algorithm for Data Synchronization Used in Digital Protective Relaying

摘要

In this paper, data synchronization of bay layer device is proposed. Then, an approach based on quadratic interpolation is presented. To identify any disturbances, the fundamental frequency (various harmonic frequencies) component is usually extracted by means of the full-cycle DFT algorithm. But the new sequence of quadratic interpolation may contain oscillatory components with different frequencies as well as decaying DC offset during fault conditions. These nuisance components might eventually affect the performance of quadratic interpolation algorithm implemented in digital protective relays. The purpose of this paper is to use an advanced full-cycle DFT algorithm to ensure that the interpolation factor is the only source of error. This advanced algorithm can extract the fundamental frequency (various harmonic frequencies) component amplitude and/or phase by removing decaying DC offset. Then, the result of quadratic interpolation will not be affected by the decaying DC offset. At last, the simulation results of the amplitude and phase error are presented by means of MATLAB.