Shorter Window DFT based Technique for Fault Current Filtering

C.-S. Yu, S.-Y. Lee, S.-C. Wang, and Y.-L. Chen (Taiwan)


Discrete Fourier transform, damping, decaying dc component, subsynchronous frequency component.


This work presents a shorter window DFT (SWDFT) based technique for fault current filtering in series compensated lines. First, the shorter windows DFT based mimic filter is developed to damp the measurement. Then, a reiterative scheme is proposed to reconstruct the damped measurement and achieve further damping. The proposed algorithm not only can support enough damping to both the decaying dc and the subsynchronous frequency components. Thus, the proposed algorithm is appropriate to the filtering design on both the conventional and series compensated transmission lines protection. Meanwhile, the recursive form is developed to reduce the computation burden. Simulations results illustrate the algorithm significantly reduces the time to obtain the accurate fundamental phasor and provides better performance than that of the conventional DFT algorithm.

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