Use Hamming window for detection the harmonic current based on instantaneous reactive power theory

This paper proposes a new digital real-time method for accurate detection of harmonic current. This method was modified from a well-known technique that is based on the instantaneous reactive power theory. Using complex integral algorithm and employing Hamming windowing to suppress spectral leakage, it was proven to improve the detection precision significantly. It not only measures the total harmonic current, but is also able to differentiate between positive-sequence and negative-sequence components of each harmonic. The capability of this method has been verified via computer simulations as well as through its application in a 30-kVA active filter prototype.