A Filtering Scheme to Reduce the Penetration of Harmonics into Transmission Systems

The widespread adoption of energy efficient but harmonic-producing loads in residential homes has led to increased injection of harmonic currents into transmission systems. In response to this situation, a novel filtering scheme that can reduce the harmonic penetration into transmission systems is proposed. The scheme utilizes the tertiary winding of a substation transformer to construct a tuned low-impedance path for the harmonic currents. The proposed scheme is capable of trapping two zero-sequence harmonics and three nonzero-sequence harmonics simultaneously. A design procedure has been developed. Performance of the scheme is evaluated and demonstrated through simulation studies. In addition, economic analysis reveals that the scheme is a cost-effective solution in comparison with other applicable methods.