Analysis of Unbalanced Harmonic Propagation in Multiphase Power Systems

Harmonics related concerns were initially centered at a few large harmonic-producing devices until the early 1980s. Because these devices, such as HVDC and SVC, and their supply systems are well balanced among three phases, harmonic analysis based on positive sequence network representations was generally sufficient. The situation has changed significantly in recent years. More and more harmonic-producing loads are being connected to systems which are unbalanced. The effects of single phase harmonicproducing loads are also becoming important. The need to investigate harmonic propagation in unbalanced systems with unbalanced harmonic excitations has emerged.