Harmonic suppression analysis of a harmonic filtering distribution transformer with integrated inductors based on field–circuit coupling simulation.

This study analyses and evaluates the feasibility of a harmonic filtering distribution transformer (HFDT) for a harmonic reduction in low‐voltage distribution networks. With this new‐type transformer, power quality of the distribution systems can be improved by preventing the low‐voltage‐side harmonic currents from penetrating the higher voltage side. As the physical size of available space in prefabricated substations is strictly limited, necessary low space occupying filtering techniques are needed. Therefore, an HFDT with integrated filtering inductors (IFIs) capable of being implemented in regular air‐insulated prefabricated substations is proposed. Two sets of passive filters configured by IFIs and external capacitors are employed for harmonic filtering. Two methods for estimating the inductance parameter are provided. One is the dimension‐based method and the other is the reduced‐order inductance matrix method. The relevant harmonic reduction analysis is based on simulations with a field–circuit coupling model, which consists of a three‐dimensional finite‐element electromagnetic model of an HFDT with IFIs and a corresponding electric circuit of a simplified distribution network. These simulations prove that the described HFDT can effectively reduce specific harmonic currents with IFI‐based filters. Finally, the successful suppression of harmonics is demonstrated and discussed based on field‐test measurements. [ABSTRACT FROM AUTHOR]