Modeling and new tuning of the distribution transformer-integrated passive power filter and its effects on the transformer performance and network power quality

Abstract

• A new model is proposed for Transformer-integrated Passive power filter (TIPPF) in the presence of the mutual-inductances between the filter inductors and the primary/secondary windings. • A new scheme for modifying the integrated filter designing, is proposed. • Effects of the transfer of current harmonics from the main windings of the transformer to the filter inductors on the amount of losses, derating and efficiency of the transformer are investigated. In this paper, a new model is proposed for Transformer-integrated Passive power filter (TIPPF) to cancel the effects of not complete elimination of mutual-inductances and improve the filter performance. In this model, the mutual-inductances between the filter inductors and the primary/secondary windings are considered. To improve the power quality, a new scheme for modifying the filter designing, based on the determination of the filter share of the harmonic load current, is proposed. Theoretical analysis is validated using simulations in 3DAnsoft/Maxwell and MATLAB/Simulink software. Moreover, the effects of the transfer of current harmonics from the main windings of the transformer to the filter inductors on the losses, operating capacity and efficiency of the transformer are investigated. 2D finite element simulation of a 50-kVA distribution transformer in 2DAnsoft/Maxwell environment is used to estimate the losses including ohmic, eddy and stray losses in the windings. The results show the new method will substantially decrease the THD of network current.