Evaluation and validation of Norton approaches for nonlinear harmonic models

Distorted currents and voltages are an increasing problem in electrical power networks. Primarily, they are caused by loads and decentralized power supply units which are connected by power electronic interfaces. In order to analyze the effects of a widespread use of such nonlinear appliances, nonlinear models have to be developed. Beside the current source model (CSM), which is suitable only for one specific voltage distortion, the Norton approaches are one of the most common approaches in frequency domain. In this paper, the classic Norton model (NM) and the advanced coupled NM are calculated based on various measurement sets and analyzed regarding their practical applicability in harmonic studies. The limitations of application are emphasized and suitable measurement sets for the calculation of the model parameters are evaluated.