Harmonic Analysis Based on the Matrix Model of Nonlinear Element

This paper presents a new method to calculate the harmonic conditions for systems including switching-mode electronic nonlinear elements. The method is based on the harmonic coupled admittance matrix models for nonlinear elements. A thyristor controlled reactor (TCR) was used as an example of the nonlinear element to demonstrate the performance of the proposed method. Since the admittance model for the nonlinear TCR element is linear, a linear network solution in harmonic domain is sufficient to obtain the harmonic results. This paper also investigates the impact of high harmonic voltage distortions on the accuracy of the coupled admittance model and the associated harmonic power flow results. An iterative method was proposed to improve the original linear network solution accuracy for cases involving very high amount of harmonic voltage distortions.