Equivalent Modeling and Harmonic Conduction Mechanism Analysis of AC/DC Hybrid Power Grid

Abstract

This paper considers the AC/DC power grid as three parts of the external grid, the internal main grid and the internal low voltage grid separately according to the demand of harmonic conduction research. The external power grid with far electric distance is equivalent to simple model. The internal main grid which is main harmonic conduction channel is kept intact. The internal low voltage grid, which would have influence on harmonic conduction, is equivalent to accurate model. The accuracy of the model is verified by comparing the PSCAD simulation results with the measured harmonic data. In this paper, the multi-input interaction factor is applied to the harmonic frequency, and the factor is improved considering the current inflow through the self-harmonic impedance of two nodes. This improved multi-infeed interaction factor under harmonic frequency is used to analyse the AC/DC power grid models. Compared with the measured harmonic data, it is verified that this factor can reflect the actual harmonic conduction of the power grid.