Modeling and Analysis of AC Side Equivalent Harmonic Impedance of HVDC Converter

摘要

The AC side equivalent harmonic impedance of HVDC converter is the key to study the harmonic instability and the design of AC filter in HVDC transmission system. Based on the switching function method, this paper deduces a new model of AC equivalent harmonic impedance of converter by analyzing the harmonic transformation mechanism of 12-pulse converter and considering the repeated modulation of AC side harmonic through converter. Finally, using PSCAD/EMTDC electromagnetic simulation software, based on CIGRE HVDC system standard model, the improved time domain simulation calculation is used to verify the proposed method. The comparison between the results of mathematical model calculation and time-domain simulation shows that the new AC equivalent harmonic impedance model in this paper has has high accuracy in the low frequency range.