Modelling Harmonic Propagation in HVDC System Power Cables

In this paper a three level Voltage Source Converter (VSC) based HVDC system is implemented and simulations are carried out to monitor the harmonic profile along HVDC cables. The harmonic profile of the sending and receiving end of the cables are analyzed under different conditions. The impact of changes in background harmonic sequence on the harmonic profile of the HVDC cables is analyzed. The obtained simulation results can be used to visualize the complete harmonic frequency spectrum of HVDC cables. The potential impact of harmonic distortion on cable insulation is discussed in terms of the correlation between harmonic frequency and the different mechanisms responsible for cable ageing and degradation such as partial discharges and electrical treeing. The simulation results presented in this paper will help to improve the understanding of the harmonic propagation within HVDC cables and the harmonic impact on cables insulation.