Mechanism of Broadband Harmonic Amplification and Insulation Deterioration in DC Submarine Cables

With the increase of the proportion of cable lines, the harmonic problem caused by offshore wind power and solar power connected to the high-cabled power grid becomes more and more serious, which seriously affects the safety and stability of the DC transmission network. In this paper, the model of cable circuit in harmonic environment is established, and the serial impedance matrix Z and the serial admittance matrix Y are obtained, the influence of soft joint distribution on harmonic amplification is studied by considering the harmonic transmission model of multi-segment cable interconnection with soft joint. Finally, the initiation and growth characteristics of XLPE tree under DC superposition typical harmonic environment are investigated.