Abstract: The interaction between power electronic equipment, renewable energy units and power grids in the new power system leads to broadband resonance problems. Power cables are key links of renewable energy integration and their non-negligible distributed capacitance increases the risk of broadband resonance. The existing research mainly includes time-domain simulation and impedance analysis. However, the distributed parameter characteristics and frequency-dependent characteristics are ignored during the modeling, which leads to inaccurate stability assessment, lower efficiency of simulation and imaginary oscillation. The traditional Bergeron model fails to take the frequency-dependent characteristics into consideration, which causes problems like high-order harmonic amplification. In order to determine the modeling method suitable for power cables in the harmonic frequency range, the simplified calculation of power cable parameters is summarized according to the cable structure. On this basis, the advantages of Bergeron model are explored deeply, and the cable electrical parameters are modified according to the related harmonic frequency to improve the traditional Bergeron mode. Finally, the results obtained by the simplified calculation method of power cable electrical parameters are compared with those obtained by the calculation in PSCAD/EMTDC, and the proposed improved model is tested in time domain to verify its correctness and effectiveness.