Frequency Dependent Model of Underground Cables for Harmonic Calculations in Frequency Domain

Modeling underground cables for application in harmonic calculations in frequency domain is discussed thoroughly in this paper. At first, equations and frequency-dependent parameters to describe the zero-, negative-, and positive-sequence cable impedances as well as the coupling between them are presented. Afterwards, the influence of cable arrangement on the zero-, negative-, and positive-sequence cable impedances is investigated over the frequency. In this regard, some representative cable systems with different arrangements are simulated. Physical interpretation of the simulation results for the different cable arrangements contributes to comprehend the behavior of underground cables over the frequency in zero, negative, and positive sequences. Subsequently, based on the findings, modeling underground cables for harmonic calculations in the frequency domain is discussed. Finally, the validity of the proposed model is proved by comparing the simulation results with measurements on a medium voltage cable.