Low-complexity graph-based traveling wave models for HVDC grids with hybrid transmission lines: Application to fault identification

•A graph-based description of grids comprising hybrid lines is proposed.•The path taken by any traveling waves can be specified.•A parametric model of the TW based on both physical and behavioral parts is proposed.•An application to the identification on the faulty line segment in MTDC grid is presented. Faults affecting hybrid transmission lines comprising both overhead and underground parts, generate numerous traveling waves may be difficult to describe and evaluate. This paper proposes a combined knowledge-based and behavioral modeling approach to represent the voltage and current waveform after the fault occurrence. The grid is reprensente as a graph which facilitates the selection of waves traveling through the grid for a finite time-horizon simulation. A relatively compact description of the waves is then derived. The obtained model depends explicitly on the characteristics of the grid and on the fault parameters. An application of the model to the identification of the faulty portion of an hybrid line within an HVDC grid is proposed.