Impact of an Advanced Cable Model and Synchronous Generator on Stability of HVDC Grid

The interconnection of ac grids using HVDC grids across countries posses questions regarding interactions and stability. Such analysis with mixed short circuit ratio (SCR) will be time-consuming since; detailed models and multiple simulations of the entire system will be required in order to develop a complete understanding of the modes of interactions and existing stability margins. In addition, stability and interaction are impacted by the cable and generator model. The paper investigates the impact of cable models on the interaction and stability margins. In addition, the synchronous generator model is also investigated. A lower-order frequency-dependent model of cable is shown to be effective in predicting the interaction, when frequency-dependent shunt capacitance and conductance are used. It is observed that the cable model has a significant impact on controller interaction and instability.