The integration of new technologies in the electric grids made them more and more complex, and most likely future growth of power grids will be based more on underground cables than overhead lines. One problem here, is that the mathematical model for electromagnetic simulation of power cables still has some shortcomings regarding stability, accuracy and passivity. In this thesis, we evaluate the cable parameters using analytical and numerical methods.

This thesis addresses the transient stability analysis of hybrid AC/DC electric transmission systems. More precisely two questions sought to be investigated: What is the impact of a DC contingency on AC transient stability? How can we take advantage of the DC transmission systems as control inputs in order to enhance AC transient stability?