Deployment of Information and Communication Technologies (ICT) on Power Systems added a new complexity to Power Systems. New vulnerabilities evolved from this highly interconnected System-of-Systems due to the interdependencies among and within their components. We develop an Eigen-spectral analysis using complex-valued graphs and Hermitian Adjacency Matrices to model these interdependencies and to identify the most critical components, taking into account the information flow direction in each infrastructure, which should help to describe the structure of the coupled system. The proposed methodology is demonstrated on a typical French distribution network including a surrounding ICT network.