Nowadays, economy, security and quality of life heavily depend on the resiliency of a number of critical infrastructures, including the Electric Power System (EPS), through which vital services are provided. In existing EPS two cooperating infrastructures are involved: the Electric Infrastructure (EI) for the electricity generation and transportation to final users, and its Information-Technology based Control System (ITCS) devoted to controlling and regulating the EI physical parameters and triggering reconfigurations in emergency situations. This paper proposes a modeling framework to capture EI and ITCS aspects, focusing on their interdependencies that contributed to the occurrence of several cascading failures in the past 40 years. A quite detailed analysis of the EI and ITCS structure and behavior is performed; in particular, the ITCS and EI behaviors are described by discrete and hybrid-state processes, respectively. To substantiate the approach, the implementation of a few basic modeling mechanisms inside an existing multiformalism/ multi-solution tool is also discussed.