This paper describes an approach for modeling smart grids for wide area control applications. More specifically, it is proposed to model smart grids as a set of interdependent composite networks. A composite network is one whose evolution in time and/or space is described as a composition of more than one category of networks. This work proposes an interconnection of a communication network, information network, and a power system network to model smart grids. More specifically this work proposes a quantitative model focusing on bulk generation and transmission. The resulting model will be used for studying and simulating wide area measurement and control techniques and contingencies of components. The modeling methodology is based on the initial partitioning by the National Institute of Standards and Technology (NIST) of the smart grid domains. A basic example with control of load (demand response) and generator set points over a communication link is presented.