This paper describes a cyber-physical system approach for wide area control applications in power grids. Specifically, it is proposed to use cyber-physical system modeling methodology, to include explicit physical and behavior-based models, to facilitate the application of traditional controller design and analysis to wide area control applications. Our proposed approach allows for modeling the physical elements of the power grid (e.g. transmission network, generation, loads and measurement devices), the cyber components (e.g. execution of reactive software algorithms in data processing and control software), and the concurrent and sequential interactions of cyber and physical components. The cyber-physical interactions are critical for wide area control applications due to the multiple spatial and temporal scales present in these systems. The modeling methodology is formulated into a classical closed loop controller which the plant and the controller contain cyber and physical elements. The proposed approach allows for studying the impacts of cyber-physical interactions, evaluating the effectiveness and resiliency of wide area controllers, and can be applied as a tool to benchmark and derive specifications for final designs. The methodology is applied to a phasor measurement unit based wide area control of a static VAR compensator in a MATLAB/Simulink environment
