Systems that include a discrete (digital) and continuous (analog) interfaces are collectively called as hybrid systems. Examples include control of synchronous generators over packet-based SCADA networks, sensor-based control of HVAC systems over differential serial bus networks, and flow control in oil and natural gas pipelines using a network of sensors. The electric grid is an example of a large-scale, wide-area, real-time hybrid system. Modeling and simulation of hybrid systems is a key enabling technology for the design of next generation systems that integrate packet-based communication networks, physical systems, and advanced control technologies. As a result of deregulation and DER integration, the electric grid comprises of a tightly coupled communication and control subsystems. The evolving dynamics of such systems have to be studied to defend against inherent design vulnerabilities in the system.
ORNL is developing a novel and unique toolkit for modeling hybrid systems and evaluation
(THYME). THYME is an extensible framework for integrating continuous and discrete system models. It includes a small set of numerical integration schemes for solving ordinary differential equations and can be easily extended by end users who require specialized or especially robustness continuous system simulation algorithms. THYME is a tool for simulating network-centric systems with continuous and discrete event sub-components and building comprehensive, integrated modeling of networked controllers and plants. (Poster PDF 418KB)
