Information-Energy Flow Computation and Cyber-Physical Sensitivity Analysis for Power Systems

Power systems are the typical cyber-physical systems in which the closed-loop hierarchical control systems (HCSs) are widely used to ensure their stable and safe operation. To describe the coupling operation mechanism of an HCS and power grid by expanding current steady-state power flow analysis theory, we propose an information-energy flow model and develop a matrix-based computational approach. With the help of the methods, we can directly calculate the mutual influence of the cyber and physical parts. Since the mechanism of power flow computation is mature, we focus on the cyber side, proposing an information-flow-oriented network model as well as a matrix-based computation method for its information flow. In particular, we develop a minimum-cut-set-based partition and equivalence method to address a complex cyber network with non-linearity issues associated with data processing. Subsequently, we discuss cyber-physical sensitivity and vulnerability issues. In the case study, we calculate the information-energy flow of an IEEE 14-node system with real time-voltage stability monitoring and control application and compare the results with simulation results. The similarity of the results between the two methods verifies the effectiveness of our approach.