Dynamic contingency analysis and remedial action tools for secure electric cyber-physical systems

Abstract

In recent years, the drive to bring about technological and regulatory changes that concern energy, natural resources, and climate change has gathered significant momentum. Of the numerous changes that the power grid is undergoing, perhaps the most transformative is the increased use of communication and computing technologies. The deployment of new communication, computing, and control technologies has significantly augmented the capabilities of traditional Supervisory Control and Data Acquisition systems. These technologies characterize the “smart grid” and have transformed them into the largest and most complex cyber-physical systems ever built; they also hold the potential to revolutionize power system operation and control paradigms. The system can often be protected from widespread consequences of failures of system components and other types of faults through timely detection and remedial action. By evaluating the stability of power systems and executing a sequence of remedial actions in real time or faster than real time, power systems can be hardened against cascading failures and unfolding events which can be either initiated by failures of system components, faults, or malicious attacks. This chapter discusses the application of real-time transient stability assessment and remedial action tools in enhancing power systems against potential cascading failures utilizing the developments in communication and computing technologies. Remedial actions are classified into preventive and corrective actions based on the time available to an operator to respond. Direct methods in the form of the energy function are utilized in transient stability screening and generating remedial actions. Different methods of calculating the controlling unstable equilibrium points (an equilibrium point that the trajectory of the system will go to after a destabilizing contingency) such as a Boundary of stability region-based Controlling Unstable equilibrium point method and a homotopy-based method are presented. Explicit derivations of expressions that are needed for transient stability analysis and remedial actions as well as an illustrative example are also provided.