In the wake of the increasing integration of cyber-physical systems within power grids, ensuring the security and stability of these systems has become paramount. This paper presents a comprehensive security analysis of cyber-physical power systems (CPPS) employed for frequency control in deregulated power markets. In the era of evolving power grids, characterized by increasing renewable energy penetration and market deregulation, maintaining frequency stability becomes a critical challenge. To address this challenge, this study investigates the synergistic utilization of Unified Power Flow Controller (UPFC) device and Redox Flow Battery (RFB), to enhance the frequency control performance. A realistic two-area CPPS is considered where a cascaded Fractional-Order Proportional-Integral-Derivative-Fractional Integral (FOPID-FI) controller has been implemented for frequency control in both areas. Our analysis delves into the vulnerabilities inherent in CPPS, considering potential cyber threats and their impact on frequency control mechanisms. By employing a systematic approach, we identify critical points of vulnerability in the system architecture and propose countermeasures to mitigate cyber threats effectively. We include extensive simulation results to validate the efficacy of the proposed work by analyzing the performance of the system from vital perspective viz., sensitivity, scalability, robustness, stable, and resilient.

With the growing smart grid concept it becomes important to monitor health of the power system at regular intervals for its secure and reliable operation. Phasor Measurement Units (PMUs) may play a vital role in this regard. This paper presents voltage stability monitoring in real time framework using synchrophasor measurements obtained by PMUs. Proposed approach estimates real power loading margin as well as reactive power loading margin of most critical bus using PMU data. As system operating conditions keep on changing, loading margin as well as critical bus information is updated at regular intervals using fresh PMU measurements. Simulations have been carried out using Power System Analysis Toolbox (PSAT) software. Accuracy of proposed Wide Area Monitoring System (WAMS) based estimation of voltage stability margin has been tested by comparing results with loading margin obtained by continuation power flow method (an offline approach for accurate estimation of voltage stability margin) under same set of operating conditions. Case studies performed on IEEE 14-bus system, New England 39-bus system and a practical 246-bus Indian power system validate effectiveness of proposed approach of online monitoring of loading margin.