Quantifying Resilience of Wide-Area Damping Control Against Cyber Attack Based on Switching System Theory

Since the cyber attack on the communication network will deteriorate the performance of wide-area damping controllers (WADCs) or even cause instability, many resilient WADCs are developed to mitigate the adverse influence of cyber attacks recently. However, there is a lack of quantitative indexes to guide the controller design in order to achieve the trade-off between attack resilience and damping performance. To address this problem, an index is proposed to quantify the strongest attack that the power system with a given WADC can tolerate, which is called as resilience margin. Firstly, the power system with a WADC subjected to cyber attack is modeled as a switching system consisting of stable and unstable subsystems. Then, based on switching system theory, the definition of resilience margin is presented. To calculate the resilience margin, the Lyapunov stability analysis is implemented on the switching power system to derive a practical calculation algorithm, which combines the bisection method and the linear matrix inequalities (LMIs) technology. The case study on the 16-machine 68-bus system with a voltage source converter based high voltage direct current system is performed. Simulation results demonstrate the effectiveness of the calculation algorithm and the significance of the resilience margin in the design of WADC.