Improved L1 Networked Adaptive Approach to Load Frequency Power Control Under Cyber Attacks

Abstract

This paper investigates an adaptive control problem for switched cyber-physical systems subject to external disturbances, denial-of-service (DoS) attacks, and false data injection attacks. We consider attackers to be able to threaten the networked system performance, where the DoS depletes the network bandwidth and might randomly block out the transmission signals or produce a significant delay in transmission signals, while the false data injections fabricate the transmission signal as a disturbance. To handle the abrupt occurrence of cyber attacks, the power system is modeled as a switched system. The switched system responds to changing dynamic models and among the states when the system parameters are altered due to disturbances, denial-of-service, and false data injection attacks. The proposed controller unit involves a reliable estimation scheme to estimate and compensate for cyber attacks while sustaining the desired performance and robustness. A distinctive feature of the proposed controller is the introduction of a low-pass filter, which is particularly convenient for attenuating parameter fluctuations and guaranteeing a rapid adaptation rate. The simulation of the closed loop system shows that the proposed L1 controller outperforms the H∞ controller. A simulation study is established to illustrate the influence and robustness of the developed controller, which can enhance the transient response under different operating conditions.