Switching system-based load frequency control for multi-area power system resilient to denial-of-service attacks

Abstract

Load frequency control (LFC) scheme of modern power systems tends to employ open communication networks to transmit control/measurement signals, which makes the LFC scheme more vulnerable to cyber-attacks such as a denial-of-service (DoS) attack. The DoS attack prevents signal transmission and degrades the performance of or even results in instability in the LFC scheme. This paper proposes a switching system-based approach to the LFC scheme of a multi-area power system that is resilient to DoS attacks. After modelling the LFC scheme under DoS attacks as switching subsystems based on the duration of DoS attacks, a new stability criterion in terms of the duration and frequency of DoS attacks is developed. The derived criterion can be used to calculate the maximum duration and frequency of DoS attacks that the LFC system with a given proportional–integral (PI)-type controller can tolerate and to determine the control gains of the PI-type controller for a given duration and frequency of DoS attack. Moreover, a resilient LFC scheme is proposed based on a dual-loop communication channel equipped with the designed PI controller. The effectiveness of the proposed LFC scheme is evaluated on a traditional three-area power system and a deregulated three-area power system under DoS attacks.