Frequency regulation of an interconnected cyber-physical power system

Abstract

In this article, first a new hybrid Cyber-Physical Power System (CPPS) model to cater to the ancillary service of Load Frequency Control (LFC) for an interconnected power system is proposed. The proposed hybrid model considers network-induced delay and aperiodic sampling as time-triggered phenomena, while Bernoulli distributed stochastic data packet loss is considered as discrete network events that are independent of each other unlike in other literature of Cyber-Physical System (CPS). Secondly, a two-term Memory-based sampled-data control (MSDC) with state feedback and $H_{\infty }$ disturbance rejection criteria under variable sampling is designed. The design is accomplished for the proposed model with an improved Lyapunov-Krasovskii (LK) functional & adopting compatible integral inequality to handle the cyber domain (or network) constraints with a view to guarantee stability and disturbance attenuation of the system for a maximum delay upper bound and sampling interval. The effectiveness of the proposed control design is validated through transient and steady state response results and specifications compared to existing results under different digital communication constraints & scenarios. Further, a robustness study is carried out for the proposed CPPS under cyber attacks on the actuator side of the network as a disturbance to present the efficacy of the control design and model.