Open Access

ARTICLE

Stability Analysis of Cyber-Physical Micro Grid Load Frequency Control System with Time-Varying Delay and Non-Linear Load Perturbations

D. Vijeswaran^1,*, V. Manikandan²

1 Department of Electrical and Electronics Engineering, Coimbatore Institute of Technology, Coimbatore 641014, India.

* Corresponding Author: D. Vijeswaran. Email: .

Computer Modeling in Engineering & Sciences 2019, 121(3), 801-813. https://doi.org/10.32604/cmes.2019.07793

Abstract

In a cyber-physical micro-grid system, wherein the control functions are executed through open communication channel, stability is an important issue owing to the factors related to the time-delay encountered in the data transfer. Transfer of feedback variable as discrete data packets in communication network invariably introduces inevitable time-delays in closed loop control systems. This delay, depending upon the network traffic condition, inherits a time-varying characteristic; nevertheless, it adversely impacts the system performance and stability. The load perturbations in a micro-grid system are considerably influenced by the presence of fluctuating power generators like wind and solar power. Since these non-conventional energy sources are integrated into the power grid through power electronic interface circuits that usually works at high switching frequency, noise signals are introduced into the micro-grid system and these signals gets super-imposed to the load variations. Based on this back ground, in this paper, the delay-dependent stability issue of networked micro-grid system combined with timevarying feedback loop delay and uncertain load perturbations is investigated, and a deeper insight has been presented to infer the impact of time-delay on the variations in the system frequency. The classical Lyapunov-Krasovskii method is employed to address the problem, and using a standard benchmark micro-grid system, and the proposed stability criterion is validated.

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Keywords

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