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

2019 ◽  
Vol 121 (3) ◽  
pp. 801-813
Author(s):  
D. Vijeswaran ◽  
V. Manikandan
Keyword(s):  
Frequency Control ◽  
Load Frequency Control ◽  
Time Varying ◽  
Time Varying Delay ◽  
Linear Load ◽  
Frequency Control System ◽  
Grid Load ◽  
Non Linear Load ◽  
Varying Delay ◽  
Load Perturbations

scholarly journals Enhanced Stability Criteria of Network-Based Load Frequency Control of Power Systems with Time-Varying Delays

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5820
Author(s):  
Wenxi Feng ◽  
Yanshan Xie ◽  
Fei Luo ◽  
Xianyong Zhang ◽  
Wenyong Duan
Keyword(s):  
Power Systems ◽  
Frequency Control ◽  
Load Frequency Control ◽  
Linear Matrix ◽  
Equivalent Transformation ◽  
Time Varying ◽  
Time Varying Delay ◽  
Load Frequency ◽  
Nonlinear Inequality ◽  
Improved Stability

The stability problem for load frequency control (LFC) of power systems with two time-varying communication delays is studied in this paper. The one-area and two-area LFC systems are considered, respectively, which are modeled as corresponding linear systems with additive time-varying delays. An improved stability criterion is proposed via a modified Lyapunov-Krasovskii functional (LKF) approach. Firstly, an augmented LKF consisting of delay-dependent matrices and some single-integral items containing time-varying delay information in two different delay subintervals is constructed, which makes full use of the coupling information between the system states and time-varying delays. Secondly, the novel negative definite inequality equivalent transformation lemma is used to transform the nonlinear inequality to the linear matrix inequality (LMI) equivalently, which can be easily solved by the MATLAB LMI-Toolbox. Finally, some numerical examples are presented to show the improvement of the proposed approach.

scholarly journals An Improved Stability Criterion for Load Frequency Control of Power Systems with Time-Varying Delays

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2101
Author(s):  
Bi-Ying Chen ◽  
Xing-Chen Shangguan ◽  
Li Jin ◽  
Dan-Yun Li
Keyword(s):  
Power Systems ◽  
Stability Criterion ◽  
Frequency Control ◽  
Load Frequency Control ◽  
Linear Matrix ◽  
Time Varying ◽  
Time Varying Delay ◽  
Load Frequency ◽  
Improved Stability ◽  
The Stability

This paper aims at developing a novel stability criterion to access the influence of the time-varying delay on the stability of power systems equipped with a proportional-integral (PI)-based load frequency control (LFC). The model of the LFC scheme considering time-varying communication delays is established at first. Then, an improved stability condition related to the information of delay bounds is deduced by constructing an augmented Lyapunov–Krasovski functional and using a matrix inequality, and it is expressed as linear matrix inequalities (LMIs) for easily checking. Finally, case studies for one-area and two-area LFC systems are carried out to show the relationship between delay margins ensuring the stability and the PI gains of the LFC, and also verify the superiority of proposed stability criterion compared with the previous ones.

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