Dynamic Stability Analysis Research Articles

Investigating the Impact of Grid-Tied Photovoltaic System in the Aljouf Region, Saudi Arabia, Using Dynamic Reactive Power Control

Due to uncertain photovoltaic (PV) power generation, analyzing the voltage stability of transmission networks with a large PV plant is challenging. The stability of PV output power is a critical factor in establishing PV penetration levels in active transmission networks when assessing loading capabilities. Therefore, this article contributes to enhancing the understanding of how a static synchronous compensator (STATCOM) could be used as part of the power system network. STATCOMs are often used to improve the static and transient voltage, maintain transmission limits, and reduce low-frequency disturbances. With the help of a STATCOM unit, a proper investigation and analysis of dynamic voltage stability in a transmission system are presented. The validity of the study is evaluated by the Saudi Arabia grid code (SAGC). The system being tested is comprised of a 300 MW PV plant in Sakaka, Saudi Arabia, integrated into a 17-bus transmission power network and a STATCOM, which is employed at one of the buses. PSAT software is used to evaluate a number of case studies to determine the transient voltage stability with and without the STATCOM and the PV plant. The simulation findings demonstrate how STATCOM functions to improve the quality of the power system in accordance with the SAGC. In addition, the analysis of voltage stability demonstrates that the power network’s resilience to short circuits at the PV system’s grid connection point significantly impacts the voltage’s dynamic behavior.

Dynamic stability of single-layer spherical reticulated shell structures under earthquake action

In past decade, earthquake disasters have seriously damaged nonstructural components, so it is very important to study their dynamic stability. However, the existing researches mainly focus on the dynamic stability of multistory and high-rise buildings, and there are still deficiencies in the analysis of dynamic stability of reticulated shell structures under earthquake action. This paper takes the 40 m span K8 single-layer spherical reticulated shell structure with practical engineering significance as the research object, we study its dynamic instability characteristics under earthquake action, and propose a dynamic stability judgment method. The influence of various parameters on the critical loads of emotional stability of reticulated shell structures is systematically analyzed, including the impact of horizontal seismic action, the vertical seismic activity, and the three-dimensional seismic movement, considering the influence of material elastoplasticity; the result of different seismic inputs, the effects of initial geometric imperfections; the effects of varying rise span-ratio. In this paper, to investigate the nonlinear time-history response analysis, we uses the finite-element package ABAQUS. We first analyze the rise-span ratio as the dynamic stability of 1/3 single-layer reticulated shell structure under the action of the El Centro (1940) earthquake to reveal the dynamic loss of reticulated shell structure under earthquake action stable feature. The practical method for determining the proposed dynamic stability has a clear physical meaning and a range of applications. Our findings highlight that the critical load for dynamic stability under horizontal earthquake action is significantly lower than vertical earthquake action, and the critical load is the lowest under three-dimensional earthquake action. Material elastoplasticity influences the critical loads for dynamic stability of reticulated shell structures under different ground motions. The critical load of dynamic stability of single-layer structures with a larger rise-span ratio is lower, while those with a smaller one is higher. The initial geometric defects of the structure should be considered in practical engineering applications. The reticulated shell structure with a larger rise-span ratio needs to consider the dynamic stability problem in the strong earthquake area.

Sustainable implementation of the carbon-labeling policy with customer participation and government supervision

China is vigorously pursuing carbon neutrality targets to combat global warming. As a powerful tool for encouraging individuals to adjust their consumption patterns and fostering the advancement of green consumption, the overall planning of carbon-labeling policy is accelerating accordingly. To better comprehend and strengthen the sustainable implementation of carbon-labeling policy, this study constructs a tripartite mainstay game to explore the interactive behavior of carbon-labeled enterprises and customers, with the substantial involvement of governmental regulators. First, the evolutionary stability strategy (ESS) is determined by solving replicated dynamic equations and stability analysis of equilibrium points. Then, the practicability and rationality of the evolutionary game model are assessed ESSs corresponding to various scenarios in the carbon-labeling scheme. Finally, the first Chinese television manufacturer to acquire carbon-labeled certification, TCL Group, is utilized as evidence to validate the theoretical findings and support the subsequent arguments: There are eight equilibrium points and three potential ESSs in the game model, and the selection of each ESS is primarily determined by the trade-off between costs and revenues for each stakeholder; the level of carbon-labeled enterprises' green R&D effort has a beneficial effect on the implementation of carbon-labeling policy, while customers' identification of carbon-labeled products will potentially affect operational orientation; and governments' stringent oversight is a vital assurance that both the carbon-labeled enterprises and customers adhere to green initiatives. The results thus not only elaborate on the efficient approach and insights for the sustainable implementation of carbon-labeling policy with the participation of multiple stakeholders, but also offer suggestions for enhancing incentives to improve regulatory regimes and market outcomes.

Nonlinear dynamic stability analysis of imperfect architected cellular sandwich plate under impact loading

Nonlinear dynamic stability analysis of imperfect architected cellular sandwich plate under impact loading

Dynamic stability model and analysis of mechanical properties for railway operations

Dynamic stability model and analysis of mechanical properties for railway operations

Stability Analysis of Caputo Fractional Order Viral Dynamics of Hepatitis B Cellular Infection

We present a Caputo fractional order mathematical model that describes the cellular infection of the Hepatitis B virus and the immune response of the body with Holling type II functional response. We study the existence of unique positive solutions and the local and global stability of virus-free and endemic equilibria. Finally, we present numerical results using the Adam-type predictor–corrector iterative scheme.

Recent advances in subgrade engineering for high-speed railway

Abstract In the last decade, the design and construction technologies of subgrade in high-speed railway (HSR) developed significantly. This article reviews corresponding development in five aspects, including mechanical properties of fill materials, dynamic performance of subgrade, foundation treatment, retaining structure, and smart construction technologies. It shows that for unbonded granular materials, it is acceptable to use static strength for subgrade design, but for clayey soil it would be more appropriate to base on shakedown theory. The mechanism for lime modified clay has been thoroughly reviewed, and the effect of lime content, curing age, and curing conditions on the behavior of lime-treated clay is discussed. The dynamic response of subgrade, especially the long-term deformation and dynamic stability analysis are important to understanding the behavior of HSR subgrade. The effect of track types, operation speed, etc. on the dynamic response of subgrade are reviewed first. Then, the prediction methods, influencing factors, and corresponding issue for long-term deformation of subgrade are presented, followed by the methods used for dynamic stability analysis. Three types of foundation treatment methods, including geosynthetic-reinforced pile-supported (GRPS) embankment, pile-raft structure, and pile-plate structure are reviewed for the corresponding load transmission mechanism, and application scenario. The static and dynamic behavior of four types of retaining structures are presented, including cantilever retaining wall, geosynthetic reinforced soil retaining wall, anchored retaining structure, and retaining wall reinforced by soil nailing. Finally, a series of new technologies correlated to smart construction are introduced, relating to the survey, design, construction, detection, and management of subgrade.

Learning to Harness Bandwidth With Multipath Congestion Control and Scheduling

Multipath TCP (MPTCP) has emerged as a facilitator for harnessing and pooling available bandwidth in wireless/wireline communication networks and in data centers. Existing implementations of MPTCP such as, Linked Increase Algorithm (LIA), Opportunistic LIA (OLIA) and BAlanced LInked Adaptation (BALIA) include separate algorithms for congestion control and packet scheduling, with pre-selected control parameters. We propose a Deep Q-Learning (DQL) based framework for joint congestion control and packet scheduling for MPTCP. At the heart of the solution is an intelligent agent for interface, learning and actuation, which learns from experience optimal congestion control and scheduling mechanism using DQL techniques with policy gradients. We provide a rigorous stability analysis of system dynamics which provides important practical design insights. In addition, the proposed DQL-MPTCP algorithm utilizes the ‘recurrent neural network’ and integrates it with ‘long short-term memory’ for continuously i) learning dynamic behavior of subflows (paths) and ii) responding promptly to their behavior using prioritized experience replay. With extensive emulations, we show that the proposed DQL-based MPTCP algorithm outperforms MPTCP LIA, OLIA and BALIA algorithms. Moreover, the DQL-MPTCP algorithm is robust to time-varying network characteristics, and provides dynamic exploration and exploitation of paths.

A theoretical prediction of novel Janus NiSX (X = O, Se, Te) Monolayers: Electronic, optical, and thermoelectric properties

Using density functional theory and semi-classical Boltzmann transport theory were employed to investigate the electronic structure, phononic and optical properties, dynamic stability, and thermoelectric characteristics of Janus NiSX (X = O, Se, Te). The electronic band structure of NiSTe indicates metallic behavior while NiSO and NiSSe show semiconducting features with indirect bandgap. Phononic properties and dynamic stability analyses reveal the stability of Janus Ni compounds. These compounds can be utilized as promising wave reflectors in the infrared (IR) range. Moreover, NiSO and NiSSe are good optical absorbers in the range of far ultraviolet (FUV). NiSTe exhibits isotropic absorption in the visible as well as FUV ranges. Thermoelectric calculations at room temperature show high Seebeck coefficients of 650 and 550 µV/K for NiSO and NiSSe, respectively. The large power factor of 20.83 × 1010 and 25.16 × 1010 W/msK2 are respectively found for n-type NiSO and NiSSe. The results suggest NiSO and NiSSe as promising thermoelectric materials with figure of merit of one (ZT ∼ 1). Consequently, NiSO and NiSSe can serve as efficient alternatives to conventional thermoelectric devices. The results of the current research can be used in the design of novel nanoelectronic devices as well as providing an excellent database for future studies.

A Hybrid Robust Adaptive Sliding Mode Controller for partially modelled systems: Discrete-time Lyapunov stability analysis and application

This work presents a new discrete-time Hybrid Robust Adaptive Sliding Mode Controller, developed from the union of a Robust Model Reference Adaptive Controller, an Adaptive Sliding Mode Controller, and an Adaptive One Sample Ahead Preview Controller in an unique control structure. Robust Model Reference Adaptive Controller is an adequate direct adaptive control strategy to control partially known plants, but can present slow closed-loop response to ensure global stability. Therefore, an adaptive One Sample Ahead Preview controller is incorporated to accelerate transient regimes, once it tries to track reference signal in one sample. Furthermore, an adaptive Sliding Mode Controller is also merged in the controller structure to help controller performance in transient regime and it also improves relevantly the steady state response in a scenario of several unmodelled dynamics Stability analysis of this controller using Lyapunov criterion and its robustness proof are provided, considering the plant subjected to unmodelled dynamics, which provides controller design constraints. These proofs show the controller is globally stable, and the tracking error tends to a residual set in steady state, even in the presence of matched and unmatched dynamics. Numerical simulations of the Hybrid Robust Adaptive Sliding Mode Controller applied on an unstable nonminimum-phase plant are presented, where only part of the overall plant is take into consideration for controller design. Results corroborate the feasibility and robustness of the developed control strategy and the performance superiority when compared to an adaptive One Sample Ahead Preview controller, with a 75% tracking error reduction in a scenario of several unmodelled dynamics.

Dynamic Behavior and Stability Analysis of Automatic Voltage Regulator with Parameter Uncertainty

This research article describes a novel optimization technique called simulink design optimization (SDO) to compute the optimal PID coefficients for an automatic voltage regulator (AVR). The time-domain performance of the proposed controller was analyzed using MATLAB/Simulation, and its performance was compared with that of water cycle algorithm, genetic algorithm, and local unimodal sampling algorithm-based PID controllers. The robustness of the proposed controller was verified by applying the disturbances to the generator field voltage and the amplifier parameter uncertainty. The studies presented in literature were discussed the AVR loop stability using the Bode plot which will not give the minimum stability margins. This study proposes a novel stability analysis called disk-based stability analysis to authenticate the stability of the AVR loop which is obtained by the classical analysis. This stability was compared with the proposed stability analysis. The MATLAB results reveal that the SDO-PID controller regulates the terminal voltage of the generator precisely, is more robust to parameter uncertainty, and is more stable than the other controllers. The maximum allowable parameter uncertainty of the amplifier model was identified as 102% of its nominal parameters. The stability margins are recognized as DGM = 10.40 dB and DPM = 56.50° for the AVR stability.

Dynamic stability of sandwich panels subjected to periodic axial loads

This paper presents an analysis for the dynamic stability of sandwich beams/wide plates subjected to periodic axial loads. The formulation of the problem is done by use of the Extended High-order Sandwich Panel Theory (EHSAPT). The equations of motion are derived from Hamilton’s principle and are expressed in terms of seven generalized displacements. A sandwich panel with simply supported edges is studied as an example, and the equations of motion for a given harmonic n are further derived. Two time-variations for the axial forces, namely, harmonic axial forces and step-wise periodic axial forces, are considered in this work. By considering the features of these two periodic load profiles, Floquet theory and Bolotin’s method are adopted to perform the dynamic stability analysis. Sandwich panels with different face-to-core thickness ratios are studied. Stability maps for varying frequency and amplitude of the forces are presented. Numerical examples show that when a sandwich panel is subjected to periodic loads, it is possible that it can experience dynamic instability even when the dynamic loads are much lower than the static critical loads.

Frequency and dynamic stability analysis of the sandwich structure with honeycomb core and GOP reinforcement using deep neural network

In the presented paper, by using deep neural network (DNN), the vibrational response associated with a three-layered circular sector plate, in which the core is made of honeycomb structures and the face sheets are made of composites reinforced with graphene oxide powders is studied. Two-directional generalized differential quadrature method (2D-GDQM), as the solution method, is employed to discretize and solve ordinary differential equations. By using a momentum-based optimizer in a neural network system, the optimum value associated with different parameters is acquired. First-order shear deformation theory (FSDT) is utilized in order to attain the displacement fields based on which the governing equations are extracted. The frequency of the system is attained by using the adaptive learning method. Additionally, the results as well as the formulation of the current study are validated by using other papers. It was shown that the DNN-based model in studying these three-layered systems has less error than other models. Lastly, the impact of various parameters for the honeycomb core as well as reinforced composite face sheets, was investigated in detail.

A numerical investigation on direct and data-driven flutter prediction methods

Three alternative algorithms for dynamic aeroelastic stability analysis are investigated. They are based either on direct search of oscillatory conditions of the coupled system or on eigenvalue analysis from frequency-domain sampling of the unsteady aerodynamics. The aerodynamic forcing is obtained with a harmonic-balanced solver developed for a general-purpose finite-volume fluid dynamics solver. This new implementation is first verified against experimental flutter results from the literature. A wing with relatively low bending stiffness is then used to explore the relative performance of each approach, both in terms of the numerical robustness and of their usability to support aeroelastic design.

Dynamic modeling, stability analysis and control of interconnected microgrids: A review

This paper reviews concepts of interconnected microgrids (IMGs) as well as compare and classify their modeling, stability analysis, and control methods. To develop benefits of isolated microgrids (MGs) such as reliability improvement and their renewable energy integration, they should be interconnected, share power, support the voltage/frequency of overloaded MGs, etc. Despite maximizing their benefits and decreasing weaknesses of isolated MGs, IMGs require maintaining stability in different operation modes and employing appropriate control methods. Moreover, a basic requirement for stability analysis and controller design is system modeling. Since many articles have addressed these topics on IMGs from different views, a comparison is necessary. Therefore, IMG dynamic modeling methods are classified and their main features and challenges are discussed. Then, stability analysis and control methods of IMGs are reviewed and compared. The provided review is supported by conceptual diagrams, classification tables, off-line and real-time simulations using MATLAB and OPAL-RT simulator for comparison. Furthermore, a data set is provided to study fundamentals as well as research gaps, which are addressed for future works.

Power System Transient Stability Assessment Based on Machine Learning Algorithms and Grid Topology

This work employs machine learning methods to develop and test a technique for dynamic stability analysis of the mathematical model of a power system. A distinctive feature of the proposed method is the absence of a priori parameters of the power system model. Thus, the adaptability of the dynamic stability assessment is achieved. The selected research topic relates to the issue of changing the structure and parameters of modern power systems. The key features of modern power systems include the following: decreased total inertia caused by integration of renewable sources energy, stricter requirements for emergency control accuracy, highly digitized operation and control of power systems, and high volumes of data that describe power system operation. Arranging emergency control in these new conditions is one of the prominent problems in modern power systems. In this study, the emergency control algorithms based on ensemble machine learning algorithms (XGBoost and Random Forest) were developed for a low-inertia power system. Transient stability of a power system was analyzed as the base function. Features of transmission line maintenance were used to increase accuracy of estimation. Algorithms were tested using the test power system IEEE39. In the case of the test sample, accuracy of instability classification for XGBoost was 91.5%, while that for Random Forest was 81.6%. The accuracy of algorithms increased by 10.9% and 1.5%, respectively, when the topology of the power system was taken into account.

A method for calculating permanent displacement of seismic-induced bedding rock landslide considering the deterioration of the structural plane

The mechanism of seismic-induced bedding rock landslide is distinct from that of slope instability/landslide in normal gravity conditions; their failure modes are mainly characterized by vibration deterioration effect of rock mass structural plane due to a seismic loading, which has a significant effect on the stability of the bedding rock landslide. Several advanced methods have been proposed to assess earthquake-induced bedding rock landslide. However, the quantitative evaluation of the vibration deterioration effect of structural plane, along with its application in the dynamic stability analysis of bedding rock slopes, remains a challenging topic that requires further study. In this study, on the basic of the analysis of the cyclic shear condition and the cyclic shear test of the structural plane, the expressions to calculate the dilatancy angle and basic friction angle of structural plane under cyclic shear loading are studied. A deterioration formula for structural plane shear strength is proposed, which fully considers the deterioration effect during cyclic shear. Furthermore, a new calculating method of the seismic-induced permanent displacement of the bedding rock landslide, which introduces the deterioration effect of the structural plane, is developed. A case study was used to compare the permanent displacement calculated with the proposed method with those obtained using the Newmark and Qi methods, which demonstrates the effectiveness and applicability of the proposed method.

Controllability and control synthesis of underactuated magnetic microrobots

The control of multiple magnetic microrobots is of particular interest for therapeutic applications. Yet the controllability of such a system is not straightforward since, on most of such systems designs, there is only a single control input per axis. The paper addresses the controllability and control synthesis for several magnetic microrobots navigating in blood vessels. First, controllability requires the microrobots to magnetically interact in order to achieve trajectory tracking along an admissible reference trajectory, whether swimming at low or high Reynolds. Then the resulting nonlinear system is shown to be diffeomorphic to different nonlinear canonical forms depending on the choice of the microrobots, so that the stabilization of the system along any admissible reference trajectory can be achieved using a backstepping controller synthesis, yet sometimes at the price of a zero dynamics stability analysis. Simulation results illustrate the efficiency of the proposed approach.

Voltage monitoring based on ANN-aided nonlinear stability analysis for DC microgrids

Due to the low inertia of the DC microgrid, the DC bus voltage is prone to drop or oscillate under disturbance. It is also challenging to supervise the stability of a DC microgrid since it is a highly nonlinear dynamic system with high dimensionality and randomness. To tackle this problem, this paper proposes a new method using ANN-aided nonlinear dynamic stability analysis for monitoring the DC bus voltage, which is combined with two steps. The first step is to establish six corresponding nonlinear accurate discrete iterative models of six switching modes of the PV-battery-load-based DC microgrid system, based on the Poincaré map theory, in order to judge the stability quantitatively with a promoted stability margin index. The second step is to use artificial neural networks (ANNs) to forecast the operating mode of the system when random changes occur in environmental circumstances and load power; this will aid the first step in being efficient and adaptable while determining stability cases. And the employed ANNs are trained with the datasets, including the circuit data, ambient temperature, irradiance, and load power, which are generated by MATLAB/Simulink simulation. Theoretical and simulation analyses are carried out under different operating conditions to validate the proposed method’s efficacy in judging the DC microgrid’s destabilizing oscillation and stable running.

Dynamic Stability of Tensegrity Structures-Part I: The Time-Independent External Load.

The paper contains a parametric analysis of tensegrity structures subjected to time-independent external loads. A complete dynamic stability analysis is a three-step process. The first stage involves the identification of self-stress states and infinitesimal mechanisms. The next stage concentrates on the static and dynamic behavior of tensegrities under time-independent external loads, whereas the third is under periodic loads. In this paper, the first two stages are carried out. The structures built with the most popular tensegrity modules, Simplex and Quartex, are considered. The effect of the initial prestress on the static parameters and frequency is analyzed. To assess this behavior, a geometrically non-linear model is used.