scholarly journals Studying State Convergence of Input-to-State Stable Systems with Applications to Power System Analysis

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 92 ◽  
Author(s):  
Antonio T. Alexandridis
Keyword(s):  
Nonlinear Systems ◽  
Power Systems ◽  
Power System ◽  
System Analysis ◽  
Nonlinear Models ◽  
Sufficient Conditions ◽  
Stability And Convergence ◽  
Convergence To Equilibrium ◽  
Analysis Tool ◽  
Wide Range

In stability studies, the response of a system enforced by external, known or unknown, inputs is of great importance. Although such an analysis is quite easy for linear systems, it becomes a cumbersome task when nonlinearities exist in the system model. Nevertheless, most of the real-world systems are externally enforced nonlinear systems with nonzero equilibriums. Representative examples in this category include power systems, where studies on stability and convergence to equilibrium constitute crucial objectives. Driven by this need, the aim of the present work is twofold: First, to substantially complete the theoretical infrastructure by establishing globally valid sufficient conditions for externally enforced nonlinear systems that converge to nonzero equilibriums and, second, to deploy an efficient method easily applicable on practical problems as it is analyzed in detail on a typical power system example. To that end, in the theoretical first part of the paper, a rigorous nonlinear analysis is developed. Particularly, starting from the well-established nonlinear systems theory based on Lyapunov techniques and on the input-to-state stability (ISS) notion, it is proven after a systematic and lengthy analysis that ISS can also guarantee convergence to nonzero equilibrium. Two theorems and two corollaries are established to provide the sufficient conditions. As shown in the paper, the main stability and convergence objectives for externally enforced systems are fulfilled if simple exponential or asymptotic converging conditions can be proven for the unforced system. Then, global or local convergence is established, respectively, while for the latter case, a novel method based on a distance-like measure for determining the region of attraction (RoA) is proposed. The theoretical results are examined on classic power system generation nonlinear models. The power system examples are suitably selected in order to effectively demonstrate the proposed method as a stability analysis tool and to validate all the particular steps, especially that of evaluating the RoA. The examined system results clearly verify the theoretical part, indicating a rather wide range of applications in power systems.

Markov Jump Linear System Analysis of a Microgrid Operating in Islanded and Grid Tied Modes

2020 ◽  
Author(s):  
Gilles Mpembele ◽  
Jonathan Kimball
Keyword(s):  
Monte Carlo ◽  
Power Systems ◽  
Power System ◽  
System Analysis ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Markov Jump ◽  
Numerical Application ◽  
Conditional Moments ◽  
Markov Jump Linear Systems

<div>The analysis of power system dynamics is usually conducted using traditional models based on the standard nonlinear differential algebraic equations (DAEs). In general, solutions to these equations can be obtained using numerical methods such as the Monte Carlo simulations. The use of methods based on the Stochastic Hybrid System (SHS) framework for power systems subject to stochastic behavior is relatively new. These methods have been successfully applied to power systems subjected to</div><div>stochastic inputs. This study discusses a class of SHSs referred to as Markov Jump Linear Systems (MJLSs), in which the entire dynamic system is jumping between distinct operating points, with different local small-signal dynamics. The numerical application is based on the analysis of the IEEE 37-bus power system switching between grid-tied and standalone operating modes. The Ordinary Differential Equations (ODEs) representing the evolution of the conditional moments are derived and a matrix representation of the system is developed. Results are compared to the averaged Monte Carlo simulation. The MJLS approach was found to have a key advantage of being far less computational expensive.</div>

scholarly journals Load area aggregation considering integration of electric vehicles to the system

2015 ◽  
Vol 35 (1Sup) ◽  
pp. 42-49 ◽  
Author(s):  
Luis Fernando Rodríguez-García ◽  
Sandra Milena Pérez-Londoño ◽  
Juan José Mora-Flórez
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Vehicles ◽  
System Analysis ◽  
Original System ◽  
Computational Effort ◽  
Computational Technique ◽  
Equivalent Network ◽  
Optimal Dispatch ◽  
Equivalent Load

<span>Current electric power systems have an increasing penetration of electric vehicles, and its effect has to be considered in different <span>studies, such as optimal dispatch or voltage stability, among others. Additionally, considering that power system analysis becomes <span>complex when the number of buses increase, this paper presents a methodology for aggregation of load areas that use a measurement-based load modeling approach based on an evolutionary computational technique and a classical reduction method. This aggregate <span>load area model is proposed to reduce areas that consider electric vehicle (EV) load models. The proposed method provides a static <span>equivalent load model and an equivalent network that can be used to reduce the computational effort required by power system<br /><span>studies. In order to validate the application of the proposed methodology, a 30-bus power system considering several disturbances <span>and levels of penetration of the electric vehicles was used. The results show that the equivalent network model allows the reproduction <span>of different events with an acceptable accuracy when it is compared to the original system behavior.</span></span></span></span></span></span></span><br /><br class="Apple-interchange-newline" /></span>

scholarly journals Controlled Impedance-Admittance-Torque Nonlinear Modeling and Analysis of Modern Power Systems

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2461
Author(s):  
Panos C. Papageorgiou ◽  
Antonio T. Alexandridis
Keyword(s):  
Power Systems ◽  
Power System ◽  
System Analysis ◽  
Power Converter ◽  
Lyapunov Methods ◽  
Duty Ratio ◽  
System Response ◽  
Power Electronic ◽  
Dynamic Representation ◽  
Dynamic Description

Modern power systems are continuously transformed into decentralized ones where distributed generation (DG) plays a key role. Almost all the different distributed energy resources (DERs) are connected in geographically dispersed places through controlled power electronic interfaces in a manner that essentially affects the dynamic performance and control of the whole power system. Simultaneously, rotating machines in power production or absorption, dominate the system response and stability. In this new frame, this paper proposes a novel generalized dynamic representation and full scale modeling of a modern power system based on the well-known impedance-admittance (IA) network model for the electricity grid, substantially extended to include in detail both the power converter devices by considering the controlled power electronic dynamics and the electrical machines by inserting their full electromechanical dynamics. This formulation results in a holistic nonlinear dynamic description, defined here as controlled impedance-admittance-torque (CIAT) model of the whole system which features common structural characteristics. The model is deployed in state space, involves all the controlled inputs in DG, namely the duty-ratio signals of each power converter interface, all the other external inputs affecting the system, namely all the known or unknown voltage, current, and torque inputs. As shown in the paper, the proposed CIAT model retains its fundamental properties for any DG and network topology, standard or varying. This enables the compression of the accurate analytic power system dynamic description into a matrix-based generic nonlinear model that can be easily used for analysis studies of such large-scale systems. Taking into account the nonlinear nature of the CIAT matrix-based model and the persistent action of the external inputs, Lyapunov methods deployed on recently established input to state stability (ISS) notions are systematically applied for the system analysis. Hence, the traditionally used small-signal model-based analysis that suffers from the intermittent and continuously changing operation of DERs is completely substituted by the proposed formulation. A modern power system example with different DERs involved is analyzed by this way and is extensively simulated to verify the validity of the proposed method.

Performance of the Grid-Connected PV System in LV Microgrid Operation

2012 ◽  
Vol 512-515 ◽  
pp. 137-142
Author(s):  
Yan Li ◽  
Li Wang ◽  
Pan Pan Jing ◽  
Bin Bin Zhong ◽  
Bu Han Zhang ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
System Analysis ◽  
Low Voltage ◽  
Environmental Benefits ◽  
Pv System ◽  
Load Curve ◽  
Power System Analysis ◽  
Pv Penetration ◽  
Flexible Operation

Microgrids are a future power system configuration providing clear economic and environmental benefits compared to the legacy power systems, as the Grid-Connected PV penetration increases, its reaction in Low Voltage (LV) microgrid has to be taken into account during relative system studies. This paper presents a mathematical model for the Grid-Connected PV, it’s developed by User Define (UD) module on Power System Analysis Software Package (PSASP), PV behavior under several typical weather and typical 1-day load curve is studied in detail, Flexible Operation Strategy to achieve the reasonable voltage level are both considered, PSASP simulation environment is used to analyze the probable operation scenarios of LV microgrid, useful conclusions are summarized at last.

scholarly journals Frequency Control of Large-Scale Interconnected Power Systems via Battery Integration: A Comparison Between the Hybrid Battery Model and WECC Model

2021 ◽  
Author(s):  
Roghieh Abdollahi Biroon ◽  
Pierluigi Pisu ◽  
David Schoenwald
Keyword(s):  
Power Systems ◽  
Power System ◽  
Large Scale ◽  
System Analysis ◽  
Hybrid Control ◽  
Frequency Control ◽  
Renewable Energy Sources ◽  
Control Design ◽  
Energy Sources ◽  
The Stability

The increasing penetration of renewable energy sources in power grids highlights the role of battery energy stor- age systems (BESSs) in enhancing the stability and reliability of electricity. A key challenge with the renewables&rsquo;, specially the BESSs, integration into the power system is the lack of proper dynamic model for stability analysis. Moreover, a proper control design for the power system is a complicated issue due to its complexity and inter-connectivity. Thus, the application of decentralized control to improve the stability of a large- scale power system is inevitable, especially in distributed energy sources (DERs). This paper presents an optimal distributed hybrid control design for the interconnected systems to suppress the effects of small disturbances in the power system employing utility-scale batteries based on existing battery models. The results show that i) the smart scheduling of the batteries&rsquo; output reduces the inter-area oscillations and improves the stability of the power systems; ii) the hybrid model of the battery is more user-friendly compared to the Western electricity coordinating council (WECC) model in power system analysis.

scholarly journals Markov Jump Linear System Analysis of a Microgrid Operating in Islanded and Grid Tied Modes

2020 ◽  
Author(s):  
Gilles Mpembele ◽  
Jonathan Kimball
Keyword(s):  
Monte Carlo ◽  
Power Systems ◽  
Power System ◽  
System Analysis ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Markov Jump ◽  
Numerical Application ◽  
Conditional Moments ◽  
Markov Jump Linear Systems

The analysis of power system dynamics is usually conducted using traditional models based on the standard nonlinear differential algebraic equations (DAEs). In general, solutions to these equations can be obtained using numerical methods such as the Monte Carlo simulations. The use of methods based on the Stochastic Hybrid System (SHS) framework for power systems subject to stochastic behavior is relatively new. These methods have been successfully applied to power systems subjected to stochastic inputs. This study discusses a class of SHSs referred to as Markov Jump Linear Systems (MJLSs), in which the entire dynamic system is jumping between distinct operating points, with different local small-signal dynamics. The numerical application is based on the analysis of the IEEE 37-bus power system switching between grid-tied and standalone operating modes. The Ordinary Differential Equations (ODEs) representing the evolution of the conditional moments are derived and a matrix representation of the system is developed. Results are compared to the averaged Monte Carlo simulation. The MJLS approach was found to have a key advantage of being far less computational expensive.

scholarly journals Energy Storage System Analysis Review for Optimal Unit Commitment

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 158 ◽  
Author(s):  
Harun Or Rashid Howlader ◽  
Oludamilare Bode Adewuyi ◽  
Ying-Yi Hong ◽  
Paras Mandal ◽  
Ashraf Mohamed Hemeida ◽  
...  
Keyword(s):  
Energy Storage ◽  
Power Systems ◽  
Power System ◽  
System Analysis ◽  
Unit Commitment ◽  
Storage System ◽  
Weather Conditions ◽  
Efficient Solutions ◽  
Load Demand ◽  
Power System Flexibility

Energy storage systems (ESSs) are essential to ensure continuity of energy supply and maintain the reliability of modern power systems. Intermittency and uncertainty of renewable generations due to fluctuating weather conditions as well as uncertain behavior of load demand make ESSs an integral part of power system flexibility management. Typically, the load demand profile can be categorized into peak and off-peak periods, and adding power from renewable generations makes the load-generation dynamics more complicated. Therefore, the thermal generation (TG) units need to be turned on and off more frequently to meet the system load demand. In view of this, several research efforts have been directed towards analyzing the benefits of ESSs in solving optimal unit commitment (UC) problems, minimizing operating costs, and maximizing profits while ensuring supply reliability. In this paper, some recent research works and relevant UC models incorporating ESSs towards solving the abovementioned power system operational issues are reviewed and summarized to give prospective researchers a clear concept and tip-off on finding efficient solutions for future power system flexibility management. Conclusively, an example problem is simulated for the visualization of the formulation of UC problems with ESSs and solutions.

scholarly journals A Novel Hybrid Particle Swarm- Multiverse Optimization based Voltage Stability Improvement in IEEE 57 Bus System

2018 ◽  
Vol 7 (2.24) ◽  
pp. 381
Author(s):  
P K.Dhal ◽  
K Ramash Kumar
Keyword(s):  
Power System ◽  
Hybrid Algorithm ◽  
Voltage Stability ◽  
System Analysis ◽  
Test System ◽  
Analysis Tool ◽  
Power System Analysis ◽  
Sudden Loading ◽  
And Control ◽  
Bus System

The major role of power system is voltage stability. It is required to plan properly and smooth operation and control. It presents a new approach of voltage stability improvement in IEEE 57 bus system using hybrid algorithm. The hybrid algorithm (PSO-MVO) is combination of PSO which is used for exploitation and MVO used for exploration. It is used in an uncertain environment. The FACTS device as STATCOM is connected in IEEE 57 test system to check for event of voltage stability improvement through power system analysis tool (PSAT) software. Once the ability of system goes through sudden loading, its stability gets affected. It desires compensation to boost voltage from disturbances. The varied operative condition while not used STATCOM in the system, used with STATCOM tuned by PSO-MVO algorithm are measured judge the performance of the projected system. The hybrid PSO-MVO technique is implemented in this paper to solve the proposed problem. The simulation results are obtained by PSAT software for 57 IEEE bus systems. The hybrid algorithm validates its effectiveness compare to individual PSO and MVO algorithm.     

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