International Journal of Engineering Systems Modelling and Simulation (16 papers in press)
Fast and accurate dynamic synchrophasor estimator for protection applications
by Billal Khettaoui, Mohamed Boudour
Abstract: This paper proposes a new synchrophasor estimation algorithm capable of speeding up the rate of measurements. It reduces the computational complexity and meets the accuracy requirements of the P-class PMU (Phasor Measurement Unit) defined by the IEEE Std C37.118.1-2011 and its amendment IEEE Std C37.118.1a-2014. The proposed estimator is constructed by inserting the second order Taylor polynomial of signal model in the Modulated Sliding Discrete Fourier Transform (MSDFT) expression, taking advantage of the dynamic model of the Taylor series expansion and the low computational complexity of the MSDFT. The proposed technique is found to be as accurate as the traditional one (based on joint application of Taylors second order polynomial and the DFT) with higher reporting rates and it satisfies all the tests listed by the standard as well as the influence of wideband noise and decaying DC component.
Keywords: accuracy; fast; frequency; synchrophasor; ROCOF; estimator; dynamic; PMU; phasor measurement unit; protection; three cycles; reporting rate; MSDFT; Taylor’s series; six –parameter model.
Research on Mathematical Model of Characteristic Curve of Surface perception by PVDF Array Based on Ferguson Function
by Zhen YU, Chen-yang ZHANG
Abstract: The traditional 3D shape perception and reconstruction requires the use of relatively expensive 3D scanning equipment to obtain the coordinates of discrete feature points of the 3D shape, then 3D analysis software is used to reconstruct the 3D shape based on the 3D coordinate values of the 3D discrete feature points. The reconstruction accuracy is determined by the scanning accuracy of the 3D scanning device, generally, the accuracy is low. In this study, based on the PVDF piezoelectric film sensing array, the 3D topographic feature point coordinate value is perceived and acquired. According to the feature point coordinate value, the feature curve fitting of the 3D shape is obtained, and the slope information of the 3D topography characteristic curve is obtained. The mathematical model of the feature surface of PVDF array surface topography based on Ferguson curve is studied to realize the surface reconstruction of 3D complex topography. Theoretical research shows that three-dimensional complex topographic reconstruction technique based on Ferguson curve for PVDF piezoelectric film array surface topography perception has the advantages of simple principle, easy implementation and high precision of shape reconstruction. It can develop intelligent structure with three-dimensional complex shape perception function, which has important application value in robot intelligent object recognition and picking and intelligent manufacturing.
Keywords: PVDF Array; Intelligent Structure; Three-dimensional Complex Topography; Morphological Perception; Ferguson Function.
Extended Geographic Information Monitoring Of Urban Ecotone Based On Cell Transmission Model
by Lede Niu, Mei Pan
Abstract: The road traffic network in the urban interlaced zone is a collection of road sections and nodes. The difficulty in road traffic monitoring lies in the processing of traffic at the node locations. In this paper, the cell transmission model is used to monitor the extended geographical information of the urban interlaced zone. Using the cell transmission model, the channelization and cell outflow capacity at the intersection are calculated. According to the timing of traffic signals in the interlaced zone, calculate road traffic volume and accurately monitor vehicle density. The simulation experiment results show that the model in this paper can accurately monitor the congestion information of the gradation road network and the uniform road network in the urban interlaced zone traffic network, and the monitoring results are close to the actual results, indicating that the research method in this paper has stronger applicability.
Keywords: Cell transmission model; Urban ecotone; Graded road network; Uniform road network.
Design and Implementation of DVR as Fault Current Limiter in DFIG during Grid Faults
by Sheena Latif, Savier J.S
Abstract: The wind grid code requirements for low voltage ride through of various countries demand the DFIG to remain connected to the grid during the event of occurrence of voltage dip. Dynamic Voltage Restorer supports the grid and enables the uninterrupted operation of DFIGs during partial voltage sag. The increased depth of voltage sag causes rise in stator current and eventual increase in rotor current and dc link capacitance voltage of DFIG. This paper focuses on an enhanced topology of Fault Current Limiting Dynamic Voltage Restorer for supporting the grid and DFIG during fault currents caused by severe voltage dips. The optimal parameters design of Fault Current Limiting Dynamic Voltage Restorer for DFIG systems are discussed in detail. The novelty of the proposed control strategy of Fault Current Limiting Dynamic Voltage Restorer is justified by comparing its performance with the existing methods of fault current mitigations popular with wind farms such as crowbar protection and dc chopper methods. Analytical results of Fault Current Limiting Dynamic Voltage Restorer with DFIG in time domain prove to have the combined effect of both crowbar protection and dc chopper-controlled rotor protection during severe unbalanced grid faults.
Keywords: Keywords: Fault current rise; Low Voltage Ride Through; Dynamic Voltage Restorer; Fault Current Limiting Dynamic Voltage Restorer; fault current control; DFIG.
Study On Material Structure Evolution Of Steam Turbine Rotor Under Thermal Cycling Fatigue Load
by Lixin Liu, Jun Su
Abstract: In order to improve the structural strength of the turbine rotor, the dynamic circuit and driving mechanical model of the turbine rotor are established under the thermal cycle fatigue load. The numerical simulation principle of the stress yield evolution process of the rotor structure is analyzed. The closed vector method and Lagrange equation are used to establish the mechanical analysis and yield stress model, and the mechanical principle of the thermal cycle fatigue load of the rotor is analyzed. On this basis, the yield stress evaluation model is established to realize the material structure evolution analysis. The results show that the method can provide higher accuracy and lower yield stress estimation results, with an average error of 15.74% lower than that of the traditional method, which shows that the method can improve the anti-interference ability of turbine rotor drive and the stress intensity of rotor material structure, with good convergence.
Keywords: Thermal cycling fatigue load; turbine rotor; material; structure; yield response.
Special Issue on: IJESMS ITNT-2019 Mathematical Modelling of Technical Processes and Systems
Impact analysis and orbit reboost of payload tossing using spinning electrodynamic tether system
by Hongshi Lu, Yuriy Zabolotnov, Aijun Li
Abstract: Spinning electrodynamic tether systems are good platforms for payload transportation, but require orbit reboosts after one or several tossing manoeuvres. In this paper an impact analysis is proposed to predict the change of system orbits after payload tossing. Changes of key parameters (eccentricity, semi-major axis and tether spinning rate) are derived. Based on previous analysis, 3 control schemes are proposed to regulate current to reboost system orbits back to its original ones. One mission is assumed in numerical parts to validate the effectiveness of the proposed impact analysis and control schemes.
Keywords: spinning electrodynamic tether system;momentum exchange;payload tossing;orbit reboost;.
Phase equilibrium modelling for multi-component mixtures using highly accurate Helmholtz energy equation of state
by Taiming Luo, Alexei Chirkov
Abstract: Phase stability of a mixture at given conditions is studied. The modelling of equilibrium phase compositions is considered when the original phase of the mixture is unstable. The tangent plane distance criterion is used for stability analysis and the Gibbs energy minimization is employed for phase equilibrium calculation when the successive substitution doesnt work well. With the GERG-2008 equation of state, thermodynamic properties in single phase and two-phase equilibrium were calculated for methane-ethane mixtures. Phase envelopes were also calculated.
Keywords: phase equilibrium; phase envelopes; Helmholtz energy equation of state; stability analysis; tangent plane distance criterion.
Thematic classification with support subspaces in hyperspectral images
by Vladimir Fursov, Sergei Bibikov, Denis Zherdev
Abstract: In the study, a recognition algorithm of plant crops in hyperspectral images is analysed. The algorithm uses the conjugation index with a subspace formed by signatures of a given class. The purpose of the work is to show that this algorithm, with the data pre-processing (weighting of the feature vectors components and forming of the subclasses), provides a higher recognition quality compared to the most popular reference vector method (SVM). The experiments were conducted with the implementation of the SVM method. The Indian Pines test of close types of vegetation, including 16 marked classes of plant crops, was used in the recognition experiments. The test was rather complicated, as class signatures are highly correlated. The results show the possibility of a reliable recognition of plant crops.
Keywords: hyperspectral images; thematic classification; SVM; conjugation index.
Numerical analysis of parameter identifiability for a mathematical model of a chemical reaction
by Liana Safiullina, Irek Gubaydullin
Abstract: A numerical approach to the analysis of the parametric identifiability of a mathematical model of a chemical reaction, as well as the procedures aimed at elimination of non-identifiability and reduction of the mathematical model, are developed. The primary focus is on the reaction of low-temperature propane pyrolysis with the detailed scheme containing 157 reactions. The purpose of this work is to determine kinetic parameters of the model to be identified and to determine the parameters of the model which can be considered insignificant. The detailed propane pyrolysis scheme is reduced to a 30-reaction scheme. A kinetic model of low-temperature propane pyrolysis is proposed. The authors present the results of numerical simulation of three-dimensional dynamics of gas flow of propane pyrolysis in the reactor using the ANSYS Fluent software package and a reduced kinetic model.
Keywords: sensitivity analysis; mathematical model; Monte Carlo modeling; Sobol’s method; parametric identifiability; numerical analysis; low-temperature propane pyrolysis; reaction mechanism; reduction of mechanism; chemical kinetics.
Controlled attitude motion of the space tether system at the retraction tether stage
by Ruslan Pikalov, Vladimir Aslanov
Abstract: This study focuses on the dynamics of a rendezvous of a tug and large space debris connected by a viscoelastic tether. It is assumed that control is realized by changing the length of the tether. The goal is to study the dynamic of the maneuver of the rendezvous and to find the ways, which allow to control the attitude motion of a space tether system. The results can be applied to the implementation of rendezvous of two bodies using the tether.
Keywords: space debris; active debris removal; space tug; space tether system; attitude control.
Numerical Simulation Of Landslide Motion Based On Thermo-Plastic Mechanics
by Zhiqing Dai, ZhongFu Wang, Wei Liu, Dong Dong Li
Abstract: Landslides with long run-out and high velocities pose severe threat to infrastructures and lives in mountain areas. Frictional heating has long been considered a mechanism responsible for some remarkable characteristics of natural landslides such as surprisingly long travel distances and high velocities. In order to study the influence of this mechanism on the motion of such landslides, one method considering the thermo-plastic mechanics was combined with a depth-averaged model for simulating the long run-out motion of landslides in the condition of deformation. The effects of several key parameters on thermo-plastic mechanics were discussed by several numerical tests through he processes of landslide motion, heat production and diffusion, pore-fluid pressure generation and dissipation, and thermoplastic collapse of the soil skeleton at the shear zone Then the effectiveness of the model was verified by comparing the numerical results with the field investigation of Sanxicun landslides.
Keywords: landslide motion; long run-out; frictional heating; numerical simulation.
Research On Dynamic Simulation And Prediction Of Urban Expansion Based On Sleuth Model
by Lede Niu, Mei Pan, Yan Zhou
Abstract: In order to improve the accuracy of traditional prediction methods in the analysis of urban expansion, the method for dynamic simulation of urban expansion based on SLEUTH (slope, land use, urban area, traffic, exclusion, Hillshead) model is proposed.The method uses processed urban spatial data to establish a SLEUTH model of dynamic urban expansion, and it analyzes the driving factors of urban expansion that are used as the influencing factor of urban expansion simulation. Through dynamic simulation, the law of urban expansion is derived and input SLEUTH model as the law of free expansion.. The influencing factors are input into the model, and the prediction results are obtained with the law of free expansion. The experimental result shows that the new method has a prediction error rate of only 3.5% with the low delay and the strong reliability?compared with the traditional urban expansion prediction method.
Keywords: SLEUTH model; Urban expansion; Dynamic simulation; Simulation and prediction;.
A model of advective changes in air humidity: a stochastic approach
by Vladimir Nozhkin, Vladimir Zadorozhniy, Igor Ulshin, Olesya Kanishcheva
Abstract: The paper presents a novel approach to the solution of a moisture transfer problem described by a differential equation with the coefficients which are treated as random processes. The distribution of the projections of the instantaneous velocity vector is approximated by the Vaga-Ising law, and the parameters of such distribution are identified based on a bionic model of adaptive search behaviour. Explicit expressions for the expectation and the second-moment function are obtained.
Keywords: moisture motion in the atmosphere; variation derivative; random process; expectation; second-moment function; characteristic functional.
Oscillations and hysteresis: from simple harmonic oscillator and unusual unbounded increasing amplitude phenomena to the van der Pol oscillator and chaos control
by Mikhail. Semenov, Olga Reshetova, Peter Meleshenko, Alexander Klinskikh
Abstract: In this work we investigate various oscillating systems under hysteretic action. For a simple harmonic oscillator under hysteretic force an unusual unbounded increasing amplitude pehnomena (growing rate for the amplitude is proportional to square root of time) are obtained and discussed. For a system of coupled van der Pol oscillators (taking into account the hysteretic coupling) we investigate various dynamic regimes (both regular and chaotic) and show that the hysteresis in the link between two van der Pol oscillators may serve as an effective mechanism for chaos control. Also we consider the effect of hysteresis on synchronization processes in this system.
Keywords: hysteresis; Bouc-Wen model; van der Pol oscillator; regular and chaotic dynamics; synchronization.
Computational modeling to determine the physical characteristics of biological tissues for medical diagnosis
by Maxim Polyakov
Abstract: Timely diagnosis of breast cancer is an important task. This type of breast cancer is one of the most common diseases. The method of microwave radiothermometry is a promising direction for solving this problem. The method is based on measuring internal temperature of biological tissues in microwave frequency range. Computer simulations are used to improve the quality of diagnostics. Computer models make it possible to evaluate the effect of heat release in a malignant tumor on the thermal dynamics inside the mammary gland. It is necessary to build personalized models, taking into account the individual nature of the internal structure of the mammary gland in each patient. One of the problems is the determination of biophysical characteristics of biological components. Methods for determining these characteristics using computer simulations are proposed. The coefficient of thermal conductivity and specific heat of biological tissues are determined from known temperature distributions. Finding the physical parameters for a quasihomogeneous biological tissue is the first approximation for solving this problem. The least squares method is used as a solution method. The results obtained are in good agreement with previously known exact solutions, which indicates the applicability of this method for solving this class of problems. The efficiency of using parallel technologies in solving the inverse problem is investigated and the applicability of Open MP technology is demonstrated.
Keywords: Numerical methods; biotissues; microwave radiometry; mathematical modeling; heat dynamics; mammary gland; parallel computing; diagnosis of breast cancer; thermometric data.
Application of Digital Twin and IoT concepts for solving the tasks of hydraulically actuated heavy equipment lifecycle management
by Victor Zhidchenko, Heikki Handroos, Alexander Kovartsev
Abstract: The paper considers an approach of using Digital Twin and IoT concepts for solving the tasks related to the operation and maintenance of the hydraulically actuated heavy equipment. A technique for the camera-less remote surveillance on the heavy equipment is presented. It uses the sensor data about the pressure and position of the hydraulic actuators transmitted in IoT environment to a digital twin that reproduces the motion of the machine using its dynamic model. The forces acting in the machine calculated by the digital twin give an ability to calculate the stress levels in the mechanical structure of the machine. These data can be used to estimate the fatigue life of the machine as part of the predictive maintenance practice. The problems associated with the implementation of the proposed approach are discussed and the proof of concept system and experimental results are presented.
Keywords: Internet of Things; Digital Twin; simulation modelling; multibody dynamics; fatigue.