scholarly journals Development of a nonlinear model of a three-phase transformer to study the effect of asymmetry of the magnetic system on the operation of the device in arbitrary modes

Vestnik IGEU ◽  
2020 ◽  
pp. 22-31 ◽  
Author(s):  
A.I. Tikhonov ◽  
A.V. Stulov ◽  
A.A. Karzhevin ◽  
A.V. Podobny
Keyword(s):  
Dynamic Model ◽  
Magnetic Circuit ◽  
Magnetic System ◽  
Power Transformers ◽  
Design Stage ◽  
Nonlinear Dynamic Model ◽  
Design Features ◽  
Operating Modes ◽  
Three Phase ◽  
The Asymmetry

Currently, when designing power transformers in order to take into account the influence of the asymmetry of the magnetic system on the operation of the device, especially in transition modes, engineering analysis packages based on field models are increasingly being used. However, such models are slow. At the same time, dynamic transformer models based on the magnetic circuit model are not inferior in accuracy to field models. Existing chain models of a three-phase transformer either do not take into account the asymmetry of the magnetic system or poorly integrate with simulation packages. The purpose of this article is to develop a dynamic model of a three-phase transformer which would allow considering the design features at the design stage, in particular, the asymmetry of the magnetic system and the influence of these features on arbitrary modes of the device operation. A contour current method was used to calculate a non-linear magnetic circuit of a three-rod transformer, and a single-step method based on a modified 2nd order Rosenbrock formula was used to calculate the electrical circuit. A nonlinear dynamic model of a three-phase three-core transformer based on the use of controlled current sources and EMF has been developed. This model is able to integrate with simulation packages including MatLab Simulink SimPowerSystem. The model allows taking into account the influence of the asymmetry of the magnetic system on the transformer operation in various operating modes including emergency and asymmetric ones. The novelty of the developed model can be seen in the approach to constructing a nonlinear matrix of magnetic resistances without explicitly using inductance matrices, which increases the accuracy and stability of the model considering the asymmetry of the magnetic system. The curves of transients in the characteristic operating modes of the transformer are given. The developed models can be used in the design of power transformers, including specific ones. They enable to increase the accuracy of the verification calculation and bring it to the level of simulation modelling. These models can also be applied for constructing digital twins of power transformers taking into account the influence of the design features of transformer equipment on the operation of power grids.

scholarly journals MATHEMATICAL MODELING OF A THREE-PHASE TRANSFORMER TAKING INTO ACCOUNT A MAGNETIC CORE ASYMMETRY

2021 ◽  
Vol 295 (2) ◽  
pp. 165-171
Author(s):  
O. KIMSTACH ◽  
◽  
I. ILLIASHENKO ◽  
A. ZHEZHELO ◽  
◽  
...  
Keyword(s):  
Mathematical Model ◽  
Magnetic System ◽  
Short Circuit ◽  
Magnetic Core ◽  
Transient Processes ◽  
Three Phase ◽  
Significant Difference ◽  
The Asymmetry ◽  
High Level ◽  
The Mathematical Model

The paper analyses the aspects of modelling the operation of a three-phase core-type transformer. The features of the magnetic system construction of the transformer, which generate asymmetry, are disclosed. The fundamentals and methods for modelling a transformer in dynamic modes are considered. The main purpose of the paper is to research the influence of taking into account the asymmetry of the transformer magnetic core on its dynamic model. The paper proposes the mathematical model of a three-phase planar core-type transformer, which takes into account the asymmetry of the magnetic core. The mathematical model is based on the model of a generalized electric machine in the ABC axes, which is widely recognized and characterized by a high level of adequacy. A refined model, which takes into account the power losses in the magnetic core, has used. As is well known, such a model is characterized by higher accuracy and adequacy in the calculation of transient processes. For the proposed mathematical model, a comparative analysis of the calculated curves of transient processes for a 63 kVA transformer with a voltage of 6 / 0.4 kV is made. To disclose the effect of taking into account the magnetic core asymmetry of the transformer in the mathematical model, the current differences were calculated in pu for the modes of switching on at full power and three-phase short circuit. These modes are the most common and indicative in the analysis of the operability and stability of transformers. It was found that the most significant difference, which is obtained by taking into account the magnetic system asymmetry of the transformer, is 5…6% when it is switched on at full load. Thus, the relatively simple transformations and updating of the mathematical model of the transformer allow significantly increase its adequacy. The proposed mathematical model can be more effectively used when the non-typical design of three-phase transformers or reactors with significant asymmetry of the magnetic core is considered.

scholarly journals Performance Comparison of Multi Design Method and Meta-Heuristic Methods for Optimal Preliminary Design of Core-Form Power Transformers

2017 ◽  
Vol 61 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Tamás Orosz ◽  
Bence Borbély ◽  
Zoltán Ádám Tamus
Keyword(s):  
Optimization Problem ◽  
Power Transformer ◽  
Design Method ◽  
Power Transformers ◽  
Design Stage ◽  
Preliminary Design ◽  
Grey Wolf ◽  
Grey Wolf Optimization ◽  
Three Phase ◽  
Type Power

Large power transformers are regarded as crucial and expensive assets in power systems. Due to the competing global market, to make a good and competing power transformer design, a non-linear optimization problem should be solved in a very short time in the preliminary design stage. The paper shows and compares the performance of four different methods to solve this problem for three phase core type power transformers. The first algorithm is a novel meta-heuristic technique which combines the geometric programming with the method of branch and bound. Then this conventional multi design method is solved by a simple iterative technique and two novel evolutionary algorithms to enhance the convergence speed. One of these algorithms is the particle swarm optimization technique which is used by many other researchers and the grey wolf optimization algorithm which is a new method in this optimization sub-problem. An example design on an 80 MVA, three phase core type power transformer using these four methods is presented and its performances are analyzed. The results demonstrate that the grey wolf optimization is a good alternative for this optimization problem.

scholarly journals Methodology for selecting the rated parameters of power transformers in the town’s electrical distribution networks in settlements

2021 ◽  
pp. 33-43
Author(s):  
Yu.A. Papaika ◽  
I.M. Lutsenko ◽  
IE.V Koshelenko ◽  
P.S. Tsyhan
Keyword(s):  
Load Capacity ◽  
Operating Mode ◽  
Distribution Networks ◽  
Heating Time ◽  
Power Transformers ◽  
Design Stage ◽  
Electrical Networks ◽  
Electric Networks ◽  
Actual Structure ◽  
Operating Modes

Purpose. To substantiate a technique of a choice of nominal power of power transformers for increase of  their use efficiency in distributive electric networks of the cities Methods. Analytical processing of statistical data. Findings. The paper solves the problem of efficient use of the installed power of transformers, their rational choice in the design of urban electrical networks. It was found that the choice of transformers according to classical methods causes a significant error and an overestimation of the rated power at the design stage. The method of reducing this error was developed for selecting the power of transformers of urban electrical networks. This method takes into account the predicted indicators of the operating modes of the equipment, the type of consumers, the load capacity of the equipment, the parameters of the operating mode and the environment, constant heating time of existing types of transformers that can be accepted for installation, the appropriate level of reactive load compensation. Originality The scientific novelty lies in the development of  the method for selecting the rated power of power transformers 6 (20) /0.4 kV urban distribution networks by comprehensive consideration of the parameters of typical consumers and their actual structure, which will effectively use transformer equipment for load capacity during the regulated period of their operation. Practical value. The obtained results show the increase in the efficiency of capital and operating costs by selecting a rational rated power of distribution transformers 6 (20) / 0.4 kV with ensuring the effective use of their load capacity in the conditions of electric grids of cities.

scholarly journals Reduction of the pull effect of a cylindrical linear synchronous motor

2020 ◽  
Vol 157 ◽  
pp. 01015
Author(s):  
Sergey Shutemov ◽  
Evgeniy Сhabanov ◽  
Anastasia Shevkunova ◽  
Alexander Shapshal ◽  
Temur Тalakhadze
Keyword(s):  
Magnetic Circuit ◽  
Magnetic System ◽  
Synchronous Motor ◽  
Theory Method ◽  
Specific Force ◽  
Sliding Bearings ◽  
Electric Circuits ◽  
Linear Synchronous Motor ◽  
Three Phase ◽  
Secondary Element

A theoretical and experimental study of the effect of gravity, which occurs in a cylindrical linear synchronous motor between the secondary element and the inductor, was carried out. As a result, the forces of mechanical friction of the secondary element on the inductor are formed, which entails touching the secondary element on the surface of the inductor. An unfavourable result is a weakening of the power force that is working for a cylindrical linear synchronous motor. Two different inductor designs for a cylindrical linear synchronous motor have been studied. When solving this problem, we used an approach based on a combination of the field theory method and the theory of electric circuits. The forces of gravity, friction, and force between the secondary element and the inductor for these structures are determined. Experimentally, it was found that the pull force significantly weakens the working force of the engine. Based on the results obtained, conclusions were drawn about the need to change the design of the inductor. The design change of this element consists in the use of a non-magnetic intermediate centralizer, which is inserted between two sliding bearings located at the ends of each module of a cylindrical linear synchronous motor. Also, changes were made to the design of the magnetic circuit, in which instead of one slot for a three-phase winding system, three symmetrical slots were made, each for its own phase of the three-phase winding. As a result, the magnetic system of the engine in question became axisymmetric. The measures taken to change the design of the engine in question allowed us to dramatically reduce the effect of gravity. As a result, the specific force has increased significantly.

Inductor Saturation Compensation in Three-Phase Three-Wire Voltage-Source Converters via Inverse System Dynamics-I

2020 ◽  
Author(s):  
Ziya Özkan ◽  
Ahmet Masum Hava
Keyword(s):  
Dynamic Model ◽  
Dynamic Performance ◽  
Current Control ◽  
Inverse System ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Two Phase ◽  
Inverse Dynamic ◽  
Three Phase ◽  
Steady State Current

In three-phase three-wire (3P3W) voltage-source converter (VSC) systems, utilization of filter inductors with deep saturation characteristics is often advantageous due to the improved size, cost, and efficiency. However, with the use of conventional synchronous frame current control (CSCC) methods, the inductor saturation results in significant dynamic performance loss and poor steady-state current waveform quality. This paper proposes an inverse dynamic model based compensation (IDMBC) method to overcome these performance issues. Accordingly, a review of inductor saturation and core materials is performed, and the motivation on the use of saturable inductors is clarified. Then, two-phase exact modelling of the 3P3W VSC control system is obtained and the drawbacks of CSCC have been demonstrated analytically. Based on the exact modelling, the inverse system dynamic model of the nonlinear system is obtained and employed such that the nonlinear plant is converted to a fictitious linear inductor system for linear current regulators to perform satisfactorily.

Analysis of Tourism Ecology Capacity Based on the Nonlinear Dynamic Model

2009 ◽  
Vol 11 (2) ◽  
pp. 163-168
Author(s):  
Long LV ◽  
Zhenfang HUANG ◽  
Jiang WU
Keyword(s):  
Dynamic Model ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Model

scholarly journals Development, Modeling and Control of a Dual Tilt-Wing UAV in Vertical Flight

Drones ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 71
Author(s):  
Luz M. Sanchez-Rivera ◽  
Rogelio Lozano ◽  
Alfredo Arias-Montano
Keyword(s):  
Dynamic Model ◽  
Attitude Control ◽  
Test Bench ◽  
Aerodynamic Coefficients ◽  
Nonlinear Dynamic Model ◽  
Modeling And Control ◽  
Drag And Lift ◽  
And Control ◽  
Dynamics Method ◽  
Indoor And Outdoor

Hybrid Unmanned Aerial Vehicles (H-UAVs) are currently a very interesting field of research in the modern scientific community due to their ability to perform Vertical Take-Off and Landing (VTOL) and Conventional Take-Off and Landing (CTOL). This paper focuses on the Dual Tilt-wing UAV, a vehicle capable of performing both flight modes (VTOL and CTOL). The UAV complete dynamic model is obtained using the Newton–Euler formulation, which includes aerodynamic effects, as the drag and lift forces of the wings, which are a function of airstream generated by the rotors, the cruise speed, tilt-wing angle and angle of attack. The airstream velocity generated by the rotors is studied in a test bench. The projected area on the UAV wing that is affected by the airstream generated by the rotors is specified and 3D aerodynamic analysis is performed for this region. In addition, aerodynamic coefficients of the UAV in VTOL mode are calculated by using Computational Fluid Dynamics method (CFD) and are embedded into the nonlinear dynamic model. To validate the complete dynamic model, PD controllers are adopted for altitude and attitude control of the vehicle in VTOL mode, the controllers are simulated and implemented in the vehicle for indoor and outdoor flight experiments.

Geometry optimization of a planar double wishbone suspension based on whole-range nonlinear dynamic model

2021 ◽  
pp. 095440702110262
Author(s):  
Zhihua Niu ◽  
Sun Jin ◽  
Rongrong Wang ◽  
Yansong Zhang
Keyword(s):  
Dynamic Model ◽  
Geometry Optimization ◽  
Analytical Models ◽  
Small Displacement ◽  
Nonlinear Dynamic Model ◽  
Computational Accuracy ◽  
Suspension Systems ◽  
Geometry Design ◽  
Dynamic Performances ◽  
Suspension Geometry

Dynamic analysis is an essential task in the geometry design of suspension systems. Whereas the dynamic simulation based on numerical software like Adams is quite slowly and the existing analytical models of the nonlinear suspension geometry are mostly based on small displacement hypothesis, this paper aims to propose a whole-range dynamic model with high computational efficiency for planar double wishbone suspensions and further achieve the fast optimal design of suspension geometry. Selection of the new generalized coordinate and explicit solutions of the basic four-bar mechanism dramatically reduce the complexity of suspension geometry representation and provide analytical solutions for all of the time varying dimensions. By this means, the running speed and computational accuracy of the new model are guaranteed simultaneously. Furthermore, an original Matlab/Simulink implementation is given to maintain the geometric nonlinearity in the solving process of dynamic differential equations. After verifying its accuracy with an ADAMS prototype, the presented whole-range model is used in the vast-parameter optimization of suspension geometry. Since both kinematic and dynamic performances are evaluated in the objective function, the optimization is qualified to give a comprehensive suggestion to the design of suspension geometry.

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