Buckling Strength Analysis of Large Power Transformer Windings Subjected to Electromagnetic Force Under Short Circuit

1980 ◽  
Vol PAS-99 (3) ◽  
pp. 1288-1297 ◽  
Author(s):  
Hiroyuki Kojima ◽  
Hiroshi Miyata ◽  
Shigeru Shida ◽  
Ken'ichi Okuyama
Keyword(s):  
Electromagnetic Force ◽  
Power Transformer ◽  
Short Circuit ◽  
Strength Analysis ◽  
Large Power ◽  
Buckling Strength

Axial Nonlinear Mechanical Vibrations of Large Power Transformer Windings During Short Circuit

2001 ◽  
Author(s):  
Jian-Xue Xu ◽  
Zhen-Mao Chen
Keyword(s):  
Steady State ◽  
Shooting Method ◽  
Single Phase ◽  
Power Transformer ◽  
Short Circuit ◽  
Mathieu Equation ◽  
Response Force ◽  
Dynamical Response ◽  
Large Power ◽  
The Time Domain

Abstract In this paper, the axial nonlinear vibrations of the transformer winding under steady state operation case and short circuit case are studied in single degree and multi-degree models. In the case of having ampere-turn balance, the steady state response of the former model is obtained by using multi-scale method and periodic shooting method, analytically and numerically. At the same time, the computing method of Jacobi matrix in the periodic shooting method has been modified, so that the computing CPU time is saved. For multi-degree mechanical model of a single phase transformer windings, the time domain response and relation between the response and various parameters are obtained by Runge-Kutta method. For ampere-turn unbalance case, an electric-mechanical coupled problem, that the electric force depends the displacement of the winding are foomed, and the nonlinear forced Mathieu equation is established for this problem; and then the nonlinear dynamical response and global dynamical behaviors are analyzed. Finally, for a 20 MVA single phase three windings transformer, a series of short circuit experiments have been performed and the axial dynamical response force, magnetic field, strain etc. have been measured. The theoretical results well agree with the experimental results.

scholarly journals Non-linear Impact of the Short Circuit Impedance Selection on the Cost Optimized Power Transformer Design

2020 ◽  
Vol 64 (3) ◽  
pp. 221-228
Author(s):  
Tamás Orosz ◽  
Zoltán Ádám Tamus
Keyword(s):  
Design Process ◽  
Power Transformer ◽  
Short Circuit ◽  
Design Rule ◽  
Design Parameters ◽  
Electrical Machine ◽  
Preliminary Design ◽  
Large Power ◽  
Final Design ◽  
The Cost

Since the electrical machine design is a complex task it can be divided into sub-problems, e.g. preliminary and final design processes and checking of the final design. This paper deals with the preliminary design process, which provides the key-design parameters of the electrical machine. Traditionally, these electrical machine models in preliminary design phase neglect or use oversimplified insulation system models and the tap changing selection is not involved during the calculation of key-design parameters. The aim of this study is to assess the effect of the insulation distance minimization and tap-changing on the key design parameters of a cost-optimized large power transformer. For this purpose, the paper shows some examples, where the cost optimal design — in contrast to the classical insulation design rule — contains larger insulation distances than the possible minimum values. The effect of tap-changing methods are also investigated. These cost optimization made by a verified, metaheuristic method-based transformer optimization algorithm. The results show involving the insulation design and tap-changing selection into the preliminary design process can provide more economical designs.

Computation of Radial Electromagnetic Forces on Power Transformer LV Windings due to Short-Circuit Currents

2013 ◽  
Vol 732-733 ◽  
pp. 1069-1073 ◽  
Author(s):  
Han Bo Zheng ◽  
Jin Hua Han ◽  
Wei Wang ◽  
Xiao Gang Li ◽  
Yu Quan Li
Keyword(s):  
Mechanical Stress ◽  
Case Studies ◽  
Calculation Method ◽  
Electromagnetic Force ◽  
Radial Direction ◽  
Low Voltage ◽  
Power Transformer ◽  
Short Circuit ◽  
Leakage Flux ◽  
Short Circuit Currents

The short-circuit electromagnetic force in radial direction induces critical mechanical stress on a power transformer. In this paper, the radial short-circuit forces which are exerted on transformer low voltage (LV) windings are investigated. Firstly, the mechanisms of leakage flux and short-circuit electromechanical forces in transformer coils are analyzed. Afterwards, based on IEC standards followed by short-circuit tests, calculations of radial short-circuit forces and evaluations of the ability to withstand short currents in LV windings are developed. The case studies and comparisons with improved measures show that the evaluation and calculation method is feasible and effective, and this method also offers three useful ways to strengthen the ability to withstand short-circuit currents for transformer windings.

Finite-Element Analysis of Short-Circuit Electromagnetic Force in Power Transformer

2011 ◽  
Vol 47 (3) ◽  
pp. 1267-1272 ◽  
Author(s):  
Hyun-Mo Ahn ◽  
Ji-Yeon Lee ◽  
Joong-Kyoung Kim ◽  
Yeon-Ho Oh ◽  
Sang-Yong Jung ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Electromagnetic Force ◽  
Power Transformer ◽  
Short Circuit ◽  
Element Analysis

Fault diagnosis of actual large-power high-voltage windings using transfer function method

2011 ◽  
Vol 60 (3) ◽  
pp. 269-281 ◽  
Author(s):  
Ebrahim Rahimpour ◽  
Stefan Tenbohlen
Keyword(s):  
Fault Diagnosis ◽  
Transfer Function ◽  
High Voltage ◽  
Function Method ◽  
Power Transformer ◽  
Short Circuit ◽  
Large Power ◽  
Transfer Function Method ◽  
Comparison Algorithms ◽  
Test Objects

Fault diagnosis of actual large-power high-voltage windings using transfer function method The transfer function (TF) method is presently a well-known method used to detect various types of winding damage in power transformers. Although abundant research has been done on this subject using laboratory windings as test objects, it is hard to find one, whose test objects are actual large-power transformer windings. Hence, a 400 kV disc winding consisting of 86 discs is used in this paper to study turn-to-turn short circuit with the help of the TF method. To evaluate the effects of this type of fault on TF curves, some mathematical comparison algorithms are used in this research.

Computation and Analysis of Static and Dynamic Radial Stability of Power Transformer Inner Winding

2014 ◽  
Vol 986-987 ◽  
pp. 1926-1929
Author(s):  
Xin Sun ◽  
Yan Li ◽  
Fang Xu Han ◽  
Jian Li
Keyword(s):  
Dynamic Stability ◽  
Electromagnetic Force ◽  
Power Transformer ◽  
Short Circuit ◽  
Experimental Results ◽  
Field Calculation ◽  
Product Analysis ◽  
Instability Phenomenon ◽  
Static And Dynamic Stability ◽  
Leakage Field

In this paper, the size of winding electromagnetic force after short circuit has been acquired through leakage field calculation and analysis on power transformer, and based on the computation results, the radial stability experimental results of large capacity power transformer inner winding short-circuit model were compared to the simulation values to guide actual product analysis and checking. With the accumulated simulation experience on this model, then a type of sfz9-80MVA power transformer inner coil static and dynamic stability has been checked to confirm the radial instability phenomenon could whether or not occur on this product.

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