Mechanical breakdown of aged insulating paper around continuously transposed conductors for power transformers under the influence of short-circuit forces - analysis by numerical simulations

2015 ◽  
Author(s):  
Daniel Geissler ◽  
Thomas Leibfried
Keyword(s):  
Numerical Simulations ◽  
Short Circuit ◽  
Power Transformers ◽  
Insulating Paper ◽  
Mechanical Breakdown

scholarly journals Magneto-Thermo-Structural Analysis of Power Transformers under Inrush and Short Circuit Conditions

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3266
Author(s):  
Antonio Roniel Marques de Sousa ◽  
Marcus Vinicius Alves Nunes ◽  
Wellington da Silva Fonseca ◽  
Ramon Cristian Fernandes Araujo ◽  
Diorge de Souza Lima
Keyword(s):  
Structural Analysis ◽  
Electric Power ◽  
Short Circuit ◽  
Real Data ◽  
Short Circuit Current ◽  
Power Transformers ◽  
Inrush Current ◽  
Electric Power Supply ◽  
Axial Forces ◽  
Radial Forces

The main equipment responsible for connection and transmission of electric power from generating centers to consumers are power transformers. This type of equipment is subject to various types of faults that can affect its components, in some cases also compromising its operation and, consequently, the electric power supply. Thus, in this paper, electromagnetic, thermal, and structural analysis of power transformers was carried out with the objective of providing the operator with information on the ideal moment for performing predictive maintenance, avoiding unplanned shutdowns. For this, computational simulations were performed using the finite element method (FEM) and, from that, the different transformer operation ways, nominal currents, inrush current, and short-circuit current were analyzed. In this perspective, analyses of the effects that thermal expansion, axial forces, and radial forces exerted were carried out, contributing to possible defects in this type of equipment. As a study object, simulations were carried out on a 50 MVA single-phase transformer. It is important to emphasize that the simulations were validated with real data of measurements and with results presented in the current literature.

Analytical estimation of short circuit axial and radial forces on power transformers windings

2014 ◽  
Vol 8 (2) ◽  
pp. 250-260 ◽  
Author(s):  
Bashir Mahdi Ebrahimi ◽  
Saeed Saffari ◽  
Jawad Faiz ◽  
Alireza Fereidunian
Keyword(s):  
Short Circuit ◽  
Power Transformers ◽  
Analytical Estimation ◽  
Radial Forces

Magneto-Thermo-Structural Analysis of Power Transformers under Short Circuit Condition

2021 ◽  
Author(s):  
Antonio R. M. Sousa ◽  
Wellington Da S. Fonseca ◽  
Marcus V. A. Nunes ◽  
Ramon C. F. Araujo ◽  
Diorge de S. Lima
Keyword(s):  
Structural Analysis ◽  
Short Circuit ◽  
Power Transformers ◽  
Short Circuit Condition

scholarly journals Parametric estimation in photovoltaic modules using the crow search algorithm

2022 ◽  
Vol 12 (1) ◽  
pp. 82
Author(s):  
Oscar Danilo Montoya ◽  
Carlos Alberto Ramírez-Vanegas ◽  
Luis Fernando Grisales-Noreña
Keyword(s):  
Numerical Simulations ◽  
Search Algorithm ◽  
Short Circuit ◽  
Optimization Technique ◽  
Solution Space ◽  
Open Circuit ◽  
Parametric Estimation ◽  
Convex Optimization Problem ◽  
Processing Times ◽  
Objective Function Values

<p>The problem of parametric estimation in photovoltaic (PV) modules considering manufacturer information is addressed in this research from the perspective of combinatorial optimization. With the data sheet provided by the PV manufacturer, a non-linear non-convex optimization problem is formulated that contains information regarding maximum power, open-circuit, and short-circuit points. To estimate the three parameters of the PV model (i.e., the ideality diode factor (a) and the parallel and series resistances (R<sub>p</sub> and R<sub>s</sub>)), the crow search algorithm (CSA) is employed, which is a metaheuristic optimization technique inspired by the behavior of the crows searching food deposits. The CSA allows the exploration and exploitation of the solution space through a simple evolution rule derived from the classical PSO method. Numerical simulations reveal the effectiveness and robustness of the CSA to estimate these parameters with objective function values lower than 1 × 10<sup>−28</sup> and processing times less than 2 s. All the numerical simulations were developed in MATLAB 2020a and compared with the sine-cosine and vortex search algorithms recently reported in the literature.</p>

scholarly journals On Simplified Calculations of Leakage Inductances of Power Transformers

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4952 ◽  
Author(s):  
Tadeusz Sobczyk ◽  
Marcin Jaraczewski
Keyword(s):  
Power Transformer ◽  
Short Circuit ◽  
Power Transformers ◽  
Stray Field ◽  
Good Representation ◽  
The Finite Element Method ◽  
Leakage Inductance ◽  
Leakage Flux ◽  
Calculation Results ◽  
Discrete Differential Operator

This paper deals with the problem of the leakage inductance calculations in power transformers. Commonly, the leakage flux in the air zone is represented by short-circuit inductance, which determines the short-circuit voltage, which is a very important factor for power transformers. That inductance is a good representation of the typical power transformer windings, but it is insufficient for multi-winding ones. This paper presents simple formulae for self- and mutual leakage inductance calculations for an arbitrary pair of windings. It follows from a simple 1D approach to analyzing the stray field using a discrete differential operator, and it was verified by the finite element method (FEM) calculation results.

scholarly journals Novel Remanence Determination for Power Transformers Based on Magnetizing Inductance Measurements

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4616
Author(s):  
Chen Wei ◽  
Xianqiang Li ◽  
Ming Yang ◽  
Zhiyuan Ma ◽  
Hui Hou
Keyword(s):  
Numerical Simulations ◽  
Laboratory Experiments ◽  
Power Transformer ◽  
Power Transformers ◽  
Inrush Current ◽  
The Core ◽  
Novel Method ◽  
Simulation Results ◽  
Electro Magnetic ◽  
The Relationship

The remanence (residual flux) in the core of power transformers needs to be determined in advance to eliminate the inrush current during the process of re-energization. In this paper, a novel method is proposed to determine the residual flux based on the relationship between residual flux and the measured magnetizing inductance. The paper shows physical, numerical, and analytical explanations on the phenomenon that the magnetizing inductance decreases with the increase of residual flux under low excitation. Numerical simulations are performed by EMTP (Electro-Magnetic Transient Program) on a 1 kVA power transformer under different amounts of residual flux. The inductance–remanence curves are nearly the same when testing current changes. Laboratory experiments conducted on the same transformer are in line with the numerical simulations. Furthermore, numerical simulation results on a 240 MVA are reported to demonstrate the effectiveness of the proposed method.

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