Rapid Measurement of Power Transformer Winding DC Resistance

2013 ◽  
Vol 333-335 ◽  
pp. 22-26
Author(s):  
Xiao Fei Luo ◽  
Xian Xia ◽  
Kai Jun Wu
Keyword(s):  
Time Constant ◽  
Large Time ◽  
Power Transformer ◽  
Resistance Mutation ◽  
Transition Process ◽  
Measurement Circuit ◽  
Rapid Measurement ◽  
Transformer Winding ◽  
Simulation Results ◽  
Dc Resistance

Aim at the electric power transformer with inductance is large, resistance is small, the inherent characteristics of the large time constant, a fast measurement scheme of power transformer winding DC resistance is proposed. The scheme adopts the increase the measurement circuit loop resistance mutation method, in which the circuit transition process from a time constant is forced to another time constant, to realize the rapid measurement of winding DC resistance in power transformer. Simulation results show the effectiveness of the scheme.

scholarly journals Detection of inter turn fault in transformer windings by parameters of their transition processes

2019 ◽  
Vol 21 (3) ◽  
pp. 14-23 ◽  
Author(s):  
R. G. Mustafin
Keyword(s):  
Growth Rate ◽  
Power Transformer ◽  
High Sensitivity ◽  
Transition Process ◽  
Iron Core ◽  
Current Increase ◽  
Wide Range ◽  
Current Growth ◽  
Instrument Transformers ◽  
Transformer Winding

The proposed method of detection the inter turn fault of transformer windings relates to the area of defectoscopy and allows detecting inter turn faults in a wide range of damaged (closed) turns. Power and instrument transformers with iron-core are widely used in power networks. As the insulation ages or is damaged, the wires between various transformer sections short circuits occur, which inevitably leads to a complete damage of the transformer. Short- circuited part of the transformer forms an additional winding, the outputs of which are short- circuited. The transition process of current increasing when DC voltage is connected to the transformer outputs occurs in diverse ways in undamaged (cut-off) winding section and in the damaged (short-circuited) section. The current growth rate in the undamaged section of the winding is determined by high magnetization inductance. The inductance of the short-circuited part of the winding is much less, so, the current growth rate in the short-circuited part is significantly greater than the current growth rate in the undamaged part of the winding. The article presents observations from computer models and real measurements of the substation auxiliary power transformer, which show the possibility of determining the presence of a turn fault in regards to the transition process parameters, the rate of current increase and decay in the transformer winding. The device aimed to find the inter turn faults in the transformer windings, working according to the proposed method will be quite simple and have a high sensitivity.

The Effect of Mass Flow Distribution Inaccuracies in a Hydraulic Network Model for OD Zig-Zag Cooled Power Transformer Windings

2015 ◽  
Vol 789-790 ◽  
pp. 336-341
Author(s):  
Joris Coddé ◽  
Wim Van der Veken ◽  
Martine Baelmans
Keyword(s):  
Mass Flow ◽  
Cfd Simulation ◽  
Power Transformer ◽  
Flow Distribution ◽  
Network Models ◽  
Good Correspondence ◽  
Transformer Winding ◽  
Hydraulic Network ◽  
Transformer Design ◽  
Simulation Results

In this paper the mass flow distribution in zig-zag cooled power transformer windings is shown to play a crucial factor to accurately predict the winding temperature. In order to enable thermo-hydraulic network models for transformer design, new correlations are derived for combining and dividing T-junctions and elbow configurations. Good correspondence is achieved in comparison with CFD simulation results for a zig-zag cooled power transformer winding.

scholarly journals Prediction of Stress in Power Transformer Winding Conductors Using Artificial Neural Networks: Hyperparameter Analysis

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4242
Author(s):  
Fausto Valencia ◽  
Hugo Arcos ◽  
Franklin Quilumba
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Finite Element ◽  
Power Transformer ◽  
Network Models ◽  
Activation Function ◽  
Neural Network Models ◽  
Transformer Winding ◽  
Artificial Neural ◽  
Femm Software

The purpose of this research is the evaluation of artificial neural network models in the prediction of stresses in a 400 MVA power transformer winding conductor caused by the circulation of fault currents. The models were compared considering the training, validation, and test data errors’ behavior. Different combinations of hyperparameters were analyzed based on the variation of architectures, optimizers, and activation functions. The data for the process was created from finite element simulations performed in the FEMM software. The design of the Artificial Neural Network was performed using the Keras framework. As a result, a model with one hidden layer was the best suited architecture for the problem at hand, with the optimizer Adam and the activation function ReLU. The final Artificial Neural Network model predictions were compared with the Finite Element Method results, showing good agreement but with a much shorter solution time.

Research on Very Fast Transient over-Voltages Distribution in Large Power Transformer Windings

2012 ◽  
Vol 433-440 ◽  
pp. 7287-7292
Author(s):  
You Hua Gao ◽  
Zeng Feng Lai ◽  
Xiao Ming Liu ◽  
Guo Wei Liu ◽  
Ye Wang
Keyword(s):  
Power Transformer ◽  
Simulation Software ◽  
Large Power ◽  
Telegraph Equations ◽  
Backward Differentiation Formulas ◽  
Space Discretization ◽  
Simulation Results ◽  
Fast Transient ◽  
The Time Domain ◽  
Differentiation Formulas

To analyze the transient response of transformer windings under very fast transient over-voltage (VFTO), multi-conductor transmission line (MTL) model based on the representation of transformer windings by its individual turns are established. Space discretization is needed for solving the time-domain telegraph equations of MTL. To calculate the voltage distributions along transformer windings, through combining the compact finite difference (CFD) theory and the backward differentiation formulas (BDF). Simulation software ATP is introduced, and the simulation results demonstrate that the proposed approach is feasible.

Determination of Damping Factors Based on the Measured Frequency Responses of Power Transformer Windings. Part 2. Analysis of Measurement Results

2021 ◽  
Vol 2 (2) ◽  
pp. 22-28
Author(s):  
Vasily S. LARIN ◽  
◽  
Daniil A. MATVEEV ◽  
Keyword(s):  
Active Component ◽  
Power Transformer ◽  
Neutral Current ◽  
Response Analysis ◽  
Reactive Component ◽  
Input Admittance ◽  
Equivalent Scheme ◽  
Frequency Responses ◽  
Measurement Results ◽  
Transformer Winding

In the first part of the article, based on the results of theoretical studies performed for a simplified transformer winding equivalent scheme, it was shown that the damping factors can be estimated from the width of the resonant peaks of the frequency responses of the module and the reactive component of the voltage at the midpoint of the equivalent scheme, as well as the active component of the input admittance and neutral current of the considered resonant scheme. In this part of the article, the practical possibility of applying the obtained theoretical relations between the damping factors and the width of resonant peaks in relation to the frequency responses of power transformer windings is considered. The results of calculations of the damping factors at the two power transformers made by using the fitting of the free component of transient voltage and by determining the width of the resonance peaks of the active component of winding neutral current and the voltage transfer function, corresponding to intermediate points of the winding. It is shown that the evaluation of the values of the winding damping factors can be performed as a byproduct of transformer condition assessment by frequency response analysis (FRA).

Restoration of terahertz continuous wave image obtained by continuous scan mode with large time constant

2014 ◽  
Vol 53 (32) ◽  
pp. 7735 ◽  
Author(s):  
Xiao Lou ◽  
Lei Hou ◽  
Gaoyuan Guo ◽  
Wei Shi
Keyword(s):  
Time Constant ◽  
Large Time ◽  
Continuous Wave ◽  
Wave Image

A New Lattice Boltzmann Model for Phase Transition Process

2009 ◽  
Author(s):  
Longjian Li ◽  
Jianbang Zeng ◽  
Quan Liao ◽  
Wenzhi Cui
Keyword(s):  
Phase Transition ◽  
Lattice Boltzmann ◽  
Equations Of State ◽  
Density Ratio ◽  
Transition Process ◽  
Lattice Boltzmann Model ◽  
New Model ◽  
Phase Transition Process ◽  
Simulation Results ◽  
Boltzmann Model

A new lattice Boltzmann model, which is based on Shan-Chen (SC) model, is proposed to describe liquid-vapor phase transitions. The new model is validated through simulation of the one-component phase transition process. Compared with the simulation results of van der Waals fluid and the Maxwell equal-area construction, the results of new model are closer to the analytical solutions than those of SC model and Zhang model. Since the range of temperature and the maximum density ratio are increased, and the value of maximum spurious current is between those of SC and Zhang models, it is believed that this new model has better stability than SC and Zhang models. Therefore, the application scope of this new model is expanded. According to the principle of corresponding states in Engineering Thermodynamics, the simulations of water and ammonia phase transition process are implemented by using this new model with different equations of state. Compared to the experimental data of water and ammonia, the results show that the Peng-Robinson equation of state is more suitable to describe the water, ammonia and other substances phase transition process. Therefore, these simulation results have great significance for the real engineering applications.

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