Novel field-circuit assisted FEA of 110 kV power transformer for noise control and vibration reduction

2020 ◽  
Vol 64 (1-4) ◽  
pp. 289-298
Author(s):  
Li Li ◽  
Dianhai Zhang ◽  
Zhi Wang ◽  
Yanli Zhang ◽  
Xiaopeng Fan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Goodness Of Fit ◽  
Power Transformer ◽  
Coupling Model ◽  
Power Transformers ◽  
Accurate Calculation ◽  
Load Current ◽  
Large Power ◽  
Novel Approach ◽  
Structural Force

The vibration and noise are serious problems for large oil-immersed power transformers, which directly affect the performance and stability of transformers. The no-load current, as the excitation source, is very important for accurate calculation of vibration and noise. This paper provides a novel approach based on the new field-circuit coupling model to calculate no-load current of large power transformers. For one 110 kV large oil-immersed power transformer, the multi-physics coupling problem including magnetic field, structural force field and acoustic field under alternating magnetic field is analyzed. Following the multi-physics coupling calculation, distributions of vibration and noise are obtained. To validate feasibility and applicability of the proposed method, the actual vibration and noise of transformer are measured experimentally. Finally, the simulation results are compared with experimental ones, which show better goodness of fit.

The Heating System of Agricultural Facilities Using Excess Heat Power Transformers

2020 ◽  
Vol 67 (1) ◽  
pp. 42-47
Author(s):  
Anatoliy I. Sopov ◽  
Aleksandr V. Vinogradov
Keyword(s):  
System Design ◽  
Heat Supply ◽  
Cooling System ◽  
Power Transformer ◽  
Electric Heating ◽  
Heating System ◽  
Power Transformers ◽  
Large Power ◽  
Excess Heat ◽  
Power Centers

In power transformers, energy losses in the form of heat are about 2 percent of their rated power, and in transformers of large power centers reach hundreds of kilowatts. Heat is dissipated into the environment and heats the street air. Therefore, there is a need to consume this thermal energy as a source of heat supply to nearby facilities. (Research purpose) To develop methods and means of using excess heat of power transformers with improvement of their cooling system design. (Materials and methods) The authors applied following methods: analysis, synthesis, comparison, monographic, mathematical and others. They analyzed various methods for consuming excess heat from power transformers. They identified suitable heat supply sources among power transformers and potential heat consumers. The authors studied the reasons for the formation of excess heat in power transformers and found ways to conserve this heat to increase the efficiency of its selection. (Results and discussion) The authors developed an improved power transformer cooling system design to combine the functions of voltage transformation and electric heating. They conducted experiments to verify the effectiveness of decisions made. A feasibility study was carried out on the implementation of the developed system using the example of the TMG-1000/10/0.4 power transformer. (Conclusions) The authors got a new way to use the excess heat of power transformers to heat the AIC facilities. It was determined that the improved design of the power transformer and its cooling system using the developed solutions made it possible to maximize the amount of heat taken off without quality loss of voltage transformation.

scholarly journals A Fuzzy Logic Model for Power Transformer Faults’ Severity Determination Based on Gas Level, Gas Rate, and Dissolved Gas Analysis Interpretation

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 1009 ◽  
Author(s):  
Rahman Azis Prasojo ◽  
Harry Gumilang ◽  
Suwarno ◽  
Nur Ulfa Maulidevi ◽  
Bambang Anggoro Soedjarno
Keyword(s):  
Fuzzy Logic ◽  
Power Transformer ◽  
Local Population ◽  
Gas Analysis ◽  
Power Transformers ◽  
Support Vector ◽  
Dissolved Gas ◽  
New Approach ◽  
Dissolved Gas Analysis ◽  
Novel Approach

In determining the severity of power transformer faults, several approaches have been previously proposed; however, most published studies do not accommodate gas level, gas rate, and Dissolved Gas Analysis (DGA) interpretation in a single approach. To increase the reliability of the faults’ severity assessment of power transformers, a novel approach in the form of fuzzy logic has been proposed as a new solution to determine faults’ severity using the combination of gas level, gas rate, and DGA interpretation from the Duval Pentagon Method (DPM). A four-level typical concentration and rate were established based on the local population. To simplify the assessment of hundreds of power transformer data, a Support Vector Machine (SVM)-based DPM with high agreements to the graphical DPM has been developed. The proposed approach has been implemented to 448 power transformers and further implementation was done to evaluate faults’ severity of power transformers from historical DGA data. This new approach yields in high agreement with the previous methods, but with better sensitivity due to the incorporation of gas level, gas rate, and DGA interpretation results in one approach.

scholarly journals Analysis of Operating Modes of Oil-Immersed Power Transformers with a Voltage of 10 (6) / 0.4 kV

2021 ◽  
Vol 24 (4) ◽  
pp. 80-91
Author(s):  
A.E. Fokeev ◽  
I.N. Tumakov
Keyword(s):  
Ambient Temperature ◽  
Thermal Aging ◽  
Power Transformer ◽  
Spectral Composition ◽  
Operating Conditions ◽  
Power Transformers ◽  
Load Factor ◽  
Calculation Algorithm ◽  
Load Current ◽  
Aging Rate

The rate of thermal aging of the power transformers windings insulation depends on the effects of the electric field, mechanical stresses, temperature and processes that cause changes in these factors. A calculation algorithm is considered that allows determining the temperature of the most heated point of the windings of an oil power transformer at known values of the load current and ambient temperature. Calculation of the most heated winding point temperature and the rate of thermal aging of insulation for an oil power transformer at different ambient temperatures during the year, different values and different spectral composition of the electric load current showed that in some cases it is possible to violate the permissible operating conditions of power transformers. According to the calculation results, the dependences of the thermal aging rate of insulation on the ambient temperature are constructed, with different load parameters and different load coefficients of power transformers. For the considered modes, in the warm season, the value of the thermal aging rate of insulation significantly exceeds the nominal value. Based on mathematical models of oil power transformers with natural and forced oil circulation, expressions are obtained for determining the coefficient of reduction of the oil power transformers permissible load when the ambient temperature exceeds the normal value of 20 °C. On the basis of these expressions, for practical use, the dependences of the coefficient of reduction of the permissible load on the ambient temperature are constructed. The influence of ambient temperature must be taken into account when choosing the power of oil power transformers, for which it is assumed to operate in full redundancy mode or high load factor values (³ 0.8) in normal mode. To ensure the normative service life of the insulation of the windings, it is necessary to determine the design power of oil power transformers using the coefficient of reduction of the permissible load under the influence of higher harmonics of the current and the coefficient of reduction of the permissible load under the influence of ambient temperature.

Study on the Power Transformers Deterioration State Evaluation Index System

2013 ◽  
Vol 732-733 ◽  
pp. 954-957
Author(s):  
Qing Xie ◽  
Shan Shan Hou ◽  
Feng Liao ◽  
Wei Tao Hu
Keyword(s):  
Health Status ◽  
Power System ◽  
Index System ◽  
Power Transformer ◽  
Evaluation Index System ◽  
Evaluation Index ◽  
Power Transformers ◽  
Large Power ◽  
State Evaluation ◽  
Accurate Judgment

Large power transformers as the the hub of power system equipment, its operation reliability directly related to the security and stability of the power system. When we have to make a more comprehensive and accurate judgment for running health status of the power transformer,we must get the characteristics of the transformer state. In this paper, we can pick out representative indicators from the existing power transformers deterioration state elements. Thereby, we can study more systematic and targeted the deteriorated state of the power transformer. Keywords: power transformers; deterioration state ;evaluation

Simulation Analysis and Benchmarking Validation of Magnetic, Electromagnetic and Hybrid Shields in Large Power Transformers

2013 ◽  
Vol 873 ◽  
pp. 871-876
Author(s):  
Yue Ning Li ◽  
Yong Gang Li ◽  
Zhi Guang Cheng
Keyword(s):  
Flux Density ◽  
Simulation Analysis ◽  
Model Simulation ◽  
Power Transformer ◽  
Power Transformers ◽  
Stray Field ◽  
Product Model ◽  
Large Power ◽  
Magnetic Shields ◽  
Magnetic Shunt

according to different theories the magnetic shunt, the electromagnetic shield and a combination of both in power transformer have protective shielding functions to mental components and decrease stray-field loss ( including eddy current loss and hysteresis loss), avoiding damage to insulation devices caused by partial overheating for overconcentration of the loss. This paper will build a 2D modeling and simulation which proves the improved platform measuring the the shield loss and flux density of the transformer product model can provide a more reasonable flux complementary condition. Three kinds of shield in the model will be calculated by 3-D model simulation to research and compare the loss and flux density of the magnetic shunt, the electromagnetic barrier and the hybrid shield, which is of significant analyzable and referable value for optimizing the design of magnetic shields in large power transformers.

scholarly journals Influence of capacitive no-load current component in large power transformers

2017 ◽  
Vol 202 ◽  
pp. 176-182
Author(s):  
Goran Rovišan ◽  
Goran Plišić ◽  
Franjo Kelemen
Keyword(s):  
Power Transformers ◽  
Current Component ◽  
Load Current ◽  
Large Power

On the Magneto-Heat Coupling Model for Large Power Transformers

2017 ◽  
Vol 22 (3) ◽  
pp. 683-711 ◽  
Author(s):  
Xujing Li ◽  
Shipeng Mao ◽  
Kangkang Yang ◽  
Weiying Zheng
Keyword(s):  
Heat Equation ◽  
Eddy Current ◽  
Maxwell’S Equations ◽  
Energy Exchange ◽  
Maxwell's Equations ◽  
Current Model ◽  
Coupling Model ◽  
Power Transformers ◽  
Weak Formulation ◽  
Large Power

AbstractThis paper studies the magneto-heat coupling model which describes iron loss of conductors and energy exchange between magnetic field and Ohmic heat. The temperature influences Maxwell's equations through the variation of electric conductivity, while electric eddy current density provides the heat equation with Ohmic heat source. It is in this way that Maxwell's equations and the heat equation are coupled together. The system also incorporates the heat exchange between conductors and cooling oil which is poured into and out of the transformer. We propose a weak formulation for the coupling model and establish the well-posedness of the problem. The model is more realistic than the traditional eddy current model in numerical simulations for large power transformers. The theoretical analysis of this paper paves a way for us to design efficient numerical computation of the transformer in the future.

Numerical Analysis on Short-Circuit Force Parameters of Windings for Power Transformer

2011 ◽  
Vol 138-139 ◽  
pp. 764-769
Author(s):  
Jian Jun Liu ◽  
Jian Min Wang ◽  
Chong You Jing ◽  
Chang Zai Fan ◽  
Yuan Zhai
Keyword(s):  
Magnetic Field ◽  
Numerical Analysis ◽  
Power Transformer ◽  
Short Circuit ◽  
Strength Test ◽  
Power Transformers ◽  
Simplified Model ◽  
Leakage Magnetic Field ◽  
Set Up ◽  
Short Circuit Condition

The Simplified model of both calculating leakage magnetic field and mechanical force of windings at short circuit condition for a 120MVA/220kV power transformer is set up. The leakage magnetic field ‚ short-circuit force and stress in transformer windings are analyzed and their distributing characteristics are acquired respectively by using FEM. The calculation method and results are validated by withstanding short circuit strength test of the product. A number of useful suggestions are given for design of power transformers.

A Solid-State On-Load Tap Changer for the Power Transformers of 10—0.4 kV Distribution Networks

Vestnik MEI ◽  
2020 ◽  
Vol 6 (6) ◽  
pp. 82-90
Author(s):  
Dmitriy I. Panfilov ◽  
◽  
Mikhail G. Astashev ◽  
Aleksandr V. Gorchakov ◽  
◽  
...  
Keyword(s):  
Solid State ◽  
Physical Model ◽  
High Speed ◽  
Power Transformer ◽  
Voltage Control ◽  
Power Transformers ◽  
Control Algorithms ◽  
Load Voltage ◽  
Tap Changer ◽  
Load Tap Changer

The specific features relating to voltage control of power transformers at distribution network transformer substations are considered. An approach to implementing high-speed on-load voltage control of serially produced 10/0.4 kV power transformers by using a solid-state on-load tap changer (SOLTC) is presented. An example of the SOLTC circuit solution on the basis of thyristor switches is given. On-load voltage control algorithms for power transformers equipped with SOLTC that ensure high reliability and high-speed operation are proposed. The SOLTC performance and the operability of the suggested voltage control algorithms were studied by simulation in the Matlab/Simulink environment and by experiments on the SOLTC physical model. The structure and peculiarities of the used simulation Matlab model are described. The SOLTC physical model design and its parameters are presented. The results obtained from the simulating the SOLTC operation on the Matlab model and from the experiments on the SOLTS physical model jointly with a power transformer under different loads and with using different control algorithms are given. An analysis of the experimental study results has shown the soundness of the adopted technical solutions. It has been demonstrated that the use of an SOLTC ensures high-speed voltage control, high efficiency and reliability of its operation, and arcless switching of the power transformer regulating taps without load voltage and current interruption. By using the SOLTC operation algorithms it is possible to perform individual phase voltage regulation in a three-phase 0.4 kV distribution network. The possibility of integrating SOLTC control and diagnostic facilities into the structure of modern digital substations based on the digital interface according to the IEC 61850 standard is noted.

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