Transformer Design and Optimization: A Literature Survey

With the fast-paced changing technologies in the power industry, new references addressing new technologies are coming to the market. Based on this fact, there is an urgent need to keep track of international experiences and activities taking place in the field of modern transformer design. The complexity of transformer design demands reliable and rigorous solution methods. A survey of current research reveals the continued interest in application of advanced techniques for transformer design optimization. This paper conducts a literature survey and reveals general backgrounds of research and developments in the field of transformer design and optimization for the past 35 years, based on more than 420 published articles, 50 transformer books, and 65 standards.

[1]  R. S. Girgis,et al.  Magnetic flux distributions in transformer core joints , 2000 .

[2]  Eric Van den Bulck,et al.  Modelling of the mixed convection in the windings of a disc-type power transformer , 2000 .

[3]  L. Bolduc,et al.  Study of the Acceptable DC Current Limit in Core-Form Power Transformer , 1997, IEEE Power Engineering Review.

[4]  P. R. Price,et al.  Geomagnetically Induced Current Effects on Transformers , 2002, IEEE Power Engineering Review.

[5]  Chih-Kun Cheng,et al.  Asymmetrical winding configuration to reduce inrush current with appropriate short-circuit current in transformer , 2005 .

[6]  G. Sridhara Rao,et al.  Parameter estimation of three-winding transformers using genetic algorithm , 2002 .

[7]  Norio Takahashi,et al.  Magnetic performance of step-lap joints in distribution transformer cores , 1982 .

[8]  Daniel Tylavsky,et al.  Prediction of top-oil temperature for transformers using neural networks , 2000 .

[9]  K. L. Butler,et al.  Finite Element Analysis of Internal Winding Faults in Distribution Transformers , 2001, IEEE Power Engineering Review.

[10]  Jiahui Zhang,et al.  Coolant flow distribution and pressure loss in ONAN transformer windings. Part II: Optimization of design parameters , 2004, IEEE Transactions on Power Delivery.

[11]  P. A. Abetti,et al.  Application of Digital Computers to Transformer Design [includes discussion] , 1956, Transactions of the American Institute of Electrical Engineers. Part III: Power Apparatus and Systems.

[12]  M.M.A. Aziz,et al.  Heat Conduction Problems in ${\rm SF}_{6}$ Gas Cooled-Insulated Power Transformers Solved by the Finite-Element Method , 2008, IEEE Transactions on Power Delivery.

[13]  Ibrahim El-Amin,et al.  Factors that influence transformer no-load current harmonics , 2000 .

[14]  J. Pedra,et al.  PSPICE computer model of a nonlinear three-phase three-legged transformer , 2002 .

[15]  Drago Dolinar,et al.  Dynamic model of a three-phase power transformer , 1993 .

[16]  D.R. Swatek,et al.  Specifying transformer winter and summer peak-load limits , 2005, IEEE Transactions on Power Delivery.

[17]  V. Woivre,et al.  Transient overvoltage study and model for shell-type power transformers , 1993 .

[18]  R. S. Girgis,et al.  Other Factors Contributing to the Core Loss Performance of Power and Distribution Transformers , 2001 .

[19]  B.A. Mork,et al.  Transformer modeling for low- and mid-frequency transients - a review , 2005, IEEE Transactions on Power Delivery.

[20]  R.S. Girgis,et al.  Measuring no - load and load noise of power transformers using the Sound Pressure and Sound Intensity methods — Part - I: Outdoors measurements , 2008, 2008 IEEE Power and Energy Society General Meeting - Conversion and Delivery of Electrical Energy in the 21st Century.

[21]  Tapan Kumar Saha,et al.  Investigating the effects of oxidation and thermal degradation on electrical and chemical properties of power transformers insulation , 1999 .

[22]  Matti Lehtonen,et al.  Dynamic thermal modelling of power transformers , 2004 .

[23]  K. Zakrzewski,et al.  Simulation of forces and 3-D field arising during power autotransformer fault due to electric arc in HV winding , 2002 .

[24]  J. Anger,et al.  Combination of finite and boundary element methods in investigation and prediction of load-controlled noise of power transformers , 2002 .

[25]  N. E. Wakil,et al.  Numerical study of heat transfer and fluid flow in a power transformer , 2006 .

[26]  Sheng-Nian Yeh,et al.  Calculating the current distribution in power transformer windings using finite element analysis with circuit constraints , 1995 .

[27]  R. S. Girgis,et al.  Experimental investigations on effect of core production attributes on transformer core loss performance , 1998 .

[28]  Frédéric Robert.  A theoretical discussion about the layer copper factor used in winding losses calculation , 2002 .

[29]  K. J. Frohlich,et al.  Elimination of transformer inrush currents by controlled switching. II. Application and performance considerations , 2001 .

[30]  Chin E. Lin,et al.  Investigation of magnetizing inrush current in transformers. I. Numerical simulation , 1993 .

[31]  H. Bernhoff,et al.  Calculating the coupling factor in a multilayer coaxial transformer with air core , 2004, IEEE Transactions on Magnetics.

[32]  D.J. Tylavsky,et al.  Transformer thermal modeling: improving reliability using data quality control , 2006, IEEE Transactions on Power Delivery.

[33]  J.A. Jardini,et al.  Power transformer temperature evaluation for overloading conditions , 2005, IEEE Transactions on Power Delivery.

[34]  J. A. Ebert.  Criteria for reliable dual voltage power transformers , 1994, Proceedings of IEEE/PES Transmission and Distribution Conference.

[35]  J. Anger,et al.  Relevance of magnetostriction and forces for the generation of audible noise of transformer cores , 2000 .

[36]  S. A. Khaparde,et al.  Transformer Engineering: Design and Practice , 2004 .

[37]  N. D. Hatziargyriou,et al.  AI helps reduce transformer iron losses , 1999 .

[38]  Kimon P. Valavanis,et al.  A Systematic Stochastic Petri Net Based Methodology for Transformer Fault Diagnosis and Repair Actions , 2006, J. Intell. Robotic Syst..

[39]  B.A. Mork,et al.  Parameter determination for modeling system transients-Part III: Transformers , 2005, IEEE Transactions on Power Delivery.

[40]  Wilsun Xu,et al.  A Sequential Phase Energization Method for Transformer Inrush Current Reduction—Transient Performance and Practical Considerations , 2007, IEEE Transactions on Power Delivery.

[41]  D. Martin,et al.  A Comparative Study of the Chemical Stability of Esters for Use in Large Power Transformers , 2006, 2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena.

[42]  S. A. Khaparde,et al.  Evaluation of eddy losses due to high current leads in transformers , 1997 .

[43]  Bruce A. Mork,et al.  Five-Legged Core Transformer Equivalent Circuit , 1989, IEEE Power Engineering Review.

[44]  L. Sainz,et al.  Effects of symmetrical voltage sags on three-phase three-legged transformers , 2004, IEEE Transactions on Power Delivery.

[45]  Zoran Radakovic,et al.  A new method for the calculation of the hot-spot temperature in power transformers with ONAN cooling , 2003 .

[46]  C. Koley,et al.  Time-frequency representation of resistance for modeling of transformer winding under impulse test , 2006, IEEE Transactions on Power Delivery.

[47]  D. Atherton,et al.  Anisotropic flux density dependence of magnetic Barkhausen noise in oriented 3% Si-Fe steel laminates , 2003 .

[48]  T. Oommen.  Vegetable oils for liquid-filled transformers , 2002 .

[49]  A. Adly.  Computation of inrush current forces on transformer windings , 2001 .

[50]  M. Steurer,et al.  The Impact of Inrush Currents on the Mechanical Stress of High-Voltage Power Transformer Coils , 2001, IEEE Power Engineering Review.

[51]  F. de Leon,et al.  Complete transformer model for electromagnetic transients , 1994 .

[52]  N.Y. Abed,et al.  Modeling and Characterization of Transformers Internal Faults Using Finite Element and Discrete Wavelet Transforms , 2007, IEEE Transactions on Magnetics.

[53]  A. Moses,et al.  A novel method of reducing iron losses in power transformer cores , 1984 .

[54]  Y. Imai,et al.  Long-term reliability of amorphous alloy wound core distribution transformers , 1994 .

[55]  R. S. Girgis,et al.  Calculation of Core Hot-Spot Temperature in Power and Distribution Transformers , 2002, IEEE Power Engineering Review.

[56]  N. D. Hatziargyriou,et al.  Iron lamination efficient representation in power transformers , 2001 .

[57]  G. Swift.  Excitation current and power loss characteristics for mitered joint power transformer cores , 1975 .

[58]  H. Mohseni.  Multi-Winding Milti-Phase Transformer Model with Saturable Core , 1991, IEEE Power Engineering Review.

[59]  M.Q. Feng,et al.  Earthquake simulator testing of base-isolated power transformers , 2006, IEEE Transactions on Power Delivery.

[60]  Stefanos D. Kollias,et al.  A synergetic neural network-genetic scheme for optimal transformer construction , 2002, Integr. Comput. Aided Eng..

[61]  A. Narang,et al.  Topology based magnetic model for steady-state and transient studies for three-phase core type transformers , 1994 .

[62]  W. M. Grady,et al.  An investigation of the harmonic characteristics of transformer excitation current under nonsinusoidal supply voltage , 1999 .

[63]  G. Usry,et al.  Prediction of Far Field Sound Radiation from Transformers , 1980, IEEE Transactions on Power Apparatus and Systems.

[64]  William Gerard Hurley,et al.  Optimized transformer design: inclusive of high-frequency effects , 1998 .

[65]  A. Basak,et al.  Optimum design of transformer cores by analysing flux and iron loss with the aid of a novel software , 1992 .

[66]  M. Arjona,et al.  Object-Oriented Knowledge-Based System for Distribution Transformer Design , 2008, IEEE Transactions on Magnetics.

[67]  F. Judd,et al.  Design optimization of small low-frequency power transformers , 1977 .

[68]  S.A. Ryder,et al.  A simple method for calculating core temperature rise in power transformers , 2004, IEEE Transactions on Power Delivery.

[69]  S. Lu,et al.  FEM analysis of DC saturation to assess transformer susceptibility to geomagnetically induced currents , 1993 .

[70]  Luc Dupré,et al.  Comprehensive model of magnetization curve, hysteresis loops, and losses in any direction in grain-oriented Fe-Si , 2002 .

[71]  F. de Leon,et al.  Efficient calculation of elementary parameters of transformers , 1992 .

[72]  F. Gomide,et al.  Participatory Learning in Power Transformers Thermal Modeling , 2008, IEEE Transactions on Power Delivery.

[73]  K. Preis,et al.  Thermal-electromagnetic coupling in the finite-element simulation of power transformers , 2006, IEEE Transactions on Magnetics.

[74]  Pavlos S. Georgilakis.  Decision support system for evaluating transformer investments in the industrial sector , 2007 .

[75]  Joydeep Mitra,et al.  Hybrid Transformer Model for Transient Simulation—Part I: Development and Parameters , 2007, IEEE Transactions on Power Delivery.

[76]  R.S. Girgis,et al.  Measuring no — load and load noise of power transformers using the sound pressure and sound intensity methods — Part - II: Indoors measurements , 2008, 2008 IEEE Power and Energy Society General Meeting - Conversion and Delivery of Electrical Energy in the 21st Century.

[77]  Yu Cui,et al.  A sequential phase energization technique for transformer inrush current reduction - Part I: Simulation and experimental results , 2005 .

[78]  G. Buchgraber,et al.  Prediction of Magnetizing Current Wave-Forms in a Three-Phase Power Transformer Under DC Bias , 2008, IEEE Transactions on Magnetics.

[79]  E. F. Fuchs,et al.  Corrections to "measured transformer derating and comparison with harmonic loss factor (F/sub HL/) approach" , 2000 .

[80]  G. Meunier,et al.  An energy-based formulation for dynamic hysteresis and extra-losses , 2006, IEEE Transactions on Magnetics.

[81]  Nabeel A. O. Demerdash,et al.  Finite element formulation and analysis of three dimensional magnetic field problems , 1980 .

[82]  D. Tien,et al.  Active noise control of transformer noise , 1998, Proceedings of EMPD '98. 1998 International Conference on Energy Management and Power Delivery (Cat. No.98EX137).

[83]  R. S. Girgis,et al.  Calculation of spatial loss distribution in stacked power and distribution transformer cores , 1998 .

[84]  Carlos Alberto Brebbia,et al.  The boundary element method for electromagnetic problems , 1987 .

[85]  U.D. Annakkage,et al.  An improved low frequency transformer model for use in GIC studies , 2004, 2003 IEEE Power Engineering Society General Meeting (IEEE Cat. No.03CH37491).

[86]  J. L. Guardado,et al.  A Comparative Study of Neural Network Efficiency in Power Transformers Diagnosis Using Dissolved Gas Analysis , 2001, IEEE Power Engineering Review.

[87]  J. S. Hsu,et al.  Experimental study of harmonic-flux effects in ferromagnetic materials , 1989 .

[88]  Hyeong-Seok Kim,et al.  Modal analysis for the transient internal voltage of a transformer , 2004, IEEE Transactions on Magnetics.

[89]  J. A. Ebert.  Application considerations for variable volts per turn power transformers , 1994 .

[90]  H. Borsi,et al.  Drying of transformer insulation using zeolite , 2004, IEEE Electrical Insulation Magazine.

[91]  B. S. Ram.  Variation of transformer sheet winding eddy current loss with frequency , 2001 .

[92]  M. Vakilian,et al.  Power Transformers Internal Insulation Design Improvements Using Electric Field Analysis Through Finite-Element Methods , 2008, IEEE Transactions on Magnetics.

[93]  R. Herman,et al.  A thermal loading guide for residential distribution transformers based on time-variant current load models , 2004, IEEE Transactions on Power Systems.

[94]  H. Hirano,et al.  Magnetic field analysis by edge elements of magnetic components considering inhomogeneous current distribution within conductor windings , 2006, IEEE Transactions on Magnetics.

[95]  Y. Bertrand,et al.  Vegetal oils as substitute for mineral oils , 2003, Proceedings of the 7th International Conference on Properties and Applications of Dielectric Materials (Cat. No.03CH37417).

[96]  Y. Champoux,et al.  Application of the intensity technique to the characterization of transformer noise , 1988 .

[97]  N. Tutkun,et al.  Design optimisation of a typical strip-wound toroidal core using genetic algorithms , 2004 .

[98]  H. Igarashi,et al.  A reduced model for finite element analysis of steel laminations , 2006, IEEE Transactions on Magnetics.

[99]  C. Wu,et al.  Minimum weight EI core and pot core inductor and transformer designs , 1980 .

[100]  Eric Lesniewska,et al.  The use of 3-D electric field analysis and the analytical approach for improvement of a combined instrument transformer insulation system , 2002 .

[101]  E. So,et al.  Measurement and Correction of No-Load Losses of Power Transformers , 2004, 2004 Conference on Precision Electromagnetic Measurements.

[102]  Pan Seok Shin,et al.  A Free Vibration Analysis of Helical Windings of Power Transformer by Pseudospectral Method , 2007, IEEE Transactions on Magnetics.

[103]  A. Beroual,et al.  Experimental investigations on different insulating liquids and mixtures for power transformers , 2004, Conference Record of the 2004 IEEE International Symposium on Electrical Insulation.

[104]  J. Driesen,et al.  Reducing Losses in Distribution Transformers , 2002, IEEE Power Engineering Review.

[105]  M. Lukaniszyn,et al.  Three-dimensional model of one- and three-phase transformer for leakage field calculation , 1992 .

[106]  H. Braunstein,et al.  Distribution Transformer Loss Evaluation: I - Proposed Techniques , 1981, IEEE Transactions on Power Apparatus and Systems.

[107]  R. Belmans,et al.  Influence of the stacking method on the iron losses in power transformer cores , 1990, International Conference on Magnetics.

[108]  Marjan Popov,et al.  Improved Calculations for No Load Transformer Switching Surges , 2001 .

[109]  S. Zhang,et al.  Analysis of some measurement issues in bushing power factor tests in the field , 2006, IEEE Transactions on Power Delivery.

[110]  Jiahui Zhang,et al.  Oil cooling for disk-type transformer windings-part 1: theory and model development , 2006, IEEE Transactions on Power Delivery.

[111]  G. Swift,et al.  A fundamental approach to transformer thermal modeling. II. Field verification , 2001 .

[112]  Han Li,et al.  Application research based on improved genetic algorithm for optimum design of power transformers , 2001, ICEMS'2001. Proceedings of the Fifth International Conference on Electrical Machines and Systems (IEEE Cat. No.01EX501).

[113]  M. Lahtinen,et al.  GIC Occurrences and CIC Tests for 400 KV System Transformer , 2002, IEEE Power Engineering Review.

[114]  C. R. Souza,et al.  The application of intelligent systems in power transformer design , 2002, IEEE CCECE2002. Canadian Conference on Electrical and Computer Engineering. Conference Proceedings (Cat. No.02CH37373).

[115]  S.V. Kulkarni,et al.  Analysis of Half-Turn Effect in Power Transformers Using Nonlinear-Transient FE Formulation , 2007, IEEE Transactions on Power Delivery.

[116]  A. Ahfock,et al.  DC magnetisation of transformers , 2006 .

[117]  Woo-Seok Kim,et al.  Analysis of AC losses in HTS pancake windings for transformer according to the operating temperature , 2005, IEEE transactions on magnetics.

[118]  S. Liu,et al.  Finite-element-based nonlinear physical model of iron-core transformers for dynamic simulations , 2006, IEEE Transactions on Magnetics.

[119]  Paul R. Barnes,et al.  Reactive power demand of transformers with DC bias , 1994 .

[120]  I. Uglesic,et al.  Elimination of Overshooting Effects and Suppression of Numerical Oscillations in Transformer Transient Calculations , 2008, IEEE Transactions on Power Delivery.

[121]  S. Tojo.  Proposition of individual loading guide for power transformers , 2006 .

[122]  Bertrand Poulin,et al.  Transformer Design Principles: With Applications to Core-Form Power Transformers , 2001 .

[123]  R. M. Del Vecchio.  Applications of a multiterminal transformer model using two winding leakage inductances , 2006 .

[124]  L. Schiel,et al.  Ultrasaturation Phenomenon in Power Transformers—Myths and Reality , 2008, IEEE Transactions on Power Delivery.

[125]  F. Bettinali,et al.  Seismic qualification of transformer high voltage bushings , 1998 .

[126]  Guoqiang Zhang,et al.  Automatic design of impedance in shell-form power transformer , 2000 .

[127]  Kokubu Works.  DEVELOPMENT OF LARGE CAPACITY LOW-NOISE GAS-INSULATED TRANSFORMER , 1998 .

[128]  G.B. Gharehpetian,et al.  Comparison of Transformer Detailed Models for Fast and Very Fast Transient Studies , 2008, IEEE Transactions on Power Delivery.

[129]  Amr A. Adly.  Determination of total transformer losses resulting from semirotating flux excitation , 1995 .

[130]  Norio Takahashi,et al.  Optimal design of tank shield model of transformer , 2000 .

[131]  Colin Gordon.  A Method for Predicting the Audible Noise Emissions from Large Outdoors Power Transformers , 1979, IEEE Transactions on Power Apparatus and Systems.

[132]  Stanislaw Grzybowski,et al.  Accelerated aging of high voltage encapsulated transformers for electronics applications , 2000, Proceedings of the 6th International Conference on Properties and Applications of Dielectric Materials (Cat. No.00CH36347).

[133]  O. W. Andersen.  Optimum Design of Electrical Machines , 1967 .

[134]  C. Rosas,et al.  Improvement of the cooling process of oil-immersed electrical transformers using heat pipes , 2005, IEEE Transactions on Power Delivery.

[135]  N.D. Hatziargyriou,et al.  A neural network framework for predicting transformer core losses , 1999, Proceedings of the 21st International Conference on Power Industry Computer Applications. Connecting Utilities. PICA 99. To the Millennium and Beyond (Cat. No.99CH36351).

[136]  M. Lehtonen,et al.  Dynamic thermal modeling of power transformers: further Development-part I , 2006, IEEE Transactions on Power Delivery.

[137]  R. Yokoyama,et al.  Transformer noise level optimization based on reverse calculation problem and linear programming , 2008, 2008 IEEE Power and Energy Society General Meeting - Conversion and Delivery of Electrical Energy in the 21st Century.

[138]  L. Sainz,et al.  Theoretical Calculation of Inrush Currents in Three- and Five-Legged Core Transformers , 2007, IEEE Transactions on Power Delivery.

[139]  S. Gyimothy,et al.  Calculation of losses in laminated ferromagnetic materials , 2004, IEEE Transactions on Magnetics.

[140]  J. Turowski,et al.  Eddy current losses and hot-spot evaluation in cover plates of power transformers , 1997 .

[141]  S. E. Wright,et al.  Validation of acoustic intensity measurements for power transformers , 1991 .

[142]  E. So,et al.  Measurements and correction of no-load losses of power transformers , 2005, IEEE Transactions on Instrumentation and Measurement.

[143]  Anthony John Moses,et al.  Problems in the design of power transformers , 1974 .

[144]  S. A. Khaparde,et al.  Stray loss evaluation in power transformers-a review , 2000, 2000 IEEE Power Engineering Society Winter Meeting. Conference Proceedings (Cat. No.00CH37077).

[145]  M. P. Papadopoulos,et al.  Leakage flux and force calculation on power transformer windings under short-circuit: 2D and 3D models based on the theory of images and the finite element method compared to measurements , 1994 .

[146]  M. Clabian,et al.  Neural networks for the prediction of magnetic transformer core characteristics , 2000 .

[147]  B. Polajzer,et al.  Determining Magnetically Nonlinear Characteristics of Transformers and Iron Core Inductors by Differential Evolution , 2008, IEEE Transactions on Magnetics.

[148]  A. Basak,et al.  Efficient transformer design by computing core loss using a novel approach , 1994 .

[149]  P.S. Georgilakis,et al.  Geometry optimization of magnetic shunts in power transformers based on a particular hybrid finite-element boundary-element model and sensitivity analysis , 2005, IEEE Transactions on Magnetics.

[150]  Masataka Iwakuma,et al.  Fabrication of Superconducting Traction Transformer for Railway Rolling Stock , 2006 .

[151]  Marcel A. Lamoureux.  Electricity Production and Greenhouse Gas Emissions , 2002, IEEE Power Engineering Review.

[152]  B. Tomczuk,et al.  Analysis of 3-D magnetic fields in high leakage reactance transformers , 1994 .

[153]  V. Madzarevic,et al.  Numerical calculations of three-phase transformer transients , 2005, IEEE Transactions on Power Delivery.

[154]  N. Takahashi,et al.  Study of modeling method of lamination of Reactor core , 2006, IEEE Transactions on Magnetics.

[155]  Sang-Hyun Kim,et al.  Manufacturing and test of model double-pancake coils of HTS transformer for cryogenic insulation design , 2004, IEEE transactions on applied superconductivity.

[156]  S. J. Salon,et al.  Hybrid finite element boundary element solutions for three dimensional scalar potential problems , 1986 .

[157]  Brian Sadden,et al.  Hydropower Development in Southern and Southeastern Asia , 2002, IEEE Power Engineering Review.

[158]  D. D. Mairs,et al.  Overvoltages on five legged core transformers on rural electric systems , 1988 .

[159]  G. Olivier,et al.  3-D computation of transformers overheating under nonlinear loads , 2005, IEEE Transactions on Magnetics.

[160]  Oszkar Biro,et al.  Prediction of magnetising current waveform in a single-phase power transformer under DC bias , 2006 .

[161]  M. Vitelli.  Numerical evaluation of 2-D proximity effect conductor losses , 2004, IEEE Transactions on Power Delivery.

[162]  L. Haydock,et al.  Calculating stray losses in power transformers using surface impedance with finite elements , 1992 .

[163]  M. A. A. Wahab.  A Newly Modified Forced Oil-Cooling System and Its Impact on in-Service Transformer Oil Characteristics , 2002, IEEE Power Engineering Review.

[164]  T. Noda,et al.  Accurate Modeling of Core-Type Distribution Transformers for Electromagnetic Transient Studies , 2002, IEEE Power Engineering Review.

[165]  F. de Leon,et al.  Detailed modeling of eddy current effects for transformer transients , 1994 .

[166]  Jacek Smolka,et al.  Numerical modelling of thermal processes in an electrical transformer dipped into polymerised resin by using commercial CFD package fluent , 2004 .

[167]  S. Y. Merritt,et al.  No-load versus load loss , 2003 .

[168]  M. Poloujadoff,et al.  New transformer model including joint air gaps and lamination anisotropy , 1998 .

[169]  W.H. Tang,et al.  A Probabilistic Classifier for Transformer Dissolved Gas Analysis With a Particle Swarm Optimizer , 2008, IEEE Transactions on Power Delivery.

[170]  R. M. Del Vecchio.  Geometric effects in the electrical breakdown of transformer oil , 2004, IEEE Transactions on Power Delivery.

[171]  Song-Yop Hahn,et al.  Development of a three phase 100 kVA superconducting power transformer with amorphous cores , 1999, IEEE Transactions on Applied Superconductivity.

[172]  Mayergoyz,et al.  Mathematical models of hysteresis. , 1986, Physical review letters.

[173]  G. Swift,et al.  A fundamental approach to transformer thermal modeling. I. Theory and equivalent circuit , 2001 .

[174]  Derek B. Ingham,et al.  Enhanced numerical model of performance of an encapsulated three-phase transformer in laboratory environment , 2007 .

[175]  D. J. Wilcox,et al.  Calculation of self and mutual impedances between sections of transformer windings , 1989 .

[176]  G. C. Paap,et al.  Computation of Very Fast Transient Overvoltages in Transformer Windings , 2002, IEEE Power Engineering Review.

[177]  Bruce A. Mork,et al.  Five-legged wound-core transformer model: derivation, parameters, implementation and evaluation , 1999 .

[178]  P. Verho,et al.  Studies to Utilize Loading Guides and ANN for Oil-Immersed Distribution Transformer Condition Monitoring , 2007, IEEE Transactions on Power Delivery.

[179]  R. Wang,et al.  A combined vector potential-scalar potential method for FE computation of 3D magnetic fields in electrical devices with iron cores , 1991 .

[180]  Enrique E. Mombello,et al.  New power transformer model for the calculation of electromagnetic resonant transient phenomena including frequency-dependent losses , 2000 .

[181]  J. Turowski,et al.  Fast 3-dimensional interactive computation of stray field and losses in asymmetric transformers , 2000 .

[182]  Enrique Acha,et al.  The study of inrush current phenomenon using operational matrices , 2001 .

[183]  M. Enokizono,et al.  The calculation considered two-dimensional vector magnetic properties depending on frequency of transformers , 2006, IEEE Transactions on Magnetics.

[184]  P. J. Griffin,et al.  Real-Time Dynamic Loading and Thermal Diagnostic of Power Transformers , 2002, IEEE Power Engineering Review.

[185]  Stefanos D. Kollias,et al.  Prediction of iron losses of wound core distribution transformers based on artificial neural networks , 1998, Neurocomputing.

[186]  Jacek Smolka,et al.  Experimental validation of the coupled fluid flow, heat transfer and electromagnetic numerical model of the medium-power dry-type electrical transformer , 2008 .

[187]  W. J. Chatterton,et al.  Environmental and life cycle considerations for distribution and small power transformer selection and specification , 2002, Conference Record of the the 2002 IEEE International Symposium on Electrical Insulation (Cat. No.02CH37316).

[188]  H. Nomura,et al.  Some considerations on superconducting transformers from a design-point of view , 1996 .

[189]  L. Sainz,et al.  Harmonic nonlinear transformer modeling , 2004, IEEE Transactions on Power Delivery.

[190]  R. Iravani,et al.  An accurate hysteresis model for ferroresonance analysis of a transformer , 2008, 2008 IEEE Power and Energy Society General Meeting - Conversion and Delivery of Electrical Energy in the 21st Century.

[191]  D. G. Ece,et al.  Modeling of Hysteresis and Power Losses in Transformer Laminations , 2002, IEEE Power Engineering Review.

[192]  Jian Li,et al.  Electric Properties of Vegetable Oil-Based Dielectric Liquid and Lifetime Estimation of the Oil-Paper Insulation , 2006, 2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena.

[193]  S. Liu,et al.  Investigation of the harmonic behavior of three phase transformer under nonsinusoidal operation using finite element and wavelet packets , 2006, IEEE Transactions on Magnetics.

[194]  M. Pompili,et al.  Partial discharge pulse sequence patterns and cavity development times in transformer oils under AC conditions , 2005, IEEE Transactions on Dielectrics and Electrical Insulation.

[195]  N. Soda,et al.  Finite Element Analysis Of Transformer Model Core With Measured Reluctivity Tensor , 1997, 1997 IEEE International Magnetics Conference (INTERMAG'97).

[196]  W. M. Grady,et al.  A PC-based computer program for teaching the design and analysis of dry-type transformers , 1992 .

[197]  Chin E. Lin,et al.  Investigation of magnetizing inrush current in transformers. II. Harmonic analysis , 1993 .

[198]  D. A. Koppikar,et al.  Evaluation of flitch plate losses in power transformers , 1999, IEEE Power Engineering Society. 1999 Winter Meeting (Cat. No.99CH36233).

[199]  T. Durbaum,et al.  Calculating core losses in transformers for arbitrary magnetizing currents a comparison of different approaches , 1996, PESC Record. 27th Annual IEEE Power Electronics Specialists Conference.

[200]  R. S. Girgis,et al.  Flux distribution and core loss calculation for single phase and five limb three phase transformer core designs , 2000 .

[201]  Xianguo Li,et al.  Oil cooling for disk-type transformer windings-part II: parametric studies of design parameters , 2006 .

[202]  J. Sanz,et al.  A moisture-in-oil model for power transformer monitoring - Part I: Theoretical foundation , 2005, IEEE Transactions on Power Delivery.

[203]  O. W. Andersen.  Transformer Leakage Flux Program Based on the Finite Element Method , 1973 .

[204]  Albana Ilo,et al.  Behavior of Transformer Cores with Multistep-Lap Joints , 2002 .

[205]  X.H. Wang,et al.  Correlation Analysis of Waveforms in Nonsaturation Zone-Based Method to Identify the Magnetizing Inrush in Transformer , 2006, IEEE Transactions on Power Delivery.

[206]  N. Takahashi,et al.  Circulating current computation and transposition design for large current winding of transformer with multi-section strategy and hybrid optimal method , 2000 .

[207]  Afshin Rezaei-Zare,et al.  Analysis of Ferroresonance Modes in Power Transformers Using Preisach-Type Hysteretic Magnetizing Inductance , 2007, IEEE Transactions on Power Delivery.

[208]  R.M.D. Vecchio.  Multiterminal Three Phase Transformer Model With Balanced or Unbalanced Loading , 2008, IEEE Transactions on Power Delivery.

[209]  K.G.N.B. Abeywickrama,et al.  Computation of Parameters of Power Transformer Windings for Use in Frequency Response Analysis , 2007, IEEE Transactions on Magnetics.

[210]  J R Saunders,et al.  A particle swarm optimizer with passive congregation. , 2004, Bio Systems.

[211]  F. de Leon,et al.  Reduced order model for transformer transients , 1992 .

[212]  T. Tran-Quoc,et al.  Correction of the measured core losses under distorted flux [power transformers] , 1997 .

[213]  F. Muzi,et al.  Vibro-acoustic techniques to diagnose power transformers , 2004, IEEE Transactions on Power Delivery.

[214]  V. Vittal,et al.  Risk Assessment for Transformer Loading , 2001, IEEE Power Engineering Review.

[215]  S. Ersoy,et al.  Seismic response of transformer-bushing systems , 2004, IEEE Transactions on Power Delivery.

[216]  H. Wu,et al.  Transformer design using time-sharing computer , 1970 .

[217]  W.H. Tang,et al.  A simplified transformer thermal model based on thermal-electric analogy , 2004, IEEE Transactions on Power Delivery.

[218]  K. D. Srivastava,et al.  Review of condition assessment of power transformers in service , 2002 .

[219]  M. Nishioka,et al.  Internal winding failure due to resonance overvoltage in distribution transformer caused by winter lightning , 2006, IEEE Transactions on Power Delivery.

[220]  P. Purkait,et al.  Investigation of an expert system for the condition assessment of transformer insulation based on dielectric response measurements , 2004, IEEE Transactions on Power Delivery.

[221]  N. Takahashi,et al.  Numerical modeling for anisotropic magnetic media including saturation effects , 1997 .

[222]  Adam Semlyen,et al.  Computation of electromagnetic transients using dual or multiple time steps , 1993 .

[223]  W. Fu,et al.  A dynamic core loss model for soft ferromagnetic and power ferrite materials in transient finite element analysis , 2004, IEEE Transactions on Magnetics.

[224]  Y. Shibuya,et al.  Experimental investigation of high frequency voltage oscillation in transformer windings , 1998 .

[225]  A. Savini,et al.  Influence of flux collectors on stray losses in transformers , 2000 .

[226]  Osamu Ichinokura,et al.  Design and analysis of noise-reduction transformer based on equivalent circuit , 1998 .

[227]  K.C. Schneider,et al.  Initial transformer sizing for single-phase residential load , 1991, Proceedings of the 1991 IEEE Power Engineering Society Transmission and Distribution Conference.

[228]  R. Escarela-Perez,et al.  Improved insert geometry for reducing tank-wall losses in pad-mounted transformers , 2004, IEEE Transactions on Power Delivery.

[229]  S. Hahn,et al.  Analysis of AC losses in HTS pancake windings for transformer according to the operating temperature , 2005 .

[230]  E.I. Amoiralis,et al.  Hybrid Numerical-Analytical Technique for Power Transformer Thermal Modeling , 2009, IEEE Transactions on Magnetics.

[231]  Nikos D. Hatziargyriou,et al.  Three phase transformer modelling for fast electromagnetic transient studies , 1994 .

[232]  R. T. Hemmes,et al.  Measurement of Self Cooled Transformer Sound Levels in Relatively High Ambients , 1970 .

[233]  Chih-Kun Cheng,et al.  Novel approach to reducing the inrush current of a power transformer , 2004 .

[234]  O. Mohammed,et al.  Nonlinear three dimensional field computation methods in laminated iron cores under saturated conditions , 1983 .

[235]  R.P.P. Smeets,et al.  Analysis of Very Fast Transients in Layer-Type Transformer Windings , 2007, IEEE Transactions on Power Delivery.

[236]  M. Pompili,et al.  PD pulse burst characteristics of transformer oils , 2006, IEEE Transactions on Power Delivery.

[237]  Cui Xiang,et al.  Losses calculation in transformer tie plate using the finite element method , 1998 .

[238]  J. Faiz,et al.  Three- and Two-Dimensional Finite-Element Computation of Inrush Current and Short-Circuit Electromagnetic Forces on Windings of a Three-Phase Core-Type Power Transformer , 2008, IEEE Transactions on Magnetics.

[239]  S.L. Ho,et al.  Numerical simulation of transient force and eddy current loss in a 720-MVA power transformer , 2004, IEEE Transactions on Magnetics.

[240]  Masato Enokizono,et al.  Core loss analysis of transformer by improved FEM , 1999 .

[241]  N. Sadowski,et al.  Implementation of an Anisotropic Vector Hysteresis Model in a 3-D Finite-Element Code , 2008, IEEE Transactions on Magnetics.

[242]  R. M. Morais,et al.  Furfural analysis for assessing degradation of thermally upgraded papers in transformer insulation , 1999 .

[243]  C. P. McShane,et al.  Vegetable-oil-based dielectric coolants , 2002 .

[244]  M. Hyvarinen,et al.  Temperature rises in an OFAF transformer at OFAN cooling mode in service , 2005, IEEE Transactions on Power Delivery.

[245]  James H. Harlow,et al.  Electric Power Transformer Engineering , 2003 .

[246]  M. Jablonski,et al.  Internal faults in power transformers , 2007 .

[247]  K.T. Muthanna,et al.  Transformer insulation life assessment , 2006, IEEE Transactions on Power Delivery.

[248]  S. Trabulus.  Design criteria for SF/sub 6/ gas insulated power transformers up to 2500 kVA , 1999, 1999 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.99CH36319).

[249]  V. Jayashankar,et al.  Impulse testing of power transformers - a model reference approach , 2004 .

[250]  A. Beroual,et al.  Improvement of power transformers by using mixtures of mineral oil with synthetic esters , 2005, IEEE International Conference on Dielectric Liquids, 2005. ICDL 2005..

[251]  S. Cabral,et al.  Semianalytic Solution for a Simple Model of Inrush Currents in Transformers , 2008, IEEE Transactions on Magnetics.

[252]  P. Odessey.  Transformer Design by Computer , 1974 .

[253]  S. Hoole,et al.  Shape optimization of windings for minimum losses , 1996 .

[254]  R.A. Jabr,et al.  Application of geometric programming to transformer design , 2005, IEEE Transactions on Magnetics.

[255]  K. Zakrzewski,et al.  Magnetic field analysis and leakage inductance calculation in current transformers by means of 3-D integral methods , 1996 .

[256]  K. F. Goddard,et al.  High temperature superconducting power transformers: conclusions from a design study , 1999 .

[257]  S.M. Gubanski,et al.  Exploring possibilities for characterization of power transformer insulation by frequency response analysis (FRA) , 2006, IEEE Transactions on Power Delivery.

[258]  L. W. Pierce.  Predicting hottest spot temperatures in ventilated dry type transformer windings , 1994 .

[259]  Vlatko Cingoski,et al.  Design improvements on graded insulation of power transformers using transient electric field analysis and visualization technique , 1997 .

[260]  S. J. Salon,et al.  Comparison of assumptions in computation of short circuit forces in transformers , 2000 .

[261]  Ewald F. Fuchs,et al.  Modeling and simulation, and their validation of three-phase transformers with three legs under DC bias , 1999 .

[262]  Yann-Chang Huang,et al.  Evolving neural nets for fault diagnosis of power transformers , 2003 .

[263]  A. Basak,et al.  Optimum Design of Transformer Cores by Analysing Flux and Iron Loss With the Aid of a Novel Software , 1992, Digest of the Fifth Biennial IEEE Conference on Electromagnetic Field Computation.

[264]  N. D. Doulamis,et al.  Optimal distribution transformers assembly using an adaptable neural network-genetic algorithm scheme , 2002, IEEE International Conference on Systems, Man and Cybernetics.

[265]  J. V. Oldfield,et al.  The digital computer applied to the design of large power transformers , 1958 .

[266]  E. N. Andreev,et al.  Investigation of a model HTSC transformer with amorphous alloy cores , 2007 .

[267]  F. de Leon,et al.  A simple representation of dynamic hysteresis losses in power transformers , 1995 .

[269]  I. Hohlein,et al.  Aging of cellulose at transformer service temperatures. Part 2. Influence of moisture and temperature on degree of polymerization and formation of furanic compounds in free-breathing systems , 2005, IEEE Electrical Insulation Magazine.

[270]  Guangzheng Ni,et al.  3-D nonlinear transient eddy current calculation of online power transformer under DC bias , 2005, IEEE Transactions on Magnetics.

[271]  L. Haydock,et al.  Transient analysis of power transformers using magnetic and electric equivalent circuits , 1994 .

[272]  M. Lehtonen,et al.  Dynamic thermal modeling of power transformers: further Development-part II , 2006, IEEE Transactions on Power Delivery.

[273]  T. Todaka,et al.  Flux distribution in a wound core of a single-phase transformer , 1996 .

[274]  T. O. Rouse.  Mineral insulating oil in transformers , 1998 .

[275]  A. Graczkowski,et al.  Frequency response of oil impregnated pressboard and paper samples for estimating moisture in transformer insulation , 2006, IEEE Transactions on Power Delivery.

[276]  Anthony John Moses,et al.  Measurement of magnetostriction and vibration with regard to transformer noise , 1974 .

[277]  J. De La Ree,et al.  Harmonics generated from a DC biased transformer , 1992 .

[278]  W.L.A. Neves,et al.  Estimation of transformer saturation characteristics from inrush current waveforms , 2006, IEEE Transactions on Power Delivery.

[279]  A. Konrad,et al.  Virtual Air Gap Length Computation With the Finite-Element Method , 2007, IEEE Transactions on Magnetics.

[280]  P.S. Georgilakis,et al.  Hybrid numerical techniques for power transformer modeling: a comparative analysis validated by measurements , 2004, IEEE Transactions on Magnetics.

[281]  Bjorn Gustavsen.  Wide band modeling of power transformers , 2004 .

[282]  Barry W. Kennedy.  Energy Efficient Transformers , 1997 .

[283]  I. Hohlein,et al.  Aging of cellulose at transformer service temperatures. Part 1: Influence of type of oil and air on the degree of polymerization of pressboard, dissolved gases, and furanic compounds in oil , 2005, IEEE Electrical Insulation Magazine.

[284]  R. D. Findlay,et al.  Measurement of rotational iron losses in electrical sheet , 2000 .

[285]  Gert Tinggaard Svendsen,et al.  How should greenhouse gas permits be allocated in the EU , 2004 .

[286]  Koji Fujiwara,et al.  An improved numerical analysis of flux distributions in anisotropic materials , 1994 .

[287]  H. Nordman,et al.  Temperature Responses to Step Changes in the Load Current of Power Transformers , 2002, IEEE Power Engineering Review.

[288]  S. Gubanski,et al.  Determination of Complex Permeability of Silicon Steel for Use in High-Frequency Modeling of Power Transformers , 2008, IEEE Transactions on Magnetics.

[289]  S. Sieradzki,et al.  Apparent core losses and core losses in five-limb amorphous transformer of 160 kVA , 1998 .

[290]  L. W. Pierce.  An investigation of the thermal performance of an oil filled transformer winding , 1992 .

[291]  J.W. Stahlhut,et al.  A Preliminary Assessment of the Impact of Ambient Temperature Rise on Distribution Transformer Loss of Life , 2008, IEEE Transactions on Power Delivery.

[292]  J. Turowski,et al.  Recent development in eddy current analysis , 1987 .

[293]  D. J. Wilcox,et al.  Theory of transformer modelling using modal analysis , 1991 .

[294]  D. C. Johnson,et al.  Calculation and reduction of stray and eddy losses in core-form transformers using a highly accurate finite element modelling technique , 1993 .

[295]  M. Sumner,et al.  Characteristics of Jiles–Atherton Model Parameters and Their Application to Transformer Inrush Current Simulation , 2008, IEEE Transactions on Magnetics.

[296]  M.K. Pradhan,et al.  On the estimation of elapsed life of oil-immersed power transformers , 2005, IEEE Transactions on Power Delivery.

[297]  R.-L. Lin,et al.  Magnetizing inrush model of transformers based on structure parameters , 2005, IEEE Transactions on Power Delivery.

[298]  Wim Desmet,et al.  On the influence of core laminations upon power transformer noise , 2004 .

[299]  T. K. Saha,et al.  Experience with Return Voltage Measurements for Assessing Insulation Conditions in Service Aged Transformers , 2002, IEEE Power Engineering Review.

[300]  P. Costa,et al.  Recurrent Neurofuzzy Network in Thermal Modeling of Power Transformers , 2007, IEEE Transactions on Power Delivery.

[301]  T. Saha,et al.  Review of time-domain polarization measurements for assessing insulation condition in aged transformers , 2003 .

[302]  Daniel Tylavsky,et al.  Assessing the reliability of linear dynamic transformer thermal modelling , 2006 .

[303]  B. Gustavsen,et al.  Parameter determination for modeling system transients-Part I: overhead lines , 2005, IEEE Transactions on Power Delivery.

[304]  K. L. Butler,et al.  Modeling Transformers with Internal Incipient Faults , 2002, IEEE Power Engineering Review.

[305]  S.Y. Merritt,et al.  One from menu A, one from menu B: optimising NEMA TP 1 transformers for process industry substation service , 2005, IEEE Industry Applications Magazine.

[306]  Pavlos S. Georgilakis,et al.  Advanced design methodology for single and dual voltage wound core power transformers based on a particular finite element model , 2006 .

[307]  M. Poloujadoff,et al.  Analytical model of iron losses in power transformers , 2003 .

[308]  P. Purkait,et al.  Deriving an equivalent circuit of transformers insulation for understanding the dielectric response measurements , 2005, IEEE Transactions on Power Delivery.

[309]  L. Jauregui-Rivera,et al.  Acceptability of Four Transformer Top-Oil Thermal Models—Part II: Comparing Metrics , 2008, IEEE Transactions on Power Delivery.

[310]  J. F. Baranowski,et al.  An alternative evaluation of distribution transformers to achieve the lowest TOC , 1991, Proceedings of the 1991 IEEE Power Engineering Society Transmission and Distribution Conference.

[311]  P. A. Abetti,et al.  Complete Design of Power Transformers with a Large-Size Digital Computer , 1958, Transactions of the American Institute of Electrical Engineers. Part III: Power Apparatus and Systems.

[312]  Ronnie Belmans,et al.  The potential for global energy savings from high efficiency distribution transformers , 2005 .

[313]  P. Kundur,et al.  Assessing and limiting impact of transformer inrush current on power quality , 2006, IEEE Transactions on Power Delivery.

[314]  William D'haeseleer,et al.  Simulating greenhouse gas (GHG) allowance cost and GHG emission reduction in Western Europe , 2007 .

[315]  Istvan Ver,et al.  Field Study of Sound Radiation by Power Transformers , 1981, IEEE Transactions on Power Apparatus and Systems.

[316]  A. S. Farag,et al.  Diagnosing Failed Distribution Transformers Using Neural Networks , 2001, IEEE Power Engineering Review.

[317]  Ward Jewell.  Transformer design in the undergraduate power engineering laboratory , 1990 .

[318]  E.I. Amoiralis,et al.  Global Transformer Optimization Method Using Evolutionary Design and Numerical Field Computation , 2009, IEEE Transactions on Magnetics.

[319]  Fabrizio Marignetti,et al.  New Perspectives in HTS Transformer Design , 2006 .

[320]  M.K. Pradhan,et al.  Estimation of the hottest spot temperature (HST) in power transformers considering thermal inhomogeniety of the windings , 2004, IEEE Transactions on Power Delivery.

[321]  V. Miranda,et al.  Knowledge discovery in neural networks with application to transformer failure diagnosis , 2005, IEEE Transactions on Power Systems.

[322]  C.P. McShane,et al.  Retrofilling aging transformers with natural ester based dielectric coolant for safety and life extension , 2003, Cement Industry Technical Conference, 2003. Conference Record. IEEE-IAS/PCA 2003.

[323]  G. Diaz,et al.  Analytical approach to internal fault simulation in power transformers based on fault-related incremental currents , 2006, IEEE Transactions on Power Delivery.

[324]  Jiahui Zhang,et al.  Coolant flow distribution and pressure loss in ONAN transformer windings $Part I: Theory and model development , 2004 .

[325]  Henry Wu,et al.  Winding deformation identification using a particle swarm optimiser with passive congregation for power transformers , 2006 .

[326]  E. E. Mombello.  Impedances for the Calculation of Electromagnetic Transients within Transformers , 2002, IEEE Power Engineering Review.

[327]  O.W. Andersen.  Optimized design of electric power equipment , 1991, IEEE Computer Applications in Power.

[328]  Jiahui Zhang,et al.  Coolant flow distribution and pressure loss in ONAN transformer windings $Part I: Theory and model development , 2004, IEEE Transactions on Power Delivery.

[329]  M. Lindenmo,et al.  Review of the types, properties, advantages, and latest developments in insulating coatings on nonoriented electrical steels , 2001 .

[330]  Tang Renyuan,et al.  Numerical calculation of 3D eddy current field and short circuit electromagnetic force in large transformers , 1992 .

[331]  Janusz Turowski,et al.  Dependence of forces, eddy current and stray losses on screening in power transformers , 2001, ICEMS'2001. Proceedings of the Fifth International Conference on Electrical Machines and Systems (IEEE Cat. No.01EX501).

[332]  W. Hribernik,et al.  Inherent transient recovery voltage of power transformers-a model-based determination procedure , 2006, IEEE Transactions on Power Delivery.

[333]  C.P. McShane,et al.  Aging of paper insulation in natural ester dielectric fluid , 2001, 2001 IEEE/PES Transmission and Distribution Conference and Exposition. Developing New Perspectives (Cat. No.01CH37294).

[334]  Marina A. Tsili,et al.  Numerical techniques for design and modeling of distribution transformers , 2005 .

[335]  W. M. Grady,et al.  Calculation of winding temperatures in distribution transformers subjected to harmonic currents , 1988 .

[336]  N. Abeywickrama,et al.  High-Frequency Modeling of Power Transformers for Use in Frequency Response Analysis (FRA) , 2008, IEEE Transactions on Power Delivery.

[337]  W.W.L. Keerthipala,et al.  Electronic circuits for active control of acoustic noise generated by high voltage transformers , 1998, 1998 International Conference on Power Electronic Drives and Energy Systems for Industrial Growth, 1998. Proceedings..

[338]  M. F. Lachman,et al.  Influence of single-phase excitation and magnetizing reactance on transformer leakage reactance measurement , 1997 .

[339]  Z. Valkovic,et al.  Influence of transformer core design on power losses , 1982 .

[340]  F. de Leon,et al.  Time domain modeling of eddy current effects for transformer transients , 1993 .

[341]  K.W.E. Cheng,et al.  Calculation of Eddy Current Field in the Ascending Flange for the Bushings and Tank Wall of a Large Power Transformer , 2008, IEEE Transactions on Magnetics.

[342]  J. Faiz,et al.  Novel techniques for treating singularity problems in the boundary element method applied to electric field evaluation within the tank of a power transformer , 2000 .

[343]  M. Djurovic,et al.  3-dimensional computation of transformer leakage fields and associated losses , 1975 .

[344]  D. Linhjell,et al.  Aging of oil-impregnated paper in power transformers , 2004, IEEE Transactions on Power Delivery.

[345]  Janusz Turowski,et al.  Method of three-dimensional network solution of leakage field of three-phase transformers , 1990 .

[346]  Yves Bernard,et al.  Dynamic hysteresis modeling based on Preisach model , 2002 .

[347]  W. S. Mota,et al.  Magnetic core model , 2007 .

[348]  Yasuro Hori,et al.  Transformer Noise Reduction with New Sound Insulation Panel , 1983, IEEE Transactions on Power Apparatus and Systems.

[349]  E.I. Amoiralis,et al.  Artificial Intelligence Combined with Hybrid FEM-BE Techniques for Global Transformer Optimization , 2006, IEEE Transactions on Magnetics.

[350]  S. S. Venkata,et al.  A three-phase three-winding core-type transformer model for low-frequency transient studies , 1997 .

[351]  L. Sainz,et al.  Symmetrical and unsymmetrical voltage sag effects on three-phase transformers , 2005, IEEE Transactions on Power Delivery.

[352]  W. Xu,et al.  A sequential phase energization technique for transformer inrush current reduction - Part II: theoretical analysis and design guide , 2004, IEEE Transactions on Power Delivery.

[353]  M. Yamamoto,et al.  A design study of amorphous core transformer , 1984 .

[354]  S. Fujita,et al.  Influence of VFT on Shell-Type Transformer , 2007, IEEE Transactions on Power Delivery.

[355]  F. Loffler,et al.  Relevance of step-lap joints for magnetic characteristics of transformer cores , 1995 .

[356]  L. Jauregui-Rivera,et al.  Acceptability of Four Transformer Top-Oil Thermal Models—Part I: Defining Metrics , 2008, IEEE Transactions on Power Delivery.

[357]  Tang Renyuan,et al.  Resultant magnetic fields due to both windings and heavy current leads in large power transformers , 1996 .

[358]  Tien Nguyen.  Constrained optimisation procedure for evaluating cyclic loading of power transformers , 1995 .

[359]  K. R. Farmer,et al.  Acoustic energy shifting in transformer oil at different temperatures , 2005, IEEE Transactions on Power Delivery.

[360]  H. Braunstein,et al.  Distribution Transformer Loss Evaluation: II - Load Characteristics and System Cost Parameters , 1981, IEEE Transactions on Power Apparatus and Systems.

[361]  S. Elia,et al.  Design of cast-resin distribution transformers by means of genetic algorithms , 2006, International Symposium on Power Electronics, Electrical Drives, Automation and Motion, 2006. SPEEDAM 2006..

[362]  R. Escarela-Perez,et al.  Asymmetry During Load-Loss Measurement of Three-Phase Three-Limb Transformers , 2007, IEEE Transactions on Power Delivery.

[363]  P. M. Balma,et al.  The effects of long term operation and system conditions on the dielectric capability and insulation coordination of large power transformers , 1999 .

[364]  M. R. Patel.  Instability of the continuously transposed cable under axial short-circuit forces in transformers , 2002 .

[365]  W. M. Grady,et al.  Modeling of magnetizing and core-loss currents in single-phase transformers with voltage harmonics for use in power flow , 1997 .

[366]  R. C. Degeneff,et al.  Linear, lumped parameter transformer model reduction technique. Discussion. Reply , 1995 .

[367]  S. V. Kulkarni,et al.  Circulating-current loss in transformer windings , 1998 .

[368]  P. N. Adkins,et al.  Transformer Noise Reduction witk a Close-Fitting Mass-Law Enclosure , 1963 .

[369]  Hong-Tzer Yang,et al.  Adaptive fuzzy diagnosis system for dissolved gas analysis of power transformers , 1999 .

[370]  O.W. Andersen.  PC-based field calculations for electric power applications , 1989, IEEE Computer Applications in Power.

[371]  Wang Shishan,et al.  The study of eddy current losses in coaxially insulated windings of power transformer , 2002, Proceedings. International Conference on Power System Technology.

[372]  W. M. Grady,et al.  Corrections to "measurement of eddy-current loss coefficient P/sub EC-R/ , derating of single-phase transformers, and comparison with K-factor approach" , 2000 .

[373]  M. Poloujadoff,et al.  A contribution to the modeling of three phase transformers using reluctances , 1996 .

[374]  M. Hori,et al.  Observation and Analysis of Incident Surge Voltage Waveforms in Substations by Winter Lightning , 2007, IEEE Transactions on Power Delivery.

[375]  K. J. Frohlich,et al.  Elimination of transformer inrush currents by controlled switching. I. Theoretical considerations , 2001 .

[376]  Pavlos S. Georgilakis,et al.  A heuristic solution to the transformer manufacturing cost optimization problem , 2007 .

[377]  T. Matsuura,et al.  Long-term reliability of iron-based amorphous alloy cores for oil-immersed transformers , 1990 .

[378]  M. Masoum,et al.  Derating of Asymmetric Three-Phase Transformers Serving Unbalanced Nonlinear Loads , 2008, IEEE Transactions on Power Delivery.

[379]  Alfredo Vaccaro,et al.  Parameter identification of power transformers thermal model via genetic algorithms , 2001 .

[380]  S. Ryder,et al.  A Simple Method for Calculating Winding Temperature Gradient in Power Transformers , 2002, IEEE Power Engineering Review.

[381]  O. Biro.  Computation of the flux linkage of windings from magnetic scalar potential finite element solutions , 2002 .

[382]  Joydeep Mitra,et al.  Hybrid Transformer Model for Transient Simulation—Part II: Laboratory Measurements and Benchmarking , 2007 .

[383]  Ruifang Liu,et al.  Modeling of Eddy-Current Loss of Electrical Machines and Transformers Operated by Pulsewidth-Modulated Inverters , 2008, IEEE Transactions on Magnetics.

[384]  A. Pahwa,et al.  Sensitivity of Transformer's Hottest Spot and Equivalent Aging to Selected Parameters , 2002, IEEE Power Engineering Review.

[385]  L. W. Pierce.  Predicting liquid filled transformer loading capability , 1992, [1992] Record of Conference Papers Industry Applications Society 39th Annual Petroleum and Chemical Industry Conference.

[386]  N. Takahashi,et al.  3-D non-linear eddy current analysis using the time-periodic finite element method , 1989, International Magnetics Conference.

[387]  B.A. Mork,et al.  Parameter Estimation Methods for Five-Limb Magnetic Core Model , 2008, IEEE Transactions on Power Delivery.

[388]  Sun Cai-xin,et al.  Artificial Immune Network Classification Algorithm for Fault Diagnosis of Power Transformer , 2007, IEEE Transactions on Power Delivery.

[389]  F.P. Dawson,et al.  Transformer design considerations for mitigating geomagnetic induced saturation , 1999, IEEE International Magnetics Conference.

[390]  L. W. Pierce.  An investigation of the temperature distribution in cast-resin transformer windings , 1991 .

[391]  Nabeel A. O. Demerdash,et al.  Nonlinear three dimensional magnetic vector potential finite element solution of field problems including experimental verification , 1981 .

[392]  P. P. Silvester,et al.  Calculation of transformer winding resonances by a specialized finite element method employing substructures , 1988 .

[393]  B. S. Ram.  Loss and current distribution in foil windings of transformers , 1998 .

[394]  S. Liu,et al.  A Practical Method for Building the FE-Based Phase Variable Model of Single Phase Transformers for Dynamic Simulations , 2006, IEEE Transactions on Magnetics.

[395]  F. Henrotte,et al.  Simulation of a three-phase transformer using an improved anisotropy model , 2004, IEEE Transactions on Magnetics.

[396]  T. S. Ramu,et al.  Prediction of hottest spot temperature (HST) in power and station transformers , 2003 .

[397]  S. Charap,et al.  A core loss model for laminated transformers , 1974 .

[398]  Y. Higuchi,et al.  Integral equation method with surface impedance model for 3D eddy current analysis in transformers , 2000 .

[399]  Yusheng Zhou,et al.  Influence of High Temperature Superconducting Transformer Geometry on Leakage Magnetic Field , 2008, IEEE Transactions on Magnetics.

[400]  Chang-Chou Hwang,et al.  Thermal analysis of high-frequency transformers using finite elements coupled with temperature rise method , 2005 .

[401]  N. D. Hatziargyriou,et al.  Effective use of magnetic materials in transformer manufacturing , 2001 .

[402]  A. Kladas,et al.  Multiple Grade Lamination Wound Core: A Novel Technique for Transformer Iron Loss Minimization Using Simulated Annealing With Restarts and an Anisotropy Model , 2008, IEEE Transactions on Magnetics.

[403]  Patrice Labie,et al.  A shell element for computing 3D eddy currents-application to transformers , 1995 .

[404]  N. Sadowski,et al.  Finite Element Three-Phase Transformer Modeling Taking Into Account a Vector Hysteresis Model , 2009, IEEE Transactions on Magnetics.

[405]  R. Yacamini,et al.  Phenomenon of sympathetic interaction between transformers caused by inrush transients , 1995 .

[406]  Ahmed Rubaai.  Computer aided instruction of power transformer design in the undergraduate power engineering class , 1994 .

[407]  Venkata Dinavahi,et al.  Modelling and simulation of three-phase transformers for inrush current studies , 2005 .

[408]  J. Turowski,et al.  Evaluation of eddy current losses in the cover plates of distribution transformers , 2004 .