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Thermal behavior of a three phase isolation transformer under load conditions with the finite element analysis

ABSTRACT
Transformers are generally designed to operate under the sinusoidal excitation and the method called classical design method is used in design process. Nevertheless, they have to operate under the partly or fully nonlinear excitation because of the increasing amount of the nonlinear loads such as rectifiers, electric motor drivers, compact fluorescent lamps and computers etc. Nonlinear loads cause abnormal temperature rise both in the core and in the windings of the transformer which is designed for sinusoidal excitation. Nowadays in the virtual environment provided by the electromagnetic design software, transformers can be easily modelled with the finite element method for any type of nonlinear loads or excitations. In this study, three-dimensional electromagnetic and thermal modelling of the isolation transformer at a certain rated power level have been carried out. Then, the core and the winding temperatures of the transformer have been comparatively reported under the linear and nonlinear load conditions. Besides, forced air-cooling method of the transformer has been tested with the computational fluid dynamics. This study has shown that, transformer temperature can be kept in the safe operating region in any type of load by deciding the fan speed providing the required air flow according to the transformer temperature.
KEYWORDS
PAPER SUBMITTED: 2019-07-06
PAPER REVISED: 2019-09-15
PAPER ACCEPTED: 2019-09-22
PUBLISHED ONLINE: 2019-10-06
DOI REFERENCE: https://doi.org/10.2298/TSCI190706386B
REFERENCES
  1. Balci, S., et al. Loss Behavior of the Dry-Type Power Transformer According to the Load Type. Proceeding (Abstract) 5. European Conference on Renewable Energy Systems (ECRES), Sarajevo/ Bosnia and Herzegovina, (2017), pp.49.
  2. Digalovski, M., et al. Impact of current high order harmonic to core losses of three-phase distribution transformer. IEEE Eurocon, Zagreb, Croatia, (2013), pp.1531-1535.
  3. Loizos, G., et al. Flux Distribution Analysis in Three-Phase Si-Fe Wound Transformer Cores. IEEE Transactions on Magnetics, Vol. 46, (2010), pp.594-597.
  4. Silva, D. C. L. et al. Contributions to the study of energy efficiency in dry-type transformer under nonlinear load. IEEE 24th International Symposium on Industrial Electronics (ISIE), Buzios, Brazil, (2015), pp.456-461.
  5. Taher, M.A., et al. K-Factor and Transformer Losses Calculations under Harmonics. IEEE Eighteenth International Middle East Power Systems Conference (MEPCON), Cairo, Egypt, (2016).
  6. IEEE Standard C57.110-1998. IEEE Recommended Practice for Establishing Transformer Capability when Supplying Non-sinusoidal Load Currents, IEEE Publications, 445 Hose Lane, P.O Box 1331, Piscataway, Nj 08855-1331, USA, (1998).
  7. Arjona, M.A., et al. Thermal Analysis of a Dry-Type Distribution Power Transformer Using FEA. IEEE 2014 International Conference on Electrical Machines (ICEM), (2014), pp.2270-2274.
  8. Ghahfarokhi, P.S., et al. Hybrid thermal model of a synchronous reluctance machine", Case Studies in Thermal Engineering, Vol. 12, (2018), pp.381-389.
  9. Alyozbaky, O.S., et al. A Novel Method to Enhance the Core Design of Power Transformers Using Particle Swarm Optimization (PSO) Technique. International Journal of Simulation: Systems, 19(6), (2019), doi 10.5013/IJSSST.a.19.06.42.
  10. Xingmou Liu, X., et al., Numerical research on the losses characteristic and hot-spot temperature of laminated core joints in transformer, Applied Thermal Engineering, 110, (2017), pp.49-61.
  11. Ding, L., et al., Temperature Field Simulation Research on the Leakage" Thermal Science, Vol. 22, Suppl. 2, (2018), pp. S649-S654.
  12. Balci, S. The Analysis, Design and Implementation of the Medium Frequency Power Transformer with the Nanocrystalline Core Material. (In Turkey). PhD. Thesis, Gazi University-Institute of Science and Technology, (20169.
  13. Upadhyayl, G., et al., FEM based No-load Loss Calculation of Triangular Wound Core Transformer. 1st IEEE International Conference on Power Electronics. Intelligent Control and Energy Systems (ICPEICES-2016), Delhi, India, (2016), pp.1-4, 4-6.
  14. Battal, F., et al., An Analysis on Vibration Effects of Dry Type Transformers Operating Under Nonlinear Load Conditions, (In Turkey), GU J Sci, Part C, 7(3), (2019), pp.729-740.
  15. Salam, S.M., et al., New Approach to Develop a Template Based Load Model that can Dynamically Adopt different types of Non-linear Loads. IEEE International Conference on Electrical, Computer and Communication Engineering (ECCE), Cox's Bazar, Bangladesh, (2017), pp.708-712.
  16. Jabbar, R.A., et al., Impacts of Harmonics caused by Personal Computers on Distribution Transformers. IEEE Third International Conference on Electrical Engineering, ICEE '09, (2009).
  17. Matanov, N., et al., Electrical Loads and Profiles of Public Buildings. IEEE 15th International Conference on Electrical Machines, Drives and Power Systems (ELMA), (2017), pp.233-237.
  18. IEC 61000-2-2:2002, Electromagnetic compatibility (EMC)-Part 2-2: Environment - Compatibility levels for low-frequency conducted disturbances and signaling in public low-voltage power supply systems, webstore.iec.ch/publication/4133, (2002).
  19. Ciufu, L., et al., Experimental Mitigation Techniques to reduce the Total Harmonic Distortion of Low Voltage Non- Linear Power Sources. 10th International Symposium on Advanced Topics in Electrical Engineering (ATEE), Bucharest, Romania, (2017), pp.138-141.
  20. Tripathi, A., et al., Investigations on Optimal Pulse Width Modulation to Minimize Total Harmonic Distortion in the Line Current. IEEE Transactions on Industry Applications, Vol. 53, (2017), pp.212-221.
  21. Najafi, A. and Iskender, I., A novel concept for derating of transformer under unbalance voltage in the presence of non linear load by 3-D finite element method, Electr Eng (2015) 97:45-56.
  22. Steinmetz, C.P. On the law of hysteresis, In American lnstitute of Electrical Engineers Transactions, Vol. 9, (1892), pp.3-64.
  23. Sefa, I., et al., Core Losses of PWM Excited Inverter Transformers with Finite Element Method. 7th International Conference on Technical and Physical Problems of Power Engineering, Near East University Lefkosa, TR Northern Cyprus, (2011).
  24. Balci, S., et al., Core Material Investigation of Medium-Frequency Power Transformers. IEEE-16th International Power Electronics and Motion Control Conference and Exposition (PEMC), (20149, pp.861-866,
  25. Sefa, I., et al., A Comparative Study of Nanocrystalline and SiFe Core Materials for Medium-Frequency Transformers. IEEE International Conference-6th Edition, Electronics, Computers and Artificial Intelligence (ECAI), (20149, pp.43-48.
  26. Yao, X. G., et al., Influence of Switching Frequency on Eddy-Current Losses in a Three-Phase, Three-Limb Transformer Core Subjected to PWM Voltage Excitation, IEEE Powereng Conference, (20079, pp. 324-329.
  27. Villar, I., et al., Transient thermal model of a medium frequency power transformer, IEEE-34th Annual Conference of Industrial Electronics (IECON), Orlando, FL, USA, (2008), pp.1033-1038.
  28. Lienhard, H. J., A heat transfer textbook, Cambridge: Phlogiston Press. (2004), pp.1-6.
  29. Raeisiana, L., et al., Thermal management of a distribution transformer: An optimization study of the cooling system using CFD and response surface methodology, Electrical Power and Energy Systems, 104, (2019,) pp. 443-455.
  30. Hannun, R.M., et al., Heat Transfer Enhancement from Power Transformer Immersed in Oil By Earth Air Heat Exchanger, Thermal Science, (2018), doi.org/10.2298/TSCI171231116H, pp.116-116,
  31. Balci S., et al., An analysis on cooling requirements of the high power medium frequency inductors, IEEE 12th International Conference on Compatibility, IEEE Power Electronics and Power Engineering (CPE-POWERENG 2018), Qatar, (2018).
  32. Mayda, M., An Efficient Simulation-Based Search Method for Reliability-Based Robust Design Optimization of Mechanical Components, ISSN 1392-1207. Mechanika, Vol. 23, (2017), pp.696-702.