To study the transient magnetic field and temperature field of a dry-type transformer core and analyze the core loss and hot spot temperature rise of the core, a magnetic and temperature field coupling analysis method based on finite element method was proposed: the transient magnetic field of dry-type transformer was calculated first, and the core loss under a no-load condition was obtained. Then, the core loss density distribution was coupled to the temperature field as the heat source, and the temperature field distribution in the transformer was calculated by the fluid-thermal coupling method to obtain the hot spot temperature and the position of the core. Compared with the traditional average heat source method, the temperature field distribution calculated by the proposed method is close to the actual temperature distribution of the core. Finally, based on this method, the magnetic field and temperature field of the transformer core under different excitations were calculated, and the effect of harmonics on the core loss and temperature rise of the core was analyzed.
"Three-Dimensional Magnetic and Temperature Field Coupling Analysis of Dry-Type Transformer Core Under Different Excitations," Progress In Electromagnetics Research C,
Vol. 95, 75-89, 2019. doi:10.2528/PIERC19070401
1. Rajini, V., "Accurate location of transformer hottest spot by FEM and thermal models," International Journal of Computer Applications, Vol. 37, No. 6, 36-41, 2012. doi:10.5120/4615-6616
2. Eslamian, M., B. Vahidi, and A. Eslamian, "Thermal analysis of cast-resin dry-type transformers," Energy Conversion and Management, Vol. 52, No. 7, 2479-2488, 2011. doi:10.1016/j.enconman.2011.02.006
3. Wang, S., L. Zhao, K. Lu, et al. "Calculation of transformer loss and insulation life under harmonic currents," Proceedings of the CSU-EPSA, Vol. 28, No. 7, 79-88, 2016.
4. Lv, F. and Y. Guo, "Comparative analysis of core loss calculation methods for medium frequency transformer under non-sinusoidal excitation," High Voltage Engineering, Vol. 3, 808-813, 2017.
5. Xu, Y., F. Liu, and Y. Qi, "Prediction of winding temperature in power transformers based on fluid network," High Voltage Engineering, Vol. 43, No. 5, 1509-1518, 2017.
6. Zhou, L., H. Tang, L. Wang, et al. "Simulation on three-dimensional temperature field and oil flow field of oil-immersed transformer based on polyhedral mesh," High Voltage Engineering, Vol. 44, No. 11, 3524-3531, 2018.
7. Kefalas, T. D. and A. G. Kladas, "Harmonic impact on distribution transformer no-load loss," IEEE Transactions on Industrial Electronics, Vol. 57, No. 1, 193-200, 2010. doi:10.1109/TIE.2009.2030207
8. So, E., R. Arseneau, and E. Hanique, "No-load loss measurements of power transformers under distorted supply voltage waveform conditions," IEEE Transactions on Instrumentation and Measurement, Vol. 52, No. 2, 429-432, 2003. doi:10.1109/TIM.2003.809910
9. Tian, M., J. Zhu, J. Song, et al. "Temperature field simulation of coal dry-type transformer based on fluid-solid coupling analysis," High Voltage Engineering, Vol. 42, No. 12, , 3972-3981, 2016.
10. Feng, Z., L. Zhao, W. Zhou, et al. "Study on temperature rise and load capacity of dry-typetransformer under harmonic current," Proceedings of the CSU-EPSA, Vol. 29, No. 12, 69-75, 2017.
11. Buccella, C., C. Cecati, and F. de Monte, "A coupled electrothermal model for planar transformer temperature distribution computation," IEEE Transactions on Industrial Electronics, Vol. 55, No. 10, 3583-3590, 2008. doi:10.1109/TIE.2008.2003102
12. Liu, G., C. Chi, L. Sun, et al. "Influence of non-uniform temperature on the 2D non-sinusoidal steady AC-DC compound electric field in +-500 kV converter trans-former," Proceedings of the CSEE, Vol. 38, No. 8, 2521-2562, 2018.
13. Hwang, C. C., P. H. Tang, and Y. H. Jiang, "Thermal analysis of high-frequency transformers using finite elements coupled with temperature rise method," IEE Proceedings --- Electric Power Applications, Vol. 152, No. 4, 832-836, Aug. 2005. doi:10.1049/ip-epa:20045247
14. Preis, K., O. Biro, G. Buchgraber, and I. Ticar, "Thermal-electromagnetic coupling in the finite-element simulation of power transformers," IEEE Transactions on Magnetics, Vol. 42, No. 4, 999-1002, 2006. doi:10.1109/TMAG.2006.871439
15. Liu, G., Y. Jin, Y. Ma, et al. "Two-dimensional temperature field analysis of oil-immersed transformer based on non-uniformly heat source," High Voltage Engineering, Vol. 43, No. 10, 3361-3370, 2017.
16. Tsili, M. A., E. I. Amoiralis, A. G. Kladas, and A. T. Souflaris, "Power transformer thermal analysis by using an advanced coupled 3D heat transfer and fluid flow FEM model," International Journal of Thermal Sciences, Vol. 53, 188-201, 2011.
17. Zhang, Y. B., Y. L. Xin, T. Qian, X. Lin, W. H. Tang, and Q. H. Wu, "2-D coupled fluid-thermal analysis of oil-immersed power transformers based on finite element method," 2016 IEEE Innovative Smart Grid Technologies --- Asia (ISGT-Asia), 1060-1064, Melbourne, VIC, 2016.
18. Zhou, W., D. Wan, H. Ye, et al. "Calculation distribution transformer loss and insulation life assessment under harmonic currents disturbance," Electrical Measurement & Instrumentation, Vol. 55, No. 6, 52-58, 2018.