- Volume 9 Issue 3
Converter transformers play important roles in high-voltage direct current transmission systems. This paper presents experimental and analysis results of the combined electrical and thermal aging of oil-impregnated paper at pulsating DC voltages. Breakdown voltages and time-to-breakdown of oil-paper specimens were measured by using short-time and constant-stress tests. The breakdown characteristics of combined electrical and thermal aging on insulation system were discussed. According to the relationship between failure time and aging temperature, the two-parameter Weibull model was improved. On the basis of the competing risk algorithm and the improved Weibull model, the two factors failure model was calculated. And the influence of temperature in the insulation system has been analyzed. This model performs better than the two-parameter Weibull model when both time and temperature are considered as variables in estimating the lifetime of oil-paper insulation.
Converter transformer;Oil-paper insulation;Combined electrical and thermal aging;Pulsating DC voltages;Two factors failure model
- L. Fan, Z. Miao, and D. Osborn, "Wind farms with HVDC delivery in load frequency control," IEEE Transactions on Power Systems, vol. 24, no. 4, pp. 1894-1895, Nov. 2009. https://doi.org/10.1109/TPWRS.2009.2030256
- W. X. Lu and B.T. Ooi, "Optimal Acquisition and Aggregation of Offshore Wind Power by Multiterminal Voltage-Source HVDC", IEEE Trans. Power Delivery, vol. 18, no. 1, pp. 201-206, Jan. 2003. https://doi.org/10.1109/TPWRD.2002.803826
- W.J. Zao, High Voltage Direct Current Transmission Engineering Technology, 2nd ed., Peking: China Electric Power Press, 2011, pp.308-309. (in Chinese)
- CIGRE Joint Task Force B4.04/A2-1, "Analysis of HVDC Thyristor Converter Transformer Performance," in Proceedings of Council on Large Electric Systems, Canada, Feb. 2004.
- Y. Wang, J. Li, Y. Y. Wang, S. Grzybowski, "Electrical breakdown properties of oil-paper insulation under AC-DC combined voltages," in Proceedings of IEEE Conf. Power Modulator and High Voltage, Atlanta, America, May 2010.
- H. Nowaczyk, S. Grzybowski, and E. Kuffel, "Electrical breakdown strength of paper-oil insulation under pulsating voltages," IEEE Transactions on Electrical Insulation, vol. EI-22, no. 3, pp. 249-253, June 1987. https://doi.org/10.1109/TEI.1987.298986
- D. Fabiani and L. Simoni, "Discussion on application of the Weibull distribution to electrical breakdown of insulating materials," IEEE Transactions on Dielectrics and Electrical Insulation, vol. 12, no. 1, pp. 11-16, Feb. 2005. https://doi.org/10.1109/TDEI.2005.1394010
- T. Dimitrakopoulou, K. Adamidis, and S. Loukas, "A lifetime distribution with an upside-down bathtubshaped hazard function," IEEE Transactions on Reliability, vol. 56, no. 2, pp. 308-311, June 2007. https://doi.org/10.1109/TR.2007.895304
- T. Tsuboi, J. Takami, S. Okabe, K. Inami, and K. Aono, "Aging effect on insulation reliability evaluation with weibull distribution for oil-immersed transformers," IEEE Transactions on Dielectrics and Electrical Insulation, vol. 17, pp. 1869-1876, Dec. 2010. https://doi.org/10.1109/TDEI.2010.5658240
- B.S. Dhillon, "Life distributions," IEEE Trans. Reliability, vol. R-30, no. 5, pp. 457-460, Dec. 1981. https://doi.org/10.1109/TR.1981.5221168
- G. C. Stone and J. F. Lawless, "The application of Weibull statistics to insulation aging tests," IEEE Transactions on Electrical Insulation, vol. EI-14, no. 5, pp. 233-239, Oct. 1979. https://doi.org/10.1109/TEI.1979.298226
- K. Wang, F. Hsu, and P. Liu, "Modeling the bathtub shape hazard rate function in terms of reliability," Reliability Engineering and System Safety, vol. 75, no. 3, pp. 397-406, March 2002. https://doi.org/10.1016/S0951-8320(01)00124-7
- F. Pascual, "Accelerated life test planning with independent weibull competing risks," IEEE Transactions on Reliability, vol. 57, no. 3, pp. 435-444, Sep. 2008. https://doi.org/10.1109/TR.2008.928205
- D. Kundu and A. M. Sarhan, "Analysis of incomplete data in presence of competing risks among several groups," IEEE Transactions on Reliability, vol. 55, no. 2, pp. 262-269, June 2006. https://doi.org/10.1109/TR.2006.874919
- J. V. Deshpande and S. G. Purohit, Life Time Data: Statistical Model and Methods. Singapore: World Scientific Press, 2005.
- R. Jiang and D. N. P. Murthy, "Study of n-fold weibull competing risk model," Mathematical and computer modelling, vol. 38, no. 11, pp. 1259-1273, Dec. 2003. https://doi.org/10.1016/S0895-7177(03)90128-2
- Y. Wang, J. Li, Y. M. Zhao, Z. M. He, S. C. Wu, and L. W. Bao, "Failure Evaluation Model of Oil-Paper Insulation under AC-DC Combined Voltages," in Proceeding of the IEEE Conference on High Voltage Engineering and Application, Shanghai, China, Sep. 2012, pp. 497-500.
- IEC 60243-1, "Electrical Strength of Insulating Materials - Test Methods - Part 1: Tests at Power Frequencies," IEC Publication, 1998.
- IEC 60212, "Standard Conditions for Use Prior to and During the Testing of Solid Electrical Insulating Materials," IEC Publication, 2010.
- ANSI/IEEE Std 930, "IEEE Guide for the Statistical Analysis of Electrical Insulation Voltage Endurance Data," IEEE Publication, 2004.
- Enhancing Insulating Performances of Presspaper by Introduction of Nanofibrillated Cellulose vol.10, pp.5, 2017, https://doi.org/10.3390/en10050681
- Failure analysis of transformer liquid — solid insulation system under selective environmental conditions using Weibull statistics method vol.65, 2016, https://doi.org/10.1016/j.engfailanal.2016.03.017
- Study on Electrical Aging Characteristics of Fiber Sheath Materials in Power Transformer Oil vol.14, pp.1, 2019, https://doi.org/10.1007/s42835-018-00041-5