Breakdown Characteristics of Transformer Oil Under Bipolar Oscillating Impulse

被引：0
|
作者：
Ni H. [1 ]
Zhang Q. [1 ]
Zhao Y. [1 ]
Guo N. [1 ]
Fan X. [1 ]
Liu X. [1 ]
机构：
[1] State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an
来源：
Gaodianya Jishu/High Voltage Engineering | 2019年 / 45卷 / 12期
基金：
国家重点研发计划;
关键词：
Bipolar oscillating impulse voltage; Discharge characteristics; Streamer propagation process; Transformer oil; Waveform parameters;
D O I：
10.13336/j.1003-6520.hve.20181206005
中图分类号：
学科分类号：
摘要：
When the external overvoltage impinges the oil-immersed transformer winding, the turn-to-turn insulation will suffer from bipolar oscillating impulses. Based on the study of breakdown characteristics of transformer oil under bipolar oscillating impulses, this paper aims to provide a significant reference for rational designs of longitudinal insulation and academic researches on liquid discharge mechanism. The waveform parameters of bipolar oscillating impulses voltages were strictly controlled by using adjustable circuit components, and the impulse breakdown characteristics of transformer oil in quasi-uniform and non-uniform field under impulses with various waveform variables were acquired experimentally. The probability distributions of breakdown voltages were analyzed through statistics, and so were the distribution characteristics of discharge moments. The morphologies of streamers under bipolar oscillating impulses were photographed by framing camera, and typical features such as the reversal of streamer polarity were illustrated. The results show that, whether the electric field is uniform or not, all the increase of oscillation coefficient, the decrease of oscillation frequency, and the decrease of front time can lower the 50% breakdown voltage of transformer oil, which sometimescan be below the tolerance level of standard lightning impulse if the oscillation coefficient is larger than 0.55; when the oscillation frequency is low, breakdown usually occurs at the first or second positive peak, but the discharge moments move backward as the oscillation frequency increases and the probability of discharging at negative peaks increases accordingly. Moreover, combined with the light signals of streamers recorded by photomultiplier tube, the reasons for variations of breakdown voltages and discharge moments are explained from the perspective of the propagation of streamers. © 2019, High Voltage Engineering Editorial Department of CEPRI. All right reserved.
引用
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页码：3827 / 3835
页数：8
相关论文
共 23 条
  • [1] Zheng J., Converter transformer and its supervision technology, (2016)
  • [2] Liu Z., Guo X., Insulation structure of UHV power transformer, High Voltage Engineering, 36, 1, pp. 7-12, (2010)
  • [3] Zhang T., Nie D., Ma W., Design of ±1100 kV UHVDC converter transformers, High Voltage Engineering, 38, 12, pp. 3240-3243, (2012)
  • [4] Li Y., Zhang Q.G., Zhao Y., Et al., DC withstand test with partial discharge measurement of converter transformers: problems and suggestions for improvement, IEEE Transactions on Dielectrics and Electrical Insulation, 24, 2, pp. 1105-1109, (2017)
  • [5] Gao M., Zhang Q., Ding Y., Et al., Moisture diffusion characteristics in turn-to-turn paper insulation of oil-impregnated transformers, High Voltage Engineering, 45, 1, pp. 117-123, (2019)
  • [6] Ni H., Zhang Q., Zhao Y., Et al., Effect of waveform on breakdown characteristics of oil-paper insulation under double-exponential non-standard lightening impulse, High Voltage Engineering, 45, 3, pp. 743-750, (2019)
  • [7] Wang T., Xie L., Tao F., Et al., Empirical formula for impulse insulation strength of transformer oil in wide time regime, High Voltage Engineering, 44, 9, pp. 2934-2939, (2018)
  • [8] Liang G., Zhu X., Dong H., Simulation modeling of transformer windings at high frequencies, High Voltage Engineering, 35, 2, pp. 393-398, (2009)
  • [9] Zheng Y., Wang Z., Characteristics of inter-turn voltage oscillation in typical graded insulation windings of ultra-high voltage transformers, High Voltage Engineering, 40, 12, pp. 3933-3941, (2014)
  • [10] Nakanishi K., Fujita S., Kurita H., Et al., High-frequency voltage oscillation in transformer windings and electrical breakdown properties of interturn insulation immersed in oil at VFT voltage, Electrical Engineering in Japan, 132, 4, pp. 1228-1234, (2000)
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