恒定电压下变压器油隙放电特性
Discharge Behaviors of Transformer Oil-Gap under Constant Voltage

DOI: 10.12677/CMP.2016.54008, PP. 53-62

Keywords: 变压器油，场致电离，载流子，空间电荷，流注
Transformer Oil, Field Ionization, Charge Carriers, Space Charge, Streamer

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Abstract:

以变压器油作为研究对象，采用有限元方法(finite element method, FEM)对应用场致电离机理建立的用于表述液体电介质流注放电过程中载流子的产生及输运特性的偏微分方程(partial differential equations, PDE)进行求解分析，获得直流电压下变压器油隙放电过程空间电荷动力学特性。数值模拟结果表明，场致电离导致液体击穿的根本原因是油隙中自由载流子的产生、迁移形成了预击穿电流，由此产生的焦耳热使得油隙中形成低密度区，利于流注发展。根据这些现象得出的结论能够很容易理解液体电介质的击穿机理，有利于液体电介质在电力系统领域得到更合理的应用。
The transformer oil was taken as the object of study, and the finite element method (FEM) was employed to analyze and solved the partial differential equations (PDE) which was built by field ionization for describing the generation and transport properties of free charge carriers. The results showing that the dynamic characteristics of space charges in the liquid-gap discharge under DC were gained. According to the simulating results, the fundamental causes of the dielectric liquids breakdown by the electric field dependent molecular ionization are described as following; the pre-breakdown current is firstly formed by the generation and migration of the charge carriers in the oil gap, then the joule heat generated from it makes liquid-gap to form the low density region in the liquid, which facilitate initiated little streamer emergence as avalanche in gas discharge, meanwhile, the streamer is continuously evolving. Then these conclusions enable ones easily understand breakdown mechanism of the liquid dielectrics that are reasonably applied to power system fields.

References

[1]	Hwang, J.-W.G. (2010) Elucidating the Mechanisms Behind Pre-Breakdown Phenomena in Transformer Oil Systems. PhD Thesis, Massachusetts Institute of Technology.
[2]	Jadidian, J., Zahn, M., Lavesson, N., et al. (2012) Impulse Breakdown Delay in Liquid Dielectrics. Applied Physics Letters, 100, 192910. https:/doi.org/10.1063/1.4716464
[3]	Kim, M., Hebner, R.E. and Hallock, G.A. (2008) Modeling the Growth of Streamers during Liquid Breakdown. IEEE Transactions on Dielectrics and Electrical Insulation, 15, 547-553. https:/doi.org/10.1109/TDEI.2008.4483476
[4]	Denat, A. (2006) High Field Conduction and Prebreakdown Phenomena in Dielectric Liquids. IEEE Transactions on Dielectrics and Electrical Insulation, 13, 518-525.
[5]	Qureshi, M.I., Beroual, A. and Al-Ammar, E.A. (2014) Optical Observation of Streamer Propagation and Breakdown in Seed Based Insulating Oil under Impulse Voltages. International Journal of Physical Sciences, 9, 292-301. https:/doi.org/10.5897/IJPS2014.4147
[6]	Aka-Ngnui, T. and Beroual, A. (2006) Determination of the Streamers Characteristics Propagating in Liquids Using the Electrical Network Computation. IEEE Transactions on Dielectrics and Electrical Insulation, 13, 572-579. https:/doi.org/10.1109/TDEI.2006.1657970
[7]	Hallac, A., Georghiou, G.E. and Metaxas, A.C. (2003) Secondary Emission Effects on Streamer Branching in Transient Non-Uniform Short-Gap Discharge. Journal of Physics D: Applied Physics, 36, 2498-2509. https:/doi.org/10.1088/0022-3727/36/20/011
[8]	Dang, V. and Beroual, A. (2012) Investigations on Streamers Phenomena in Mineral, Synthetic and Natural Ester Oils under Lightning Impulse Voltage. IEEE Transactions on Dielectrics and Electrical Insulation, 19, 1521-1527. https:/doi.org/10.1109/tdei.2012.6311496
[9]	Wang, Z.D., Liu, Q., Wang, X. and Jarman, P. (2011) Discussion on Possible Additions to IEC60897 and IEC 61294 for Insulating Liquid Tests. IET Electric Power Applications, 5, 486-493. https:/doi.org/10.1049/iet-epa.2010.0209
[10]	Sullivan, A. (2007) Model for the Initiation and Propagation of Electrical Streamers in Transformer Oil and Transformer Oil Based Nanofluids. Massachusetts Institute of Technology, USA.
[11]	杨韦国. 变压器油纳秒脉冲流注发展的数值仿真及放电光谱分析[D]: [硕士学位论文]. 哈尔滨: 哈尔滨理工大学, 2015.
[12]	王正伟. 快脉冲电压下环烷基液体介质击穿特性[D]: [硕士学位论文]. 哈尔滨: 哈尔滨理工大学, 2014.
[13]	Qian, J., Joshi, R.P., Schamiloglu, E., Gudet, J. and Woodworth J.R. (2006) Analysis of Polarity Effects in the Electrical Breakdown of Liquids. Journal of Physics D: Applied Physics, 39, 359-369. https:/doi.org/10.1088/0022-3727/39/2/018
[14]	Lesaint, O. and Jung, M. (2000) On the Relationship between Streamer Branching and Propagation in Liquids: Influence of Pyrene in Cyclohexane. Journal of Physics D: Applied Physics, 33, 1360-1368. https:/doi.org/10.1088/0022-3727/33/11/315
[15]	Torshin, Y.V. (2003) Prediction of Breakdown Voltage of Transformer Oil from Predischarge Phenomena. IEEE Transactions on Dielectrics and Electrical Insulation, 10, 933-941. https:/doi.org/10.1109/TDEI.2003.1255769
[16]	O’Sullivan, F. (2006) Modeling the Effect of Ionic Dissociation on Charge Transport in Transformer Oil. Proceedings of IEEE Conference on Electrical of Insulation, Kansas City, 15-18 October 2006, 756-759. https:/doi.org/10.1109/ceidp.2006.312042
[17]	Hwang, J.G. (2009) Modeling Streamers in Transformer Oil: The Transitional Fast 3rd Mode Streamer. Proceedings of the 9th International Conference on Properties and Applications of Dielectric Materials, Harbin, 19-23 July 2009, 573-578.
[18]	George Hwang, J. and Zahn, M. (2012) Mechanisms behind Positive Streamers and Their Distinct Propagation Mode in Transformer Oil. IEEE Transactions on Dielectrics and Electrical Insulation, 19, 162-174. https:/doi.org/10.1109/TDEI.2012.6148515
[19]	O’Sullivan, F.M., George Hwang, J. and Zahn, M. (2008) A Model for the Initiation and Propagation of Positive Streamers in Transformer Oil. IEEE International Symposium on Electrical Insulation, Cambridge, 9-12 June 2008, 210-214. https:/doi.org/10.1109/elinsl.2008.4570312
[20]	Beroual, A., Zahn, M., et al. (1998) Propagation and Structure of Streamers in Liquid Dielectrics. IEEE Electrical Insulation Magazine, 14, 6-17. https:/doi.org/10.1109/57.662781

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