Analysis Method of Electrical Stresses During Switching Process of Vacuum On-load Tap-changer in Converter Transformers

被引:0
|
作者
Sima W. [1 ]
Liu H. [1 ]
Li X. [2 ]
Yang M. [1 ]
Wang K. [3 ]
Zhang H. [2 ]
Yang C. [4 ]
机构
[1] State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Shapingba District, Chongqing
[2] State Grid Economic and Technological Research Institute Co., Ltd., Changping District, Beijing
[3] China Electric Power Research Institute, Haidian District, Beijing
[4] Xi’an XD Transformer Co., Ltd., Shaanxi Province, Xi’an
关键词
converter transformer; harmonic; vacuum interrupter; vacuum on-load tap-changer; ±800kV HVDC;
D O I
10.13334/j.0258-8013.pcsee.213167
中图分类号
学科分类号
摘要
Vacuum on-load tap-changer (OLTC) is a crucial component of converter transformers. However, OLTCs for ultra-high voltage converter transformers in China are all imported. Independent research and development are still at a critical stage requiring the study of the transient characteristics of OLTC. The waveforms of the switching electrical stresses of vacuum OLTC in converter transformers are very complex which affected by many factors. At present, simulations are widely used to obtain the waveforms of the switching electrical stresses, but they are not easy to apply to sensitivity analysis and critical operating conditions searching. Meanwhile, the co-simulation analysis of OLTC and DC systems is too time-consuming to support the applications like OLTC design and parameter selection. Therefore, an analysis method of switching electrical stresses of OLTC in converter transformers was proposed in this paper. First, the harmonic characteristics of the load currents of converter transformers were analyzed by Fourier decomposition, and the effects of trigger angle and commutation angle on the harmonics were analyzed quantitatively. Second, each physical circuit of more than ten steps during the OLTC switching process was extracted to derive analytical expressions of voltage and current waveforms with harmonics in the process of OLTC switching. Furthermore, the breaking current and recovery voltage change rates of vacuum interrupters in OLTC were obtained analytically. Finally, a ±800kV LCC-HVDC system was built in PSCAD to validate the analysis method. The analysis method can provide theoretical basis and calculation tool for sensitivity analysis and critical operating conditions searching. It can also support the design, selection, and test of vacuum OLTC in converter transformers. ©2022 Chin.Soc.for Elec.Eng.
引用
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页码:6908 / 6918
页数:10
相关论文
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