直流偏磁对不同铁心结构和联结组别变压器感应电动势的影响  

Influence of DC Bias on Electromotive Force of Transformers with Different Iron Core Structures and Winding Connections

作　　者：王东阳 武朝强 李志强 许国瑞[2] WANG Dongyang;WU Chaoqiang;LI Zhiqiang;XU Guorui(China Electric Power Research Institute,Beijing 100192,China;School of Electrical and Electronic Engineering,North China Electric Power University,Beijing 102206,China)

机构地区：[1]中国电力科学研究院有限公司,北京100192 [2]华北电力大学电气与电子工程学院,北京102206

出　　处：《华北电力大学学报（自然科学版）》2020年第1期42-49,共8页Journal of North China Electric Power University：Natural Science Edition

基　　金：国家电网公司总部科技项目:超高比例新能源送出特高压直流输电系统关键技术研究(XT71-18-036)

摘　　要：特高压直流输电系统单极运行会导致临近变压器出现直流偏磁现象,而变压器感应电动势会对电网电压产生重要影响。为了研究直流偏磁对不同铁心结构和联结组别变压器感应电动势的影响,本文将三相三柱式和五柱式变压器时步有限元模型与YNy和YNd连接的外部电路相结合,建立了能够反映不同联结组别和铁心结构的变压器场-路耦合模型。研究了变压器感应电动势和励磁电流的基波及谐波含量随直流偏磁程度的变化规律,揭示了感应电动势波形畸变率与铁心结构及联结组别之间的关系;最后通过实验验证了结果的正确性。结果表明,直流偏磁对三相五柱式变压器感应电动势的影响较大,采用YNd联结会减小感应电动势波形的畸变率;而直流偏磁对三相三柱式变压器感应电动势基本没有影响。DC magnetic bias will occur nearby transformers during the monopole operation of UHVDC transmission system. Meanwhile, the Electromotive Force(EMF) of transformers also affect the voltage of power grid. To study the influence of DC magnetic bias on the EMF of transformers with different iron core structure and winding connections, this paper established a field and circuit coupled time stepping finite element model of transformer by combining the time stepping finite element model of three-limb and five-limb transformer with electric circuit model of YNy and YNd winding connections. This paper observed the variation of excitation current and the EMF of transformers along with the degree of DC bias and revealed the relationship between Total Harmonic Distortion(THD) of EMF and the iron core structure, winding connections. The experimental results verify that DC bias seriously deforms the waveform of EMF of five-limb transformer while the deformity rate can be decreased in YNd winding connection and that DC bias has little effect on the EMF of three-limb transformer.

关 键 词：联结组别 铁心结构 直流偏磁 变压器 感应电动势 

分 类 号：TM14[电气工程—电工理论与新技术]