换流变压器直流偏磁对油箱涡流损耗的影响  

The Influence of Converter Transformer DC Bias on Eddy Current Loss of Tank

作　　者：黄天超 王泽忠[1] 李宇妍 Huang Tianchao;Wang Zezhong;Li Yuyan(Key Laboratory of High Voltage&EMC North China Electric Power University,Beijing 102206 China)

机构地区：[1]华北电力大学高电压与电磁兼容北京市重点实验室,北京102206

出　　处：《电工技术学报》2023年第8期2004-2014,共11页Transactions of China Electrotechnical Society

基　　金：国家重点研发计划专项(2016YFC0800103);国家自然科学基金(52177081)资助项目。

摘　　要：换流变压器直流偏磁状态下油箱涡流损耗会大幅增加,导致变压器温度升高,威胁其安全稳定运行,因此快速评估直流偏磁下油箱涡流损耗的大小就显得十分必要。该文首先分析了换流变压器在额定和空载直流偏磁状态下油箱表面漏磁场的分布特点。再结合实际换流变压器非线性负载电流和励磁电流波形,得到了不同换流器触发角和直流电流下油箱涡流损耗的变化规律。并在IEC/IEEE 60076-57-129标准的基础上,给出了换流变压器直流偏磁状态下油箱涡流损耗的计算公式。针对一台800 kV单相四柱式换流变压器,利用场路耦合法进行油箱涡流损耗有限元计算。通过对损耗仿真数值以及油箱表面磁通密度和涡流损耗分布的分析,验证了理论分析的正确性,并获得了不同工况下,计算公式中的损耗占比值。利用不同属性的线性负载替代换流器触发角的变化,对两台单相四柱式380 V交流变压器进行了直流偏磁实验,进一步验证了理论分析的正确性。For the converter transformer,the eddy current loss of the tank under DC bias will increase significantly,which will lead to the temperature rise of the transformer and threaten its safe and stable operation.Therefore,it is necessary to quickly evaluate the eddy current loss of the tank under DC bias.At present,given the particularity of the load current of the converter transformer,much research work has been carried out to study the relationship between the stray losses of the structural components corresponding to different harmonic contents.However,the research conclusions do not consider the impact of DC bias applied to the converter transformer.The research on the stray loss of tanks,pull plates,and other structural parts under DC bias is mainly based on AC transformers.Therefore,considering the characteristics of the nonlinear load current of the converter transformer,this paper analyzes the change of eddy current loss of the tank under DC bias.Firstly,the distribution of the magnetic circuit on the tank surface under different working conditions is analyzed.Combined with the actual nonlinear load current waveform and eddy current loss calculation formula,the influence of converter trigger angle and DC on the tank eddy current loss at the rectifier and inverter sides is obtained.According to the analysis conclusion,a loss ratio factor k is introduced,and a simplified formula for calculating the eddy current loss of the tank when the dc bias is applied is given.Then,the finite element simulation software COMSOL is used to build a finite element model of the eddy current loss of the tank of an 800 kV converter transformer.The field circuit coupling simulation is carried out with the external circuit of the primary and secondary sides of the converter transformer.The converter transformer tank current loss index under rated conditions has a small error compared with the value of the IEC standard,which also proves the correctness of the model to a certain extent.The simulation value variations of tank loss und

关 键 词：直流偏磁 换流变压器 换流器触发角 油箱涡流损耗 

分 类 号：TM41[电气工程—电器]