三相五柱变压器负载直流偏磁计算分析  

Calculation and Analysis of Load DC Magnetic Bias of Three-phase Five-column Transformer

作　　者：郭苏鑫 王泽忠[1] 梁书原 GUO Suxin;WANG Zezhong;LIANG Shuyuan(Beijing 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：《高压电器》2023年第12期113-121,129,共10页High Voltage Apparatus

基　　金：国家重点研发计划专项资助项目(2016YFC0800100);国家自然科学基金项目(51677068)。

摘　　要：在中国大容量的电力传输中,大多数采用三相五柱变压器,由于三相五柱变压器中零序磁路的存在导致直流入侵后磁路会发生严重饱和。为深入研究三相五柱变压器直流偏磁问题,搭建磁场有限元仿真模型,并配合变压器YNyn0联结的外电路方程进行耦合,通过在原边侧中性点输入不同大小的直流电流,首次模拟直流偏磁对三相五柱变压器负载下的影响。文中通过计算变压器原、副边电流和励磁电流波形与空载直流偏磁进行对比,并重点分析尖顶波处的变压器磁场分布,发现直流入侵对负载下副边绕组电流影响较小,原边电流随着直流电流增大发生一定程度的畸变,励磁电流波形与空载励磁电流波形一致。结合在励磁电流特殊点处的磁场分布,解释了三相五柱变压器三相电流偏磁特征,及其在波形上的对称性。The three-phase five-column transformer is commonly used in high power transmission in China.However it can suffer from severe magnetic circuit saturation due to the presence of a zero-sequence magnetic circuit when sub-jected to DC invasion.In order to study the problem of DC magnetic bias in three-phase five-column transformer,the fi-nite element simulation model of magnetic field is set up,and coupled with coordination of the external circuit equa-tion of YNyn0 connection of transformer.The influence of DC magnetic bias on the load of three-phase five-column transformer is simulated for the first time by applying different DC current at the neutral point of primary side.In this paper,through the calculation of primary and secondary side current of transformer and excitation current wave forms are compared with no-load DC magnetic bias,and the distribution of transformer magnetic field at the peak wave is an-alyzed emphatically.It is found that DC invasion has little influence on the secondary winding current under load.The primary current has a certain degree of distortion with the increase of DC current,and the excitation current waveform is identical to that of no-load.Combined with the magnetic field distribution at the special point of excitation current,the magnetic bias characteristics of three-phase five-column transformer and its symmetry in waveform are explained.

关 键 词：直流偏磁 三相五柱变压器 场路耦合模型 额定负载 磁场分布 

分 类 号：TM41[电气工程—电器]