大型电力变压器直流偏磁分析的磁路建模与应用  

Magnetic Circuit Modelling of the DC Biased Large Power Transformer and the Application

作　　者：李泓志[1] 崔翔[1] 刘东升[2] 卢铁兵[1] 程志光[2] 

机构地区：[1]华北电力大学电气与电子工程学院,北京102206 [2]保定天威集团有限公司,保定071056

出　　处：《高电压技术》2010年第4期1068-1076,共9页High Voltage Engineering

基　　金：国家自然科学基金(50677016)~~

摘　　要：为了深入理解电力变压器在直流偏磁工况下的运行特性以提高电网安全运行性能和变压器本体设计,针对大型电力变压器产品的直流偏磁计算要求,提出了改进的磁路模型;根据铁心和绕组的几何结构形成磁路的拓扑,在铁心磁阻的计算中考虑涡流效应的作用,同时将铁心接缝气隙的作用引入计算模型中,建立了大型电力变压器直流偏磁的磁路模型;基于矢量匹配法获得铁心等效磁路模型中元件参数的最优解;基于铁心接缝气隙的几何结构和磁场分布特性,通过分段处理,建立了气隙等效磁路模型。作为应用实例,计算了2种不同铁心结构的大容量电力变压器产品的直流偏磁性能。验证了这些模型分析大型电力变压器直流偏磁的有效性。计算表明直流偏磁使变压器产品建立工作磁场更加困难;变压器的绕组漏磁显著增加,而且不同的变压器铁心结构受直流偏磁的影响存在差异。For the sake of analyzing the DC biased large power transformer,a comperhensive magnetic circuit of the transformer was found based on the improved magnetic circuit model presented by the authers. The topology of the magnetic circuit was constructed according to the geometry of the core and coil. The effects of the eddy current was taken into consideration of the reluctance of the core. Meanwhile,the effects of the air gap of the core were included in the computational model. The optimal value of the components of the core magnetic circuit was achieved by using the vector fitting technique. The core joint section was divided into serval segments according to the charactertistics of the structure and materials. And the equivalent magnetic circuit of the air gap was establised based on such segments. The performance of two different types of large power transformer products was analyzed. The effectiveness of the presented model was validated. Results indicate that it is more difficult to establish the working magnetic field for the transformer product due to the DC bias than that in normal condition. And the leakage flux of the coil was signifcantly increased. Meanwhile,the influences of the DC bias on transformers varies according to their different types of core were observed.

关 键 词：电力变压器 直流偏磁 磁路 矢量匹配 气隙 激磁电流 

分 类 号：TM41[电气工程—电器]