直流偏磁下不同磁化曲线对变压器铁心损耗仿真的影响

Effect of Different Magnetization Curves on Simulation for Transformer Core Loss under DC Bias

直流偏磁下变压器铁心材料磁化特性采用不同的表述方式,将会产生不同的损耗仿真结果。本文基于爱泼斯坦方圈试验测量了30ZH120取向硅钢片的交流磁滞回环和交流偏磁磁滞回环,详细阐述并解释了交流磁化曲线、直流磁化曲线、平均磁化曲线、交流偏磁磁化曲线和交直流共同作用下磁化曲线的提取方法。从实验数据和理论分析的角度指出了交直流共同作用下磁化曲线与直流磁化曲线是同一条曲线。以两台干式变压器产品模型为例,设计并搭建了使变压器工作在直流偏磁条件的实验电路,测试并仿真计算了直流偏磁下电力变压器铁心的空载损耗。研究表明,计算分析直流偏磁电工设备时,可以用直流磁化曲线描述硅钢片材料的磁性能,为提高直流偏磁下变压器损耗仿真准确性提供了参考依据。

By using different methods to describe the magnetization characteristics of transformer core under direct current(DC) bias, the simulation results for core loss will be different. In this paper, biased on Epstein test, the alternating current(AC) hysteresis loops and biased hysteresis loops of an oriented silicon steel sheet, 30ZH120, are measured. The abstraction methods of several magnetization curves such as AC magnetization curve, DC magnetization curve, average magnetization curve, AC bias magnetization curve, and resultant magnetization curve of AC and DC, are depicted in detail and explained. In terms of experimental data and theoretical analysis, it is pointed out that the resultant magnetization curve of AC and DC and DC magnetization curve are the same curve. Taking two dry-type transformers product model as an example, the experimental circuit which make transformer operate under DC bias conditions is designed and made up, and the no-load loss of power transformers core under DC bias is simulated and tested. Studies show that magnetism in the silicon steel material can be described by DC magnetization curve when analyzing electrical equipment operating under DC bias, which provides a reference for improving the simulation accuracy for transformer core losses under DC bias.