基于ANSYS的三相一体自耦变压器分差零差保护误动分析

Analysis on Mis-operation of Zero-sequence Differential and Phase Differential Protection for Three-phase Compact Auto-transformer Using ANSYS

自耦变压器的分差零差保护在原理上虽然不受励磁涌流的影响,但对国产三相一体自耦变压器空充时其保护时有误动。通过对比国产与合资330kV三相一体自耦变压器的空充电流波形,分析了国产自耦变压器空充时保护误动的主要原因是公共绕组电流互感器铁芯饱和导致电流传变发生异常,其本质因素在于自耦变压器内部结构和材料工艺存在问题,需要改善。同时,利用基于有限元原理的电磁场仿真软件ANSYS进行建模仿真,对文中分析加以验证。

Phase differential and zero-sequence differential protection for auto-transformer cannot be affected by magnetizing inrush current, but protection for the three-phase compact auto-transformer made in China sometimes mis-operates when energizing. By comparing the energizing current waveforms of domestic or joint-venture 330 kV three-phase compact auto- transformers, it has been found that the main reason for the mis-operating of domestic ones is that the saturation of common winding current transformer core will lead to the abnormal current transformation. It is further studied that the essential factors for the abnormality exist in the internal structures and materials of auto-transformers, which need to be improved. Finally, the analysis is verified using the professional simulation software, ANSYS, based on the finite element method.