中文摘要：

为了阐明变压器有载合闸及穿越性涌流幅值较低时差动保护误动的机理,建立了一个新的有载合闸变压器模型.通过该模型建立一组非线性微分方程组,通过简化铁心磁化特性的描述,利用4阶龙格（库塔算法求解.结合考虑磁滞效应TA模型的建立,分析了变压器有载合闸过程中一二次涌流的波形及其谐波特征,并指出：低穿越性涌流情况下的变压器差动保护误动现象主要是由 TA局部暂态饱和造成的.通过仿真试验验证了上述观点.

英文摘要：

A novel model for analyzing the transient course of transformer switch-in with load is proposed to explain the real-operation of the differential protection during the loaded transformer energization accompanied by lower through inrush. A set of non-linear differential equations are formed using this model. With the description of the simplified characteristic of the transformer core, a 4-order Runge-Kutta algorithm is utilized to solve the inrush. Together with the setup of the TA model involving the magnetic hysteresis effect, the waveform and harmonics characteristics of the primary and secondary inrushes are analyzed. It is pointed out that the mal-operation of the transformer differential protection during the lower through inrush mainly results from the local transient saturation of the TA. This point of view is verified with the simulation tests.