基于Lagrange插值法的变压器励磁涌流评估与应用

Evaluation and application of transformer inrush current based on Lagrange interpolation method

二次谐波含量是作为判断变压器励磁涌流的主要特征之一。对于一台变压器,影响励磁涌流二次谐波含量因素中合闸角度、铁心磁通饱和点、变压器容量、变压器结构、变压器电压等级是确定的,唯一不确定的是剩磁的大小。将根据MATLAB建立的模型仿真出来的离散数据,通过Lagrange插值法得到高次非线性插值函数,并画出函数的图形,评估剩磁影响下变压器励磁涌流二次谐波含量的边界范围。基于一起事件案例,证实该方法的实用性和有效性。

The second harmonic content is one of the main characteristics to judge inrush current of transformer.For a transformer,the closing angle,the core flux saturation point,the transformer capacity,the transformer structure and the transformer voltage grade are certain,the only uncertain factor is the remanence.Based on the discrete data simulated by the model established by MATLAB,the higher order nonlinear interpolation function is obtained by Lagrange interpolation method,and the graph of the function is drawn,the boundary range of the second harmonic content of transformer inrush current under the influence of remanence is evaluated.Based on a case study,this paper proves the practicability and effectiveness of the proposed method.