中文摘要：

提出了一种基于标准化网格曲线的励磁涌流识别新方法。首先对励磁涌流和短路电流的奇异特征产生机理进行了分析,并介绍了网格分形的基本概念和计算方法,然后利用该方法在提取畸变的同时,形成各自的网格曲线。在比较网格曲线变化特点的基础上,提出了两种新型变压器保护方案,即时域法和频域法。通过对网格曲线进行标准化处理,使判据定值的选取更具有普遍性,与具体变压器的参数和类型无关。动模试验计算结果表明新原理能够有效区分励磁涌流和内部故障电流,受电流互感器饱和的影响小。

英文摘要：

　A novel algorithm based on the normalized grille curve for the discrimination between inrush current and fault current is proposed. First,the singularity difference between the inrush current and internal fault is analyzed,and the grille fractal concept along with its calculation method to extract singularity characteristics is developed. Moreover,two new criteria to identify inrush current in the time and frequency domains are developed respectively in detail. The normalization of the grille curve makes the threshold has little relation with the parameter of the transformer,which has more universal meaning in the determination of the threshold. The experimental results indicate that the proposed technique is reliable during discrimination between internal faults and magnetizing inrush currents,and current transformer saturation has little influence on the technique.