利用波形非正弦度分形估计值识别励磁涌流

以正确鉴别变压器励磁涌流和短路电流为目的,提出一种利用波形非正弦度分形估计的电力变压器励磁涌流与内部故障电流识别方案。利用变压器励磁涌流和内部故障电流波形特征的不同,对差动电流波形进行波形非正弦度计算并分析。通过复合形态滤波算法滤除信号中的各种噪声和扰动,保证了算法的可靠性。在比较励磁涌流与短路电流波形非正弦度各自特点的基础上,提出了一种新的变压器保护方案。仿真试验结果表明:该方法能可靠识别励磁涌流与短路电流,对轻微内部故障也有较高的灵敏度。

Identification of Transformer Inrush Current by Using of Fractal Evaluation of Waveform Non-Sinusoidal Level

Taking the correct identification of Transformer inrush current and fault current as objective,a novel scheme to identify inrush current and internal fault current by comparing the non-sinusoidal level fractal evaluation of waveform is proposed in this paper.Based on the different waveform characteristics between inrush current and internal fault current,the non-sinusoidal level of differential current waveform is calculated and analyzed.To ensure the reliability of the grille fractal,the complex morphological filter is used to filtrate the noises and interference signals.On the basis of comparing the feature of inrush and fault current waveform of non-sinusoidal level value,a novel transformer protection scheme is proposed.The simulation tests show that the proposed method can identify inrush current rapidly and reliably,and still keeps good sensibility even in the case of slight internal fault.