基于PWM波形特征的励磁涌流识别方法

Identification of inrush current based on characteristics of PWM waveform

在分析励磁涌流与区内故障电流波形特征差异的基础上,提出了一种利用调制得到脉冲宽度调制(PWM)波形特征来识别励磁涌流的方法。分析了利用励磁涌流调制得到PWM波形与利用故障电流调制得到PWM波形的差异,设置了2个判据来识别励磁涌流和区内故障电流。所提方法原理简单,灵敏性好,具有一定抗电流互感器饱和能力,可靠性高。MATLAB仿真结果表明,所提方法可准确、快速识别各种情况下的励磁涌流和变压器区内故障电流。

Based on the analysis of the difference characteristics of inrush cun：ent and fault current of internal faults, a method to identify inrush current using PWM（Pulse Width Modulation） waveform is proposed. The difference be- tween PWM waveform modulated with the inrush current and that with internal fault current is analyzed, based on which,two criteria are set to identify inrush current and internal fault curt＇cut. The proposed method is simple and sensitive, and has a certain ability to resist current transformer saturation with high reliability. The simulative results by MATLAB show that the proposed method can accurately and quickly identify the inrush current and the internal fault current in various situations.