基于频域反射的电缆缺陷定位优化方法

Cable Defect Location Optimization Based on Frequency Domain Reflection

针对传统的频域反射法难以有效定位电缆缺陷的问题,该文提出了一种基于频域反射的电缆缺陷定位优化算法。该方法首先利用改进的短时傅里叶变换对反射系数谱的解析信号进行分析,得到三维缺陷定位图;然后根据三维缺陷定位图分析缺陷处反射信号的能量衰减特性,从而选择合理的分析频率范围;最后将对应频率范围的三维缺陷定位图转变为缺陷定位曲线,开展电缆缺陷定位。1000m仿真电缆模型的缺陷定位结果表明,相比于传统的阻抗相位变化比率方法,该文方法受采样点数影响较小。40m和500m真实电缆的缺陷定位结果表明,因为该文方法考虑了电缆中反射信号的衰减效应,所以该文方法不仅可以有效定位短电缆的缺陷,而且可以有效定位长电缆中缺陷。

To solve the problem that it is difficult for the traditional frequency domain reflection to locate the cable defects effectively,the cable defect location optimization based on frequency domain reflection is proposed in this paper.Firstly,the analytical signal of the reflection coefficient spectrum is analyzed by using the improved short time Fourier transform,obtaining the three dimensional defect location picture.Then the energy attenuation characteristic of the reflected signal at the defect is analyzed in the three dimensional defect location picture to select a reasonable analysis frequency range.Finally,to locate the cable defect,the three dimensional defect location picture in the reasonable analysis frequency range is transformed into the defect location curve.The defect location result of the 1000 m simulated cable model shows that,compared with the traditional impedance phase change ratio method,the proposed method is less affected by the number of sampling points.The defect location results of 40 m and 500 m actual cables show that,because the attenuation effect of the reflected signal in the cable is considered in the proposed method,the proposed method is effectively able to locate not only the defect of a short cable,but also the defect in a long cable.