基于输入阻抗谱的电力电缆本体局部缺陷类型识别及定位

In order to solve the deficiencies of the partial discharge (PD) method and the reflection coefficient spectrum (RCS) method in the identification and location of local defect types in power cables, a method for identifying and locating local defect types in power cables based on the input impedance spectrum is proposed. Firstly, according to the distributed parameter model of power cables, through simulation analysis, the characteristics of the input impedance spectrum of power cables with capacitive/inductive defects are obtained. Then, the input impedance spectrum of power cables and the Kaiser window are used to achieve high-sensitivity location of local defects in power cables, obtaining intuitive location spectrograms. Finally, two types of local defect samples (defects of copper shielding layer loss and thermal aging defects) are made on a 13m-long power cable in the laboratory to verify the effectiveness of the proposed method. The simulation and experimental results show that this method has a high identification sensitivity for local defects with a length greater than 5cm or a capacitance change greater than ±5%. It can not only identify the types of local defects in the power cable body but also achieve effective location of weak defects.

为解决局部放电(PD)法和反射系数谱(RCS)法在电力电缆本体局部缺陷类型识别及定位方面存在的不足,提出一种基于输入阻抗谱的电力电缆本体局部缺陷类型识别及定位方法。首先,依据电力电缆分布参数模型,通过仿真分析,得到含有容性/感性缺陷的电力电缆输入阻抗谱特征。然后,运用电力电缆输入阻抗谱、Kaiser窗实现对电力电缆局部缺陷的高灵敏度定位,得到具有直观性的定位谱图。最后,在实验室13m长的电力电缆上制作两种局部缺陷样本(铜屏蔽层缺损缺陷与热老化缺陷),用于验证所提方法的有效性。仿真和实验结果表明,该方法对长度大于5cm或电容变化大于±5%的局部缺陷具有较高的识别灵敏度,不仅能对电力电缆本体局部缺陷类型进行识别,还能实现对微弱缺陷的有效定位。