基于电磁耦合注入的电力电缆局部缺陷在线定位方法

为了解决现有频域反射方法仅能在离线情况下对电缆缺陷进行定位检测的不足，提出了一种基于频域反射法和电磁耦合技术的电缆缺陷在线定位方法。首先，依据电缆分布参数模型对含有局部缺陷的电缆进行仿真建模，分析了不同电容变化程度的缺陷点与不同测试频率对电缆缺陷定位效果的影响。然后，探究了传感器结构对信号注入效率的影响。最后，分别在实验室105 m和500 m电力电缆上进行验证，在离线测试情况下，通过改变105 m电缆末端负载阻值，模拟不同电缆负载下的线路情况，并分析其对局部缺陷处和电缆末端处反射强度的影响。在带电测试情况下，通过串联谐振平台对500 m电缆进行通电，利用所提在线定位方法对该电缆进行测试，以检验所提方法的有效性。仿真及实验结果表明：相较于电缆离线定位测试方法，该方法能够在电缆通电的状态下，实现对电缆缺陷点的在线定位，且具有较高定位精度和识别灵敏度。

An Online Location Method for Local Defects in Power Cables Based on Electromagnetic Coupling Injection

In order to solve the shortcoming that the existing frequency domain reflection method can only locate and detect cable defects in offline situations, this paper proposes an online cable defect location method based on frequency domain reflection method and electromagnetic coupling technology. Firstly, based on the cable distribution parameter model, the cables with local defects are simulated and modeled, and the influence of the defect points of different capacitance changes and different test frequencies on the positioning effect of the cable defects is analyzed. Then the influence of the sensor structure on the signal injection efficiency was explored. Finally, it was verified on 105 m and 500 m power cables in the laboratory. In the case of offline testing, the load resistance of the 105 m cable end was changed to simulate different cable loads. The line condition, and analyze its influence on the reflection intensity at the local defect and the end of the cable. In the case of live test, the 500 m cable is energized through the series resonance platform, and the cable is tested using the online positioning method proposed in this article to verify the effectiveness of the method proposed in this article. The simulation and experimental results show that: compared with the cable offline positioning test method, this method can realize the online positioning of the cable defect point when the cable is energized, and has higher positioning accuracy and recognition sensitivity.