基于首末两端环流的电缆交叉互联箱缺陷识别定位方法

长电缆线路交叉互联箱在出现接地、进水、三相相序错误等缺陷时，难以对其进行快速识别和定位。针对交叉互联箱3类典型缺陷，建立长电缆线路交叉互联模型，分析缺陷下环流幅值及相位的变化规律，并对首末两端环流比值与缺陷箱号数的散点数据进行曲线拟合，获得缺陷定位公式，最后通过实例加以验证。结果表明：箱内接地时，缺陷相环流幅值增大，非缺陷相正常；三相相序错误时，两相环流幅值明显增大，另一相环流幅值较小；箱内进水时，各相环流幅值均增大且基本相等。定位公式的拟合度在0.96左右，通过实例验证可确定缺陷箱号数的范围。所提方法不受线芯电流和接地电阻变化的影响，可为长电缆线路交叉互联箱缺陷识别定位提供参考。

Defect identification and location method of cable cross-bonded box based on head-end circulation

It is difficult to identify and locate the defects quickly when the long cable line cross-bonded box has defects such as grounding, water inflow and three phase sequence error. Aiming at three types of typical defects of cross-bonded box, a cross-bonded model of long cable lines was established to analyze the amplitude and phase change rule of circulation under the defects, and the curve fitting of the ratio of circulation at both ends and the scatter data of defect box num-ber was carried out to obtain the defect location formulas. Finally, it was verified by an example. The results show that the circulation amplitude of the defective phase increases and the non-defective phase is normal when the ground is grounded inside the box. When the phase sequence is wrong, the amplitude of two-phase circulation increases obvious-ly, and the amplitude of the other phase circulation is smaller. When the tank is filled with water, the circulation ampli-tude of all phases increases and is basically equal. The fitting degree of the positioning formula is about 0.96, and the range of defect box number can be determined through the example verification. The proposed method is not affected by the change of wire core current and ground resistance, and can provide reference for the defect identification and location of long cable line cross-bonded box.