电容测试法判断测井电缆系统故障

Logging Cable System Malfunction Judgment through Capacitance Testing Method

测井电缆因长途颠簸、拉伸及绞车缠绕挤压,电缆连接器、电缆、绞车滑环、滑环连线等部位极易出现故障。电容测试法是一种简易、快速的检测方法,该法可在现场准确诊断出故障电缆的位置。以四芯铠装电缆为例,每根缆芯的正常阻值约为80Ω/1 000m,两缆芯间的分布电容约为170PPF/1 000m。在实际检测中,根据电容较小时测点的位置,可以有效判断故障部位;而电缆故障位置则可利用电阻及电容的线性关系进行计算予以确定。

Because of bumpiness, stretching during long transportation, winch twisting and extruding, areas of logging cable connector, cable, winch slip-ring, slip-ring connecting wire are very easy to be out of action. The capacitance testing method is an easy, quick detection method, can correctly detect malfunction area and position on the spot. To take 4-core armored cable as example, every cable core normal numerical value of resistance is about 80Ω/1000m, distributed capacitance between two cable cores about 170PPF/ 1000m. In practical detection, malfunction area can be effectively judged by smaller capacitance of measuring point; while malfunction position can be estimated through linear relation between resistivity and capacitance.