直线扫描CT检测碳纤维复合芯导线缺陷研究

碳纤维复合芯导线作为常见的增容导线之一,在架空输电线路中应用广泛.由于碳纤维复合芯导线芯棒在施工过程中易受损伤,并诱发导线断股和断线等故障,亟需研究在役碳纤维复合芯导线的无损检测技术.由于传统的X射线检测方法尚无法检测多股铝线和有机复合材料芯棒绞合结构条件下芯棒的损伤,文中提出了一种利用直线扫描CT检测在役碳纤维复合芯导线的方法.此方法采用射线源—探测器围绕固定检测对象作相对平行直线运动的扫描方式,具有结构简单、便于安装等优点.设计了一段以及两段直线扫描CT模型,搭建了原理实验平台,在实验室条件下对断裂、劈裂和裂痕3种常见芯棒缺陷进行了小批量检测实验.结果表明,一段直线扫描CT可快速检测较大的芯棒缺陷,两段直线扫描CT可检测微小的芯棒缺陷.相比于传统的X射线透射成像检测,直线扫描CT成像为在役架空导线内部缺陷检测提供了新思路和参考.

Inspecting defects of ACCC by linear scanning CT

As one of the common capacity-building conductors, aluminum conductor composite core (ACCC) is widely used in overhead power transmission lines. However, its mandrel is vulnerable to damage in the construction process, which may lead to breakage of conductor strand and wire. Therefore it is urgent to study the nondestructive testing technique for ACCC in service. Because the ACCC is made of outer aluminum conductor and inner composite core, the traditional detection methods cannot effectively inspect the defects in the mandrel. This paper proposes a method to detect defects of in-service ACCC using a linear scanning computed tomography (CT). In this CT method, an X ray source and a detector are moved in a relatively parallel line around the fixed detection object, which has the advantages of simple structure and convenient installation. Furthermore, one and two linear CT scanning modes are designed according to different situations, and the corresponding principle experiment platform is built. The three common mandrel defects of fracture, split and crack were tested in small batches under laboratory conditions. The experimental results show that one relative linear scanning CT can be used for rapid detection of mandrel defects with large defects, and two relative linear scanning CT can be used for fine detection of small defects existing in mandrel. Compared to traditional X-ray transmission imaging detection, the method in this paper provides a new idea and reference for inspecting the internal defects of the ACCC.