Review of condition monitoring and defect inspection methods for composited cable terminals

Composited cable terminals are critical for reliable power delivery of traditional and traction power supply systems.During its operation,the cable terminal continually undergoes complex circumstances where humidity,temperature,field strength,mechanical stress and other factors continuously change at different levels.In extreme cases,defects or even failures may occur in the cable terminals,leading to catastrophic accidents.This makes the condition monitoring and defect detection of composited cable terminals become an imperative need for the power industry.The“state-of-the-art”technology of cable terminal condition assessment is focussed and a systematic review of the current research progress of cable terminal condition assessment from the operation circumstances to failure mechanisms is provided.It covers both online/offline condition monitoring methods and defects detection approaches.In addition,challenges and future research directions for cable terminal condition assessment are also addressed.It is concluded that the non-destructive and non-intrusive methods like terahertz imaging and ultrasonic testing,and multi-source information fusion methods as well as the digital twin technology have been gaining popularity for cable terminal defect inspection.It is expected the presented work can provide a global field of vision for further advancement of both scholars and industrial engineers in this field.