Modeling for life estimation of HVDC cable insulation based on small-size specimens

The long-term performance of cable insulation has been severely challenged [1-3] by the technological advances of high voltage DC (HVDC) power lines for bulk long-distance subsea or underground transmission worldwide [4-8]. In particular, its life plays an important role in the reliability of the whole transmission system, which has received a great deal of attention and been extensively investigated over many years [1], [9-19]. Several competing life expressions, based on different mechanisms, have been developed with the aim of quantifying relationships between applied stresses (electrical, thermal and mechanical) and time to failure (lifetime). These have been used for theoretical studies and practical engineering applications. In their favor, the mean life data of laboratory tests can be fitted well to the model expressions. Alternatively different endurance characteristics of insulating material candidates can be compared with investigate their performances for a given cable system [1], [10], while providing feedback and insights on power cable design and manufacture.