Ageing state identification and analysis of AC 500 kV XLPE submarine cable based on high-voltage frequency dielectric response

• Published in: IET science, measurement & technology measurement & technology, 2020-10, Vol.14 (8), p.977-984
• Main Authors: Dai, Xize, Hao, Jian, Jian, Zheng, Gao, Zhen, Cheng, Jialu, Zheng, Xinlong
• Format: Article
• Language: English
• Subjects: AC cross‐linked polyethylene submarine cable; AC XLPE submarine cable; ageing; ageing differences; ageing state identification; cable insulation; carbonyl index; Cole‐Cole model parameter; dielectric loss; dielectric losses; electro‐thermal ageing cable; high‐voltage frequency dielectric response; insulation condition measurement; insulation testing; loss quantity parameter; low‐frequency area; nonuniform ageing phenomenon; permittivity; power cable insulation; power cable testing; Research Article; state identification; submarine cables; testing voltage; voltage 200.0 V; voltage 2000.0 V; voltage 500.0 kV; XLPE insulation
• ISSN: 1751-8822; 1751-8830
• DOI: 10.1049/iet-smt.2020.0056

Carrying out the insulation condition measurement and analysis is important for the safe operation of the submarine cable. In this study, the high-voltage frequency dielectric response is used to identify the ageing state of the AC 500 kV cross-linked polyethylene (XLPE) submarine cable. The complex capacitance and tanδ in the low-frequency area for the new, thermal ageing, electro-thermal ageing cable all increase with the testing voltage increased from 200 to 2000 V. It is founded that the dielectric response at high voltage is more likely to detect the ageing differences. Based on the carbonyl index and the dielectric loss of the XLPE specimens at different position of the insulation layer, the non-uniform ageing phenomenon of the cable insulation is presented for the thermal ageing and electro-thermal ageing cable. The loss quantity parameter and its changing behaviour with testing voltage based on the frequency dielectric response could be used to identify the ageing state. The comparison of the modified Cole–Cole model parameter under 200 and 2000 V also indicates that the higher voltage dielectric response is helpful to identify the ageing differences.