Interfacial space charge characteristic of PPLP insulation for HVDC cables

• Main Authors: Xuefeng Zhao, Lu Pu, Zhiqiang Xu, George Chen, Wei Duan, Haofei Sun, Zeli Ju
• Format: Article
• Language: English
• Published: Wiley 2020-04-01
• Series: High Voltage
• Subjects: paper; space charge; power cable insulation; electric breakdown; electrical conductivity; hvdc power transmission; hvdc power convertors; wind power plants; interfacial space charge characteristic; hvdc cables; high-voltage dc cables; high-voltage ac cables; long distance power transmission; off-shore wind farm; polypropylene; paper insulation; highest voltage level; electrical performance; pplp insulation system; kraft paper acts; charge carriers; optimal electric field distribution enhances
• Online Access: https://digital-library.theiet.org/content/journals/10.1049/hve.2019.0395

High-voltage DC (HVDC) cables show more efficiency than high-voltage AC cables over the long distance power transmission and have attracted significant attention recently due to rapid developments in off-shore wind farm. Polypropylene laminated paper (PPLP) insulation based HVDC cables have provided a reliable operation for many years and are the highest voltage level in operation at the moment. In this study, the authors intend to understand the electrical performance of PPLP insulation system by examining space charge in detail, especially at the interfaces. It has been found that the interface between polypropylene and Kraft paper acts as trap for charge carriers, resulting in an optimal electric field distribution in PPLP insulation system. The optimal electric field distribution enhances overall electrical performance of PPLP insulation, including higher dc breakdown strength and lower electrical conductivity.