Insulation design of -800 kV gas insulation transmission line for negative ion based neutral beam injector

Abstract

The high-voltage transmission line carries electricity, water, and gas for the high-potential components in the NNBI system. High voltage transmission lines used in -800 kV acceleration grade NNBI systems require the transmission of multiple high voltages of different voltage levels. Its insulation design not only guarantees the reliability of insulation but also requires a small occupation volume. The FEA method is used for insulation design of multi-conductor transmission lines. In the design of -800 kV transmission line, coaxial and non-coaxial structures are mainly considered. In the case of SF6 filling space, conductor radius and conductor position are the main factors affecting insulation strength. Both structures can make its insulation strength meet the requirements. However, it is found that the coaxial transmission line is more compact and concise when it meets the insulation requirements, but it is difficult to install and maintain.