Indigenous Development of Large Dimension Insulator for High Voltage Bushing of Indian Test Facility (INTF)

High voltage bushing is one of the key components of Indian Test Facility. It is designed to provide 100 kV electrical isolation to all high voltage feedlines from the electrically grounded vessel. It also forms vacuum boundary between the vessel and the outer atmosphere. Conventional vacuum compatible porcelain insulator is selected for this purpose. However, to accommodate several high voltage feedlines in a single insulator, diameter of the insulator has been kept as similar to 1 m. Further, steps have been provided at both the ends for porcelain-metal vacuum seal transitions which is the challenging step during the fabrication of insulator. This paper describes the design criteria, analysis, manufacturing phases, encountered issues and remedial actions taken to optimize the design, ensuring its manufacturability without compromising operational requirements.