Research on the distributed capacitance for high-voltage key components on CRAFT NNBI

• Published in: Plasma science & technology Vol. 27; no. 4; pp. 44007 - 44012
• Main Authors: LIU, Bo, LIU, Zhimin, JIANG, Caichao, LIU, Sheng, PAN, Junjun, CHEN, Shiyong, WEI, Wei, QU, Yuchen, LIANG, Lizhen, BAI, Ruoxin, XIE, Yuanlai
• Format: Journal Article
• Language: English
• Published: Plasma Science and Technology 01.04.2025
• Subjects: direct-current high voltage; distributed capacitance; finite elements analysis; NNBI; power supply system
• ISSN: 1009-0630; 2058-6272
• DOI: 10.1088/2058-6272/adc23b

The negative ion based neutral beam injector (NNBI) with a beam energy of 400 keV is one of the subsystems at the Comprehensive Research fAcility for Fusion Technology (CRAFT) in China. The distributed capacitance of the high-voltage components is an important basis for the design of surge suppression devices at CRAFT NNBI. This study conducted calculations of distributed capacitance for the key components, including the high-voltage deck, transmission line and isolation transformer in the power supply system using the finite element method. The relationship between the high-voltage deck (HVD) distributed capacitance and the distance from the wall is discussed. The differences in distributed capacitance and energy storage between non-coaxial and coaxial transmission lines are also debated. Finally, the capacitance between the primary and secondary windings of the −400 kV isolation transformer, as well as between the secondary winding and the oil tank casing, was calculated.