NSTX Electrical Power Systems
S. Ramakrishnan, C. Neumeyer, E. Baker, R. Hatcher, A. Ilic, R. Marsala, D. O'Neill, and A. von Halle
Date of PPPL Report: December 1999
Presented at: The 18th IEEE/NPSS (Institute for Electrical and Electronics Engineers/Nuclear and Plasma Science Society) Symposium on Fusion Engineering (SOFE) which was held in Albuquerque, NM, on October 25-29, 1999.
The National Spherical Torus Experiment (NSTX) has been designed and installed in the existing facilities at the Princeton Plasma Physic Laboratory (PPPL). Most of the hardware, plant facilities, auxiliary subsystems, and power systems originally used for the Tokamak Fusion Test Reactor (TFTR) have been used with suitable modifications to reflect NSTX needs. The design of the NSTX electrical power system was tailored to suit the available infrastructure and electrical equipment on site. Components were analyzed to verify their suitability for use in NSTX. The total number of circuits and the location of the NSTX device drove the major changes in the Power System hardware. The NSTX has eleven circuits to be fed as compared to the basic three power loops for TFTR. This required changes in cabling to insure that each cable tray system has the positive and negative leg of cables in the same tray. Also, additional power cabling had to be installed to the new location. The hardware had to be modified to address the need for eleven power loops. Power converters had to be reconnected and controlled in anti-parallel mode for the Ohmic heating and two of the poloidal-field circuits. The circuit for the Coaxial Helicity Injection (CHI) System had to be carefully developed to meet this special application. Additional Protection devices were designed and installed for the magnet coils and the CHI. The thrust was to making the changes in the most cost-effective manner without compromising technical requirements.
This paper describes the changes and addition to the Electrical Power System components for the NSTX magnet systems.