Computer model of the ZTH energy system at Los Alamos

As part of the US national magnetic fusion energy research program to develop fusion energy as a practical, economical energy resource, Los Alamos is investigating two concepts of fusion: the reversed field pinch (RFP) and the compact toroid. Using the results of an experimental small fusion energy machine (ZT-40M) at Los Alamos as a basis, a larger, higher energy machine is being constructed, called ZTH. The ZTH machine originally had a design plasma current magnitude of 4 MA, compared to the smaller ZT-40M machine, at 450,000 A. The system is presently under construction in a 2-MA-rated configuration. A description is given of the ZTH electrical system, which includes a 1430-MVA generator, the generator's drive and excitation hardware, the system protection and control circuits, AC-to-DC voltage converters, and the magnetic coil circuits. The system computer model, which is based on the EMTP code, Version 43-plus, is described. The computer results are briefly discussed.