Design considerations of power protection systems in superconducting magnets

The intent of this thesis is to investigate means of protecting superconducting magnet systems. The types of magnet systems considered are those employed in tokamak fusion reactors for containment of the plasma. The magnetic systems to be considered have current ratings ranging from 10,000 A to 25,000 A dc. The maximum voltages associated with protection of these coils are 1000 V and 2500 V, respectively. The maximum energy storage capability of these coils is approximately 200 megajoules.

The thesis discusses several types of protection systems. The functions of all major power devices of the protection systems are reviewed. The thesis addresses three major current interrupting devices considered for use in the magnetic system protection scheme. The pros and cons of each system will be discussed, and one is selected for use in the protection system. The reasons for selection of this device, rather than the others, will be reviewed. Also, design considerations in engineering the coil dump resistor will be reviewed.

One power interrupter circuit is reviewed in detail to include test results along with a dynamic computer model. The computer model uses the Super-Sceptre II computer program for modeling the transient portion of the circuit. Two types of dump resistors are reviewed in detail to complete the understanding of "Design Considerations of Power Protection Systems in Superconducting Magnets."