Switching transients in a superconducting coil
A study is made of the transients caused by the fast dump of large superconducting coils. Theoretical analysis, computer simulation, and actual measurements are used. Theoretical analysis can only be applied to the simplest of models. In the computer simulations two models are used, one in which the coil is divided into ten segments and another in which a single coil is employed. The circuit breaker that interrupts the current to the power supply, causing a fast dump, is represented by a time and current dependent conductance. Actual measurements are limited to measurements made incidental to performance tests on the MFTF Yin-yang coils. It is found that the breaker opening time is the critical factor in determining the size and shape of the transient. Instantaneous opening of the breaker causes a lightly damped transient with large amplitude voltages to ground. Increasing the opening time causes the transient to become a monopulse of decreasing amplitude. The voltages at the external terminals are determined by the parameters of the external circuit. For fast opening times the frequency depends on the dump resistor inductance, the circuit capacitance, and the amplitude on the coil current. For slower openings the dump resistor inductance and the current determine the amplitude of the voltage to ground at the terminals. Voltages to ground are less in the interior of the coil, where transients related to the parameters of the coil itself are observed.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6845586
- Report Number(s):
- UCRL-89205; CONF-831203-156; ON: DE84012592
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
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700202* -- Fusion Power Plant Technology-- Magnet Coils & Fields
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CIRCUIT BREAKERS
COMPUTERIZED SIMULATION
ELECTRICAL EQUIPMENT
ELECTRICAL TRANSIENTS
ELECTROMAGNETS
EQUIPMENT
EQUIPMENT PROTECTION DEVICES
MAGNETS
MATHEMATICAL MODELS
QUENCHING
SAFETY
SIMULATION
SUPERCONDUCTING DEVICES
SUPERCONDUCTING MAGNETS
SWITCHES
TRANSIENTS
VOLTAGE DROP