Modular High Current Test Facility at LLNL

Abstract

This paper describes the 1 MA, 225 kJ test facility in operation at Lawrence Livermore National Laboratory (LLNL). The capacitor bank is constructed from three parallel 1.5 mF modules. The modules are capable of switching simultaneously or sequentially via solid dielectric puncture switches. The bank nominally operates up to 10 kV and reaches peak current with all three cabled modules in approximately 30 μs. Parallel output plates from the bank allow for cable or busbar interfacing to the load. This versatile bank is currently in use for code validation experiments, railgun related activities, switch testing, and diagnostic development.

Optimized use of superconducting magnetic energy storage for electromagnetic rail launcher powering

“…The conclusion drawn from these preliminary simulations is that S 3 EL system may indeed operate with a much lower current when compared to non-coupled SMES powering, even if the coupling between the launcher and the SMES is rather low (divided by 3 if k max = 0.15). Moreover, in this configuration the SMES inductance is augmented (up to 10 times) for an identical initial storage, which increases the selfdischarge time constant.…”

“…Some realistic scaling ideas may, however, be derived from the results of the SARG experiments, in which the coupling reached 13% [15]. Even if the coil was not used to power the launcher in these experiments, its coupling to the rails was similar to the one present in an S 3 EL system. Detailed S 3 EL simulation results obtained for plausible coupling values are compared with classical capacitor powering and SMES powering configurations in table 3.…”

“…In order to obtain a good output speed the current must be very high, ranging from 100 kA for a very small launcher to more than 1 MA for a large launcher [2,3]. On the other hand, the kinetic energy of the projectile is moderate, never exceeding a couple of MJ.…”

Electro-thermal-mechanical validation experiments

“…Given the low impedance load and capacitor lifetime considerations, minimization of voltage reversal was achieved via modifications to the number of load cables and/or the cable lengths. Further discussion of the bank may be found in a previous publication [2]. …”