High temperature superconducting opening switches

A continuing challenge in power systems and pulsed power applications is the development of reliable, high current opening switches. The opening switch is a particularly critical component in inductive energy storage systems. The high temperature superconductor materials have the unique property of becoming superconducting at or near liquid nitrogen temperatures. By manipulating the current density and the external magnetic field of these materials, they can be made to switch from a zero resistance state to a normal (resistive) state. Because they have zero resistance in the superconducting state, they have zero losses when closed, and do not load the system. In the open state, a resistance of several milliohms may be present. This is appropriate for switching currents into certain low resistance loads. This paper presents a description of possible applications of these switches in inductive energy storage systems, as well as data on the performance of various switch configurations. Maximum currents switched are approximately 100 amps, with potential scaling up to 3000 amps or higher. The switches are triggered using either a self generated magnetic field or an external field of up to 3.5 Tesla.