Welded splice design in a mid-size superconducting magnetic energy storage system

The splice design is one of the most important issues in the design of a superconducting magnetic energy storage (SMES) system. A welded splice is made by overlapping two sheath-free stabilized conductors and welding at the sides of the contact interface. To achieve the ultimate goal in the SMES reliability, one of the primary concerns is the electrical resistance across welded joints though high-purity aluminum (HPA) stabilizers. Highly resistive welds could lead to conductor instability. This paper addresses the splice design for a 30 MW, 1800 MJ mid-size SMES system. The splices are required to transmit current at the level of 16,000 A under the normal operating conditions. Gas-tungsten arc welding has been chosen its the joining method for its high reliability, high quality, low distortion and low cost. The welding setup and welding parameters mere determined for the present splice design. Other design issues such as the splice protection, support and cooling, have been also addressed.