First tests of a 800 kJ HTS SMES

TL;DR

This paper reports the design, construction, and initial testing of an 800 kJ high-temperature superconductor SMES system operating at 20 K, demonstrating its potential for high-power pulsed applications with simplified cryogenics.

Contribution

First successful design and testing of an 800 kJ HTS SMES using Bi-2212 tapes with conduction cooling at 20 K.

Findings

SMES delivered 425 kJ at 244 A to a resistance load.

Maximum power output reached 175 kW.

Cooling system operated as designed during tests.

Abstract

SMES using high critical temperature superconductors are interesting for high power pulsed sources. Operation at temperatures above 20 K makes cryogenics easier, enhances stability and improves operation as pulsed power source. In the context of a DGA (Delegation Generate pour l'Armement) project, we have designed and constructed a 800 kJ SMES. The coil is wound with Nexans conductors made of Bi-2212 PIT tapes soldered in parallel. The coil consists in 26 superposed simple pancakes wound and bonded on sliced copper plates coated with epoxy. The rated current is 315 A for an energy of 814 kJ. The external diameter of the coil is 814 mm and its height 222 mm. The cooling at 20 K is only performed by conduction from cryocoolers to make cryogenics very friendly and invisible for the SMES users. The cooling down has been successfully carried out and the thermal system works as designed. After a brief description of the SMES design and construction, some tests will be presented. From a current of 244 A, the SMES delivered 425 kJ to a resistance with a maximum power of 175 kW.