DC Short-Circuit Tests of a 50 kV Resistive Superconducting Fault Current Limiter

Abstract

Resistive Superconducting Fault Current Limiters (RSFCL) are a promising solution for the protection of medium and high voltage DC and AC power links, including Multi-Terminals Direct Current grids (MTDC grids). In the event of a fault, the rapid increase in the RSFCL’s electrical resistance reduces the amplitude of the fault currents, thereby decreasing electrical constraints on the existing elements of the line and/or grid. As the device reacts directly to the fault current, no fast fault detection is required, and the increase of the device’s resistance begins within a few tens of microseconds. Consequently, the fault can be cleared without the need for high-performance fast clearing circuit breakers. Based on the protection requirements of future HVDC and MTDC architecture, SuperGrid Institute has developed and tested a small scale 50 kVDC RSFCL prototype operating in subcooled condition. The device consists of ten superconducting coils connected in series, each wound in a bifilar pancake structure to obtain negligible inductance. Power tests up to 50 kVDC were performed on our RSFCL at the High-Power Source (HPS) facilities. The RSFCL was mounted inside a vertical cryostat in a dead-tank configuration. The superconducting coils were immersed in a pumped subcooled liquid nitrogen bath at approximately 68 K. This article reports on our RSFCL prototype power tests, where the RSFCL’s voltage was raised up to 46.5 kVDC with 1.8 MJ injected. With a prospective current of 43.6 kA, the RSFCL managed to limit the current to 5.3 kA.

D. Brasiliano – SuperGrid Institute ; C. Creusot – SuperGrid Institute ; N. Deveaux – SuperGrid Institute

Published in IEEE Trans.Appl.Supercond. – IEEE Transactions on Applied Superconductivity 

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