Design of the shunt resistor for a DC Resistive SFCL

A DC-operating resistive-type superconducting fault current limiter for AC applications (in short a “DC Resistive SFCL”) is based on the synergistic use of the resistive and the rectifier fault current limiter concepts, and allows the superconductor to operate in nearly DC current conditions. This regime of operation drastically reduces AC losses thus opening completely new perspectives with regard to materials, architecture of the cable, lay out of windings and cryogenics. In this paper, some configuration of the superconducting coil able to produce the required inductive and resistive effect in the central branch of the rectifier bridge are investigated. Appropriate connections of external shunt resistor in order to reduce the Joule heating during the limiting phase without the need of one additional current leader are considered. Numerical simulation with reference to application of the proposed SFCL to 20 kV distribution system are carried out by means EMTP software.