A study on required volume of superconducting element for flux flow resistance type fault current limiter

We have proposed a fault current limiter (FCL) suppressing an overcurrent only by a flux flow resistance of a high temperature superconductor (HTS). If the fault current is interrupted within an allowable time t/sub a/ after the fault occurs, the flux flow resistance type FCL can instantly recover to the superconducting state and pass a load current. In this paper, the volume V/sub r/ of the HTS in the FCL required to satisfy the specified limiting effect and t/sub a/ was investigated theoretically. The volume V/sub r/ depends on the critical current density and the flux flow resistivity of the HTS. As the flow resistivity and/or critical current density increase, V/sub r/ can be reduced to obtain a certain current limiting effect. When t/sub a/ is specified, V/sub r/ has a maximum value at a certain flux flow resistance. If both the limiting effect and t/sub a/ are given, the required volume is constant and independent of critical current density or flux flow resistance.