Evaluation of a Superconducting Fault Current Limiter Model for Electric Power System

Abstract

Fault current limiters (FCLs) are devices for to suppress current in electric power system. The FCL is extensively expected to suppress fault current, particularly required for trunk power systems heavily connected high-voltage transmission lines, such as 500 kV class power system. For this reason, FCLs based on various principles of operation have been developed. Most of the FCLs under development which employ superconductors are based on the quenching phenomenon peculiar to the superconducting state, that is, making use of a rapid transition to normal conducting state, an electrical resistance appears, and this resistance is used to suppress fault currents. However, this elevation of resistance, although increasing the fault current suppression effect, also tend to raise the overvoltage occurring FCL, the ascertainment of the overvoltage is important as regards the protection of the FCL as well as other power system devices.Hence the waveform created in the FCL was simulated in detail by the time varying resistance model which constitutes one of the analytical functions of EMTP, thereby analyzing the overvoltage and power system stability when the superconducting FCL is introduced into an actual power system.