Fault current limiters - R&D status of two selected projects and emerging utility integration issues

Emerging technologies of nondisruptive fault current limiters (FCL) are of increasing interest to the electric power industry. In this work an update on two selected superconducting FCL projects is given. Successful testing of resistive type prototype three-phase devices at voltages up to 10 kV are reported. While such tests clearly indicate the technical feasibility of novel FCLs for medium voltage applications, several system integration issues are still not addressed properly. The paper discusses the need for standard FCL testing procedures and important impacts of FCL on existing and future power system protection systems. It is concluded that novel medium voltage FCLs may lead to substantial benefits on future all-electric navy ships from significant reductions in weight and size of equipment. Furthermore, it is proposed to study more thoroughly the impact of FCLs on protection systems by means of transient system simulations.