R & D Status of Fault Current Limiter

In order to realize bulk power transmission with high reliability and high efficiency, electric power companies have made efforts to connect several electric power systems together. In this case, fault current may exceed the rated current of such power devices as a circuit breaker and a power transformer in the case of contingency and they have to be replaced with the devices with the higher rated value. Fault current limiters (FCL) have been expected to be installed in an electric power system to suppress fault current and to prevent the replacement. This paper first reviews the necessity of FCL in electric power system, and R & D status of various types of FCL in the world. The review is focused on superconducting FCL made of AC superconducting wires. Second, the experimental evaluation of the new superconducting FCL which has been developed by Tokyo Electric Power Co. and Toshiba Corporation is described. The success of the current suppression up to 1, 800A is emphasized.