Development and Analysis of Bridge-Type Saturated-Core Fault Current Limiter

The saturated-core fault current limiter (SFCL) is an effective device for limiting fault current. This paper proposes and analyzes a novel bridge-type SFCL (BSFCL) that uses a permanent magnet (PM) to reduce dc bias while improving the stability of the PM. The bridge structure in the BSFCL consists of four coils and a fault-limiting reactor which is used to limit fault current. The ac and the dc share coils to help reduce energy loss. The iron core uses air-gap branches to offer paths for ac flux, which reduces eddy current in the PMs and enhances their stability. The operating principle and characteristics of the BSFCL were analyzed using the electromagnetic coupling method. To investigate the effects of parameters on the performance of the BSFCL, various finite-element analysis simulations were performed by Maxwell. Experimental results of a 220 V prototype verify the effectiveness of the BSFCL.