Saturated Core Fault Current Limiters in a Live Grid

With two recent successful installations in a U.K. live grid, the saturated core fault current limiter (SCFCL) has become one of the leading candidates for commercial fault current limiting devices. In this work, we review the concept developed at Bar-Ilan University, which was later adapted by GridON, for a novel compact SCFCL. This SCFCL utilizes a superposition of a closed dc magnetic circuit and an open ac magnetic circuit to overcome the intrinsic problem of transformer coupling found in traditional SCFCL designs. It also allows the use of a single magnetic core for a full ac current cycle limiting. In addition, the relatively short path for the dc magnetic circuit supports copper coils as an alternative to superconducting bias coils, allowing easier market penetration. The performances of the SFCL devices installed in live grids are described.