A Saturated Amorphous Alloy Core-based Inrush Current Limiter

In this paper, a new saturated amorphous alloy core-based inrush current limiter (ICL) has been designed and built to limit the inrush current of a power transformer. A toroidal core with a middle limb is developed using the Metglas amorphous alloy and the middle limb is excited with a dc-current to saturate the core. Under normal condition, this developed ICL imposes low impedance and has a negligible effect on the operation of the system. During switching on to energize a power transformer connected in series with the ICL, the large inrush current desaturates the ICL core, increasing the ac winding impedance which limits the peak amplitude of the transformer inrush current. To validate the proposed saturated amorphous alloy core-based ICL, a prototype ICL has been built and tested in the laboratory and the core power loss, core saturation, and inrush current, are compared with those from sheet steel core-based ICL, and the performance of the proposed saturated amorphous alloy core-based ICL is found to be significantly better. It is expected that the proposed saturated amorphous alloy core can be used in future as an inrush current limiter that can help to improve the performance of the power transmission and distribution system.