Experimental Identification of the Inrush Safety Regions in Single-Phase Power Transformers

This paper investigates the inrush current phenomenon in single-phase power transformers. A suitable experimental setup is designed to identify the locus of the point in the Br-θ0 plane, called the Inrush Safety Region (ISR), where the inrush current phenomenon does not occur. In particular, it is verified that, for a fixed value of Br, an Inrush Safety Angle Range exists in which the transient current value is comparable with its value in the steady state. This means that, in order to avoid the occurrence of the inrush current phenomenon, it is necessary that the operating point belongs to the ISR. From the above experimental results, it is expected that new inrush current control methods will be developed.