Transformer inrush current is harmful to the transformer's windings and may bring about inadvertent tripping of the protective relays. In order to reduce the magnitude of inrush current, a bidirectional impedance-type inrush current limiter (BIT-ICL) is proposed in this paper. When a power transformer is energized, the BIT-ICL immediately and automatically inserts into the circuit to suppress the inrush current without any control or detection circuit. After completing transformer inrush suppression, the BIT-ICL is bypassed automatically, and the transformer appears to connect directly to the voltage source. Thus, when the transformer is loaded, there is almost no distortion in the steady-state load voltage and current waveforms due to the voltage-compensation effect in the limiter. The feasibility and performance of the proposed BIT-ICL are verified by a low-voltage single-phase power transformer under different residual flux and load conditions. Moreover, as long as the power loss that results from the related components in the BIT-ICL can be greatly reduced, this limiter can be applied to high-voltage and large-capacity distribution transformers.
All Science Journal Classification (ASJC) codes
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering