  Inrush current problems of the industrial transformers are occasionally more
serious than the utility transformers. A new Solid-State Inrush Current Limiter
(SSICL) is proposed for medium voltage power transformers. The SSICL consists
of three similar sets. Each set includes a bidirectional semiconductor switch
and an inrush current limiter resistor. Using a control strategy based on
Kalman filtering, transformer inrush current is suppressed during magnetization
process. In fact, built up profile of the inrush current is dictated in
accordance with the estimated current by a slow dynamic Kalman filter. A
single-phase prototype SSICL is developed and tested. The proposed control
scheme is simulated in MATLAB-SIMULINK. By using Real Time (RT) toolbox of the
MATLAB software and a PCI_1711U, interrelationship between the SSICL and its
controlling system is realized. Some experiments are carried out to evaluate
the performance of the SSICL. The results show that the proposed SSICL can
considerably suppress inrush current of the transformer
