Abstract:Transformer no-load closing may cause large inrush current. This large current may cause the fail of transformer closing and the malfunction of generator vacuum circuit breaker (VCB). In order to improve the success rate of transformer closing, and thus to ensure the safe operation of offshore platform, it is essential to suppress inrush current. The cause of inrush current is introduced, and three common suppression methods including phase control, soft start and pre-magnetizing technology are described. The advantages and disadvantages of these methods, as well as their applications in offshore platforms, are compared briefly.