The oil-immersed inverted current transformer possesses many advantages compared to the traditional upright current transformer and has a large-scale application in the 500kV power system. But acci-dents have occurred in the actual operation and a large proportion of them are insulation accidents. Startingfrom the three key parts of the insulation design of the inverted current transformer

this paper analyzes theinsulation structure of the inverted current transformer and gives three examples of the correspondingfaults. The reason of the problems in the use of inverted current transformer is analyzed and suggestionfrom the point of product optimization design

process control and equipment operation and maintenance isgiven.