In order to study the distribution and diffusion law of moisture in the current transformer（TA） during the damp process on the basis of measurable characteristics

this paper proposes a dynamic deduction method of moisture content in the TA during the damp process. Firstly

a three-dimensional simulation model of electric-thermal-fluid multi-physics coupling for 220 kV inverted oil-immersed current transformer（IOCT） is established. By using the finite element analysis and multi-physics coupling analysis

the temperature field and the distribution law of moisture content in the IOCT during the damp process are obtained. Then

by analyzing the influence of ambient temperature on the moisture diffusion

the correlation between the moisture content in the oil-paper insulation inside the IOCT and the moisture content of the insulating oil at the oil intake valve is established. On this basis

the dynamic deduction model of internal insulation moisture content of IOCT based on regression decision tree algorithm is established. Finally

the experimental platform of LVB-220 W3 IOCT is built to verify the validity of the simulation and dynamic deduction model. The results show that the maximum deviation between the calculation results of the dynamic deduction model and the experimental results is 2.51%

which can provide a new idea for the operation

maintenance and detection of oil-paper insulation equipment.