Application: The oil immersed current transformer is an outdoor single-phase oil immersed fully sealed structure, which is widely used in transmission lines with a frequency of 50Hz and a rated voltage of 110kV ~ 220kV. The oil immersed current transformer is a device for measuring by converting a large current at the primary side into a small current at the secondary side according to the principle of electromagnetic induction. It is connected in series in the line and provides current signal for electrical measuring instruments, instruments and protection and control device.