The maintenance of current transformers is generally divided into three types. One is minor repairs. The minor repairs here include the need to open small covers and oil changes when necessary. Generally, they are repaired once a year. The current transformer includes the body to be overhauled. We need to clean and dry the process and need all minor repairs. Usually, it is necessary to carry out the repair of the section and repair it in 5-10 years. The last one is overhaul. This overhaul is a project that requires partial or complete replacement of the windings and includes all minor and medium repairs. The repair time is 15-20 years.
The personnel who need to be repaired need 4~6 people. The tools they need to bring are the common fitter tools and some special maintenance items. These people have to be very skilled in repairing and prevent the maintenance personnel from being dangerous when the maintenance is improper.
The overhaul of the windings is to check whether the windings are clean or not, and clean them with a brush and oil. Then check the insulation for damage, discoloration, deformation, breakdown or looseness. If you want to judge the insulation of the windings. Grades are usually classified into four levels of insulation aging.
1. The first level: the insulation elasticity is very good, the color is also fresh and uniform, which means that the insulation is very good.
2. The second level: the insulation is a bit hard but the hand will not deform when it is pressed on the top. It will not break or fall off. Only the color is lighter, so it can be used.
3. The third level: the insulation has become brittle and the color is also dim. The finger presses back the oil with a slight crack but the deformation is not too large, which will result in the insulation being unreliable and can be selectively replaced.
4. The fourth level: the insulation has been broken and the brittle finger will peel off when pressed, so that it can only be replaced to solve.