Treatment of local fault of transformer core

The common local faults of transformer core and their repair process are as follows:

(1) When the insulation between the upper iron yoke sheets is aged and the other parts of the iron core are normal, you only need to remove the upper iron yoke sheets to remove the paint film and paint them, and the other parts do not need to be moved.

(2) The insulation tube of the through-core bolt of the old transformer is broken, and the local iron sheet is short-circuited, causing a short circuit between the local iron core sheets. When repairing, the upper iron yoke should be removed, the winding of the faulty phase should be lifted out, and the through-core bolt with broken insulation tube should be removed.

If there are not many short-circuit sheets and the depth is not deep, a special scraper can be used to remove the burrs of adhesion, and then apply No. 1032 paint. Take this opportunity to remove all the through-core bolts on the core column, and then use the lathless tape to tie instead of the through-core bolts for tightening. But be careful not to make the lathless tape binding hoop too thick to prevent affecting the sleeve winding. Generally, the thickness of the lathless tape binding hoop of the distribution transformer is 1~2 mm. If necessary, several more hoops can be added to reduce the thickness of the binding hoop. If the short-circuited laminations are severely burned, the depth is deep, and they have been bonded together, remove the core column laminations, use a flat shovel to pick out the short-circuit, remove the burrs, smooth it out, remove the residual paint film, repaint it, and dry it.

(3) The ground fault causes the iron core to short-circuit. When dealing with it, use a thin flat shovel to pick apart the adhered laminations on the surface of the iron core, remove the burrs, and then paint it.

(4) The iron yoke clamps or other metal parts are loose, causing vibration, resulting in overheating and discoloration of the iron core, burnt paint film, etc. After inspection, if the fault is serious, the faulty sheet is removed for repair, and the intact part is left untouched. When assembling the damaged laminations, the repaired and intact laminations should be mixed and arranged alternately. After repair, iron loss and temperature rise tests should be performed.