1. Partial failure of lead wire

Detection method: The unbalance rate of the three-phase DC resistance greatly exceeds 4% or a certain phase is not connected at all.

Treatment method: The core should be suspended for inspection to determine the fault location, and the poor contact can be re-grinded and pressed. Re-welding for poor welding. Insufficient butt welding surface should be enlarged. Insufficient lead cross section should be replaced (increased) to meet the demand.

Two, tap changer failure

Detection method: Measure the DC resistance of different taps. If it is completely blocked, it means that the switch is burned; if the direct resistance of a tap is unbalanced, it means that the contacts are individually burned; if the scorching smell is heavy, it means overheating or arcing.

Treatment method: The core should be suspended for inspection. If the switch contacts only have overheating, poor contact or slight arc traces, they can be removed for maintenance and reused. If the burn is severe or the contacts are discharged to the ground, replace the switch with a new one. When the contact is discharged to the ground, it may generally cause deformation of the turns of the voltage regulating section of the high-voltage coil. In serious cases, the coil should be repaired or re-wound (replaced) the coil.

Three, coil failure

Detection method: In general, coil failures often result in fuel injection from the oil conservator, swelling of the tank, and burnt oil. Insulation resistance and DC resistance can be measured, insulation resistance is "zero", and DC resistance increases and is not stable.

Handling method: Check the hanging core to determine the fault condition. If the damage is minor, it can be repaired and used. If the fault is serious, consider replacing the coil. Technical transformation should be carried out for the lack of tight seal of the oil conservator.

Fourth, insulation decline

Detection method: Regular insulation resistance and oil test of the transformer. If the measured value changes greatly or is lower than the requirements of the "Regulations", it can be determined that the transformer is damp or the oil insulation resistance has decreased.

Treatment method: the transformer insulation resistance should be thoroughly dried when the insulation resistance drops, and the oil can be changed or filtered. The transformer should be repaired if the transformer is not tightly sealed and the moisture absorber failure.

Five, iron core failure

Detection method: Measure the insulation resistance of the core screw, if it is less than 10 megohms, it should be overhauled.

Treatment method: After lifting the core, pull out the damaged core screw and replace the insulation.