What are the common problems of oil immersed transformer cores?

The iron core of the oil-immersed transformer mainly plays the role of magnetic conductivity. Magnetoelectric conversion can only take place after the permeance. The iron core of the oil-immersed transformer plays the role of guiding the magnetism and bone. Due to the changing electromagnetic field of the magnetically permeable element of the oil-immersed transformer, the magnetic susceptibility and magnetic induction of the iron core are also changing. If there is an iron core, it can better achieve mutual induction bonding at one time.

When the oil-immersed transformer is in normal operation, due to the normal operation of the oil-immersed transformer, there is an AC magnetic field around the winding wire, which cannot be grounded at multiple points. Affected by electromagnetic induction, there is parasitic capacity between the high-voltage coiled wire and the low-voltage coiled wire, the low-voltage coiled wire and the iron core, and the iron core and the shell. Due to the combined effect of the parasitic capacitance, the charged coil pair generates a floating potential. Since the distance between the iron core and other metal parts is not equal to the coiled wire, there is a potential difference between the parts. A spark discharge occurs when the potential difference between two points reaches a point that can destroy the insulation between them. Discharge is interrupted. In the long term, the oil and solid insulation of oil-immersed transformers are adversely affected. In order to eliminate this phenomenon, the iron core does connect with the beginner, which is equal to the potential of the beginner. However, when a core or other metal part is grounded at two or more points, the grounded locations form a closed circuit, causing circulation and drainage. Local overheating brings oil breakdown and a reduction in insulating properties. In serious cases, the silicon steel plate of the iron core is broken, which mainly leads to major accidents. The main thing is to change the grounding point of the iron core.

The main grounding faults of oil-immersed transformer cores are short-circuits caused by construction procedures and poor design of grounding plates, multi-point grounding of accessories and external reasons, burrs caused by metal foreign objects, and poor core engineering in the transformer. There is rust, welding slag, etc.