Due to Improper / Poor Maintenance
In case of transformer following faults may develop due to improper or poor maintenance :
- Loose core bolts and clamps results into more vibrations of stampings and more noise.
- Improper supports and clamps for windings result in collapse of winding during external short circuit fault.
- Bad solding results into more heating at joints and carbonising of oil in contact with it.
- Oil leakage will reduce oil in tank resulting in over heating of transformer oil and windings.
- Dirt and dust deposited on the insulators (bushings) will provide low resistance to leakage current into flash over and damaging the insulator.
- If slug is formed in transformer oil it blocks free circulation of oil and results into over heating.
- Cracks or broken bushing may result into failure of transformer.
- Loose connections in conducting parts result in over heating.