Cork-wood sealing was burned out because Eddy current and transformer oil came out. The original cork seals are degraded more rapidly where an oil leak means that they are exposed to oil, air and Eddy Current. At the same time, this has the effect of “burning” the cork causing accelerated failure.
Complete flange was sandblasted to a SSPC-SP5 white metal finish to remove all corrosion. All possible leakage area was sealed with 1-min epoxy. Devcon SF was put on the flange and bolts. Sabloons mounted around were filled with Flexane 80 L as a vibration proof outside layer.
The repair was effected to the cork seals on the transformers construction bolts where the originals had failed. It was possible to complete the repair from the outside without the requirement to open up the transformer. This meant a huge time and cost saving as the implications of opening up the transformer and exposing the oil to air and associated moisture contact with the hygroscopic oil are considerable.
It was also possible to make the repair in the field without the need for a costly uplift of the transformer back to a workshop.
Each stage of the process was a rapid cure so the overall repair could be effected within one day. This saves considerable downtime, as transformers can often be in remote locations and are essential to supply electricity to areas, especially important where they are stand alone and not a network of transformers on one site.