Transformer Transportation Damage, A Case Presentation of a Low ...

Gaps Observed at the Top of the Windings.
Figure 17
The core dimensions were measured after the windings were removed and it was reported that there was no
detectable movement in the core limbs.
REPAIRS
The objective of the repairs from the perspective of the utility was to return the transformer to a new condition. The
following list notes the major repairs made to the transformer:
Replacement of top core yoke laminations that were damaged. There was damage due to shifting of the
yoke steel that caused buckling and permanent deformation of some laminations. A loose or shifted block
near the core came in contact with the steel and caused damage. Handling of the laminations also created
some damage, especially at the miter joints.
The main blocks between the clamping rings and the core clamping frames were twisted and several
showed separation at the glue lines between the pieces making up the blocks. Typically, high density
laminated wood material used in transformers has a shiny platen surface which prevents adhesives from
bonding properly to the surface. To help with adhesion, the blocks were separated and scuffed to remove
the shiny surfaces to allow proper bonding. Two (2) wooden dowel pins were added to each block through
all layers to prevent the pieces of the blocks from shifting and pivoting. The blocks were aligned properly
as they were reassembled between the frames and clamping rings.
The top coil blocks were realigned and glued in place. The blocks at the top of individual coils were placed
back on their radial spacer columns, aligned properly and glued in place.
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