The load on power lines and transformers is much higher during summer than in the winter. Transformer efficiency also goes down because of exposure to direct sunlight, which results in transformers failing or breaking down more often in the summers.
A simple fiberglass rectangular enclosure can save the transformer from direct sunlight or Wapda can come up with a better design. It may also chose to insulate transformer terminals and wires and use approved clamps to tie wires to high tension power lines, reducing erosion of high tension lines.
M Akram Niazi
Rawalpindi