HERMETICAL TYPE DISTRIBUTION TRANSFORMERS
Hermetical type distribution transformers are produced as contactless to atmosphere by adjusting the pressure at factory environment. It can be designed to resist the effects of changing oil pressure as a result of heat by expansion and contraction of corrugated wall.
Since it has no expansion tank, oil process is conducted at special vacuuming rooms. With oil filling process that conducted under vacuum, the lifespan of transformer increases.
EXPANSION TANK TYPE DISTRIBUTION TRANSFORMERS
Between the power levels of 25 KVA and 2500 KVA and 36 KV high voltage level, oil expansion tank type distribution transformers are produced with 3 or 1 phase levels, oily, natural cooling systemic ( ONAN), idle-load tap changer or under-load automatic tap changer.
Expansion tank type transformers are identical with hermetical type transformers in terms of their core and coil structure.
The dimensions of expansion tanks are designed by calculating the expansion levels, of heated oil. Since the expansion tank type transformers are open to atmosphere, air intake provided by the slicagel which is ate the tank of the transformer.
This slicagel and the oil should be changed periodically because slicagel lost its feature as a result of air exchange.