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Hermetically Sealed

Hermetically Sealed

Hermetically Sealed Distribution Transformers

These type of transformers have a system of oil preservation, that prevent exposing the insulating oil to oxygen or humidity. This improves the operating condition of the oil so that no maintenance is required during the life time of transformer. Hermetically sealed transformers are recommended for being used in high humid environment, limitation of maintenance service, pole-mounted transformers, and confined space conditions such as package or compact substation units. Three phase oil immersed Hermetically Sealed distribution transformers are the main part of productions that are designed and manufactured in Iran Transfo Corporation (ITC) and the scope of work is 25-5000 KVA up to maximum system voltage of 36 KV.

Mainly two kind of the transformers are produced:

1. Hermetically sealed without gas cushion

Closed construction type without conservator, without gas cushion, fully oil filled, and with elastic corrugation tank.



2. Hermetically sealed with gas cushion

Closed construction type without conservator, with gas cushion (nitrogen gas), rigid flat plate tank and with removable or welded on radiators.



In the fully oil filled hermetically sealed transformers, oil expansion is taken up by the flexible corrugated steel tank (variable volume tank design), where by the maximum operating pressure remains at only a fraction of the usual. The transformers are always shipped completely filled with oil and sealed for their lifetime. Bushings can be exchanged from the outside without draining the oil below the top of the active part. In case of hermetically sealed transformers with gas cushion oil expansion taken up by the nitrogen cushion above the oil level. Generally these transformers made up rigid tank with cooling radiators (removable or welded on), and the HV, LV bushings are fitted to the long side of the tank.In case of hermetically sealed transformer (Without gas cushion) the tank cover is equipped with a filling pipe which is high enough to ensure a safe oil filling level in the insulating elements at all times for DIN type bushings.

 Special accessories:

Oil level indicator

Hermetic protection relay

 Pressure relief device

 pressure and vacuum gauge

 Sudden pressure relay

 Gas filling valve

 DGPT2 and DMCR multi-function relays