Transformers.

Weather influences and constant load changes of transformers cause temperature fluctuations and thus pressure equalization with the environment.
The humid ambient air sucked in during cooling leads to hydrolysis of the cellulose paper in the transformer and thus to a reduction of its degree of polymerization. GIEBEL dehumidifiers protect the transformer by effectively drying and filtering the humid supply air.

In order to prevent damage caused by condensation, the use of a dehumidifier is an indispensable measure. The incoming air is dried and a strong reduction of the water content and the dew point is achieved. In addition to a mechanical valve system and an air filter element, these silica gel dryers take advantage of the regenerative capacity of the desiccant used.

Damage caused by water

  • Defective seals – Loss of oil due to leaks
  • Winding damage
  • Mechanical damage to the boiler/chassis
  • Rusty / silted active part
  • Aged, contaminated insulating oil

How adsorbers work on transformers

The following graphics show in 4 steps, what happens inside a transformer without and with an adsorber when the ambient air is enricht with moisture. Just move the handle over the pictures to see the differences.

Left: Transformer without an adsorber. Ambient air enriched with moisture.
Right: Transformer useing an adsorber with desiccant. Ambient air enriched with moisture.

Left: Transformer cools down, the oil level drops and pressure is compensated by incoming moist air.
Right: Transformer cools down, the oil level drops and pressure is compensated by incoming air. The adsorber seperates moisture up to 2% rH (10% rH on average).

Left: Transformer heats up, the oil level is rising and pressure is equalized by outflowing moist air.
Right: Transformer heats up, the oil level is rising and pressure is equalized by outgoing dry air.

Left: When the ambient air cooles down below drew point, it emerges condensation in the interior. Droplets form and water flows into the insulating oil.
Right: When the ambient air cooles down below drew point, ther is no condensation in the interior. No droplets form and no water flows into the insulating oil.

Humidity and dew point

Absolute Humidity
Content of water vapor
Relative Humidity
Percentage to maximum humidity

Example
Temperature = 20°C
Air humidity = 80% rF

Water 13.8g/m³
Dew point 16,4°C

Permissible temperature range = 3,6°C

Humidity after adsorber installation
Average 10% rH
Content of water: 1,7 g/m³
Dew point: -12,5°C

Find the right size

Adsorber for drying the supply air

Please click on the power / oil volume below

Videos

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Downloads

Presentation Transformers (English)
Presentation Transformers (German)

References – Our Adsorbers in action

Transformer boiler / tap changer

Oil: insulation oil
Power: 20 MVA
Oil volume: 10 tons

Adsorbers: TB-RV 5M (for transformer vessel) & TB-RV 3M (for tap changer)

Rectifier

Oil: insulation oil
Power: 40 MVA
Oil volume: 20 tons

Adsorber: TB-RV 5L

Oil transformer

Oil: insulation oil
Power: 10 MVA
Oil volume: 5 tons

Adsorber: VV-RV 3L

Oil transformer offshore

Oil: insulation oil
Power: 30 MVA
Oil volume: 15 tons

Adsorber: VM-RV 5M

Power transformer

Oil: insulation oil
Power: 20 MVA
Oil volume: 10 tons

Adsorber: TB-RV 5M

Converter transformers

Oil: insulation oil
Power: 60 MVA
Oil volume: 30 tons

Adsorber: TB-RV 5L (for transformer vessel) & TB-RV 3M (for tap changer)