Transformers

transformers

Weather influences as well as constant load changes of transformers cause temperature fluctuations and thus a pressure equalization with the environment.
The moist ambient air drawn in during cooling leads to hydrolysis of the cellulose paper in the transformer and thus to a reduction in its degree of polymerization. GIEBEL dehumidifiers protect the transformer by effectively drying and filtering the humid supply air.
To prevent damage caused by condensation water, the use of a dehumidifier is an indispensable measure. The incoming air is dried and thus 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 make use of the regenerative capacity of the desiccant used.

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FORMATION OF WATER IN THE Transformer

Transformator WITHOUT Adsorber

-> Use without dehumidifier
Ambient air enriched with moisture
Transformer cools down
Oil level drops
Pressure equalization by incoming air

-> Inflowing air humidity according to ambient air!
Transformer heats up
Oil level is rising
Pressure equalization by outflowing moist air
Cooling of the ambient air below dew point
-> Emergence condensation in the interior
-> Drops form and water flows into the insulating oil

FUNCTIONAL TRANSFORMATOR - HUMIDITY AND DEW POINT

Air intake from the environment

Passive air exchange
due to temperature fluctuations
Absolute Humidity
Content of water vapor
Relative Humidity
Percentage to maximum humidity

Content of water
at 25°C and 90% rF -> 20.7 g/m³
at 20°C and 80% rF -> 13.8 g/m³
at 15°C and 60% rF -> 7.7 g/m³

DAMAGE CAUSED BY WATER

Consequences:

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

AVOIDANCE OF WATER IN THE TRANSFORMER

Transformator WITH Adsorber

-> Use of an adsorber with desiccant
Ambient air enriched with moisture
Transformer cools down
Oil level drops
Pressure equalization by incoming air
Moisture is separated

-> -> Incoming air humidity against 0% rF!
Transformer heats up
Oil level is rising
Pressure equalization by outgoing dry air
Cooling of the ambient air below dew point
-> No condensation inside
-> No drops of water
-> No water in the insulating oil

Adsorber lowers the air humidity to below 2%RH
and the dew point to below -40°C
Humidity after Adsorber
average 10% rH
Content of water: 1,7 g/m³
Dew point: -12,5°C

References

SELECTION OF A STANDARD ADSORBER

Adsorber VV-RV

Usage
Drying Incoming Air

Materials
Polycarbonate, polyamide
FKM Silica gel Orange

Substance
Hydraulic oil, Gear oil,
Biological oil, Vegetable oil,
Transformer oil, Insulating oil,
AdBlue (urea), Diesel fuel,
Isocyanates, Polyols, Anhydrite

Valves
Yes

Rechargeable
Yes

Usage according ATEX 2014
No

Offhore suitable
No

Amount Adsorbents
Silica gel
0,1 – 4,6 kg

Adsorber TB-RV

Usage
Drying Incoming Air

Materials
Polycarbonate, polyamide
FKM Silica gel Orange

Substance
Transfomer oil

Valves
Yes

Rechargeable
Yes

Usage according ATEX 2014
No

Offhore suitable
No

Amount Adsorbents
1,0 – 4,8 kg

Adsorber TM-RV

Usage
Drying Incoming Air

Materials
Stainless steel A4, FKM
Silica gel Orange

Substance
Transformer oil

Valves
Yes

Rechargeable
Yes

Usage according ATEX 2014
Yes

Offshore suitable
Ja

Amount Adsorbents
Silica gel
1,1 – 5,0 kg

DETERMINATION OF SIZE


		DIN 42562	DIN 42567A	DIN 42567B	DIN 42567C G 1“ / G ¾“ / G ½“	DIN 42562	DIN 42567C G 1“
Adsorber	VV-RV	TB-RV				TM-RV
Usage	upright	hanging
Materials	Polycarbonate, polyamide, FKM Silica gel Orange	Aluminium, Polycarbonate, polyamide, FKM Silica gel Orange				Stainless steel A4, FKM Silica gel Orange
Usage according ATEX 2014	No	No				Yes
Use Indoor / below deck	Yes	Yes				Yes
Use outdoor / on land	Yes	Yes				Yes
Use on deck / offshore	No	No				Yes
Power/ oil volume
0 – 5 MVA up to approx. 2.500l oil	VV-RV 3M	TB-RV 3M	TB-RV 3M	TB-RV 3M	TB-RV 3M	TM-RV 3M	TM-RV 3M
5 – 10 MVA up to approx. 5.000l oil	VV-RV 3L	TB-RV 3L	TB-RV 3L	TB-RV 3L	TB-RV 3L	TM-RV 3L	TM-RV 3L
10 – 30 MVA up to approx. 15.000l oil		TB-RV 5M	TB-RV 5M	TB-RV 5M	TB-RV 5M	TB-RV 5M
30 – 60 MVA up to approx. 30.000l oil		TB-RV 5L			TB-RV 5L	TM-RV 5L
60 – 100 MVA up to approx. 50.000l oil		TB-RV 5XL				TM-RV 5XL