Transformer Services

With transformer it is a bit similar to humans: It's the inner values that count. This is why the new transformer services of SZM (SchaltanlagenZubehör Bad Muskau) for oil-cooled transformer is mainly dedicated to oil analysis and oil treatment. This is because the oil is contaminated (depending on how it is used) by water, decomposition products and foreign particles, thus changing its properties to the negative. Water in particular becomes a problem, because it accelerates the decomposition of the cellulose with which the windings are insulated. It also reduces the dielectric properties of oil as an insulating fluid. This increases the risk of voltage breakdowns, which can ultimately lead to greater damage such as explosions.

Incipient faults often unnoticed

Various types of stresses and moisture often age the transformer and subject them to incipient faults. The major causes of ageing and deterioration of insulation are thermal stresses, electrical stresses. The consequences are e.g. a lower efficiency or due to water or foreign matter accumulating in the transformer oil. In the worst case, damage such as explosions and collateral damage can occur.

Similar to blood sampling in humans, oil is sampled and sent to a certified laboratory for analysis. The result provides detailed conclusions about the condition of the transformer. While humans can say that something hurts and where, this is the only way to reliably detect incipient transformer faults and preventive maintenance can be performed and help to prevent further damage. Incidentally, the oil is extracted by means of an EGS extraction system, so as not to distort the result by ambient air, and during ongoing operation.

SZM’s procedure is gentler and more sustainable

If the transformer oil is heavily contaminated, it is reprocessed similar to dialysis in humans: The insulating oil of the transformer is processed physically/mechanically or is additionally cleaned chemically (by adsorption) within the scope of an oil regeneration. The special feature of the SZM method is that it removes water and other substances from the oil more sustainably - without interruption, i.e. during operation. With the SZM method, the solid insulation is also dried gently and sustainably over a period of two to three weeks during ongoing operation.

The new transformer service from SZM is of interest to all energy producers, such as power stations and operators of biogas plants, wind turbines (windmills) and photovoltaic parks, but also to all larger energy consumers where the high voltage (110 kV, 220 KV, 380 kV) is transformed into medium voltage (up to 36 kV) or low voltage. In particular, industrial companies requiring energy, such as cement works and plants in the building materials industry, also benefit from the SZM transformer service.

Do you have any questions? Contact us!

Dipl.-Ing. Frank Banduch
Leiter Transformatorentechnik
Telefon: +49 40 72923-151
Telefax: +49 35771 58-333
Mobiltelefon: +49 172 4374304
E-Mail: frank.banduch(at)

Jens Redenz
Projektleiter Transformatorentechnik
Telefon: +49 40 72923-151
Telefax: +49 35771 58-333
Mobiltelefon: +49 172 4374305
E-Mail: jens.redenz(at)