Oil distribution transformers

More than 70 years of know-how and experience is reflected in the oil distribution transformers made by SGB-SMIT Group. Our production (in Germany and Malaysia) is based on high-quality production materials, and we place the highest emphasis on first-class workmanship. The result: oil distribution transformers of maximum reliability!

Products and Services

For our durable oil distribution transformers we use only high-grade production materials and attach very great importance to sound workmanship, because the higher the material processing quality, the lower the running costs. These principles are incorporated into the following products:

  • Oil distribution transformers from 50 to 3,150 kVA
  • Large oil distribution transformers up to 20 MVA
  • Pole mounted transformers
  • Transformers for heating of track-switches or for pre-heating of trains
  • Neutral grounding transformers
  • Earthing transformers
  • Arc suppression coils
  • Transformers for special rectifier operation

We would above all like to point out that the use of special cooling/insulation material (e.g. Midel) is possible to enable operations at sites with special requirements regarding environment and fire protection. As a proven expert we furthermore offer a complex Transformer Logistics Package from a single source. 

Components and systems for neutral-point conncetion

Medium-voltage systems in Europe are largely operated as resonant-earthed systems. SBG offers a complete range of products for the necessary neutral-point connection:

  • Arc suppression coils
  • Fixed coils as well as coils variable under load. The variable coils can be operated with the fitted electronic regulators and have an automatic mode.
  • Neutral electromagnetic couplers
  • Earthing transformers
  • Earth fault combinations consisting of neutral electromagnetic couplers and arc suppression coils.

In special cases the use of oil-immersed equipment is restricted due to environmental protection considerations. In these cases we use special synthetic or organic esters (e.g. Midel 7131).

Product Selection

Technical Information

Details

Iron Core

Cold-rolled grain-oriented sheets in "Step-lap" lamination reduce no-load losses and no-load currents as well as noise emission.

Low Voltage Foil Winding

  • axial current distribution adjusts freely
  • reduces shearing forces

 After winding, the Prepreg is stuck over the conductor sheet to form a compact tube by a tempering process.

High Voltage Winding

  • fully and semi-automatic winding machines
  • enamel-insulated winding wire with steady winding pull on carrier cylinder, or directly on the LV winding
  • layer insulation of high-quality cable paper
  • covering bandage made of shrinking foil for compact winding with good short-circuit response and optimum impulse voltage distribution

Assembly of active parts and vacuum drying

  • short-circuit proof assembly with profile steel and
  • support of coils
  • secure fixation of the electrical connections

The active part is securely joined to the cover and supported against the bottom of the tank.

  • low frequency or solvent vapour drying
  • filling of dried and degassed mineral oil

Tank

  • corrugated tank up to 10 MVA manufactured in-house
  • modern folding facility processes the steel sheet into high-quality corrugated walls
  • after the tank has been robot-welded, it is checked for leakage with control liquid and ultraviolet light.

Cover

The cover is made of doubling-free high-quality steel. It is bolted to the tank, and can also be welded to the tank on request. Besides bushings and lifting lugs the required control and monitoring devices are located on the cover.

Corrosion protection

  • Coating of tank and cover based on hydro-coating material by flooding or dipping method. (Standard RAL 7033)
  • On request the tank can also be manufactured in a hot-dip galvanised design.

Quality Test

Routine tests acc to din dve 0532

  • test with applied voltage (winding test)
  • test with induced voltage (turn test)
  • measurement of winding resistance
  • measurement of voltage ratio and determination of vector group
  • measurement of short-circuit voltage and of short-circuit losses
  • measurement of no-load current and of no-load losses

type and special tests acc to din vde 0532

  • temperature rise test
  • impulse voltage test
  • measurement of sound/noise level
  • partial discharge measurement

short-circuit strength

This test is performed within the scope of type tests, however, it can also be carried out in well-known and reputable test laboratories on request. After long-standing testing practice as well as positive experience on the part of our clients, the use of a cylinder block stuck to LV windings in combination with the HV layer windings has proved to be problem-free.
 
Reducing the noise emitted by the transformer in the environment is becoming more and more important. Therefore our oil distribution transformers also offer – besides the standard design acc. to DIN 42500 – reduced losses and noise levels too. In addition to the choice of flux density and core material, the step-lap technique of joining the legs and yoke also reduces noise levels and no-load losses in SGB transformers.

Downloads

References

Power Generation

Liquid filled Transformers within special Low-Loss-Design for renewable applications increase the efficiency of plants.

Solar power stations
Oil and Gas Power plants

Power Distribution

Reliability of Distribution Transformers for all kinds of Power Distribution purposes support the productivity of our customers. Therefore, our Distribution Transformers comply with the highest standards in design and manufacuring.

Low Voltage distribution

Industry

Reliability of Distribution Transformers for all kinds of Industrial purposes support the productivity of our customers. Therefore, our Distribution Transformers comply with the highest standards in design and manufacuring and meets special customer requirements.

Chemical
Oil and Gas
Steel
Automotive
Glas
Pulp and Paper

Railways

Reliability of Distribution Transformers for all kinds of Power Distribution purposes support the productivity of our customers. Therefore, our Distribution Transformers comply with the highest standards in design and manufacuring.

Mass Transit Systems
Main Line Systems
Underground

Infrastructure

Reliability of Distribution Transformers for all kinds of Power Distribution purposes support the productivity of our customers. Therefore, our Distribution Transformers comply with the highest standards in design and manufacuring.

Clinics
High Rise Facilities
Colleges and Universities
Hotel facilities
Datacentres
Banks
Shopping centres

Contact person