S11 Series
Oil-Immersed Power Transformer

S11 series oil-immersed transformer is applicable to the 3-phase, 50Hz distribution network system. ...

Oil-Immersed Power Transformer

S11 seriesoil-immersed transformer is applicable to the 3-phase, 50Hz distributionnetwork system. It is used for primary power input and second power output ofpower grid. This s11 series transformers accord with domestic and foreignstandards such as IEC60076, GB/T6451 and GB1094.


1. The iron core of the transformers ismanufactured from a high grade, low loss, cold rolled grain oriented siliconsteel sheet. The step-lap joint structure of the iron core can be either 3steps or 5 steps. Two advanced cutting lines are used to realize automaticproduction of this lamination. Compared with normal structure, the loss of ouriron core is reduced by 7~10%, the no-load current is reduced more than 30%. 

2. The coil is made of oxygen-free copperelectromagnetic wire. As a result, the usable range of layer winding isextended and the axial oil duct is added. It has following features:

  1. High volume ratio
  2. Simple winding technologygood manufacturability
  3. It has high longitudinal capacitance, improving the lightning impulse voltage distribution. High anti-thunder performance.
  4. High cooling efficiency due to axial oil duct.
  5. Good balance of ampere-turn, small axial mechanical force.
  6. Plate heat exchanger is used for oil tank to realize excellent cooling performance. It also reduces the volume of the transformer to have a good looking. 
3. All products will be inspected through the 3 levelsinspection system: self-inspection by technician, inspection by workshop andspecial inspection.

4. Insulating parts are fabricated using compactingtechnology to realize a minimum shrinkage.

5. The advanced drying system is based onthe phase-change theory of kerosene to quickly squeeze the water out frominsulating parts and fully dry the whole components. The warm-up and vacuumizingof the system can be done automatically by the microcomputer.  The vacuum level can reach 6 Pa. The systemalso has the functions like fault self-detection and remote diagnosis.

Item Unit Data Data Data 
Rated voltage kV 10/0.4 35/0.4 13058
Tapping range/±2x2.5%±2x2.5%±3x2.5%
Rated power kVA50~2500 630~3150 2000~40000 
Short-circuit impedance(%) %4/4.5 6.5/7 6.5~8 
Connection symbol Dyn11,Yyn0 Dyn11,Yyn0 Dyn11,YNd11 
Rated frequency Hz 505050
Heat resistance grade 
Insulation level kV LI85 AC35 LI220 AC85 LI220 AC85/LI85 AC35 

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