10kV Oil-immersed Distribution Transformer
Technical Features of 10kV Oil-immersed Distribution Transformer
Production technical features: “Three Lows”, “One High”, “One No”
Full sealing, maintenance free, low loss, low noise, low temperature rise, high resistance to short-circuit capacity, no leakage, safe and reliable operation.
I. “Three Lows”: Low Loss, Low Noise, and Low Temperature Rise
1. Low Loss:
The transformers select fine high permeability magnetic silicon steel and the iron core adopts internationally advanced step-lap banding structure, making the electric field distribution among iron core seams more even. Compared with full-angle of 45 ° seams as commonly used, the no-load loss has been reduced 5-10%.
2. Low Noise: For the transformer has adopted the step lap core structure, the magnetic circuit enjoys a small resistance, so that noises resulting from the contraction of core hysteresis have a marked reduction. The noise level of transformers is 5dB lower than the GB Average.
3. Low Temperature Rise: In order to improve the operation reliability and extend service life of the products, the following measures have been adopted by us in temperature rise design:
a. Increasing secondary oil path for the winding;
b. Using cylindrical coil to lower flux leakage of the winding end;
c. Increasing the cooling area.
By taking the above measures, the temperature rise of the transformers produced in our company is 5K lower than the international standard in average, namely:
Winding Temperature rise — 60K
Top end oil temperature rise — 50K
Oil tank and the structural parts surface — 75K
II. “One High”: High Resistance to Short-circuit Capacity
To improve safety and reliability of transformer operation, our company, in the manufacturing process of the bidding device, will explore the following new technology initiatives:
a. Tubular structure with high and LV winding, making the coil end transit smoothly and the axial mechanical strength of the winding enhanced by using the whole plate compression;
b. High and LV winding uses circled winding under high and low pressure of the domestic leading level which is indentified with winding dense and non-cover space, so as to improve the short-circuit resistance capacity; double-sided mesh papers are used for layer insulation which has improved the insulation strength. After vacuum treatment, rubber on mesh becomes curing and bonding between the layers. The Insulators are manufactured by use of laminated wood, increased compression strength. The inner layers of LV winding adopt 5mm formed insulating paper tube.
III. “One No”: No Leakage for Tank
The transformer tanks use barrel hanging core free structure, selecting cold-rolled sheet formed corrugated tanks or installing plate radiators, which have increased heat dissipation area, and improved thermal coefficient of low temperature rise. Welding tank uses carbon dioxide gas protecting welding, and adopts fluorescence lysimeter method to test seams in welding process; tanks as shaped shall accept 25kp, 12-hour water pressure leakage testing and 20kp, 12-hour oil pressure leakage testing. Finally, the overall surface of the tanks will go through thermal spray processing, which will not only ensures the tanks in no leakage and also fine appearance, corrosion resistance and anti-aging ability.