Our three-phase oil-immersed distribution transformer adopts new type insulation structure for its body that further improves its short-circuit resistant capacity; its iron core is made of high quality cold-rolled steel sheet; all HV windings are made of oxygen-free copper, and adopt multi-layer barrel type structure; all fasteners have gone through special tightening treatment. 
The product is featured with high efficiency, low loss, it is able to save much electric energy and running cost, has significant social benefits, is a high-new-tech product popularized by the nation.  

Reliable structure 
Depending on mature technologies, we made a lot of improvements on the basis of traditional structure: 
◎ Spiral winding with longitudinal oil duct that enjoys good inner heat dissipation; 
◎ Effective support at winding end surface that further improve the short-circuit resistant capacity of winding; 
◎ Adoption of new hoisting structure and body positioning structure that guarantee safety in long-distance transport and in service; 
◎ More unique and reliable structures for your option; 
◎ Adoption of transformers with more excellent performances to improve the technical content. 

Excellent materials 
◎ Because we use oxygen-free copper wires of lower resistivity, which will become smoother and burr-free after a series of surface treatment, so the load loss of our transformer is lower and the electric performance is better.
◎ We use high-quality silicon-steel sheets which are of lower specific loss, so the no-load loss of the transformers is lower.
◎ We use high quality wooden laminating insulation pieces, which won’t split or move even under the influence of short circuit current.
◎ We use thoroughly filtrated transformer oil containing less water, gas or impurities, which makes our transformers work better.
◎ We use high quality rubber sealing material, which can prevent the transformers from aging or leakage effectively.
◎ All raw materials have passed the quality testing, and all the raw material factories have passed the national standard IS09000 inspection.

Good technology and economic performance
Improved from S9 series product, S11 series product reduces the no-load loss by 31%; no-load current by 75-90%; average temperature-rise by 10k; noise level by 3-5 db; and double the products’ service life. Even under 20% overloads, it can also work for a long period of time.

Hermetically sealed
The “M” in S11 (M) stands for omniseal structure that the oil tank employed. Compared with common oil-immersed transformer, omniseal oil-immersed transformer discards the oil conservator but adopts wing-like corrugation for replacing oil tube as component of heat dispersion. The corrugated oil tank which is made of high-quality cold-rolled sheets is produced on the special production lines. The wing-like corrugation will expand and compress as that the volume of transformer dose, so that the transformer is separated from the atmosphere and can prevent or slower deterioration of oil and breathing of insulation. All these ensure the reliability of operation and without maintenance.
After the treatment of deoiling, derusting and parkerizing, the surface of corrugated oil tank is coated with paint which provides three-proofing function. It is suitable for the use in the environment such as metallurgy, petrochemical industry and mining, etc.