SG(B)11-R series refers to new generation of Class-H, insulating, open, Toroidal-Core and dry-type distribution transformer, structured in Toroidal-Core shape and manufactured together with new insulating system based on NOMEX paper from DuPont certified by USA UL, featuring high efficiency, energy saving and environmental protection. Compared with performance indicators in Group B of GB/T 10228-2008 Technical parameters and requirements of dry-type power transformer, it features no-load loss on average for 10% lower, load loss reduced for 5% down, no-load current for 60% lower as well as noise reduction for 20%. It is characterized at strong over-load, high voltage withstanding, strong thermal shock withstanding, non-flammable insulating material, flame retardant, high fire resistance, low loss and noise, low partial discharge, insensitivity to humidity and dust, compact, light, convenient maintenance, long service life, operation safety, reliability, energy saving, simple recovery after life expiration as well as pollution-free characteristics. It is most suitable for harsh environment which requires high fire protection, and has high load fluctuations and dirty wet characteristics, widely used in: airport, subway, power plant, metallurgical industry, hospital, high-rise building, shopping center, densely populated area as well as petrochemical, power station and other special circumstances.