Dry-type power transformers produced by XJ Group have been awarded "China famous brand product" and approved of "III Enviromental Protection Product",which are usded in many important projects in China.Recently,XJ has completed the development of 1E dry-type power transformer which meet the requirement of state nuclear project with features match international advanced level. Main characteristics LV winding adopts copper foil. HV winding adopts copper foil. Because the serial capacitance k per unit length increases, the distribution gradient coefficient of the impact voltage will decrease (a=c/k, c: winding to ground capacitance, k: serial capacitance per unit length.). Meanwhile, the shock wave can be uniformly distributed to the winding, which will help to avoid the partial damage to the winding, and improve its anti-lightning impact capacity greatly. LV winding also adopts copper foil. Because the potential on both ends of the winding are equal, the effective resistance of the wire will be increased, so will the copper loss. Both HV and LV windings are vacuum poured. Both the HV and LV windings are poured under 1mbar vacuum conditions, which can ensure that there is no air bubbles inside the winding. Pouring with filling If adding inorganic filling, i.e. silica powder, into the resin, the insulation and conduction performance of the winding will be clearly improved, and the expansion coefficient of the filling will be close to that of copper foil. Plus glass fiber, it is guaranteed that there will be no cracks on the transformer even after long-term operation. The iron core adopts four-stage step forward lamination. Four-stage step forward lamination plus high-strength polyester bandage, can ensure that the no-load loss of this transformer is 10% lower, its noise is 10-15dB (A) lower than that of other transformers domestically made. Airway of the winding adopts cellular structure. Cellular structure is adopted here to guarantee good ventilation. Forced air cooling system As to transformers of different capacities, different cooling systems are equipped. While adopting forced air cooling system, it is necessary to run 150% of the rated load.