The Hermetically-sealed transformer is the transformer of which inner tank is totally isolated from the outside atmosphere. Its volume changes with shrinkage and expansion of the corrugated tank sides. Moisture and oxygen can not enter the tank from outside, thus slowing down the aging of the insulating material. It doesn't need core-lifting check before operation or maintenance after putting into operation, which greatly improves the reliability of transformer.

It adopts PCCAD as its design software, and meets IEC60076, GB1094 standard, and has passed the ISO9001 quality system certification. The coil, wound by high intensity enameled wire (or paper wrapped) with cylinder (or disc) structure and Ampere-Turn balance, reasonable insulation structure have a good short-circuit withstand capacity. All sealing material is made of high quality acrylic rubbery which can effectively prevent against light-aging, electricity aging and heat aging. It is equipped with "remote sensor" signal thermometer and pressure relief valves to enhance the reliability of transformers.

Without such device like conservator and air breather, it ensures that the transformer oil is not in contact with air. So commonly, the transformers can be used continuously for 20 years without any particular treatment. Excellent rubber is adopted in the sealing parts. Vacuum oil-filling process is used.

It can be widely used in urban power network as well as petrochemical, metallurgical, textile and humid, inaccessible enterprises, and mining.