◎  Oil tank adopts structure of flat top, bell jar type, which add the mechanical strength of oil tank and also make the appearance beautiful and graceful, site installation tend to be more convenient.
◎  Pipeline with gas relay such as the oil tube and bushing hoist support on top of oil tank is with hoist gradient, to facilitate the gas in transformer flow to gas relay.
◎  Vacuum oiling is adopted, there is no leakage and permanent distortion in the following test. vacuum- pumping :759mmHg load voltage test: bear 2 times the oil pressure of oil conservator oil surface for 24 hours.
◎  The structure of transformer is convenient for disassembly and change of bushing and porcelain element.
◎  The oil drip valve is set on the bottom of oil tank, sampling valve is set in the middle.
◎  Collective gas connecting tube is fixed on the bushing hoist support.
◎  Transformer is of full-sealed structure, the upper and down oil tanks are required to welded fully. 

Oil conservation tank 
◎  Adopt capsule type, finger type oil level indicator oil conservation tank. 
◎  The structure is convenient for internal cleaning, the capacity can ensure no oil overflow in 40 ambient temperature with full load, and oil shall be seen from oil level indicator before put into operation in -25.◎  Oil conservation tank is equipped with oil-sealed moisture absorber. 

Safety protection device:
◎  Gas relay is fixed in transformer, the standard complies with ZBK41004-89Gas relay.
◎  There is enough and reliable pressure release device, and matched with oil spray pipe, the direction of oil spraying is downward. 

Oil temperature measuring device
◎  There is pipe support of mercury thermometer, which is  set on the top of oil tank.
◎  There is temperature controller,  the accuracy of thermometer complies with the related standard. Quantity and technical requirement shall as per tender document. 

Each component  of transformer shall be prefabricated once in manufacture factory, marked, to ensure the smooth procedure of site assembly. Before Ex-factory, inner core shall be check, and clean the fifth in transformer.