Transformer life span of 20 years.
The national standard, the transformer according to the 20-year service life design, in fact, the operation of most transformers tend to exceed this life. In practice, is based on the operation of the industry regulations in advance of the elimination, for example, before and after 1976 production of a number of aluminum coil thin insulation transformer, the state in advance of the issuance of the elimination.
Extended information:
Transformers are mainly categorized
1, according to the number of phases:
1) Single-phase transformers: used for single-phase loads and three-phase transformer group.
2) three-phase transformer: used for three-phase system voltage rise and fall.
2, according to the cooling mode:
1) dry-type transformer: rely on air convection for natural cooling or increase fan cooling, mostly used in high-rise buildings, high-speed toll station electricity and local lighting, electronic circuits and other small capacity transformer.
2) oil-immersed transformer: rely on oil as a cooling medium, such as oil-immersed self-cooling, oil-immersed air-cooled, oil-immersed water-cooled, forced oil circulation.
3, according to the use of points:
1) power transformer: used for transmission and distribution system voltage rise and fall.
2) instrumentation transformer: such as voltage transformer, current transformer, for measuring instruments and relay protection devices.
3) test transformer: can produce high voltage, high voltage test of electrical equipment.
Baidu Encyclopedia - Transformer
Baidu Encyclopedia - Power Transformer Residual Life Assessment