What Is the Relationship Between Transformer Insulation and Transformer Life

The most widely used power transformers are oil-immersed transformers and dry-type resin transformers. The insulation of the power transformer is the insulation system composed of the transformer insulation material, which is the basic condition for the normal operation and operation of the transformer. The service life of a transformer is determined by the life of the insulating material (ie oil paper or resin, etc.). Practice has proved that most transformer damage and failure are caused by damage to the insulation system. According to statistics, accidents caused by various types of insulation faults account for more than 85% of all transformer accidents. For transformers that operate normally and pay attention to maintenance management, the insulation material has a long service life.

According to theoretical calculations and experimental studies abroad, when the actual temperature of a small oil-immersed distribution transformer continues at 95 °C, the theoretical life expectancy will reach 400 years. Experience in design and field operation shows that a well-maintained transformer can have a real life of 50-70 years. According to the design requirements and technical indicators of the manufacturer, the life expectancy of the transformer is generally set at 20 to 40 years. Therefore, protecting the normal operation of the transformer and enhancing the reasonable maintenance of the insulation system can largely ensure that the transformer has a relatively long service life.

Preventive and predictive maintenance are key to improving transformer life and improving power supply reliability. In oil-immersed transformers, the main insulating materials are aging of so-called transformer insulation, such as insulating oil and solid insulating materials, insulating paper, cardboard and wood blocks. It is these materials that are decomposed by environmental factors, reducing or losing the dielectric strength.