Study on TSC characteristics of aged insulation cardboard in oil-immersed transformer

The bad thermal-resistance of insulation cardboard in oil-immersed transformer can directly lead to the aging of the oilpaper insulation system and the subsequent poor performance of the oil-paper system, which would affect the reliability and stability of power system. In this paper, based on the home-made thermal aging test platform, the insulation cardboards have been aged under different aging temperatures (90 °C, 110°C, 130 °C) for different days. By using the thermally stimulated current (TSC) method to test the trap charge characteristics of the aged samples, the variation of the trap charge amounts with different aging temperatures and different aging days are compared. The test results show that the increase of aging temperature can make the speed of oil paper insulation´s aging increase. At the beginning of the aging, the traps in the sample are a large number of shallow traps because of the thermal effects. The energy level and amount of the trapped charge both increase with a further increase of aging time.