Investigation on Heating Aging Mechanism of Cellulose Paper for Oil-Immersed Transformer Main Insulation

Power transformer plays a vital role in maintaining reliable and efficient electricity supply. However, in service is increasing and growing older, much and much attention has been paid on their aging condition and life assessment than ever. The aging and degradation of transformer insulation will determine the life-time of its operation. The intensities of these depend on mechanical, thermal and environmental stresses that act on the insulations. Due to the temperature rise, the lifetime of insulation material will be shortened. The accelerated thermal aging method is often adopted to do some evaluation on the oil-paper insulation materials under different temperature for the thermal lifetime model. According to existing aging test, both insulation paper and mineral oil were aged at the same temperature. In this paper, the thermal aging experiments were implemented on the transformer main insulation model made with modified and unmodified insulation paper. The accelerated thermal aging tests were finished, and the superior electric characteristics of the nano-TiO2 and cellulose composition insulation were validated.