Research on the Aging Mechanism of Transformer Spacer under Preload and Thermal Aging

Currently, the mechanical properties of transformer spacer under the action of a single factor have been studied, but the corresponding aging mechanism is unclear. Therefore, this paper combines the actual operating conditions of 750kV transformer insulation spacer to construct an accelerated aging test platform under preload and thermal aging. It can be found that the degradation rate of spacer under thermal aging was greater than that under the synergistic effect of preload and thermal aging, which was greater than that under preload alone. One reason is that preload reduces the size of the voids and gaps between the spacer layers and within the spacer, further reduces the moisture content in the voids and gaps, and slows down the hydrolysis process of cellulose molecular chains. Another reason is that thermal aging enlarges the voids and gaps between the insulation spacer layers and within the spacer, accelerates the hydrolysis and oxidation reaction process of cellulose molecular chains. This study can provide reference for the maintenance and structural optimization of 750kV transformers.