抄録
In conjunction with the previous experiments to study the effect of peroxide decomposition products and antioxidants (AOs) in XLPE insulation on electrical tree generation, authors conducted experiments to examine the tree suppression of phenolic AO. Experiments were conducted using XLPE slabs containing 4 kinds of phenolic AO. Among the specimens containing these AOs, the specimen containing 4, 4' thiobis (3-methyl-6-tert.-buthylphenol) was found to show the highest tree inception voltage. To examine the reasons of the significant increase of tree inception voltage of the specimen containing 4, 4' thiobis (3-methyl-6-tert.-buthylphenol), further experiments were carried out using XLPE specimen containing both phenolic AO and sulfur-containing AO. The result demonstrated that the tree inception voltages of specimens containing both phenolic and sulfur-containing AOs are higher than those of the specimens containing either only phenolic or sulfur-containing AO. Taking the schemes of auto-oxidation of polymeric materials into consideration, the roles of antioxidants in XLPE dielectrics was discussed. It was presumed that the great increase in the tree inception voltage of XLPE specimen containing 4, 4' thiobis (3-methyl-6-tert.-buthylphenol) could be due to the synergetic effect between the phelolic AO and the sulfur-containing AO.
