Effect of Polycyclic Aromatic Compounds Content on Electrical Tree and Partial Discharge of XLPE

This paper focuses on the effect of the content of polycyclic aromatic compounds (PAC) additive on the electrical treeing degradation and partial discharge of XLPE insulation for high-voltage cables. XLPE insulation samples containing different contents of PAC are prepared and their electrical treeing and partial discharge characteristics are investigated under AC voltage. The results show that the PAC additives cause the reduction of partial discharge amplitude and the inhibition of electric treeing degradation, which enhances the resistance to degradation and the AC breakdown strength. However, the excessive PAC additives cause a downward trend in both the resistance to the electrical tree and AC breakdown strength of XLPE insulation. It is indicated that the PAC additive in XLPE uses the UV energy generated by partial discharge to trigger the hydrogen capture reaction, which promotes the formation of a re-cross-linked structure in the low-density region of XLPE insulation and prevents its expansion, thus inhibiting the electrical treeing degradation.