The Effect of Voltage Stabilizers on the Electrical Resistance Properties of EPDM Bulk for Cable Accessories

As a critical component in high-voltage cable accessories, ethylene-propylene-diene monomer (EPDM) reinforced insulation faces severe issues of surface discharge and bulk breakdown at the insulation interface. To enhance the electrical resistance of EPDM bulk and insulation interfaces, the 4-allyloxy-2-hydroxybenzophenone was employed as a voltage stabilizer to modify EPDM. A systematic study was conducted on the influence of the voltage stabilizer on the DC breakdown strength of EPDM, the anti-migration properties of the voltage stabilizer, and its effect on the surface breakdown voltage of EPDM. Additionally, pressure and surface breakdown test setups were designed. The results indicate that the DC breakdown strength of EPDM decreases with increasing external pressure, and this decline is more pronounced in EPDM modified with the voltage stabilizer. Surface breakdown experiments demonstrate that the voltage stabilizer has a positive effect on improving the surface breakdown voltage of EPDM, with a more significant enhancement observed at the EPDM/XLPE bilayer dielectric interface. Surface potential tests reveal that the grafted voltage stabilizer introduces numerous shallow traps, inhibiting surface charge accumulation and thereby increasing the surface breakdown voltage.