Space Charge Characteristics of XLPE at Different Temperatures for Long-time Vulcanization Process

The insulation performance of XLPE cables is crucial to the safe and stable operation of the power system. The space charge characteristics of XLPE for different vulcanization temperatures are analyzed in this paper. Disc-shaped samples were prepared with 500 kV XLPE pellets by hot pressing at $120^{\circ} \mathrm{C}, 140^{\circ} \mathrm{C}, 160^{\circ} \mathrm{C}$ and $180^{\circ} \mathrm{C}$ for $1 \mathrm{~h}$, respectively. Then, a pulsed electroacoustic (PEA) system was used to measure the space charge distribution and electric field strength distribution at $30^{\circ} \mathrm{C}$ and $70^{\circ} \mathrm{C}$. Finally, the results show that the samples prepared by vulcanization at $160^{\circ} \mathrm{C}$ have a good distribution of space charge and electric field strength. While vulcanization temperature at $180^{\circ} \mathrm{C}$ enhances the space charge accumulation and electric field distortion rate. It can be inferred that during the long vulcanization process, proper reducing vulcanization temperature is helpful to improve the internal space charge distribution and electric field distortion of XLPE.