Effect of Curing on the AC and DC Breakdown Strength of Cable Insulation

Cross-linked polyethylene (XLPE) is one of the most used insulation materials in the cable manufacturing industry due to its excellent properties compared to other insulating materials. The manufacturing of XLPE cable involves the curing process where the insulation is subjected to a high temperatures and pressures for a certain defined duration in order to ensure the proper crosslinking and thereby enhance the material's performance. In this paper, lab-made XLPE samples are subjected to different curing temperatures (uncured, 150°C, 180°C and 200°C) in order to investigate breakdown characteristics under both AC and DC conditions. A possible optima for temperature, where the insulation is properly cross-linked but not deteriorated, is touched upon briefly. The results, albeit preliminary, will be a good starting step, which will hopefully guide the industry in improving the efficiency and reliability of the cable.