Analysis of the Impact of High-voltage Cable Laying Process on Insulation Performance in Supercritical Units

To explore the impact of high-voltage cable laying process on insulation performance in supercritical units. Cable sample groups with different preset laying conditions were prepared and subjected to accelerated thermo-mechanical cycle aging. Electrical testing techniques, including power frequency breakdown, partial discharge spectroscopy, dielectric loss frequency domain spectroscopy, and space charge distribution, were comprehensively utilized to evaluate insulation performance. Critical or poor laying processes introduce initial mechanical damage to the insulation layer and interface. These defects, under the synergistic action of electric and thermal fields, become deep traps for charge capture and initiation points for partial discharge, leading to increased space charge accumulation, severe local electric field distortion, nonlinear steep increase in dielectric loss, and significant decrease in breakdown voltage. The laying process is a crucial precondition for determining the long-term operational reliability of high-voltage cables in supercritical units. Key parameters such as minimum bending radius and traction tension must be strictly regulated and controlled to avoid implanting irreversible initial insulation defects.