Investigation on Dielectric Insulation Properties of ±525 kV HVDC XLPE Material for High Temperatures Applications

With the increasing demand of long-length and large-capacity power transmission around the world, the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 525$</tex> kV high voltage direct current (HVDC) Cross-Linked Polyethylene (XLPE) cable system has been widely recognized as the potential technology for power transmission. To further enhance the HVDC cable transmission capacity at a more economical level, the high conductor operation temperature is indispensable. However, higher temperature is more dangerous for XLPE cable insulation especially under HVDC stress. Therefore, it is recommended by Cigre TB 852 [1] that the high temperature performance of insulation material should be examined. Various dielectric insulation tests at different temperatures are performed on sliced XLPE samples from real HVDC cable. The testing results are carefully analyzed and can provide guidance for the efficient design of insulation system for high temperature <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 525\text{kV}$</tex> HVDC cable system applications.