Research On Steady State Electrical Field Distribution Of Crosslinked Polyethylene HVDC Power Cable Insulation And Its Accessories

HVDC power cable is the physical basis for DC power grid and its steady electric field distribution determines its safe operation.The temperature-field strength characteristics of XLPE conductivity will affect the electric field distribution in the insulation layer and accessories.As the preparation technology of XLPE material will affect its conductivity characteristics,significant difference will be existence in the steady state electric field of XLPE insulation and its accessories.It's of great engineering significance to study the electric field distribution of XLPE insulation its accessories under different XLPE materials.The 200 kV HVDC power cable and its intermediate joints and terminals are used as physical models.The research material are imported DC cable insulation materials(denoted as XLPE-A),photocrosslinked cable materials(denoted as XLPE-B)and domestic high purity cable insulation material(referred to as XLPE-C).The electric distribution of HVDC cable insulation and its accessories under different current-carrying is calculated through multiphysics simulation software.The calculation results show that the cable insulation layer using XLPE-C material has the lowest degree of electric field reversal,while the XLPE-B electric field reversal is the most serious and its maximum electric field strength is XLPE-C under 3000 A ampacity 1.2 times.In the cable terminal,XLPE-C has the lowest DC electric field strength when the current carrying capacity is above 1000 A.Under 0A and 500 A capacity,XLPE-B has the lowest electric field strength at the interface of XLPE insulation layer and stress cone.XLPE-C has the lowest electric field strength when the current carrying capacity is above 1000 A.The highest field strength in the intermediate joints exist in theinterface between the core and XLPE insulation layer and at the interface between reinforced insulation and XLPE insulation layer.XLPE-C has the lowest DC electric field strength above 1000 A.The results of this paper show that the insulation of HVDC cable with XLPE-C has high reliability both for cable insulation and its accessories.