±535kV交联聚乙烯绝缘直流电缆设计与试验验证

Design and Test Verification of ±535kV XLPE DC Cable

±535 kV交联聚乙烯绝缘直流电缆具有较大的传输容量,为满足国网项目需求,展开±535 kV交联聚乙烯绝缘直流电缆结构设计及试验验证。通过计算载流量确定导体截面为3000 mm2;通过COMSOL仿真计算校核绝缘厚度,确定绝缘厚度为30 mm;对电缆进行电缆热变形试验,确定阻水缓冲层选用4层2.0 mm×100 mm的半导电缓冲阻水带,最终确定电缆整体结构。为验证电缆性能,参照GB/T 31489.1—2015,对电缆进行例行试验和全性能型式试验。试验结果显示,电缆弯曲试验、导体透水试验、负荷循环、直流耐压及叠加冲击等均全部通过,负荷循环过程中导体最高温度高于70℃,绝缘最大温差超过14℃。

The fact that±535 kV XLPE DC cable has a large transmission capacity,in order to meet the requirements of the State Grid project,the structure design and test verification of±535 kV XLPE DC cable were carried out.The conductor cross section was 3000 mm^(2) by calculating the carrying current.Check the insulation thickness through COMSOL simulation calculation,determine the insulation thickness was 30 mm.The cable thermal deformation test was carried out to determine the water blocking buffer layer with 4 layers of 2.0 mm×100 mm semi⁃conductive buffer water blocking belt,and the overall structure of the cable was finally determined.In order to verify the performance of the cable,according to GB/T 31489.1—2015,the cable was subjected to routine test and type test.The cable bending test,conductor permeability test,load cycle,DC voltage and superimposed impact test were all passed.In the process of load cycle,the maximum temperature of conductor is higher than 70℃,and the maximum temperature difference of insulation is higher than 14℃.