临界反转温差约束下66 kV交流XLPE电缆改为直流运行的电压等级和载流量分析  

Analysis of DC Voltage Level and Ampacity of 66 kV AC XLPE Cable in DC Operation Under Constraint of Critical Inversion Temperature Difference

作　　者：杨帆[1] 房占凯 汪洋 乐彦杰 余鹏 卢旭 余晓 YANG Fan;FANG Zhankai;WANG Yang;LE Yanjie;YU Peng;LU Xu;YU Xiao(State Key Laboratory of Power Transmission Equipment&System Security and New Technology,Chongqing University,Chongqing 400044,China;Zhoushan Power Supply Company of State Grid Zhejiang Electric Power Company,Zhejiang Zhoushan 316021,China;Shenzhen Power Supply Bureau Co.,Ltd.,Guangdong Shenzhen 518000,China)

机构地区：[1]重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400044 [2]国网浙江省电力公司舟山供电公司,浙江舟山316021 [3]深圳供电局有限公司,广东深圳518000

出　　处：《高压电器》2020年第8期161-167,共7页High Voltage Apparatus

基　　金：国家重点研究项目(2017YFB0902703);国家“111”项目(B080360)。

摘　　要：准确有效地评估交流电缆改为直流运行时的增容效果对电缆交改直后的安全运行至关重要。现有研究主要基于缆芯温度70℃为阈值确定交改直的电压等级和载流量,并未考虑绝缘层的稳态电场强度。因此,文中综合考虑临界反转时稳态电场强度较小和温升限值约束,提出了以绝缘层中的电场强度5 MV/m为限值的交改直电压等级和载流量判定方法;并且以66 kV交流XLPE电缆为例进行仿真计算,分析了直埋土壤敷设下交流电缆改为单极直流和双极直流运行时的增容效果。研究结果表明:当电缆在直埋土壤敷设下以66 kV单极直流运行和双极直流运行时,最大输送功率分别为改造前的1.53倍和1.12倍。所采用的分析方法可为电缆线路交改直工程提供一定的参考。Accurately determining DC voltage level and ampacity of AC cable is vital for safety of AC⁃DC conver⁃sion.The current researches mainly determine the voltage level and ampacity based on the threshold value of core temperature 70℃,but does not consider the steady electric field strength of the insulating layer.In this paper,a method for judging the DC voltage level and ampacity with the electric field strength limitation of 5 MV/m in insula⁃tion layer is proposed under the constraint of small steady⁃state electric field strength and temperature rise limit in critical reversal.In addition,taking the 66 kV AC XLPE cable for example,the compatibilization effect of applying the AC cable to unipolar DC or bipolar DC operation is analyzed.Calculation results show that when the 66 kV cable laid in soil operates in unipolar DC mode and bipolar DC mode,the maximum transmission power is 1.53 times and 1.12 times of the original value before the transformation,respectively.This analysis method may serve as a refer⁃ence for AC⁃DC conversion of cable line.

关 键 词：交流XLPE电缆 交改直 临界反转温差 直流电压等级 直流载流量 增容效果 

分 类 号：TM721.1[电气工程—电力系统及自动化]