直埋XLPE电缆在不同敷设条件下的温升与载流量仿真

Simulation of temperature field and current carrying capacity of direct buried XLPE cables under different laying conditions

土壤直埋因具有施工周期短、散热性能好等优点而被广泛应用于电力电缆的敷设。埋设过程中各种敷设条件对电缆的温升和载流量都有着重要影响,文中采用Comsol有限元仿真软件,以110 kV交联聚乙烯(cross-linked polyethylene,XLPE)电力电缆为研究对象,在直埋敷设的基础上考虑回填沙土、加盖混凝土保护板、装设套管等多种因素,建立包含电磁场、热场和流体场的耦合模型,分析这3种敷设条件对电缆温度场变化及载流量的影响。仿真结果表明:回填沙土会提升电缆载流量,随着回填沙土厚度的增加电缆载流量提升速度变缓;加盖混凝土保护板对载流量的影响较小,与不加盖时相比载流量提升幅度在0.5%以下;在排管内填充高导热材料会提升电缆载流量,相比于无填充情况,三相均填充高导热材料与中间相填充高导热材料、其他两相填充低导热材料时载流量的提升幅度均高于50%;在考虑上述因素同时存在情况下,有利于电缆载流量的提升。

Soil direct burial is widely used for laying power cables because of its advantages of short construction period and good heat dissipation performance.During the burial process,various laying conditions have an important impact on the temperature rise and load capacity of the cable.In this paper,in order to investigate the influences of various laying conditions such as backfilling sand,adding concrete protection plates and installing sleeves on the temperature field and load capacity of direct buried cables,Comsol finite element simulation software is applied and electromagnetic field,thermal field and fluid field are modeled on 110 kV cross-linked polyethylene(XLPE)power cables.The results show that backfilling with sand increases the cable load capacity,and the increase of the cable load capacity slows down with the increase of the backfilling thickness.The adding concrete protection plate has less effect on the load capacity,and the increase of the load capacity is less than 0.5%compared with that without the cover.The filling high thermal conductivity material in the drainage tube increases the cable load capacity,and the increase of the load capacity is higher than 50%when all three phases are filled with high thermal conductivity material and the middle phase is filled with high thermal conductivity material compared with the case without the filling.Compared with the case of no filling,the increase of load capacity when all three phases are filled with high thermal conductivity material,the middle phase is filled with high thermal conductivity material,and the other two phases are filled with low thermal conductivity material is higher than 50%.When the above factors are considered at the same time,it is favorable to the increase of cable load capacity.