土壤冻结时考虑导体传热的接地装置散流失效模型  

A Failure Model for Scattered Flow Performance of Grounding Device Considering Heat Transfer of Conductor in Soil Freezing Process

作　　者：袁涛[1] 常飞童 司马文霞[1] 任健行 范荣全 曾文慧 YUAN Tao;CHANG Feitong;SIMA Wenxia;REN Jianxing;FAN Rongquan;ZENG Wenhui(State Key Laboratory of Power Transmission Equipment Technology(Chongqing University),Shapingba District,Chongqing 400044,China;State Grid Sichuan Electric Power Company,Chengdu 610041,Sichuan Province,China)

机构地区：[1]输变电装备技术全国重点实验室(重庆大学),重庆市沙坪坝区400044 [2]国网四川省电力公司,四川省成都市610041

出　　处：《中国电机工程学报》2024年第23期9484-9495,I0032,共13页PROCEEDINGS OF THE CHINESE SOCIETY FOR ELECTRICAL ENGINEERING

基　　金：国家自然科学基金(面上项目)(51777020);中央高校基本科研业务费专项资金资助项目(2023CDJXY-027)。

摘　　要：西藏地区新能源送出走廊不可避免的会途经极寒冻土地区,接地装置面临着冻结失效的风险。以往的研究中,接地装置散流性能计算前提是将冻土考虑成静态水平分层结构,忽略接地装置与杆塔相连时整体的散热效应对土壤冻结结构的影响,导致实际运行中接地装置散流性能分析不准确。因此,该文首先建立考虑接地导体传热的土壤水热场耦合模型,计算得到杆塔散热条件下土壤的冻结结构;然后,在此冻结结构下构造接地装置冲击散流失效模型;最后,利用该模型与传统模型对比,探究接地导体的半径、长度和土壤初始温度等因素对接地装置散流性能的影响。研究表明,由于接地导体具有良好的导热性能,其所接触的土壤易形成局部冻结,与传统模型相比,-10℃低气温下相同接地装置失效时刻提前约18 d;若低温持续时间相同,半径6 mm的单根垂直接地导体达到3.3 m就不会失效,而传统模型下则是1.6 m,相差约2倍。此外,减小接地导体半径或降低接地导体导热系数均可减缓局部冻结。The new energy transmission corridor in Xizang will inevitably pass through extremely cold land areas,and the grounding device is facing the risk of freezing failure.In previous studies,the premise of calculating the dispersion performance of the grounding device is to consider the frozen soil as a static horizontal layered structure,ignoring the influence of the overall heat dissipation effect on the soil freezing structure when the grounding device is connected to the tower,thus resulting in the inaccurate analysis of the dispersion performance of the grounding device in actual operation.Therefore,the coupling model of soil water and heat field considering the heat transfer of the grounding conductor is established in this paper,and the soil structure under different freezing times is calculated.Then the failure model for scattered flow of grounding device is constructed.Finally,compared with the traditional model,the influence of the radius and length of the grounding conductor and the initial soil temperature on the dispersion performance of the grounding device is explored.The results show that due to the good thermal conductivity of the grounding conductor,the soil it contacts is easy to form local freezing,and compared with the traditional model,the failure time of the same grounding device at a low temperature of-10℃is about 18 days earlier.If the low temperature duration is the same,a single vertical conductor with a radius of 6 mm will not fail when it reaches 3.3 m,which is a difference of about two times compared to 1.6 m under the conventional model.In addition,reducing the radius of the grounded conductor or decreasing the thermal conductivity of the grounded conductor can slow down local freezing.

关 键 词：土壤冻结过程 冲击接地电阻 局部冻结结构 低温 接地装置失效 

分 类 号：TM862[电气工程—高电压与绝缘技术]