基于暂态电热场特性的高压直流电缆线路动态增容能力评估  

Dynamic Capacity Expansion Evaluation for HVDC Cable Lines Based on Transient Electrical and Thermal Field Characteristics

作　　者：刘潇镁 刘英[1] 李文清 LIU Xiaomei;LIU Ying;LI Wenqing(School of Electrical Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学电气工程学院,西安710049

出　　处：《高电压技术》2025年第4期1674-1683,共10页High Voltage Engineering

摘　　要：电力需求的增长和系统容量的提升对输配电电缆的传输容量和运行可靠性提出了更高的要求,有效利用高压直流(high voltage direct current,HVDC)电缆线路的动态增容潜力对于实现电力资源优化配置具有重要意义。通过有限元分析(finite element analysis,FEA)方法建立了不同敷设环境中高压直流电缆线路的暂态热场及电场模型,仿真分析了电缆在多种典型动态负荷下的温度分布及绝缘电场特性,研究发现:相比于架空及土壤直埋敷设,隧道敷设的HVDC电缆系统热响应时间常数达到数百小时,因此具有更好的动态增容能力。论文以隧道中敷设为例,通过相应FEA模型反演计算了不同初始负荷与应急时长下直流电缆的允许最大过负荷电流,给出了针对HVDC电缆线路短时动态增容能力的评估方法,并对直流电缆线路动态增容过程中的暂态电热特性进行了分析。结果表明:初始负荷率高,应急持续时间长,绝缘电导率温度敏感性强的高压XLPE直流电缆在动态增容过程中场强变化幅度大,应予以特别关注;初始负荷率不超过50%的隧道敷设双极直流电缆线路,单级可在1.5倍额定电流下安全运行2 h。该结果可为工程中HVDC电缆线路动态增容与优化调度提供理论指导。The growth of power supply demands and the improvement of power system capacity have put forward a higher requirements for the transmission capacity and operation reliability of cables in power transmission and distribution network.It is of great significance to effectively use the dynamic capacity expansion potential of high-voltage direct-current(HVDC)cable lines for the optimal allocation of electric power resources.In this paper,the finite element analysis(FEA)method is used to establish the transient thermal and electric field models of HVDC cables laid in different environments,and the temperature distribution and insulation electric field characteristics of cables under typical dynamic loads are simulated and analyzed.The research reveals that,compared with the systems laid in air or buried in soil,the HVDC cable system laid in a tunnel has the thermal response time constant of several hundred hours,and thus has the highest dynamic capacity expansion capability.Taking the cable laid in a tunnel as a case study,we calculated the allowable maximum overload currents of it under different initial load rates and permitted emergency durations through an iterative inversion process based on the corresponding FEA model.In addition,we proposed an evaluation technique for the short-term dynamic expanded capacity of HVDC cable lines,and analyzed the transient electric and thermal characteristics in the overload duration.The results indicate that,for HVDC XLPE cables with high initial load rates,long emergency durations and high temperature dependencies of the insulation conductivity,significant electric field changes will take place during dynamic capacity expansion,and thus should be given specific attention.For bipolar DC cable lines in tunnels with an initial load rate less than 50%,any one pole can safely run with 150%rated current for 2 hours.The findings of this paper provide theoretical guidance for dynamic capacity expansion and optimization scheduling of HVDC cable lines.

关 键 词：高压直流电缆线路 交联聚乙烯绝缘 动态增容 暂态电热场分析 允许最大过负荷 

分 类 号：TM75[电气工程—电力系统及自动化]