摘要
目前电缆额定载流量均是依据IEC 60287标准计算的静态数值,然而投运电缆实际载流能力随环境温度动态变化,且高压直流海底电缆绝缘材料电导率与温度存在的耦合关系进一步影响载流量计算,为此开展高压直流海底电缆长时间服役条件下基于IEC 60287标准的载流量计算模型修正工作。首先,通过加速热老化试验,明确交联聚乙烯(cross linked polyethylene,XLPE)材料热导率随温度梯度和热老化时长的衰减演化规律,基于一级动力学规律确定XLPE热导率在135℃、150℃和175℃下的时变函数;其次,提出基于阿伦尼乌斯原理的等效时间转换模型,将XLPE材料在135℃条件下的热老化时间等效到70℃条件下,并结合XLPE热导率时变函数,构建高压直流海底电缆绝缘层热导率衰减模型;最后,经使用有限元多物理场仿真软件作对比,提出考虑材料参数时变特性的直流海底电缆载流量计算修正模型。经验证,修正模型可有效补偿热导率衰减带来的计算偏差,修正后的载流量计算结果与数值模拟的结果偏差在0.1%以内,为提升海底电缆运行安全性与输电效率提供了理论依据和技术支撑。
Currently,the rated current-carrying capacity of cables is statically calculated based on the IEC 60287 standard.However,the actual current-carrying capacity of operational cables dynamically varies with ambient temperature,and the coupling relationship between the conductivity of the insulation material and temperature in HVDC submarine cables further affects the capacity calculation.To address this,this study modifies the IEC 60287 based calculation model for the current-carrying capacity of HVDC submarine cables under long-term service conditions.Firstly,the accelerated thermal aging tests were conducted to clarify the degradation evolution of the thermal conductivity of cross-linked polyethylene(XLPE)with temperature gradient and aging duration.Time-varying functions of XLPE thermal conductivity at 135°C,150°C,and 175°C were determined based on first-order kinetics.Subsequently,an equivalent time conversion model using the Arrhenius principle was proposed to translate the thermal aging time of XLPE at 135°C to equivalent conditions at 70°C.Combined with the time-varying thermal conductivity function,a degradation model for the thermal conductivity of HVDC submarine cable insulation was established.Finally,a modified model for calculating the current-carrying capacity of DC submarine cables,considering the time-varying characteristics of material parameters,was developed and validated against finite element multiphysics simulations.It is proved the modified model effectively compensates for calculation deviations caused by thermal conductivity degradation,with a discrepancy of less than 0.1%compared to numerical simulation results,providing a theoretical basis and technical support for enhancing the operational safety and transmission efficiency of submarine cables.
作者
于是乎
李林恒
李银格
余欣
张伟超
YU Shihu;LI Linheng;LI Yinge;YU Xin;ZHANG Weichao(Guangdong Key Laboratory of Electric Power Equipment Reliability,Electric Power Research Institute of Guangdong Power Grid Co.,Ltd.,Guangzhou,Guangdong 510080,China;School of Electrical and Electronic Engineering,Harbin University of Science and Technology,Harbin,Heilongjiang 150080,China)
出处
《广东电力》
北大核心
2025年第11期95-102,共8页
Guangdong Electric Power
基金
中国南方电网有限责任公司科技项目﹝036100KC23090003(GDKJXM20231005)﹞。
关键词
交联聚乙烯
高压直流
海底电缆
IEC
60287
热导率
载流量
cross linked polyethylene(XLPE)
high voltage direct current
submarine cable
IEC 60287
thermal conductivity
current carrying capacity
