故障电流冲击下高温超导电缆磁–热耦合特性数值计算与分析  

Numerical Analysis on Coupled Magneto-thermal Properties of High Temperature Superconducting Cables Subjected to Fault Currents

作　　者：诸嘉慧[1] 栗会峰[2] 丘明[1] 李振明[1] 刘伟[1] 来小康[1] 方进[2] 袁炜嘉[3] 

机构地区：[1]中国电力科学研究院,北京市海淀区100192 [2]北京交通大学电气工程学院,北京市海淀区100044 [3]英国巴斯大学电子与电气工程学院

出　　处：《中国电机工程学报》2015年第12期3176-3181,共6页Proceedings of the CSEE

基　　金：国家自然科学青年基金项目(51207146);国家电网公司科技项目(DG71-11-009);The Royal Academy of Engineering International exchange Scheme;UK(EE1053)~~

摘　　要：冷绝缘高温超导(cold dielectric high temperature superconducting,CD HTS)电缆在电力系统输电运行中,不可避免地会受到故障电流的冲击。在故障持续时间内,超导电缆产生大量热量,导致温度升高,从而使超导电缆由超导态向正常态转变,对超导电缆载流性能产生影响。通过建立故障电流下超导电缆等效电路模型与热传导模型,提出了超导电缆在故障电流冲击时的各层电流瞬态分布解析算法,通过耦合电磁计算与传热分析模型,提出了超导电缆故障电流冲击下的温度分布数值计算法。最后,对110 k V/3 k A冷绝缘高温超导电缆在25 k A、持续3 s故障电流冲击时的电流分布和温度分布情况进行了计算分析。结果表明:在故障时间内,伴随导体层温度逐渐上升,各个导体层电流呈下降趋势,各层的温度在92 K前后上升速率不再相同,铜骨架承受近96%的故障电流,分流作用明显。分析结果为设计故障电流冲击下超导电缆的故障保护策略提供了参考依据,对保障超导电缆的稳定运行具有指导意义。In the power grid, a cold dielectric high temperature superconducting （CD HTS） cable usually subjects to the impact of fault currents in the transmission system. During the fault, a large amount of Joule heat is generated, causing the temperature of HTS cable rise and leading a transformation of HTS elements therein from a superconducting state to a normal state which would deteriorate the current carrying capacity of HTS cables. This paper proposes a new method for calculating transient currents and temperature distributions in CD HTS cables by coupling an equivalent circuit mathematical model with a thermal conduction model of HTS cables considering the impact of fault currents. The proposed method is applied to an 110 kV/3 kA CD HTS cable consisted of YBCO coated conductor with a fault current of 25 kA rms lasting 3 s. The obtained current and temperature distributions in the HTS cable show that there is a serious current diversion effect in the CD HTS cable and the currents of the superconducting layers decrease along with the rise of the temperature in the HTS cable which has different rate of change after reaching 92 K. Therefore the copper former becomes the main path for the fault current and withstands about 96%of the fault current. This analytical method provides the theoretical basis for the protection strategy of superconducting cables which is significant for the stable operation of HTS cables.

关 键 词：冷绝缘高温超导电缆 故障电流 电流分布 温度分布 磁热耦合计算 

分 类 号：TM249[一般工业技术—材料科学与工程]