CAJ | 학술논문

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 kV/3 kA冷绝缘高温超导电缆在25 kA、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。
랭절연고온초도(cold dielectric high temperature superconducting，CD HTS)전람재전력계통수전운행중，불가피면지회수도고장전류적충격。재고장지속시간내，초도전람산생대량열량，도치온도승고，종이사초도전람유초도태향정상태전변，대초도전람재류성능산생영향。통과건립고장전류하초도전람등효전로모형여열전도모형，제출료초도전람재고장전류충격시적각층전류순태분포해석산법，통과우합전자계산여전열분석모형，제출료초도전람고장전류충격하적온도분포수치계산법。최후，대110 kV/3 kA랭절연고온초도전람재25 kA、지속3 s고장전류충격시적전류분포화온도분포정황진행료계산분석。결과표명：재고장시간내，반수도체층온도축점상승，각개도체층전류정하강추세，각층적온도재92 K전후상승속솔불재상동，동골가승수근96%적고장전류，분류작용명현。분석결과위설계고장전류충격하초도전람적고장보호책략제공료삼고의거，대보장초도전람적은정운행구유지도의의。
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.