摘要
GIS母线通流产生温升发热现象,进而引起SF6的流动使其分布不均。SF6击穿特性受其分布不均性的影响极大,极易在分布不均的局部区域出现击穿现象,从而引发绝缘故障。为此文中开展了母线通流温升对GIS内部绝缘特性的影响研究。建立了考虑集肤效应、涡流损耗、电导率温升效应的1100 kV GIS气室电磁场—温度场—流场耦合模型,求解了SF6在GIS母线通流温升条件下的流动情况。结果表明:母线通流温升的确使SF6分布不均,温升越高区域SF6分布越稀薄,绝缘水平下降越厉害。为定量得到GIS内部绝缘状态,在分析SF6击穿特性基础上,根据绝缘裕度的概念建立了绝缘裕度计算模型,得到了GIS内部绝缘特性。计算结果表明:母线通流温升使GIS内部绝缘水平大幅下降,从14.51 kV/mm降到9.92 k V/mm,有被击穿的危险。这表明母线通流温升对GIS内部绝缘水平的影响不能忽略,这一点在今后的GIS内绝缘设计中应予以高度重视。
Temperature rise phenomena occurs when rated current flows through the busbar of GIS,which results in SF6 gas flowing and ultimately makes it distribute unevenly.The uneven SF6 distribution greatly influences its breakdown characteristics,and may easily cause partial discharge in local uneven distribution area and then lead to insulation faults.In this paper,an electromagnetic-temperature-flow multi-physical field coupling model considering eddy effect,skin effect,and temperature rise effect of conductivity is established to analyze the flowing characteristics of SF6 in the 1100 kV GIS.The results show that the higher the temperature rise,the thinner the SF6 gas distribution and the lower the insulation level of GIS.To quantitatively evaluate the internal insulation condition of GIS,the relationship between critical breakdown strength and SF6 gas distribution is analyzed and the concept of insulation margin is defined.Subsequently,a mathematical model is set up to calculate the internal insulation margin of GIS.The results show that the temperature rise due to current flowing through the busbar makes the internal insulation level of GIS decrease dramatically from 14.51 kV/mm to 9.92 kV/mm,which implies that under this condition the GIS will be easily broken-down if it surfers high voltage impulse such as lightning.It is concluded that that the influence of this temperature rise on the internal insulation level of GIS cannot be ignored in insulation design of GIS.
作者
吴细秀
程诗敏
周帆
吴士普
冯宇
WU Xixiu;CHENG Shimin;ZHOU Fan;WU Shipu;FENG Yu(Schoolof Automation,Wuhan University of Technology,Wuhan 430070,China;State Key Laboratory of Power Grid Environmental Protection,Wuhan 430074,China)
出处
《高压电器》
CAS
CSCD
北大核心
2020年第2期7-14,共8页
High Voltage Apparatus
基金
电网环境保护国家重点实验室开放基金项目资助(GYW51201901085).
关键词
SF6气体介质
内绝缘特性
GIS母线
击穿裕度
多物理场耦合
SF6gas
internal insulation characteristics
GIS busbar
breakdown margin
multi-physical field coupling
