特高压C_(4)F_(7)N/CO_(2)混合气体GIL温度分布

Temperature Distribution of UHV C_(4)F_(7)N/CO_(2) Mixed Gas GIL

气体绝缘金属封闭输电线路(gas insulated metal-enclosed transmission line,GIL)中绝缘气体热学特性会影响GIL整体绝缘性能。目前,国内外对C_(4)F_(7)N/CO_(2)混合新型环保气体应用于GIL的研究刚刚起步,其热学特性尚不明确。为此对特高压C_(4)F_(7)N/CO_(2)混合气体GIL建立了温度-流体多物理场仿真模型,通过开展现场温升试验对该模型进行了有效性验证,研究了额定电流下GIL内部温度场分布及内部气体密度场、流速场分布,以及不同通流水平下导体和铝合金外壳顶部温升关系,并对比分析了在C_(4)F_(7)N/CO_(2)与SF;两种不同气体下GIL内部温升的差异性。研究结果表明:C_(4)F_(7)N/CO_(2)气体GIL内部温度梯度整体大于SF;气体GIL,在后续环保型GIL设计中应关注这一问题;相同通流条件下C_(4)F_(7)N/CO_(2)气体GIL与SF;气体GIL温度分布差异的主要原因为SF;对流性能优于C_(4)F_(7)N/CO_(2)混合气体;探索了C_(4)F_(7)N/CO_(2)GIL外壳顶部温升与GIL中心导体温升间的关系,GIL导–壳温升比例系数为0.482,该系数可应用于后续基于外壳温度的中心导体温度监测系统中。

The thermal properties of the insulating gas in a gas insulated metal-enclosed transmission line(GIL)will affect the overall insulation performance of the GIL.At present,domestic and foreign research on the application of C_(4)F_(7)N/CO_(2) mixed environmentally friendly gas to GIL has just started,and its thermal characteristics are still unclear.Therefore,we established a temperature-fluid multi-physical field coupling simulation model for the environment-friendly UHV C_(4)F_(7)N/CO_(2) mixed gas GIL and conducted simulation research.An on-site temperature rise test to effectively verify the model was also conducted.The research results indicate that the internal temperature gradient of environmental-friendly GIL is larger than that of SF;GIL,which should be paid attention to in the subsequent design of environmental-friendly GIL.The convection performance of SF;is better than that of C_(4)F_(7)N/CO_(2) mixed gas,which will cause differences of temperature distribution in GIL.The relationship between the temperature rise of GIL center conductor and the top of the C_(4)F_(7)N/CO_(2) GIL shell is explored,and the GIL conductor-case temperature rise response coefficient is defined.This coefficient can be applied to the subsequent center conductor temperature monitoring system based on the shell temperature.