高导电率钢芯铝绞线在750kV输电线路中的应用研究

为了降低输电线路损耗,提高导线输送效率,750 kV输电线路采用节能导线JL(GD)/G1A-400/50高导电率钢芯铝绞线,其节能及经济特性与普通导线进行对比,表明高导电率钢芯铝绞线既具有优良的机电性能,又具备突出的节能优势,在新建线路中优势明显,是极有推广潜力的导线。

一种中强度铝合金芯高导电率铝绞线的研发与应用

结合工程实际,在满足工程力学性能的前提下,提出并研发了一种更节能的新型导线——中强度铝合金芯高导电率铝绞线。通过设计计算对比各种导线的电气、机械特性,采用年费用法对各类导线的经济性进行了分析与评价。通过对比分析,得出一种中强度铝合金芯高导电率铝绞线的电气性能、机械性能满足设计要求,且经济性能最优,同时具备节能环保特性,符合建设资源节约型、环境友好型输电线路的要求,适合推广应用于各种节能输电线路。

输电线路用高导电率铝合金芯铝绞线对比研究

以拟建的某±800 kV直流特高压线路工程为例,针对6×JL1/G2A—1250/100钢芯铝绞线的基本导线方案,选取铝合金芯铝绞线、铝合金芯成型铝绞线以及一种新型节能导线高导电率铝合金芯铝绞线这三个方案,进行了电气性能和机械性能比较,并采用最小年费用法进行了经济性分析。结果表明:随着损耗小时数提高和电价的增加,新型节能导线高导电率铝合金芯铝绞线能够具有很好的经济性。通过计算不同电价、不同资本金内部收益率下所选导线临界损耗小时数,研究比较新型节能导线与基本导线的投资回收期。

铝包钢芯高导铝绞线的技术特点及应用研究

铝包钢线具有优良的机械、电气和防腐性能。与传统钢芯铝绞线相比,用铝包钢线代替镀锌钢线的铝包钢芯铝绞线具有重量轻、电阻小、耐腐蚀、弧垂小的特点,尤其适合在沿海及重污秽地区应用;采用20.3%IACS的LB20铝包钢芯代替镀锌钢芯与高导电率铝线组成的节能导线即铝包钢芯高导铝绞线,可充分利用现有生产技术,叠加发挥两种材料的节能效果,与同规格的钢芯高导电率铝绞线相比,交流电阻进一步降低约1.6%-2.7%。500 k V线路典型算例表明：综合考虑导线价格成本和节能效益,JL3/LB20和JL2/LB20型铝包钢芯高导铝绞线具有较高的经济效益,值得推广。

劣质高镁石灰石在新型干法线的合理利用

为合理有效利用劣质高镁石灰石资源,针对新型干法生产中高MgO含量对熟料产质量的不利影响,通过一系列技术创新,特别是将硅率公式进行改进,大胆提高熟料SM值至3.5,采用超高硅率、高铝率的配料方案取得了显著效果。

锡盟—江苏±800kV特高压直流输电工程内蒙古段线路导线选型分析

针对锡盟—江苏±800 k V特高压直流输电工程的电压等级、输送容量等参数要求,根据相关国家标准及以往同类工程导线应用情况,首先推荐内蒙古段线路导线铝截面为8×1250 mm2,针对该参数,采用不同的钢芯结构,经过技术经济性分析,选出性能较优的8×JL/G3A-1250/70型钢芯铝绞线作为本标段推荐导线型号。最后,将钢芯高导电率铝绞线、铝合金芯铝绞线和全铝合金绞线3种新型节能导线与推荐的JL/G3A-1250/70型钢芯铝绞线进行了技术经济性比较,结论为在该标段实际情况下,JL/G3A-1250/70型导线具有优势。

铝包钢芯高导电率铝绞线在输电线路中的应用

铝包钢线具备钢线的优越抗拉性能和铝的良好导电性能,耐腐蚀性能大大优于镀锌钢线,耐热性能良好。采用20.3%IACS的铝包钢线代替镀锌钢线作为加强芯,与高导电率铝线组成节能导线,比同规格的钢芯高导电率铝绞线机械性能有所提高,弧垂特性稍好,耐腐蚀性能明显提高,而电晕特性、电磁环境特性保持不变;尤其适用于沿海和重污秽地区,能够延长导线的使用寿命;应用于钢比为7%、9%、13%的导线时使电阻率分别下降1.2%、1.6%、2.3%以上。在500 kV线路典型算例中,导线费用增加部分约4年即可从降低的电能损耗中收回,此后每年能有很大的经济效益,值得推广。

铝包殷钢芯高导电率超耐热导线在增容线路中的应用研究

随着我国经济的发展和技术水平的提升,电力资源在我国的经济发展中发挥着更加重要的作用。并且,随着社会用电量的激增,使得我国对于电网建设以及其输送能力提出了更高的要求。在此背景下,铝包殷钢芯高导电率超耐热导线具有多种应用优势。基于此,本文就铝包殷钢芯高导电率超耐热导线在增容线路中的应用进行深入的研究,希望可以为现代电力产业的发展提供有效的建议以及参考。

输电线路节能导线选型研究

介绍各种常用节能导线特点，分析110～500kV线路中常用的1×240-4×630mm。规格下各种节能导线的载流量、电能损耗等电气特性和弧垂、风偏、过载能力、荷载等机械特性以及建设投资经济性，然后结合某500kV线路工程计算了4×630mm2截面规格下各节能导线的年费用。最后，综合考虑实际工程的具体特点给出了110～500kV电压等级下不同规格节能导线的选型建议。

线性化AlGaN/GaN HEMT费米能级与二维电子气密度关系的解析模型

通过化简复杂非线性的费米能级EF与二维电子气密度ns关系,并利用化简后函数的一阶泰勒多项式建立了线性化AlGaN/GaN HEMT中EF与ns关系的解析模型。该模型可以根据二维电子气密度ns的范围及温度计算EF与ns非线性关系之线性近似的参数斜率a和截距EF0。计算结果表明,所述模型的线性EF-ns计算结果对非线性精确解近似效果较好,且基于该模型计算的ns-VG曲线与实验数据符合良好。

Strain rate-dependent high temperature compressive deformation characteristics of ultrafine-grained pure aluminum produced by ECAP

To explore the effect of strain rate ε on the high temperature deformation characteristics of ultrafine-grained materials, the deformation and damage features as well as microstructures of ECAP-treated pure Al at different temperatures T and strain ratesε were systematically studied through compression tests and microscopic observations. The increase in ε eliminates strain softening at T≤473 K, and largely enhances the yield strength and flow stress at 473?573 K. The shear deformation dominates the plastic deformation of ECAP-treated Al. Many cracks along shear bands (SBs) are formed at T≥473 K and secondary SBs basically disappear at 1×10?3 s?1; however, at 1×10?2 s?1, cracks are only observed at temperature below 473 K, and secondary SBs become clearer at T≥473 K. The microstructures of ECAP-treated Al mainly consist of sub-grains (SGs). The increase in ε inhibits the SG growth, thus leading to the increases both in yield strength and flow stress at high temperatures.

偏栅Al_xGa_(1-x)N/GaN HEMT的二维模拟与特性分析

采用泊松方程-薛定谔方程-流体力学方程组自洽求解的方法,对偏栅AlGaN/GaN HEMT器件的电学特性进行了二维模拟。通过与传统正栅器件的模拟结果对比分析,可以看出,偏栅结构除了可以提高器件的击穿电压外,还可以提高直流输出电流和跨导,对输出特性和转移特性均有一定的提高。

新型节能导线在500 kV输电线路设计中的选型方法

结合国家电网公司有关要求,为进一步降低输电线路电能损耗,提高电能利用效率,积极推广节能、降耗、环保的新设备、新材料在输电线路上的应用,结合输电线路设计、运行经验及目前国内外新型导线在高压输电线路的应用现状、发展趋势,在太原500 kV太原南输变电工程(线路部分)中,对钢芯高导电率铝绞线、铝合金芯铝绞线和中强度全铝合金绞线三种节能导线与普通钢芯铝绞线进行技术经济比较,从电气性能、机械性能、施工安装、节能效益及工程投资等方面分析比较,为节能导线在工程中的选择方式提供了参考。

Effect Analysis of High Strain Rate and Anisotropy on Tension⁃Compression Asymmetry of Aluminum Alloy 7050

Using the devices of split Hopkinson tension bar(SHTB)and split Hopkinson pressure bar(SHPB),the dynamic tension and compression experiments in three typical forming directions(rolling direction(RD),transverse direction(TD)and normal direction(ND))were carried out at strain rates of 1000,2000 and 4000 s-1,respectively.From the microscopic point of view,the effect of strain rate and anisotropy on tension compression asymmetry of aviation aluminum alloy 7050 was studied by scanning electron microscope(SEM),metallographic microscope and electron backscatter diffraction(EBSD).The results showed that there was obvious asymmetry between tension and compression,especially that the yield strength of the material in tension was higher than that in compression.The asymmetry in the elastic stage of tension-compression was weaker and the asymmetry in the strengthening stage was stronger with the increase of strain rate.At the same strain rate,the changing trend of the flow stress was distinct under different orientations of tension and compression,which was related to the stress direction of the grains.According to EBSD grain orientation analysis and raw material texture pole figure analysis,it was found that the larger the difference in the degree of grain refinement during tension and compression,the larger the macro-flow stress difference.

Effect of Sc and Er additions on superplastic ductilities in Al-Mg-Mn-Zr alloy

The superplasticity of Al-6Mg-0.4Mn-0.25Sc-0.12Zr and Al-6Mg-0.4Mn-0.25Er-0.12Zr(mass fraction,%)alloys sheet was investigated,and the effect of Sc and Er was discussed.The results show that the superplastic ductilities of Al-Mg-Mn-Sc-Zr alloy was higher than that of Al-Mg-Mn-Er-Zr alloy at a wide temperature range of 400-540°C and high strain rate range of1.67×10-4-1.67×10-1 s-1.A maximum elongation 673%is obtained at 520°C and 1.67×10-3 s-1 in the Sc-containing alloy;while the Er-containing alloy only gets a maximum elongation 253%at 520°C and 1.67×10-3 s-1.Moreover,the average stress exponent of Sc-containing alloy is about 2.84,which is smaller than that of Er-containing alloy(3.64).Besides,the activation energies of the Sc-containing and Er-containing alloy are 84.8 k J/mol and 87.2 k J/mol,respectively.It is indicated that grain boundary sliding is the dominant mechanism during tensile deformation.According to microstructure examination,the better superplasticity of Sc-containing alloy may be attributed to the presence of Al3_(Sc,Zr)dispersoids,which can inhibit recrystallization and grain growth effectively.

铝合金芯铝型绞线在大容量直流线路中的应用

在±800kV、输送容量为9600MW(输送电流6000A)的情况下,6×1520mm2导线方案最优。采用截面为1520mm2的导线,思路之一是采用常规钢芯铝绞线,另一种思路是采用节能导线型线。这2种方式都能够达到减少线路损耗的目的,选择最优方案必须综合考虑导线的价格、杆塔的投资,以及导线的加工和施工难度等因素。从这2种思路的应用可行性出发,重点分析各种导线方案的制造能力、对施工机具的适用性,通过对各导线方案的电气性能、机械性能和经济性进行比较,认为铝合金芯高导电率铝型绞线虽然单价略高,但可以节约杆塔等投资,且制造环节不存在技术障碍,因此可以在轻、中冰区大规模推广采用JL1X1/LHA1-1040/550型导线。

输电线路新型节能导线的推广应用

结合国家电网公司基建新技术的推广应用,介绍了高导电率钢芯铝绞线、铝合金芯铝绞线和中强度全铝合金绞线的节能原理和性能,对比分析了3种新型节能导线在电气、机械特性等方面的技术差异,并对影响线路造价的敏感因素进行了分析,采用年费用和投资回收期法对导线的经济性进行了评价,最后提出了3种新型节能导线的工程应用范围,为节能导线的推广应用提供了参考。

Low strain rate compressive behavior of high porosity closed-cell aluminum foams

The impact of a rigid body(protected structure) together with cushion material(cellular metal foam) on hard ground from a fixed height was investigated.An analytical one-degree-of-freedom colliding model(ODF-CM) was established to analyze the protection ability and energy absorption by the foam under low velocity impact conditions.For validation,drop hammer experiments were carried out for high porosity closed-cell aluminum foam specimens subjected to low velocity impact loading.The dynamic deformation behavior of the specimen was observed and the velocity attenuation of the drop hammer was measured.The results demonstrated that the aluminum foam had excellent energy absorption capabilities,with its dynamic compressive behavior similar to that obtained under quasi-static loading conditions.Finite element method(FEM) was subsequently employed to obtain stress distributions in the foam specimen.As the propagating period of stress in the specimen was far less than the duration of attenuation,the evolution of the stress was similar to that under quasi-static loading conditions and no obvious stress wave effect was observed,which agreed with the experimental observation.Finally,the predicted velocity attenuation by the ODF-CM was compared with both the experimental measurements and FEM simulation,and good agreements were achieved when the stress distribution was considered to be uniform and the "quasi-static" compressive properties are employed.