为了研究导线内存在的捻矩对覆冰导线系统的气动力稳定性及舞动特性的影响规律,首先建立覆冰导线三自由度耦合的风致振动分布参数连续体非线性动力学偏微分方程;然后,利用Galerkin离散得易于求解的常微分方程;最后以新月形覆冰分裂导线为例,借助符号运算软件Mathematica,应用Routh-Hurwitz判据进行系统稳定性分析,获得分裂导线临界起舞风速νcr随导线扭绞系数βt变化的曲线图,而βt的绝对值越小,系统的临界起舞风速值νcr越高.研究结果表明:采用不同绞向组合的分裂导线,可减小甚至消除系统内的捻矩,从而提高系统的临界起舞风速值.研究成果可为输电线路舞动治理提供一种全新的理论指导和方法.

<正>锦屏—苏南±800千伏特高压直流线路工程,是国家电网公司继成功建设向家坝—上海±800千伏特高压直流线路工程之后,又一个具有里程碑意义的重大工程。广大建设者不畏艰险,舍小家、顾大家,默默无闻,无私奉献,用智慧和忠诚谱写了一曲曲新的赞歌。

The paper illustrates the principle of metal deformation when compressed and conductor deformation process when compressed for connection,analyzes several causes to produce untwisted strands of large-sectional conductor during its compression for connection.It also puts forward several methods including increasing compressor pressure,optimizing mould design and changing compressive directions to eliminate untwisted strands.

The application of large cross-section conductor can effectively reduce the current density and realize the strategy of energy saving & consumption reduction. This paper introduces the large cross-section conductor (900 mm2) applied in the ±800 kV Jinping-Sunan UHV DC project, and focuses on the analysis of factors concerning the conductor's engineering application. The factors include structure design and manufacturing of conductor, fittings, engineering technology, etc. The conclusion is finally drawn: it is feasible and necessary to design a four-layer aluminum strand for conductors with the dimension of 900 mm2, by which the productivity has the expanding potential;there are no obstacles to the design and manufacturing of fittings;the releasing scheme should be further optimized;the existing traction and stretching machines can be used and the pulley and card conductor should be developed. It also indicates that large cross-section conductor (900 mm2) is expected to have a broad application.

This paper combines operation experiences of the foreign and domestic electric power transmission lines and ultra high voltage,and analyzes the lightning shielding failure which is the reason of high voltage electric power transmission line failure trip thoroughly.Based on the classical theory of electric power transmission line lightning prevention,this paper utilizes the last achievement of electric geometry model and lightning leader theory,and researches the application technique of lightning rod for lightning shield failure prevention of overhead electric power transmission line.The method of this kind of lightning rod in overhead grounding line reasonably can increase the shielding performance and lightning attracting effect,convert possible lightning shield failure into hit-back lightning to control it,and decrease the lightning failure trip rate.This paper also introduces the operation status and effect of this lightning rod,and accumulates the precious experiences in the lightning prevention and construction of ultra high voltage grid.

To solve the problem that the insulator string flashover voltage of some poles and towers can not be increased by adding insulator disks due to window size limit,a new type of inversed V-shape insulator string is developed.Through analysis of its design principle,structure,and functions,as well as operation tests,it is proved that the new design achieves good overall effects on preventing line flashover caused by dust and ice,windage prevention,and lightning prevention.To aged operating lines,which are limited by pole and tower windows,the new design is especially important in insulation upgrading and dust flashover prevention.

为了解决部分杆塔因窗口尺寸限制无法通过增加绝缘子片数提高绝缘子串闪络电压的问题,开发了一种新型绝缘子倒"V"串结构.通过对其设计原则、结构型式和功能的全面分析,以及试运行经验,证明倒"V"串结构对输电线路防污闪、防冰闪、防风偏、防雷击具有综合治理效果,尤其是对于杆塔窗口受到限制条件下的老旧运行线路的绝缘改造和防污闪治理,具有重要作用.

As a very important anti-pollution flashover measure, composite insulators are widely used in domestic pewer grids. In the year of 2005 it is often found in the maintenace of domestic inter-area transmission lines that composite insulators are pecked, this phenomenon directly threatens the secure operation of power system. For this reason, State Grid Corp. of China organized joint on-site investigation for four 500kV AC/DC transmission lines located in Henan, Hubei and Zhejiang provinces where the bird damage is severe, and it was found that the pecking phenomena mainly happened in the un-energized transmission lines, and the bird pecking is considerably effected by different shed shapes of composite insultors and suspension types, and it remains to be deeply studied for other factors influencing the brid pecking.

通过统计2次冰灾中电网设备受损情况,分析了事故及异常的原因,总结了经验教训,进而提出了切合实际的治理措施,对提高电网设备抵御恶劣天气的能力,促进湖北电网的安全、稳定、经济、优质运行起到了很好的推动作用,也为防止类似事故的重复发生提供了借鉴和依据.

利用"击距理论"对湖北省超高压局所辖 1 320 km 500 kV 线路已查明雷害事故进行统计、分析,得出绕击是造成超高压线路雷击跳闸的主要原因,同时对防止绕击雷害事故发生提出建议.