For the unthermal effect of the magnetic field caused by the ehv transmission line , the intensity of the magnetic field has entered the range of the dangerous window . but it is needed to continue to study in future to understand the effect of the magnetic field to human exactly 但对于输电线所产生的工频磁场所产生的非热效应，在现有的输电线下，人体内产生的磁场在数量级上已进入了有害的窗口范围内，但对于人类健康的具体影响，还需要进一步的深入研究。
Based on former productive conditions , the corporation depends on the support of all circles , introduced an international advanced 500kv ehv crosslinking line from germany , so the productive scale of producing ehv cable of our corporation reaches the domestic largest and with the highest technical level ; at the same time , introduced international advanced production and testing equipment of digital cable and data cable line , able to produce cable of 1 million km , and 5 , 6 , and 7 digital cable of 50 thousand km , which set a base for the quick development of the enterprise , here i sincerely express our thanks to all circles for your great supports 集团在原有生产条件的基础上，依靠社会各界的支持，又从德国引进了一条国际先进水平的500kv超高压交联电缆生产线，使汉缆集团超高压电缆的生产规模达到国内最大技术水平最高同时，又引进了国际先进水平的光缆数据缆生产及检测设备，可生产100万芯公里光缆5万公里5 6 7类数据缆，为企业的快速发展奠定了基础。在此，我由衷地感谢社会各界朋友的鼎立支持。
Upon existent theoretical and experimental results and based on a great of laboratory investigations carried out in chongqing university , for the first time this paper studies systematically the insulators dc discharge performance and flashover mechanism of iced insulators in the complex atmospheric environment , which will contribute to the understanding of flashover phenomena observed on ice surface at low air pressure and provide the test and theoretical reference for hv and ehv transmission lines design and safety service 为此，在国内外现有工作的基础上，通过大量的试验研究，本文主要研究了复杂环境中绝缘子的直流闪络特性及闪络机理。其结果有助于进一步了解低气压下覆冰绝缘子的闪络现象，并可为输电线路的设计和安全运行提供理论依据。
The operation characteristic of the new relay is analyzed in theory and verified by the simulation tests . the new relay operates with clear selectivity and high operation speed and can satisfy the demand of the protection for the ehv transmission line . the performance of the fault component impedance relay has been improved and the misoperaion of the healthy phase under cross - country fault and close - in fault have been avoided 理论分析及仿真计算表明，基于自适应补偿的突变量距离继电器有很好的选择性和速动性，完全能够满足高压线路保护的需要，显著提高了突变量距离的性能，解决了其在大电源出口单相故障以及正反向复故障可能会误跳三相的缺点。
Along with the development of power system , more and more generators and ehv transmission systems are put into operation . there come many new situations , such as the lengthening transmission distance , the heavier load , the increasing transient elements during the transient process . these new conditions influence the correct working of relay protections 随着电力系统的不断发展，大容量发电机组和超高压输电系统的相继投入运行，系统中出现了许多新的情况，如输电距离增大、负荷加重、故障暂态过程中的暂态分量大大增加、持续时间变长等，这些情况对目前常用的各种继电保护方法的正确动作会产生许多不利的影响，甚至不能正常运行。
