【作者】 周凯；

【导师】 金之俭； 姜益民；

【作者基本信息】 上海交通大学 ， 电气工程， 2011， 硕士

【摘要】 雷击是引起线路故障的重要原因之一,随着电压等级的升高,由于绕击而引起短路跳闸事故所占的比例越来越大,因此准确评价线路的绕击耐雷性能对于电力系统的安全稳定运行有着重要的意义。目前,评价线路绕击特性的方法主要有规程法、电气几何模型和先导发展模型。电气几何模型作为一种绕击计算方法,将雷电放电特性同线路的结构尺寸联系起来,用击距来描述物体的引雷能力,比传统的经验方法前进了一大步。因此,输电线路和建筑物的雷电绕击的保护研究,目前主要以电气几何模型(EGM)为基础。由于EGM是一个以现场观测数据为基础的雷电绕击工程计算模型,因此在进行输电线路的防雷屏蔽设计时,还需要重新积累运行经验。鉴于这种原因,随着人们对长空气间隙放电和雷击放电的研究和认识逐步深入,Eriksson、Dellera、Rizk等人将近代长空气间隙放电的研究成果用于输电线路的雷电绕击性能研究,提出了先导发展模型(LPM)。实际上是先导发展模型是EGM的进一步发展,它认为:在下行先导的作用下,接地物体上产生的上行先导的发生、发展和相遇过程,对线路的雷电绕击性能起决定作用。论文依据电气几何模型的基本思想,以华东电网500kV单回路输电线路为研究对象,深入探讨A-W电气几何模型及先导发展模型的计算方法。完成对两种方法中重要参数的数学推导并建立输电线路雷电绕击的A-W电气几何模型和先导发展模型,使用AWEGM法对500kV洛肥线路及使用先导发展模型对500kV洛繁线路进行研究分析。确立模型中各类参数,特别是对击距公式等重要数值的确定。使用AWEGM法计算出线路中绕击跳闸率最高的塔杆。使用先导发展模型法计算出线路雷电绕击跳闸率。在此基础上说明线路中各相关因素对雷电绕击跳闸率的影响,并提出各种加强防雷性能措施。更多还原

【Abstract】 In recent years, lightning stroke is one of the important causes of the accidents that occur on transmission lines. With the increase of voltage grade of transmission line, the proportion of outages because of shielding failure also increases. Therefore, exactly evaluating lightning-withstanding level and shielding failure flashover rate (SFFOR) of transmission line, is especially important for system service and stable operation.At present, the main methods to evaluate the characteristic of shielding failure for transmission line are the standard method, leader progression model(LPM)and electric geometry model(EGM).The electric geometric method relates the lightning discharging characteristic with structural dimension of transmission line together, and“striking distance”is introduced to describe the object’s lightning attracting ability. It is much more advanced than the traditional method. Therefore, the electrical geometry model (EGM) is used as the foundation method to study on transmission lines and the buildings around the protection of lightning strike is mainly by at present.Because EGM is a engineering calculation model that based on the field observation data of the lightning strike. So designing the lightning protection shielding of the transmission line , we also need to accumulate the operation experience.In view of this reason, as people gain more knowledge about long air clearance discharge and lightning stroke discharge, Eriksson, Dellera and Rizk used the recent research results of long air clearance discharge in the study on shielding failure flashover and proposed the leading progression model (LPM). Actually leading progression model is the further development of the EGM, it said: in the downward leader role, objects on ground produced would produce and extent the upward leader which encounter the downward leader at last. This encounter made the decisive role in shielding failure flashover. The paper bases on the basic ideas of electrical geometry model and studied on east China power grid single loop transmission lines. The calculation method of both A-W electrical geometry model and the leading progression model would be strong explored in paper. A-W electrical geometry model and would be built. Especially important parameters of these two models would be deduced in detail. AWEGM method would be used in studying LuoFei 500 kV line to find out the highest shielding failure flashover rate of one pole in whole line and the leading progression model would be used in studying LuoFan 500 kV line to calculate shielding failure flashover rate of line. Establish all kinds of parameters in the two models, especially to determine formula of striking distance. On the basis of these records, some important relative aspects would make inflection on shielding failure flashover rate and some kinds of measures would be given to strengthen the lightning protection performance.更多还原