高压输电线路雷击过电压的识别研究

发布时间：2018-02-03 10:30

本文关键词： 高压输电线路雷击过电压 ATP-EMTP 小波分析雷击识别分类　出处：《广西大学》2017年硕士论文　论文类型：学位论文

【摘要】：在电力系统中,高压输电线路的输送距离很长,线路可能经过不同的地形地貌且距离地面高,因此,高压输电线路遭遇雷击的概率相比其他的电力设备要大很多。因此,输电线路的雷击过电压也成为了影响电网安全运行的重要因素之一。高压输电线路的雷击过电压有两种,一种是感应雷过电压,另一种是直击雷过电压,根据雷击部位的不同又可分为反击和绕击。高压输电线路在遭受雷击后会产生过电压促使线路绝缘发生冲击闪络,进而转变成工频电弧,引起线路跳闸。因此,对输电线路雷击过电压进行识别,这样就能对不同的雷击产生的过电压采取对应的措施,防止事故的发生,保证了输电线路的可靠供电。在电网进行防雷建设时,雷击过电压的识别对防雷的架构具有指导作用,为继电保护的整定提供了可靠依据,对输电线路故障的定位、预测都有着重要的参考意义。本文阐述了雷电流的形成机理,结合电力系统暂态的分析方法分析了雷电流作用于输电线路产生故障的原因,再对输电线路雷击过电压进行分类识别。借助电力系统电磁暂态软件ATP-EMTP对输电线路进行建模,得到对应的仿真模型,结合实例对输电线路各个类别的雷击过电压进行仿真,得到其不同故障类型下的暂态过电压信号。在此基础上,结合具有强大运算能力的Matlab软件来处理和分析雷击暂态信号,根据小波变换提取到具有区分度的7个特征量,从而对输电线路雷击过电压进行分类识别。在提取出不同情况下的特征量以后,得到识别的综合判据,同时依据电网运行长期积累的经验,对判据进行适当的修改,并设置相应故障类型检测到的雷击过电压进行识别分类,验证该方法具有一定的适应性。
[Abstract]:In the power system, the transmission distance of HV transmission line is very long, the transmission line may go through different terrain and landform and be high from the ground, so the transmission distance of HV transmission line is very long. The probability of high voltage transmission lines being struck by lightning is much higher than that of other power equipments. Lightning overvoltage of transmission line has also become one of the important factors that affect the safe operation of power grid. There are two kinds of lightning overvoltage in high voltage transmission line, one is induced lightning overvoltage, the other is direct lightning overvoltage. According to the different location of lightning strike, it can be divided into counterattack and wound strike. The over-voltage of high voltage transmission line will cause the line insulation to impact and flashover after being struck by lightning, and then change to power frequency arc, which will cause line tripping. The lightning overvoltage of the transmission line can be identified, so that the corresponding measures can be taken to prevent the accident from the overvoltage caused by the different lightning strike. It ensures the reliable power supply of transmission lines. In the lightning protection construction of the power network, the identification of lightning overvoltage has a guiding role to the lightning protection framework, and provides a reliable basis for the setting of relay protection. It is very important to predict the fault location of transmission line. The formation mechanism of lightning current is expounded in this paper. Combined with the analysis method of power system transient, the causes of the failure caused by lightning current acting on transmission line are analyzed. Then the lightning overvoltage of transmission line is classified and identified, and the corresponding simulation model is obtained by using the power system electromagnetic transient software ATP-EMTP to model the transmission line. The transient overvoltage signals under different fault types are obtained by simulation of various types of lightning overvoltages in transmission lines. Combined with Matlab software with powerful computing ability to process and analyze the transient signal of lightning stroke, seven characteristic quantities with discrimination are extracted according to wavelet transform. Then the lightning overvoltage of transmission line is classified and identified. After extracting the characteristic quantity under different conditions, the comprehensive criterion of recognition is obtained, and the long accumulated experience of power grid operation is obtained. The criterion is modified appropriately, and the lightning overvoltage detected by the corresponding fault type is set to identify and classify, which verifies that the method has certain adaptability.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM863

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