特高压直流输电线路单极接地故障过电压研究

发布时间：2018-01-30 16:41

本文关键词： 特高压直流单极接地故障过电压影响因素波过程机理分析限制措施　出处：《浙江大学》2017年硕士论文　论文类型：学位论文

【摘要】：单极接地故障是特高压直流输电线路上发生概率较高且造成过电压较为严重的故障类型,因此单极接地故障过电压也是特高压直流输电线路过电压研究的重点。通过仿真计算得到故障极线路沿线发生接地故障时健全极线路上沿线过电压分布规律,并将故障极线路中点发生接地故障时,健全极线路中点的过电压分成第1次跃升和第2次跃升两个过程。将可能对该过电压产生影响的因素按照严重程度分为一般因素和关键因素,其中一般因素包括输电线路结构及参数、直流控制系统、杆塔接地电阻、线路中点杆塔装设避雷器、输电线路长度和输送功率,关键影响因素包括接地故障位置、直流滤波器参数以及直流滤波器型式。并进一步分析了各影响因素对过电压的影响,确定直流滤波器主电容是影响直流线路单极接地故障过电压的最关键因素。基于极线的电磁耦合作用和波过程阐述了两次电压跃升的产生机理以及直流滤波器主电容对过电压的影响机理,故障极线路发生单极接地故障时,会在沿线产生2次电流跃升,由于极线间的电磁耦合作用,在健全极线路上也会产生2次反向电流跃升,2次电流脉冲会对健全极线路对地电容反向充电,从而造成健全极线路电压在额定电压的基础上发生2次跃升,从而导致过电压,而直流滤波器主电容则主要通过影响第2次电流跃升作用从而影响该过电压的第2次跃升作用,并对该过电压产生影响。研究表明,直流滤波器主电容参数是限制单极接地故障过电压的关键因素,而其他因素对该过电压影响并不大,主电容越大,过电压越严重,为控制该过电压幅值不超过1.7p.u.,推荐±800kV特高压线路直流滤波器主电容参数取值范围为1～2μF。
[Abstract]:Monopole grounding fault is a kind of fault with high probability and serious overvoltage on UHVDC transmission line. Therefore, the over-voltage of single-pole grounding fault is also the focus of UHV HVDC line overvoltage research. Through the simulation calculation, the distribution of overvoltage along the perfect pole line is obtained when grounding fault occurs along the fault pole line. And grounding fault occurs at the midpoint of the fault pole line. The overvoltage at the midpoint of the sound pole line is divided into two processes: the first jump and the second jump. The factors that may affect the overvoltage are divided into general factors and key factors according to the severity of the overvoltage. The general factors include the structure and parameters of transmission line, DC control system, grounding resistance of tower, the installation of lightning arrester at the middle point of transmission line, the length of transmission line and the transmission power. The key factors include ground fault location, DC filter parameters and DC filter types. Determining the main capacitance of DC filter is the most important factor to influence the overvoltage of DC line unipolar grounding fault. Based on the electromagnetic coupling of the pole line and the wave process, the mechanism of two voltage leaps and the main DC filter are expounded. The influence mechanism of capacitance on overvoltage. When the single pole grounding fault occurs in the fault pole line, there will be two current jumps along the line, and two reverse current jumps will also occur on the perfect pole line due to the electromagnetic coupling between the pole lines. The second current pulse will reverse charge the capacitance to the ground of the sound pole line, thus causing the voltage of the sound pole line to jump twice on the basis of the rated voltage, resulting in overvoltage. On the other hand, the main capacitance of DC filter mainly affects the second jump of the overvoltage by affecting the second current jump, and has an effect on the overvoltage. The main capacitance parameter of DC filter is the key factor to limit the overvoltage of unipolar grounding fault, but other factors have little influence on the overvoltage. The larger the main capacitance, the more serious the overvoltage. In order to control the overvoltage amplitude not to exceed 1.7 p.u., it is recommended that the range of main capacitance parameters of 卤800 kV UHV DC filter is 1 渭 F.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM75

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