摘要小电流接地系统发生单相接地故障以后，断路器不会立即跳闸，系统可以继续运行一到两个小时，不过故障时产生的电压升高会对设备等造成不小的影响，因此找到一种及时有效的选线方法并且尽快排除故障就十分必要。在研究了小电流接地系统及其故障特征的基础上，比较分析各选线方法的适用情况，选出了小波变换法作为选线方案，并利用MATLAB软件对该方法进行仿真。接着，基于综合利用暂态量和稳态量的互补性将小波变换法和零序电流比幅法这两种方法结合到一起进行选线，同样用软件进行仿真。仿真结果与实际故障情况相符，验证了小波变换法以及后面融合到一起的综合选线方法的可行性和准确性。通过对各方法的研究以及仿真验证，发现小波变换法的确十分的有效，综合选线方法的互补性利用得也很成功。67640

毕业论文关键词  小电流接地系统  单相接地  故障选线  MATLAB   综合选线

毕业设计说明书（论文）外文摘要

Title    Small current grounding system single-phase      

            fault line selection method                                                

Abstract

After the small current grounding system occurred single-phase ground fault, the circuit breaker does not trip immediately, the system can continue to run one to two hours, but the fault is generated when the voltage increases such as device and caused no small impact, so it is necessary to find a timely and effective method to select line and as soon as possible to troubleshooting. On the basis of the small current grounding system and its fault characteristics, compare and analysis applies of each line selection methods, elect wavelet transform method as the line selected program, and use the MATLAB software to simulate this method.  Next, base on the comprehensive use of complementary of Transient and steady state, combine the wavelet transform method and zero-sequence current amplitude comparison method together to select line, also use the software to simulate. The simulation results and the actual fault condition are matched, and verify the feasibility and accuracy of the wavelet transform method and the comprehensive method to select line mixed together. By the research and simulation of each method, it is found that the wavelet transform method is indeed very effective, the use of the complementary of comprehensive method to select line is also very successful.

Keywords  small current grounding system   single-phase ground 

fault line selection   MATLAB   comprehensive line selection

目   次

1  绪论.1

  1.1  课题的研究背景、目的及意义...1

  1.2  国内外研究现状和发展趋势.1

       1.2.1  国内外研究现状1

       1.2.2  各国应用情况及发展趋势3

  1.3  目前存在的问题...4

  1.4  论文的主要工作...4

2  小电流接地系统特征及选线方法研究.6

  2.1  小电流接地系统特点及其故障特征...6

  2.2  选线方法描述及研究比较...7

       2.2.1  选线方法描述..7

       2.2.2  对选线方法的研究比较.11

       2.2.3  选线方案的流程描述...12

  2.3  本章小结12

3  利用MATLAB软件对选线方法进行仿真验证...13