摘要小电流接地系统在中国3～66kV中低压配电网被采纳。在小电流接地系统中，在现实生活中普遍看到的故障形式是单相接地故障，约占全部电网故障的80%或者更多。当发生故障时，故障相电压为零，非故障相电压上升为线电压，但三相电压还是对称，系统可以带故障使用1～2h，以提高系统使用的可靠性。但是必须得尽快找到故障选相，并解决故障以防事故扩大和设备损坏。小电流接地系统单相接地故障特征的研究，对所有电力系统的安好、经济的运行都具有非常重要的意义。69587

文章首先对电力系统的各个中性点的接线方式进行简明介绍，并对小电流接地系统的不一样的故障选相进行研究。系统的研究了小电流接地系统单相接地故障的分析方式，总结叙述了在发生单相接地故障后，系统的电压电流的变化情况和各相对地电容的电流。然后利用Matlab仿真软件构建了小电流单相接地故障的仿真模型，然后对中性点不接地系统进行仿真，通过设置线路和仿真等各个参数，给出了仿真结果及线路的各重要参数的波形图。最后，根据仿真结果得出重要结论及以后注意的问题。

毕业论文关键字：小电流接地系统  单相接地故障  故障选相  MATLAB仿真

Research on the method of fault phase selection for small current grounding

Abstract

 The low voltage distribution network of 3 ~ 66kV in our country adopts the small current grounding system. Single phase to earth fault in small current grounding system is the most common form of failure, accounting for more than 80% of the total network fault. When the fault occurs, the fault phase voltage is zero, the non fault phase voltage rise to the line voltage, but the three-phase voltage is still symmetrical, the system can take the fault to run 1 ~ 2H, in order to improve the reliability of the system operation. But it is necessary to find out the fault phase as soon as possible, and eliminate the trouble to prevent the expansion of the accident and equipment damage. The research on the characteristics of single phase to earth fault in small current grounding system is very important to the safety and economic operation of the whole power system.

 In this paper, a brief introduction to the power system of various neutral point wiring, and a variety of different fault phase selection method for small current grounding system is analyzed. The analysis method of single phase to earth fault in small current grounding system is studied systematically. The change of voltage and current in the system and the relative capacitance current are summarized and discussed. And by using the MATLAB simulation software established in small current grounding system, single-phase ground fault simulation model, respectively for small current grounding system neutral point ungrounded system simulation, by setting the line parameters and simulation parameters are the simulation results and line the main parameters of the waveform. Finally, based on the simulation results, we draw the conclusion and the problems that we pay attention to.

Key words: Small current grounded system  single-phase ground fault   Fault phase selection  MATLAB simulation              

目  录

摘要-Ⅰ

AbstractⅡ

目录-Ⅲ

图清单Ⅳ

绪论1

第1章 小电流接地系统接地故障的概况- -2

1.1 本课题的产生背景及研究意义 -2

1.2 接地方式现状-2

1.3 论文的首要工作- 3

第2章 小电流系统单相接地故障分析4

2.1 配电网系统的接线方式-4

2.2 两种小电流接地方式介绍5

2.3 小电流接地系统单相接地故障稳态分析-11