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摘要
谐振接地系统发生单相接地后,因为故障电流小,不至于影响系统供电,所以,按照规程可以继续运行1~2小时。但是,如果不能够及时、准确地排除故障,很容易使得故障扩大发展成多点接地、相间短路,因此,小电流接地系统中发生单相接地故障后,应尽快在规定的时间内找出故障线路,以便发出报警或切除故障线路。由于接地故障电流非常小,采用常规的继电保护装置从同一母线的多条出线中识别出故障线路非常困难,因此,在这一领域开展研究工作,具有重要的意义。
本文对谐振接地系统单相接地故障特点和规律进行了详细理论分析,并结合MATLAB软件搭建了小电流接地系统模型,并基于零序有功分量故障选线法进行了仿真验证。
关键词: 谐振接地故障选线有功分量 MATLAB
Abstract
When single-phase-to-ground fault occurs in the resonant grounding system, the short circuit current is very small and the power supply will not be disturbed. Thus the faulted power system can still operate for 1-2 hours according to the rule. However, if the fault cannotbe correctly eliminated in time, the case will e worse and even multi-point grounding fault or two-phase-to-ground fault may occur. Therefore, it is necessary to distinguish and cut the faulted line when single-phase-to-ground fault occurs in the small current grounding system. Line selection has great meaning and practical value for the continuous operation of the work and stable power supply.
In order to solve difficult problems of the resonant grounding system's fault line selection, this paper analyzes the characteristics of the small current grounding system when ground fault occurs in details. The small current grounding system model is built with Matlab . Based on the zero sequence ponent of fault line selection method is validated by simulation. MATLAB simulation results indicate that this method is effective to select the fault line.
Key words : Resonant grounding Fault line selection ponent MATLAB
目录
1 绪论 1
1
5
7
2 现有选线方法概述 9
9
14
外施影响法 19
3谐振系统单相接地故障过程分析 21
21
25
4基于有功分量的选线方法 28
理论原理 28
有功分量法的改进 30
31
5接地故障选线仿真分析 33
MatIab及Simulink简介 33
34
6 待解决的问题与展望 44
致谢 46
参考文献 47
附录 49
1 绪论
在快速发展的现代社会,用电设备不断增多,不但对电能需求量越来越大,而且对供电可靠性的要求也越来越高,电网尤其是中低