配电网小电流接地系统单相接地故障定位方法研究

发布时间：2018-07-04 14:23

本文选题：小电流接地系统 + 小波变换　；参考：《湖北工业大学》2017年硕士论文

【摘要】：我国配电网广泛采取小电流接地系统,对于该系统来说,大多数的故障属于单相接地故障。对于系统发生这种故障来说,由于发生故障时电流比较小,对系统的正常运行不会造成影响,但是一旦转化为短路故障就会严重危害系统正常运行。所以说选择合适的选线及测距方法,切确的找到故障线路并切除故障,对电网的安全运行具有非常重要的意义。本文在对现有的选线和测距方法进行了总结的基础之上,对基于小波分析的小电流接地系统单相接地故障选线方法进行了认真的研究,同时采用了一种狼群算法优化BP神经网络的故障测距新方法,并在MATLAB/ATP中进行了仿真验证。本文在对选线和测距的研究之前,首先对两种不同中性点接地方式发生单相接地故障时的稳态和暂态特性作了一些对照分析,并进行了仿真验证,通过分析发现,出现单相接地故障后的暂态过程中包含有大量的高频特征信息,为后面的选线和测距打下了基础。针对选线问题,可以利用小波变换多分辨率分析的特点来提取故障暂态的高频特征,所以本文对基于小波分析的故障选线方法进行了深入的研究,首先,对小波理论以及小波分析在电力系统中的应用作了详细的介绍,接着,利用小波变换对暂态突变信号的强大处理能力,构造了小波变换的小电流单相接地故障选线判据,该判据主要是在原来选线的基础之上作了改进,即选取模极大值的平方差值来判断故障线路。最后,在Matlab中搭建10kV小电流接地系统仿真模型,通过选线算例仿真验证了该方法的有用性。针对故障测距问题,本文对狼群算法优化BP神经网路的故障测距新方法进行了研究探讨,首先主要对固有频率与故障距离两者的数学关系进行了分析,搭建了以此为输入的测距模型,运用了狼群算法优化BP神经网络的结构,并在ATP中进行了仿真,验证了该方法的准确性。最后,对电缆-架空线故障定位装置进行了系统设计,将硬件和软件部分作了简要阐述,并将该装置运用到了黄石10kV金广厦二回线混合线路的故障定位中,通过测试验证了该装置的有效性。
[Abstract]:The small current grounding system is widely used in China's distribution network. For this system, most of the faults belong to single-phase grounding fault. For this kind of fault, because of the small current when the fault occurs, the normal operation of the system will not be affected, but once it is transformed into a short-circuit fault, it will seriously harm the normal operation of the system. Therefore, it is very important for the safe operation of the power system to choose the appropriate route selection and location method, find the fault line and remove the fault exactly. On the basis of summarizing the existing line selection and location methods, this paper makes a careful study on the single-phase grounding fault line selection method of small current grounding system based on wavelet analysis. At the same time, a new fault location method based on wolf swarm algorithm is proposed to optimize BP neural network, and the simulation is carried out in MATLAB / ATP. In this paper, before the research of line selection and location, the steady state and transient characteristics of two different neutral grounding modes are compared and analyzed, and the simulation results show that, The transient process of single-phase grounding fault contains a large amount of high frequency characteristic information, which lays the foundation for the later line selection and location. To solve the problem of line selection, we can use the characteristics of wavelet transform to extract the high frequency characteristics of fault transient, so this paper makes a deep research on the method of fault line selection based on wavelet analysis. The wavelet theory and the application of wavelet analysis in power system are introduced in detail. Then, by using the powerful processing ability of wavelet transform to transient sudden change signal, the criterion of fault line selection for small current single-phase grounding fault based on wavelet transform is constructed. The criterion is mainly improved on the basis of the original line selection, that is, selecting the square difference of the modulus maximum to judge the fault line. Finally, the simulation model of 10 kV low current grounding system is built in Matlab, and the effectiveness of the method is verified by the example of line selection. In order to solve the problem of fault location, a new fault location method based on wolf swarm algorithm is studied in this paper. Firstly, the mathematical relationship between natural frequency and fault distance is analyzed. Based on this model, the structure of BP neural network is optimized by using wolf swarm algorithm, and the simulation results in ATP are given to verify the accuracy of the method. Finally, the system design of the cable-overhead line fault location device is carried out, the hardware and software parts are briefly described, and the device is applied to the fault location of the Huangshi 10kV Guangxia secondary circuit line. The validity of the device is verified by test.
【学位授予单位】：湖北工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM862

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