【作者】 杜波；

【导师】 许跃进；

【作者基本信息】 中国农业大学 ， 电力系统及其自动化， 2004， 硕士

【摘要】 我国大多数6～35kV中压配电网均采用中性点不接地或经消弧线圈接地的运行方式。单相接地短路是最常见的故障，由于它的接地短路电流较小，使故障检测较困难。而尽快选出故障线路，对于系统的运行具有重要意义。但综合国内外的研究现状，选线问题没有得到很好的解决。本文着重研究了利用小波包变换提取故障信号的暂态高频分量，进行故障选线的方法，并结合DSP技术架构硬件装置，提出一种可行的解决方案。 本文在中性点不同接地方式下，研究和分析了线路故障特征量的暂态特点，主要从信号处理的角度，提出将小波包分析理论运用到故障选线。利用各个出线零序电流在能量最大频带上小波包系数模值的大小和方向的不同来实现故障选线。 通过典型的10kV仿真算例验证了该方法的可行性。仿真结果表明：利用小波包分析理论对电力系统故障暂态信号特征提取处理是行之有效的方法。 高速单片数字信号处理器(DSP)是近年来迅速发展和广泛应用的单片计算机，以美国TI公司生产的TMS320系列最具代表性。在本设计中，以TMS320F240为CPU，以模块化设计完成装置的开发，基本实现了小电流接地系统的选线功能。更多还原

【Abstract】 In China, neutral isolated and Peterson coil grounded system are widely used in 6 kV~35kV medium voltage distribution networks. Single phase earthed fault is the common fault in this system. To detect the faulty feeder is difficult for the fault current is very small. When single phase earthed fault occurs, it is necessary to select the fault circuit quickly. But, from existing status of this field, it has not been done very well. This paper introduces a novel fault circuit selecting method, which utilizes wavelets packet transform to obtain useful fault transient components and based on DSP, proposes a feasible solution.This paper analyses the transient character of line fault when the neutral point connects to ground in different ways. From the angle of signal processing, the wavelet packet analysis theory is introduced to selecting fault, in which the fault character is not the steady signal but the transient signal. Judging by the different magnitude and direction of the wavelet packet coefficient modular maximum, we can select the single phase-to-earth line.The data from the example of typical small current grounding neutral system validate the feasibility of the algorithms. The simulation result shows that using Wavelet packet analysis to separate the character from the transient fault signals is an efficient way.High speed single chip digital signal processor (DSP) is the fast developing single chip computer in recent years, the typical one is the TMS320 family produced by the TI. This dissertation successfully developed a VLST digital signal processing single system, using TMS320F240 as its central processing Unit (CPU), finished the function of line-selecting of non-solid grounded networks.更多还原