【作者】 程传玲；

【导师】 林军；

【作者基本信息】 福州大学 ， 电力系统及其自动化， 2003， 硕士

【摘要】 单相接地故障在小电流接地系统中出现的比较频繁，此时必须尽快找到故障线路以及大致的故障点，以避免两相对地短路。本文首先对小电流接地系统单相接地故障的选线及测距做了比较详细的综述。然后对小电流接地系统单相接地时零序电容电流的暂态过程及特点做了介绍和分析。根据故障时暂态信号的特征，提出了利用故障后信号的暂态高频分量来实现故障选线的方法。利用Morlet小波变换后的实部、虚部、模值以及相角来实现故障选线及暂态分量的提取，并比较了各种判断方法及小波算法的优缺点。设计了模拟小电流接地系统的实验室模拟电路以及高速数据采集的的硬件装置。完成了8255与PC机之间的并行通讯、高速14位A/D转换器与DMA控制器的数据采集等软件。通过大量的实验，表明利用小波变换后的实部、虚部、模值以及相角可以准确的给出故障线路并高精度的提取故障信号的暂态高频分量。更多还原

【Abstract】 The single-phase grounding fault frequently occurs in neutral ungrounded system, the fault line and fault location must be found to avoid a phase-to-phase short as soon as possible. In this dissertation, choosing the fault line and detecting the fault location in small current neutral grounding system are summarized in detail. Subsequently, the transient course and characteristics of zero sequence capacitive current are introduced and analyzed. According to the characteristics, it is presented that the realization of choosing the fault line based on the post-fault-transient electrical quantities. The Morlet wavelet transform is applied in choosing the fault line and detecting the transient high frequency signals. The virtues and flaws in various criterions and algorithm have been compared. I have designed a simulative circuit and a hardware installation of high-speed data collection. I have completed the transmission of parallel data between 8255 and PC, and the data-sample based on the 14-bit high-speed A/D converter and DMA controller. Plenty of experiments show the real, imaginary, module and angle of wavelet transform can accurately choose the fault line and precisely identify the high frequency of transient signals.更多还原