【作者】 魏文彬；

【导师】 戚宇林；

【作者基本信息】 华北电力大学 ， 通信与信息系统， 2011， 硕士

【摘要】 我国配电网大多采用的是中性点非有效接地方式,即小电流接地系统。配电网结构复杂,发生的故障大多数都是单相接地故障。因此,配电网单相接地故障能否快速准确定位,对保障电力线路正常输配电,保证整个电力系统安全、稳定、经济运行有着十分深远的意义。近年来,低频交流信号注入法在配电网单相接地故障定位中得到了有效而且较广泛的应用。由于导线分布电容的影响,低频交流信号注入法采用60Hz注入信号代替“S”信号注入法的220Hz注入信号。低频交流信号法采用二分法沿线路查找故障,探测器显示当前位置的实时电流波形,由于户外环境等因素,实时波形有时候难以判断当前位置的电流是分布电容电流还是故障电流。本文对探测器进行系统设计,硬件部分包括滤波放大电路,控制部分和显示部分,用Protel绘制电路板,主要芯片选择8051f310和UAF42来完成;软件部分设计包括单片机模数转换部分,定时计数部分,中断及频谱分析部分,用KeilC来完成程序的编译工作。本文用FFT算法对探测到的电流信号进行频谱分析,比对工频信号和注入信号含量,通过显示两信号的能量分布来判断当前位置是否是故障点。更多还原

【Abstract】 The distribution networks mostly adopt neuter point not- valid grounding in China, which is called the small current grounding system. The fault in distribution networks mostly is single-phase grounding fault because of its complex structure. The fast and accurate location that the single grounding fault, not only to the repair wire and promise dependable power supply, and circulate to the safe stability and economy that promises the whole electric power system to all have a very important function.The low frequency AC signal injection method applies effectively and widespread in distribution network single phase-to-grounding fault location. Traditional“S”injection method with 220Hz injected frequency is affected by the wires distributed capacitance, so low frequency method adopts 60Hz instead of 220Hz. The low frequency method uses dichotomy along the route to detect the fault, and its detector displays the real-time current waveform of the current position. Due to the outdoor environment factors, it’s difficult to judge the present current distributed capacitance current or the fault current through the real-time waveform. The signal detector is designed systematically in the paper. The hardware part includes filter and amplification circuit, control section and display section, using Protel to draw boards with single chip 8051f310 and the filter UAF42. The software part includes the design of microcontroller A/D part, timing counter part, disruptions and spectrum analysis, with Keil C to complete part program compiles work.A FFT algorithm is used to analyze the detected current signal’s spectrum in the paper. After compared the energy content with the power signal and the injected signal, the fault point can be judged by showing the two signals’energy content.更多还原