【作者】 杨璐；

【导师】 佘致廷；

【作者基本信息】 湖南大学 ， 控制科学与工程， 2019， 硕士

【摘要】 随着国内经济高速发展,各种不同电器设备在家庭、商业和工业不断涌现,电气线路故障引起的电气火灾也越来越多,给人们的财产和生命安全带来极大危害。近年来国内外学者针对电气线路故障电弧理论与探测装置展开了深入地研究,该课题已成为电气领域的重要研究方向。故障电弧分为三类:串联故障电弧、并联故障电弧和接地故障电弧。发生并联故障电弧和接地故障电弧时其故障电流较大,传统电气保护设备可以有效进行保护。而发生串联故障电弧时,通常串联故障电弧电流小于传统电气保护设备设定的短路和过载阈值,传统电气保护设备不能有效预防电气线路串联故障电弧引起的电气火灾。因此研究串联故障电弧特性和检测故障电弧方法有着非常重要的理论价值和实际意义。本文运用智能控制理论提出了 一种时域和频域相结合的小波变换故障电弧检测方法。该方法首先运用时域周期能量分析,计算每半周波电流能量值,然后计算故障时的能量值与正常时的能量值的比值,得出阈值作为检测故障电弧的判据1;然后运用db3小波变换理论提取故障电弧高频信号,设计Mallat算法对不同频段的信号进行分解处理,导出故障电弧的特征值作为检测故障电弧的判据2;最后将时域和频域的两个判据相结合,从而有效地判别电气线路串联故障电弧。该方法从根本上解决了传统故障电弧电流过零检测负载适应性差的不足,扩大了故障电弧检测的应用范围。在理论分析基础上,本文研究了一套基于ARM芯片STM32F405的故障电弧探测系统。该故障电弧探测系统硬件部分主要包括:ARM最小控制系统、电源模块电路、电流检测和调理电路、CAN通讯电路和声光报警电路等。本系统的软件部分主要包括:电流信号采集子程序、故障电弧检测子程序以及声光报警和CAN通讯子程序等。最后依据UL1699标准搭建了模拟故障拉弧主电路与故障电弧探测系统构成的故障电弧实验平台。在该实验平台上进行了阻性负载、阻感性负载和特殊负载等各类电气负载的拉弧实验研究,验证了本文所提出的基于小波变换故障电弧检测方法比传统故障电弧电流过零检测方法具有更广泛的负载适应性和有效性。更多还原

【Abstract】 With the rapid development of China,s economy,various electrical equipment are constantly emerging in the home,business and industry.The electrical fires caused by electrical line faults are also getting higher and higher,which brings great harm to people ’s property and life safety.In recent years,domestic and foreign scholars have conducted in-depth research on electrical circuit arc fault theory and detection devices,which become an important research direction in the electrical field.Arc fault are generally classified into three categories:series arc fault,parallel arc fault,and ground arc fault.Generally,the fault current is large when the parallel arc fault and the ground arc fault occur.The traditional electrical protection equipment can effectively protect.When the series arc fault occurs,the series fault arc current is smaller than the short circuit and overload threshold set by the traditional electrical protection equipment.Electrical protection equipment cannot effectively prevent electrical fires caused by series arc fault in electrical circuits.Therefore,it has great theoretical and practical significance to study series arc fault and the method of detecting arc fault.This paper proposes a wavelet transform arc fault detection method based on the combination of time domain and frequency domain.The method firstly uses the time domain periodic energy analysis to calculate the energy value per half cycle current,and then calculates the ratio of the energy value at the time of failure to the energy value at normal time,and obtains the threshold value as the criterion for detecting the arc fault 1;then uses the db3 wavelet The transformation theory is used to extract the high-frequency signal of the arc fault.The Mallat algorithm is designed to decompose the signals of different frequency bands,and the characteristic value of the arc fault is derived as the criterion for detecting the f arc ault.Finally,the two criteria of time domain and frequency domain are combined.Therefore,the electrical circuit series arc fault is effectively discriminated.The method fundamentally solves the problem of poor adaptability of the traditional arc fault current zero-crossing detection load,and expands the application range of the arc fault detection.Based on theoretical analysis,this paper studies an arc fault detection system based on ARM chip STM32F405.The hardware part of the arc fault detection system mainly includes:ARM minimum control system,power module circuit,current detection and conditioning circuit,CAN communication circuit and sound and light alarm circuit.The software part of the system mainly includes:current signal acquisition subroutine,fault arc detection subroutine,sound and light alarm and CAN communication subroutine.Finally,an arc fault experiment platform composed of a simulated arc fault main circuit and an arc fault detection system 1s built according to the UL1699 standard.The experimental study on the arcing of various electrical loads such as resistor load,resistor-inductance load and special load is carried out on the experimental platform.It 1s verified that the proposed method based on wavelet theory arc fault detection method has better detection method than traditional arc fault current zero-crossing detection method.More extensive load adaptability and effectiveness.更多还原