低压电弧故障检测方法及装置

发布时间：2018-07-04 14:30

本文选题：电气火灾 + 电弧　；参考：《山东建筑大学》2017年硕士论文

【摘要】：低压供电系统普遍采用低压断路器、熔断器等保护装置,通过检测电流和剩余电流有效值,能够有效防范短路、过负荷和对地漏电等故障。但对于接触不良、绝缘失效等原因引起的电弧故障则无法有效检测和可靠切除。目前,国外市场的故障电弧检测产品不适用于我国的供电系统,而且其检测准确性和可靠性也有待于进一步提高。本文对低压供电系统串联电弧故障的检测方法开展研究,基于仿真模型和模拟实验采集了多种负荷不同条件下的电流波形,优选了用于表征故障特征的频带和相应的小波基函数,以小波高频分量为基础建立了故障判据,并对故障检测装置进行了初步设计。主要研究工作和成果如下:1.基于Cassie电弧模型仿真了交流供电系统的串联电弧故障,研究了电弧电压参数对电弧电流、电压波形的影响。对故障电流波形进行快速傅里叶变换,计算故障及正常工况下各频带能量及能量比,得到表征电弧故障的特征频带。2.根据相关国家标准搭建故障电弧模拟实验平台,采集不同负荷在正常及多种故障条件下的电流波形,并对各负荷的电流波形特点进行对比。研究了阻性负载下,负荷电流、电弧燃烧剧烈程度对串联电弧故障电流波形的影响。采用多种小波基函数对故障电流波形进行分析,通过对比高频分量能量比,优化选取小波基函数和分解层数,作为电流小波高频分量的提取方法。3.对阻性负载电流的小波高频分量的统计分析,表明高频分量波动率能够准确表征串联电弧故障。在此基础上提出的小波高频分量周期方差值指标,能够较好的区分非线性负荷的正常电流与故障电流。对多种相似负荷的计算结果证明了该方法的有效性。4.在检测方法研究的基础上,对低压电弧故障检测装置进行了初步设计。硬件电路由STM32微控制器、电源及外围电路、电流互感器、电流调理电路、数据采集芯片、报警和脱扣等部分组成。软件设计包括检测装置主程序和中断服务程序设计。
[Abstract]:Low-voltage power supply system generally uses low-voltage circuit breakers, fuses and other protective devices. By detecting the effective value of current and residual current, it can effectively prevent short circuit, overload and ground leakage. However, the arc fault caused by poor contact and insulation failure can not be detected and removed reliably. At present, fault arc detection products in foreign markets are not suitable for power supply systems in China, and their accuracy and reliability need to be further improved. In this paper, the detection method of series arc fault in low voltage power supply system is studied. Based on the simulation model and simulation experiment, the current waveforms under various load and different conditions are collected. The frequency band and the corresponding wavelet basis function are selected to represent the fault characteristics. Based on the high frequency component of wavelet, the fault criterion is established, and the fault detection device is designed preliminarily. The main research work and results are as follows: 1. Based on Cassie arc model, the series arc fault of AC power supply system is simulated, and the influence of arc voltage parameters on arc current and voltage waveform is studied. The frequency band energy and energy ratio of each frequency band are calculated by fast Fourier transform for the fault current waveform, and the characteristic frequency band. 2. 2 is obtained to characterize the arc fault. According to the relevant national standards, the fault arc simulation experiment platform is built, the current waveforms of different loads under normal and various fault conditions are collected, and the characteristics of the current waveforms of each load are compared. The effects of load current and arc combustion intensity on the fault current waveform of series arc are studied. Various wavelet basis functions are used to analyze the fault current waveform. By comparing the high frequency component energy ratio, the wavelet basis function and decomposition layer number are optimized as the method of extracting the high frequency component of current wavelet. The statistical analysis of wavelet high frequency component of resistive load current shows that the fluctuation rate of high frequency component can accurately characterize the fault of series arc. On the basis of this, the periodic square difference index of wavelet high frequency component can distinguish the normal current and the fault current of the nonlinear load. The effectiveness of the method is proved by the calculation results of several similar loads. Based on the research of detection method, the low-voltage arc fault detection device is designed. The hardware circuit is composed of STM32 microcontroller, power supply and peripheral circuit, current transformer, current conditioning circuit, data acquisition chip, alarm and tripping. The software design includes detecting device main program and interrupt service program design.
【学位授予单位】：山东建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM501.2

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