文献综述
摘要:随着我国工业和经济的飞速发展,电网规模不断扩大,在工业、商业中的用电量和居民日常生活用电量也越来越大,用电安全方面问题日益受到人们的重视。电气火灾对人身安全及财产损失带来的巨大影响不容忽视。而配电线路上的电弧故障是引发电气火灾的主要原因。插拔电器的触头松动、线路绝缘层老化破损或触头接触不良都会导致电弧故障的发生。传统的低压保护电器都是以过电流和漏电流为保护对象,它们无法检测出配电线路上的串联电弧故障,已经不符合未来低压配电系统的发展需求。因此,对于研究低压配电线路中的电弧故障、设计电弧故障保护电器(AFDD)具有非常重要的意义。
本课题以低压电弧故障为主要研究对象,根据相关标准中对各种电器负载的要求配置电路,进行故障电弧的模拟实验,以获取电器负载在正常工作下和产生电弧故障时电流、电压信号。并对信号进行对比分析,提取电弧波形的特征值。由于住宅内电气线路设备长时间过负载运行或者存在不良电气连接等情况,易发生故障电弧,引发电气火灾。故障电弧发生时,电流较小,一般过流保护设备难以检测。
关键词:故障电弧,信号波形,电流信号,单片机
Abstract: With the rapid development of China#39;s industry and economy, the scale of power grid continues to expand, the power consumption in industry, commerce and residents#39; daily life is also increasing, and people pay more attention to the problem of power safety. The huge impact of electrical fire on personal safety and property loss can not be ignored. The arc fault on the distribution line is the main cause of electrical fire. Loose contacts of plug-in electrical appliances, aging and damage of line insulation layer or poor contact of contacts will lead to the occurrence of arc fault. The traditional low-voltage protection devices are all based on the over-current and leakage current as the protection object, they can not detect the series arc fault on the distribution line, which does not meet the development needs of the future low-voltage distribution system. Therefore, it is of great significance for the research of arc fault in low voltage distribution lines and the design of arc fault protection device (AFDD).
This topic takes the low-voltage arc fault as the main research object, configures the circuit according to the requirements of various electrical loads in the relevant standards, and carries out the simulation experiment of the fault arc, so as to obtain the current and voltage signals of the electrical load under normal operation and arc fault. The characteristic values of arc waveform are extracted by comparing and analyzing the signals. Due to the long-time overload operation or poor electrical connection of electrical circuit equipment in residential buildings, it is easy to cause fault arc and electrical fire. When the fault arc occurs, the current is small, so it is difficult for the general over-current protection equipment to detect.
Key words: fault arc, signal waveform, current signal, single chip microcomputer
1.电弧的概述
电弧是跨越某种绝缘介质的两个电极之间的持续放电现象,经常伴随着电极的局部挥发,是非常复杂的电磁反应过程。电弧一般在2个电极之间的空气中形成的,其中心温度高达5000~ 15000C。电弧存在的区域会产生很高的电离气压,使电弧释放出电极物质粒子和高热气体,极易引发火灾。
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