电力系统微机保护论文--10KV电动机微机保护装置设计

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1、电力系统微机保护论文题目:10KV电动机微机保护装置设计姓名:摘要····················································3关键词··················································3引言····················································3l微机保护装置的组成及功能·······························32微机保护装置工作原理···································32．1启动时

2、间过长保护·····································42．2两段式定时限过电流保护······························42．3零序过电流保护·······································52.4低电压保护·············································52.5过电压保护·············································62.6磁平衡差动保护·····································

3、···62.7差动速断保·············································72.8过热保护··············································73微机保护装置硬件设计···································83.1主控单元··············································83.2键控显示单元··········································93.3数据采集单元···················

4、·······················103.4自动复位··············································113.5报带保护信号输出单元··································114软件设计···············································11结束语···················································12参考文献·················································1

5、2U0UK10KV电动机微机保护装置设计摘要：。针对高压电动机一些常见故降及产生这些故降的原因,提出了采用正负序电流的测量对电机故降进行分析的方法,阐述了采用微机系统设计的综合保护装里的硬件原理以及软件框图,达到了电动机短路保护;不平衡保护:接地故障保护;过欠压保护的目的。关键词：电动机，微机，保护引言：大型高压电动机随着工业的发展越来越广泛地应用于各行各业,推动了电力工业的发展。但是,据原电力部的一份调查资料表明,所调查34个电厂,高压异步电动机损坏率达巧.1%,造成经济上的巨大损失。因此,研究一种高压电动机的综合监测和保护装置迫在眉睫。高压电动机微机保护装置工作原理主要是采用

6、微型计算机对电动机的早期故障及非正常运行进行监测、报警和保护,该装置的功能有:短路保护;不平衡保护;接地故障保护;过热保护;过欠压保护等。下面就电动机微机保护装置工作原理以及软硬件设计加以阐述。l微机保护装置的组成及功能微机保护装置的核心一般由CPU、存储器、定时计数器、看门狗等组成。CPU大都是嵌入式微控制器(MCU)，即通常所说的单片机：I/O通道包括数字量输入输出通道(人机接口和电脉冲、各种告警信号、跳闸信号等)以及模拟量输入通道(A／D转换、模拟量输入变换回路、低通滤波器及采样)。2微机保护装置工作原理电动机损坏常见的原因有:三相电压不平衡;电机定子绕组开路造成负荷不平衡

7、及过负荷等原因。三相电压不平衡,负荷不平衡均将造成负序电流明显增大;过负荷运行时,正序电流将增大。本装置将通过监测正序、负序电流对电动机短路故障、不平衡故障,电机过热故障等进行及时保护。2．1启动时间过长保护电动机正常启动时，电流由零突然增大，当电动机的最大相电流从零突变到超过10％Ie时开始计时直到启动电流过峰值后下降到120％Ie(Ie为电动机额定电流)时为止之间的历时称为Tstmrt，电动机启电动机启动时间过长会造成转子过热，当装置实际测量的启动时问Tstmrt超过电动机整