继电器保护毕业设计

论文编号:JD309       论文字数:31569,页数:63

摘  要

继电保护是保障电网可靠运行的重要组成部分，继电保护装置广泛使用在变电站和断路器上，用于监测电网运行状态，记录故障类型，控制断路器工作。煤矿井下工作条件特殊，如果缺乏必要和可靠的保护装置，电气设备长期过载容易引起井下火灾，漏电及短路故障容易引起瓦斯爆炸。所以，煤矿井下安全供电，就是应井下的特殊工作条件而采取的相应的措施。
本设计的重点是电流保护中低压开关的微机电流保护部分。本微机保护由硬件和软件两部分组成。微机电流保护系统硬件装置由模拟量输入系统、CPU主系统和开关量输入/输出系统三大模块组成。模拟量输入系统将从煤矿供电系统中取到的电压、电流等模拟量转换成数字量，送入CPU系统读取运算。CPU再对各种数据进行分析和运算处理，以完成保护功能。软件部分主要是通过单片机及其程序的执行来实现的。
关键词： 低压开关； 速断电流保护； 防爆； 微机保护； 硬件设计；

ABSTRACT
Protective relay is one of the most important parts in the electric power system ensuring the credibility of the transmitting network. Protective relay instruments are being widely used in the transformer substations and switches,examining the operating status, registering thepower failure and control the movements of the switches. Collier underground service condition is very particularity,if there is a lack of indispensability amd reliable protector,there will be a fire or gas explosion caused by long-term overload,creepage and short circuit. So ,collier downhole security power suplly is the homologous step for the particularity working condition.
The pivot of this rated is the microcomputer current protection of the low-voltage protection’ current protection.The microcomputer shiled is composed by two parts which are the hardware and the software.The hardware dvice of the microcomputer current protection systerm contins three macromoduls.They are analog quantity input systerm,CPU host systerm and on-off input/output systerm.Voltage signal and electric signal which are taken from the colliery power supply systerm are tansformed to digital signals and loaded to the CPU systerm to be read by the analog quantity input systerm. In order to complete the mission of the shield,different kinds of the information is analysesed and processed the CPU systerm.The software part is realized primarily by the monolithic computer and its rate .
KEYWORDS: low-voltage switch; elctric current quick break shield; blast protection; microcomputer protection; hardware design.

目    录

1 绪论 1
1.1课题意义 1
1.2国内外发展状况 3
1.3课题内容和实现方法 4
1.4应用 4
1.5预期目的 5
2 继电保护原理 6
2.1 继电保护原理 6
2.1.2微机保护原理 8
2.1.3微机电流保护的抗干扰措施 10
2.1.4系统的自检 13
2.2 整定计算 14
2.2.1 整定原则 14
2.2.1 相关计算 15
2.3 井下低压短路电流计算 16
2.3.1 计算的目的和要求 16
2.3.2 井下低压电网短路电流计算的特点 17
3 井下低压开关 18
3.1井下电网 18
3.2矿用低压电器 19
3.3 井下低压开关保护的要求 19
4 硬件设计 21
4.1 数据采集 21
4.1.1模拟信号采集 21
4.1.2 A/D转换 25
4.2微机保护主系统 28
4.2.1微机的接口 28
4.2.2掉电保持电路 30
4.2.3 复位电路 31
4.3开关量输入/输出回路 32
4.4键盘输入回路和LED显示 33
4.5防爆设计 34
5 软件设计 36
5.1 程序流程图 36
6 总结 40
6.1 本设计的基本工作 40
6.2 存在不足及改进措施 41
参考文献 42
附录 43
英文原文 44
中文译文 51
致  谢 55