智能断路器的电气设计

论文编号:DQ096   论文字数:13613,页数:30

摘  要
 低压断路器是用于接通、分断电力系统及对各种故障进行保护的一种开关电器，广泛应用于各类电网的供配电系统中，具有过载、短路漏电和接地等故障保护功能。当电路内出现过载、短路和欠压等情况时，能够自动分断，是低压配电系统中的主要原件,在配电系统中起着至关重要的作用。而智能断路器除具备传统断路器的各种保护功能外，还能够显示电路中的各种参数，各种保护功能的动作参数也可以显示、设定和修改。与传统的断路器相比有着很高的性价比，更适合现代配电电网的需求。
 智能断路器的中枢部件是智能测控单元。它承担着断路器的各种保护、报警、显示和控制功能。
 本课题以断路器智能化技术为研究内容。主要以PIC单片机为核心，介绍智能断路器的硬件设计与软件实现。在硬件设计上由单片机最小系统、开关输入电路、电压电流变换电路、通信单元等几部份组成。用单片机来完成电压电流的测量计算，从而通过预先设定脱扣方式参数来判断断路器的动作。该断路器具有与上位机的通信功能，上位机可以读到断路器的各种参数信息，控制断路器的工作状态。

关键词：智能断路器，PIC单片机，通信
 
Abstract
 Low-voltage circuit breaker is a electrical switch which is used to connect, break all kinds of power system and to is protected from a malfunction. It is widely used in various types of grid power supply system, with the function of being protected from overload, short circuit and earth leakage fault. When the circuit is overload, short circuit and under voltage, etc. The circuit breaker will be cuted automatically .It is the main original in low-voltage distribution system .It plays a vital role in distribution system .Besides have a variety of traditional protection, intelligent circuit breaker also can display a variety of circuit parameters, a variety of protection action parameters can be displayed, set and modify. Compared with the traditional circuit breaker intelligent circuit has a high cost-effective, and more suitable for the needs of a modern power distribution grid.
 The central component of intelligent circuit breaker is intelligent Control Unit.
It bears the various protection of circuit breakers such as alarm, display and control functions.
 The subject of this dissertation is to study the intelligent technology of circuit breaker.
PIC single-chip microcomputer as the core, we will be going to introduce the hardware and software design of intelligent circuit breaker. The hardware design is make up of from the smallest single-chip systems, switch input circuit, voltage and current conversion circuit, communications unit, and so on .The MCU is used to complete the calculation and measurement of voltage and current, In order to determine the way of circuit breaker action through the pre-set parameters .
The circuit breaker have the function of communication with PC, host computer can read information on various parameters of circuit breakers, control the work of the state of circuit breakers.

Key words: intelligent circuit breaker, PIC microcontroller, communication

目 录
摘要……………………………………………………………………..………………………………Ⅰ
Abstract………………………………………………………………………………………………Ⅱ
1 前言…………………………………………………….………………..……….……...……….…..1
2 断路器简介……………………………………….……………………………………..…….........2
 2.1  传统断路器的结构…………………………………………………………………………....2
 2.2  智能断路器的功能特点……………………………………………………………………....2
 2.3  三段电流的保护特性及实现原理…………………………………………………..…..........3
     2.3.1  三段保护原理……………………..…………………………………………….…..…3
     2.3.2  保护特性…………………………..………………………………………….……..…4
3 总体方案设计………………………………………….……………………..……………..….….6
 3.1  硬件总体设计………………………………………..………………….……………….……6
 3.2  PIC最小系统…………………………………….….………………..…..….……………......7
     3.2.1  pic16f877A/D转换器……………………………….………..………………..……....7
     3.2.2  通用同步异步收发器USART……………......................................................................8
 3.3  信号采集处理电路……...……………..………..…………………….…….………………...9
 3.4  电源模块.………………………………..…………………………….……….……….…….11
 3.5  按键接口电路………………………………..…….……………….………….……….…….11
 3.6  状态及参数显示接口电路…………………..…..…….…………….………………….……12
 3.7  报警和保护电路执行电路……………………………………………………….……….….14
 3.8  上位机串行接口电路…………………………………………………………….……….….15
      3.8.1  max232简介…………………………………………………………………….…...16
      3.8.2  RS232工作原理………………………………………………………………….….17
4 采样信号的有关算法和处理…………………………..……….…….………………………..18
 4.1  电流有效值的算法………………………….…….……………….…………………………18
5 软件设计……………………………………………….……..………………….………………...20
 5.1  设计思路……………………………………..…….…………...…………………...….…….20
 5.2  主程序设计…………………………………….……………………………………….….…22
6 总结……………………………………………….……………..……………………………….....24
致谢……………………………………………………….…………………………………..........…..25
参考文献………………………………………………….………………………………………..….26