摘要
本次設(shè)計(jì)的主要任務(wù)是對(duì)焦作李封火電廠的3＃發(fā)電機(jī)－變壓器組中的變壓器設(shè)計(jì)一套微型機(jī)保護(hù)系統(tǒng)。由于建廠較早，焦作李封火電廠的繼電保護(hù)裝置都是以前使用較為廣泛的電磁式保護(hù)裝置。本次設(shè)計(jì)就是在其原來所存在保護(hù)系統(tǒng)的前提下，將其換成微機(jī)型保護(hù)的實(shí)驗(yàn)型設(shè)計(jì)，以便進(jìn)一步了解、研究、利用微型機(jī)實(shí)現(xiàn)電力系統(tǒng)的自動(dòng)化。
實(shí)行微型機(jī)對(duì)電力系統(tǒng)裝置及線路的保護(hù)從而使得電力系統(tǒng)更加安全、可靠地供電，對(duì)提高人民的生活水平，發(fā)展生產(chǎn)力，推動(dòng)整個(gè)國民經(jīng)濟(jì)健康、持續(xù)、快速發(fā)展至關(guān)重要。盡管目的是實(shí)現(xiàn)電力系統(tǒng)的自動(dòng)化，提高安全系數(shù)，但是并不等于浪費(fèi)，所以如何才能更經(jīng)濟(jì)而又滿足系統(tǒng)對(duì)保護(hù)裝置的可靠性等指標(biāo)的要求是每個(gè)設(shè)計(jì)者所必須考慮的問題。在整個(gè)設(shè)計(jì)的過程中，硬件裝置是實(shí)現(xiàn)所要達(dá)到的目的的基礎(chǔ)設(shè)施，沒有它作為支撐，再好的軟件也不能實(shí)現(xiàn)其用武之地。所以，對(duì)硬件裝置的選擇就顯得至關(guān)重要。本次設(shè)計(jì)我采用了目前在市場(chǎng)上較為流行的PIC單片機(jī)。該單片機(jī)比起其它單片機(jī)種類，有很多優(yōu)越性，這里不在此作詳細(xì)介紹，在以后的章節(jié)里，我將目前是市場(chǎng)上幾種較為流行，而且市場(chǎng)占有率較高的單片機(jī)作了詳細(xì)的對(duì)比，其性價(jià)比一幕了然。該單片機(jī)內(nèi)集成了包括數(shù)據(jù)采集系統(tǒng)（S/H）、多路轉(zhuǎn)換開關(guān)(MUX)、A/D轉(zhuǎn)換器、Flash程序存儲(chǔ)器、EEPROM數(shù)據(jù)存儲(chǔ)器、RAM數(shù)據(jù)存儲(chǔ)器、串行接口、并行接口模塊等。硬件電路的其它元件有，74LS164移位寄存器、74LS244數(shù)據(jù)緩沖器、CD4051多路選擇開關(guān)、壓力傳感器、LED數(shù)碼管以及用于與PC機(jī)通信的電平轉(zhuǎn)換芯片MAX232等芯片。在盡可能滿足保護(hù)要求的條件下，盡量簡化電路，是本次設(shè)計(jì)所追求的目的。這對(duì)于保護(hù)的抗干擾性是有用的。

關(guān)鍵字： 哈佛總線   變壓器    微型機(jī)

Abstract
The main task of this graduated design is to design a set of a microcomputer preotecting system for Jiaozuo Li Feng Power plant 3# generator-transformer transformer. Jiaozuo Li Feng power plant protective devices used are more widely previous electromagnetic type protection devices becouse it has been built many years ago . This design is to substitute it on base of the original Electromagnetism type protected system,according to the graduated design ,we will further understand, study，make use of microcomputer preotection to carry out automation of electric power system.
It is very important to make use of microcomputer in the raising protection devices and circuits to make the electricity system more secure, reliable electricity. To improve the people's living standards and the development of productive forces and the promotion of health of the entire national economy, sustained and rapid development is essential. Although the aim of achieving the power system automation, improve safety factor, but is not wasted, so how can we design the economic system and the reliability of protection devices such as indicators for each designers must consider. Throughout the design process, hardware device is to achieve the desired purpose infrastructure, as it did not support, even the soft ware also be its battlefield. Therefore, the choice of hardware devices becomes critical. I used more popular PIC SCM(singel chip microcomputer) in the market at present SCM .The SCM than other types, there are many advantages, such as here is not detailed, in subsequent chapters, I will present a few more pop market, and market share higher than the most detailed  SCM the Xingjiabi scene clear. SCM includs the master data collection system (S/H), multi-path switching switches (MUX), A/D轉(zhuǎn)換器, Flash procedures ROM, EEPROM data memory, Ram data memory, serial interface , parallel interface. There are other components of hardware circuits, 74LS164 Move deposits register, 74LS244 data buffers, CD4051 multiplexed choice switches, pressure sensors, digital led and such as electricity conversion chip MAX232 chip communication for the PC . At the highest possible to meet the protection requirements, simplify circuit is the current design of the objective pursued. This is useful for the protection of interference.
Keywords:  Harvard bus    Transformer    microcomputer

前言
    本次畢業(yè)設(shè)計(jì)是對(duì)微型機(jī)繼電保護(hù)的研究的一種嘗試性設(shè)計(jì)。微型機(jī)繼電保護(hù)是未來繼電保護(hù)的發(fā)展方向，它是隨著電子計(jì)算機(jī)的發(fā)展應(yīng)運(yùn)而生的，為實(shí)現(xiàn)電力系統(tǒng)自動(dòng)化，保障電力系統(tǒng)安全運(yùn)行做出很大的貢獻(xiàn)，所以對(duì)微型機(jī)繼電保護(hù)的研究以成為現(xiàn)代電力系統(tǒng)工作人員積極從事的工作，在我國也有這方面的人才出現(xiàn)，作為一名新時(shí)代的電力系統(tǒng)工作人員，我很希望在這方面做出自己應(yīng)有的貢獻(xiàn)，盡管目前我對(duì)這方面的知識(shí)還是相當(dāng)欠缺，但是我會(huì)做出不懈的努力。
本次設(shè)計(jì)的第一章將對(duì)微機(jī)保護(hù)的發(fā)展概況的進(jìn)行闡述；第二章對(duì)變壓器所需要的保護(hù)進(jìn)行研究；第三章說明所選擇的單片機(jī)的特點(diǎn)及其與其它系列單片機(jī)相比的優(yōu)點(diǎn)；第四章對(duì)本次設(shè)計(jì)的硬件電路進(jìn)行分析說明；第五章對(duì)微機(jī)保護(hù)所用到的算法進(jìn)行研究；第六章是軟件部分設(shè)計(jì)。
總之本次設(shè)計(jì)是對(duì)大學(xué)四年的學(xué)習(xí)總結(jié)，和對(duì)自己的一次徹底的衡量。
  

 
目錄
1  緒論 1
1.1  微機(jī)保護(hù)的應(yīng)用與發(fā)展 1
1.2  微機(jī)繼電保護(hù)裝置的特點(diǎn) 2
1.3  微機(jī)保護(hù)的基本硬件電路結(jié)構(gòu) 5
1.4  本次設(shè)計(jì)的主要任務(wù) 6
2  變壓器保護(hù)的研究 7
2.1  變壓器的主保護(hù) ? 7
2.1.1瓦斯保護(hù)? 7
2.1.2差動(dòng)及電流速斷保護(hù)? 8
2.2  變壓器的后備保護(hù) 8
2.2.1變壓器相間故障的后備保護(hù)? 8
2.2.2變壓器接地短路的后備保護(hù)? 10
3  PIC單片機(jī)的特點(diǎn) 11
4  李封電廠微機(jī)型變壓器保護(hù)硬件電路分析與設(shè)計(jì) 16
4.1  主機(jī)系統(tǒng)硬件電路 16
4.1.1PIC16F877芯片內(nèi)模塊介紹 16
4.1.2PIC16F877單片機(jī)內(nèi)A/D模塊分析 21
4.2  模擬量輸入電路 26
4.2.1差動(dòng)及過電流保護(hù)的電壓形成電路 27
4.2.2瓦斯保護(hù)的電壓形成電路分析 28
4.2.3復(fù)合電壓起動(dòng)的過流保護(hù)電壓形成回路 30
4.3  人機(jī)對(duì)話電路設(shè)計(jì) 30
4.3.1鍵盤硬件接口電路 30
4.3.2顯示電路設(shè)計(jì) 32
4.4  出口電路設(shè)計(jì) 33
4.5  開關(guān)量輸入回路 34
4.6  保護(hù)系統(tǒng)與PC機(jī)的通信電路設(shè)計(jì) 35
5  微機(jī)保護(hù)算法研究 37
5.1  數(shù)字濾波 37
5.2  正弦函數(shù)模型算法 39
5.3  傅立葉算法 44
5.4  解微分方程算法 47
6  軟件設(shè)計(jì) 50
6.1  程序流程圖 50
6.1.1主程序流程圖 50
6.1.2定時(shí)器中斷服務(wù)程序流程圖 51
6.1.3差動(dòng)保護(hù)故障處理程序流程圖 52
6.1.4過流保護(hù)流程圖 53
結(jié)束語 56
致謝 57
參考文獻(xiàn) 58