【正文】 t is not easily realizable in a conventional system. This is the ability to change the relay characteristics (settings) as the system conditions warrant it. With reasonable prospects of having affordable puterbased relaying which can be dedicated to single protection function, attention soon turned to the opportunities offered by puterbased relaying to integrate them into a substation, perhaps even a systemwide network. Integrated puter systems for substations which handle relaying, monitoring, and control tasks offer novel opportunities for improving overall system performance. Computer relayingThe electric power industry has been one of the earliest users of the digital puter as a fundamental aid in the various design and analysis aspects of its activity. Computerbased systems have evolved to perform such plex tasks as generation control, economic dispatch (treated in chapter 11)and loadflow analysis for planning and operation , to name just a few application areas. research efforts directed at the prospect using digital puters to perform the tasks involved in power system protection date back to the miensixties and were motivated by the emergence of processcontrol puters a great deal of research is going on in this field, which is now referred to as puter relaying. Up to the early 1980s there had been no mercially availability protection systems offering digital puterbased relays. However, the availability of microprocessor technology has provided an impetus to puter relaying.*Microprocessors used as a replace*and solid state relays non provide a number of advantages while meeting the basic protection philosophy requirement of decentralization.There are many perceived benefits of a digital relaying system:1. Economics: with the steady decrease in cost of digital hardware, coupled with the increase in cost of conventional relaying. It seems reasonable to assume that puter relaying is an attractive alternative. Software development cost can be expected to be evened out by utilizing economies of scale in producing microprocessors dedicated to basic relaying tasks. 2. Reliability: a digital system is continuously active providing a high level of a selfdiagnosis to detect accidental failures within the digital relaying system.3. Flexibility: revisions or modifications made necessary by changing operational conditions can be acmodated by utilizing the programmability features of a digital system. This would lead to reduced inventories of parts for repair and maintenance purposes4. System interaction: the availability of digital hardware that monitors continuously the system performance at remote substations can enhance the level of information available to the control center. Post fault analysis of transient data can be performed on the basis of system variables monitored by the digital relay and recorded by the peripherals. The main elements of a digital puterbased relay are in。3氣象資料 本廠所在地區(qū)的年最高溫度為，年平均氣溫為，年最低氣溫為，年最熱月平均最高氣溫為，年最熱平均氣溫為，當(dāng)?shù)刂鲗?dǎo)風(fēng)向?yàn)闁|北風(fēng)，年雷暴數(shù)為20。該干線的的導(dǎo)線型號(hào)LGJ150，導(dǎo)線為等邊三角形排列，線距為2m；干線首端所裝設(shè)的高壓斷路器斷流容量為500MVA。該廠有二級(jí)負(fù)荷這三級(jí)負(fù)荷。在此我要特別要感謝趙順東、段曉明老師，他們?yōu)槲覀儾晦o辛苦的點(diǎn)撥，給我們解決了不少課題中的疑難問(wèn)題，提供了很多指導(dǎo)性的意見(jiàn)。結(jié)　論本次畢業(yè)是對(duì)紡織廠供配電系統(tǒng)的設(shè)計(jì)，通過(guò)完成負(fù)荷計(jì)算 、主接線設(shè)計(jì)、電源進(jìn)線及工廠高壓配電線路的設(shè)計(jì)、短路計(jì)算、高低壓電氣設(shè)備選擇、變電站幾點(diǎn)保護(hù)和防雷接地，使得一個(gè)完成的工廠供配電系統(tǒng)呈現(xiàn)在我們的面前。管間用40mm4mm的鍍鋅扁鋼焊接相連。（2）在10kV高壓配電室內(nèi)裝設(shè)GG1A（F）54型高壓開(kāi)關(guān)柜，其中配有FS410型避雷器，靠近主變壓器。 變電所的防雷保護(hù) 直擊雷防護(hù) 在變電所屋頂裝設(shè)避雷針或避雷帶，并引出兩根接地線與變電所公共接地裝置相連。避雷器是用來(lái)防止雷電產(chǎn)生的過(guò)電壓波沿線路侵入變配電所或其它建筑物內(nèi)，以免危及被保護(hù)設(shè)備的絕緣。接閃的金屬稱(chēng)為避雷針。（電流比為400/5）,低壓斷路器DZ20400/3。，（電流比為100/5）低壓斷路器DZ20100/3。該車(chē)間變電所下屬鍋爐房、水泵房、油泵房、化驗(yàn)區(qū)。,（電流比為700/5），低壓斷路器DZ20630/3。 車(chē)間變電所 。 該車(chē)間變電所下屬機(jī)修車(chē)間、倉(cāng)庫(kù)、辦公樓。，（電流比為600/5），低壓斷路器DZ20630/3。根據(jù)上述選型得出10kV側(cè)一次設(shè)備表如表65表65 10kv側(cè)一次設(shè)備總覽表選擇校驗(yàn)項(xiàng)目電壓電流斷流能力動(dòng)穩(wěn)定性熱穩(wěn)定性選擇地點(diǎn)條 件參數(shù)數(shù)據(jù)10kV額定參數(shù)高壓斷路器SN1010I/63010kV630A16kV40kA高壓隔離開(kāi)關(guān)10kV200A—高壓熔斷器RN21010kV50kA——電壓互感器JDZJ10————電流互感器LQJ1010kV100/5A—81避雷器FS41010kV———— 車(chē)間變電所 ，所以選擇低壓斷路器DW151500，低壓刀開(kāi)關(guān)HD131500/30，(電流比為1500/5) 均滿(mǎn)足負(fù)荷電流的要求。當(dāng)時(shí)。即 或 （63） 短路條件校驗(yàn) 隔離開(kāi)關(guān)、負(fù)荷開(kāi)關(guān)和斷路器的短路穩(wěn)定度校驗(yàn)（1）動(dòng)穩(wěn)定性校驗(yàn)條件或 （64）式中 、—開(kāi)關(guān)的極限通過(guò)電流（又稱(chēng)動(dòng)穩(wěn)定電流）峰值和有效值，單位為kA； 、—開(kāi)關(guān)所在處的三相短路沖擊電流瞬時(shí)值和有效值（單位kA）（2）熱穩(wěn)定校驗(yàn)條件 （65）式中 —開(kāi)關(guān)的熱穩(wěn)定電流有效值，單位為kA。一般不應(yīng)小于所在系統(tǒng)的額定電壓。 短路電流計(jì)算的方法 圖51 系統(tǒng)等效電路圖 短路計(jì)算設(shè)，即高壓側(cè),低壓側(cè)，則 計(jì)算短路電路中各元件的電抗標(biāo)幺值(1)電力系統(tǒng)，故 (2)架空線路 由資料得LGJ150的，而線路長(zhǎng)，故 (3)電力變壓器 計(jì)算公式為：查表得變壓器T1 ，變壓器T2 4，變壓器T3，變壓器T4 ，變壓器T5 因此繪短路計(jì)算等效電路如圖52 圖52 等效阻抗圖 K1點(diǎn)短路計(jì)算計(jì)算k1點(diǎn)（）的短路電路總電抗及三相短路電流和短路容量(1)總電抗標(biāo)幺值 (2)三相短路電流周期分量有效值 (3)其他短路電流 (4)三相短路容量： K2點(diǎn)短路計(jì)算求K2點(diǎn)（）的短路電路和總電抗及三相短路電流和短路容量(1)總電抗標(biāo)幺值 (2)三相短路電流周期分量有效值 (3)其他短路電流 (4)三相短路容量： K3點(diǎn)短路計(jì)算求K3點(diǎn)（）的短路電路和總電抗及三相短路電流和短路容量 (1)總電抗標(biāo)幺值 (2)三相短路電流周期分量有效值 (3)其他短路電流 (4)三相短路容量： K4點(diǎn)短路計(jì)算求K4點(diǎn)（）的短路電路和總電抗及三相短路電流和短路容量(1)總電抗標(biāo)幺值 (2)三相短路電流周期分量有效值 (3)其他短路電流 (4)三相短路容量： K5點(diǎn)短路計(jì)算求K5點(diǎn)（）的短路電路和總電抗及三相短路電流和短路容量(1)總電抗標(biāo)幺值 (2)三相短路電流周期分量有效值 (3)其他短路電流 (4)三相短路容量： K6點(diǎn)短路計(jì)算K6點(diǎn)（）的短路電路和總電抗及三相短路電流和短路容量(1)總電抗標(biāo)幺值 (2)三相短路電流周期分量有效值 (3)其他短路電流 (4)三相短路容量： 通過(guò)計(jì)算得表51表51短路點(diǎn)數(shù)據(jù)統(tǒng)計(jì)表三相短路電流/KA三相短路容量(MVA)短路計(jì)算點(diǎn)第6章 高低壓電氣設(shè)備選擇 一次設(shè)備選擇與校驗(yàn)的條件和項(xiàng)目為保證一次設(shè)備安全可靠的運(yùn)行，必須按下列條件選擇和校驗(yàn)：(1)按正常工作條件包括電壓、電流、頻率及開(kāi)斷電流等選擇。在等效電路圖上，只需將被計(jì)算的短路電流所流經(jīng)的一些主要元件表示出來(lái)，并標(biāo)明其序號(hào)和阻抗值，然后將等效電路化簡(jiǎn)。進(jìn)行短路電流計(jì)算，首先要繪制計(jì)算電路圖。 饋電給各車(chē)間（鍛工車(chē)間、紡紗車(chē)間、制條車(chē)間、軟