【正文】
在屏幕上指示使用要運(yùn)行在以電力系統(tǒng)保護(hù)期限內(nèi)是積極參與的工作數(shù)傳計(jì)。10V . 由于電流互感器二次側(cè)電流可高達(dá)數(shù)百千安,要產(chǎn)生提供給模 ─ 數(shù)轉(zhuǎn)換器 (ADC) 的需要的電壓就需要書mΩ 的并聯(lián)電阻. 另一種方法是采用中間電流互感器降低電流到較低的數(shù)值. 中間電流互感器還起到另一作用: 對(duì)電流互感器二次側(cè)與計(jì)算機(jī)輸入系統(tǒng)進(jìn)行電氣隔離.只要提供各種功能所需要的輸入和輸出信號(hào),數(shù)字計(jì)算機(jī)就可編程來執(zhí)行這些功能. 只要繼電保護(hù)的計(jì)算機(jī)執(zhí)行變電站的其它任務(wù)是很容易的事, 例如, 監(jiān)測(cè)變壓器和輸電線路中的潮流,控制斷路器和開關(guān)的分閘和合閘,對(duì)故障設(shè)備提供備用,都是繼電保護(hù)計(jì)算機(jī)可執(zhí)行的功能. 由于可編程能力和通信能力,計(jì)算機(jī)繼電保護(hù)具有傳統(tǒng)繼電保護(hù)系統(tǒng)中不可能實(shí)現(xiàn)的優(yōu)點(diǎn). 這就是按系統(tǒng)條件準(zhǔn)許而改變繼電器特性 (整定值) ,注意力很快就轉(zhuǎn)到將計(jì)算機(jī)繼電保護(hù)綜合到變電站范圍,甚至系統(tǒng)范圍的機(jī)會(huì). 變電站的綜合計(jì)算機(jī)系統(tǒng)可進(jìn)行繼電保護(hù),監(jiān)測(cè)和控制,這對(duì)整個(gè)系統(tǒng)的性能提供了新的機(jī)遇.微機(jī)繼電器電力工業(yè)已經(jīng)是數(shù)傳計(jì)算機(jī)的最早使用者之一如各種不同的設(shè)計(jì)和它的活度分析方面的一個(gè)基本的幫助。表11工廠負(fù)荷情況表車間名稱設(shè)備容量(Kw)需要系數(shù)功率因素鍛工車間38紡紗車間350制條車間88軟水站88合計(jì)826高壓側(cè)合計(jì)826機(jī)修車間300倉(cāng)庫(kù)40辦公室21外文資料翻譯Protection relayMicrouterbased Rlaying A newer development in the of power system protection is the of puters (usually microputers) for relaying. Although puters provide the same protection as that supplied by conventional relays, there are some advantages to the use of puterbased relaying. The logic capability and application expansion possibilities for puterbased relaying is much greater than for electromechanical devices. Computerbased relaying samples the values of the current, voltage, and other items covered in the protection scheme several times a second, and by use of A/D converters, change these analog values to digital form and then send them to the puter. In the event of a fault, the puter can calculate the fault’s current values and characteristics, and settings can be changed merely by reprogramming. Computerbased relaying are also capable of locating faults, which has been one of the most popular features in their application. In addition, selfchecking features can be built in and sequence of events information can be downloaded to remote puters for fast analysis of relaying operations. Computerbased relying system consists of subsystems with well defined functions. Although a specific subsystem may be different in some of its details, these subsystems are most likely to be incorporated in its design in some form. The block diagram in Figure 131 shows the principal subsystems of a puterbased relaying. The processor is the center of its organization. It is responsible for the execution of relaying programs, maintenance of various timing functions, and municating with its peripheral equipment. Several types of memories are shown in Figure 131─each of them serves a specific need. The Random Access Memory (RAM) holds the input sample data as they are brought in and processed. The Read Only Memory (ROM) or Programmable Read Only Memory (PROM) is used to store the programs permanently. In some cases the programs may execute directly form the ROM if its read time is short enough. If this is not the case, the programs must be copied form the ROM into the RAM during an initialization stage, and then the realtime execution would take place form the RAM. The Erasable PROM (EPROM) is needed for storing certain parameters (such as the relaying settings) which may be changed form time to time, but once it is set it must remain fixed even if the power supply to the puter is interrupted. The relaying inputs are currents and voltages─or, to a lesser extent─digital signals indicating contact status. The analog signals must be converted to voltage signals suitable for conversion to digital form. The current and voltage signals obtained form current and voltage transformer secondary windings must be restricted to a full scale value of 177。已知本廠高壓側(cè)有電氣聯(lián)系的架空線80km,電纜總線路總長(zhǎng)為25km。此斷路器配備有定時(shí)限過電流保護(hù)和電流速斷保護(hù)。負(fù)荷情況如表112供電情況 按照工廠與當(dāng)?shù)毓╇姴块T簽訂的供用電協(xié)議規(guī)定,本廠可由附近一條10kV的公用電源干線取得工作電源。二級(jí)負(fù)荷也屬于重要負(fù)荷。參考文獻(xiàn)[1] :電氣一次部分. [2] [3] [4] [5] [6] (第三版).[7] (第一版).[8] (第三版).[9] [10] [11] [12] 王子五. [13] (第九冊(cè)).[14] (二次部分).[15] (第三版).[16] 電氣制圖國(guó)家標(biāo)準(zhǔn)匯編[S]. 北京:中國(guó)計(jì)劃出版社,2001.[17] Paul . Power System Protection .WileyIEEE Press.附 錄 附 錄 1電氣總接線圖附 錄 2紡織廠原始資料 1 工廠負(fù)荷情況 本廠大部分車間為三班制,少數(shù)車間為兩班或一班制。在感嘆老師淵博的學(xué)術(shù)理論知識(shí)及豐富的實(shí)踐經(jīng)驗(yàn)的同時(shí),我也看到了老師嚴(yán)謹(jǐn)?shù)闹螌W(xué)態(tài)度和一絲不茍的敬業(yè)精神,這些都將使我終身受益。通過這次設(shè)計(jì),我初步了解了工廠供電的設(shè)計(jì)方法,不僅積累和鞏固了專業(yè)知識(shí),還鍛煉了自學(xué)的能力。這一學(xué)期的畢業(yè)設(shè)計(jì),由于本人個(gè)人水平限制原因,我對(duì)這個(gè)設(shè)計(jì)還不是很深入,論文本身還存在諸多欠妥之處,懇請(qǐng)老師給我提出寶貴的意見,只有發(fā)現(xiàn)問題面對(duì)問題才能解決問題,不足和遺憾不會(huì)給我打擊指揮更好的鞭策我前行,今后我更會(huì)關(guān)注新技術(shù)新設(shè)備新方案的出現(xiàn),并爭(zhēng)取盡快的掌握這些先進(jìn)的知識(shí),保持“不放棄努力本是我的任務(wù),在現(xiàn)在的基礎(chǔ)上爭(zhēng)取更是我的職責(zé)。接地電阻的驗(yàn)算滿足的要求。變壓器室有兩條接地干線、高低壓配電室各有一條接地干線與室外公共接地裝置焊接相連。 變電所公共接地裝置的設(shè)計(jì) 接地電阻的要求接地電阻的要求本變電所的公共接地裝置的接地電阻應(yīng)滿足以下條件: 式中 因此公共接地裝置接地電阻應(yīng)滿足 接地裝置的設(shè)計(jì) 、的鍍鋅鋼管數(shù),計(jì)算初選16根,沿變電所三面均勻布置(變電所前面布置兩排),管距5m,垂直打入地下。主變壓器主要靠此避雷器來防護(hù)雷電侵入波的危害。其引下線采用25mm4mm的鍍鋅扁鋼,下面與公共接地網(wǎng)焊接相連,上面與避雷器接地端螺栓連接。避雷針采用直徑20mm的鍍鋅圓鋼,避雷帶采用25mm4mm的鍍鋅扁鋼。避雷器的型式,主要有閥式和排氣式等。避雷器應(yīng)與被保護(hù)設(shè)備并聯(lián),裝在被保護(hù)設(shè)備的電源側(cè)。接閃的金屬網(wǎng)稱為避雷網(wǎng)。接閃的金屬線稱為避雷線,或稱架空地線。其中,接閃器就是專門用來接受直接雷擊(雷閃)的金屬物體。低壓母線的選擇10kV母線選擇LMY3(404), 380V母線選LMY3(12010)+806。 該變電所只供給生活區(qū) 。 車間變電所。 ,(電流比為50/5)低壓斷路器DZ20100/3。(電流比為300/5),低壓斷路器DZ20400/3。所以選擇低壓斷路器DW15600,低壓刀開關(guān)HD13600/30,(電流比為600/5)均滿足負(fù)荷電流的要求。食堂車間出線的最大負(fù)荷電流為57A,(電流比為60/5),低壓斷路器為DZ20100/3。,(電流比為700/5),低壓斷路器DZ201250/3。所以選擇低壓斷路器DW151500,低壓刀開關(guān)HD131500/30,(電流比為1500/5)均滿足負(fù)荷電流的要求。,(電流比為50/5),低壓斷路器為DZ20100/3。,(電流比為300/5),低壓斷路器為DZ20400/3。所以選擇低壓斷路器DW15400,低壓刀開關(guān)HD13400/30,(電流比為400/5)均滿足負(fù)荷電流的要求。,(電流比為150/5),低壓斷路器DZ20200/3。,(電流比為600/5),低壓斷路器DZ20630/3。該車間變電所下屬鍛工車間、紡紗車間、制條車間、軟水站。 高壓互感器的選擇與校驗(yàn)電壓互感器應(yīng)按裝設(shè)地點(diǎn)條件及一次電壓、二次電壓(一般為100v)、準(zhǔn)確度級(jí)等進(jìn)行選擇電壓互感器滿足準(zhǔn)確度要求的條件也決定于二次負(fù)荷,即其二次負(fù)荷按下式計(jì)算 (610)對(duì)于每個(gè)變壓器均要裝設(shè)一個(gè)電壓互感器對(duì)于一號(hào)變電所故選擇JDZJ10 負(fù)荷條件 其它變電計(jì)算完全相同都選擇JDZJ10型電壓互感器。 低速斷路器(如油斷路器),;高速斷路器(如真空斷路器)。短路發(fā)熱假想時(shí)間一般按下式計(jì)算: (66)在無限大容量系統(tǒng)中,由于,因此 (67)式中 —短路持續(xù)時(shí)間,采用該電路主保護(hù)的動(dòng)作時(shí)間加對(duì)應(yīng)的斷路器全分閘時(shí)間。 t—開關(guān)的熱穩(wěn)定試驗(yàn)時(shí)間,單位為s; —開關(guān)所在處的三相短路穩(wěn)態(tài)電流,單位為kA。對(duì)分?jǐn)喽搪冯娏鞯脑O(shè)備(如斷路器)來說,不應(yīng)小于它可能分?jǐn)嗟淖畲蠖搪冯娏鞯挠行е祷蚨搪啡萘?。? (61) (2)按工作電流選擇 設(shè)備的額定電流不應(yīng)小于所在電路的計(jì)算電流。 按正常工作條件選擇(1)按工作電壓選擇 設(shè)備的額定電壓。(2)按短路條件包括動(dòng)動(dòng)穩(wěn)定性和熱穩(wěn)定性進(jìn)行校驗(yàn)。短路電流計(jì)算的方法,常用的有歐姆法(有稱有名單位制法)和標(biāo)幺制法(又稱相