外文翻譯--變電站與電力系統(tǒng)繼電保護

1、<p><b>　　中文3826字</b></p><p>　　附錄1：外文資料翻譯</p><p>　　A1.1 Substation and Power System Protection</p><p>　　With the development of undertaking of the electric wire nett

2、ing , the pattern of national network has already taken shape basically. Scientific and technological level raise, electric environmental protection can strengthen, make scientific and technological competence and advanc

3、ed international standards, Chinese of power industry close day by day. Electric management level and service level are being improved constantly, strategic planning management of electric power development, production &

4、lt;/p><p>　　The purpose of a substation is to transform the characteristics of the electrical energy supplied to some form suitable for use, as for example, a conversion from alternation current to direct curre

5、nt for the use of city railway service, or a change from one voltage to another, or one frequency to another. Their functions include:</p><p>　　Tap.─TO be economical, transmission of larger amounts of power

6、over long distances must be done at voltages above 110,000 volts. Substations for supplying small amounts of power from such high-voltage lines are not satisfactory from the standpoint of operation and are also uneconomi

7、cal. It is, therefore, common practice to install a few substations at advantageous points along the high-tension lines and step down the high-transmission voltage to a lower secondary-transmission voltage from which <

8、;/p><p>　　Distribution.─Any substation that is used to transform electrical energy to a potential that is low enough for general distribution and utilization is a distributing substation. Such a substation will

9、 generally receive its energy over a few comparatively high-tension lines and distribute it over a large number of low-voltage lines.</p><p>　　Industrial.─When fairly large blocks of power are required by in

10、dustrial plants, it often becomes necessary and advisable to install an individual substation to supply such a load directly from the main high-voltage line or secondary line of lower voltage. Its simplest form would com

11、prise only switching equipment, there being no voltage transformation. In most cases a voltage transformation is probably needed; hence transformer equipment is included.</p><p>　　Sectionalizing.─In very lon

12、g high-voltage large capacity lines, particularly when several circuits are run in parallel, it is often necessary to split the lines into sections, in order that proper protection to the line and service can be obtained

13、. Such a substation is , therefore, helpful in sectionalizing damaged sections of a line, providing continuity of service. Such a substation will generally comprise only switching equipment. In long lines it may also ser

14、ve to supply power-factor-correct</p><p>　　Transmission-line Supply.─It is becoming more and more common to install the high-tension equipment of a power plant outdoors, the installation becoming nothing mor

15、e than a step-up substation receiving its power at generator voltage, then stepping up its voltage and finally sending it out over high-voltage transmission lines. Such a substation is nothing more than an outdoor distri

16、buting substation turned around, the voltage being stepped up instead of stepped down.</p><p>　　Power-factor Correction.─The voltage at the end of long lines tends to increase as the load supplied is decreas

17、ed, while on the other hand it tends to decrease as the load is increased. Owing to the inductance and capacity effects, this variation in voltage is accompanied by a wide variation in power factor of a line, it is neces

18、sary to use synchronous condensers at the end of the line. To supply such a machine the transmission-line voltage must be stepped down, hence a power-factor-correcting s</p><p>　　Railway.─Substations supplyi

19、ng railways may be generally classified under two heads, namely, as alternating current and as direct current. In the cases of alternating-current substations the problem is generally one of voltage transformation and of

20、 supplying single-phase power to the trains. It is, however, possible to supply single-phase to three-phase inside the locomotive by the use of a phase converter. In the case of direct-current railways, the substations a

21、re generally supplied whit three</p><p>　　Direct current for Light and Power.─There are still a few sections in some of out large cities, which are supplied with direct-current three-wire systems. Such a sup

22、ply is invariably obtained from synchronous converters. There are also certain types of motor loads in industrial plants, which require direct current.</p><p>　　Because many cities have experience rapid grow

23、th, their substations have often reached the limits of their capacity. As a result, downtown distribution systems are often overworked and many need a major, overhaul, overhaul, or expansion. However, space is scarce. Do

24、wntown business owners do not want “ugly” new substation marring the area’s appearance, but nor do businesses and residents grid the prospect of grid disturbances.</p><p>　　One example of a system capable of

25、 integrating equipment monitoring with substation automation is the GE Harris integrated Substation Control System (ISCS). The system can integrate data from both substation system and equipment online monitoring devices

26、 into a common data base. The data can then be processed by an expert system into information on the status and health of monitored equipment using self-diagnostic programs. This information is then sent to a CMMS for au

27、tomatic generation and tra</p><p>　　ABB Power and its industry partners have combined to develop the ABB Power System software. The system contains a diagnostic and maintenance system that reports necessary

28、maintenance before failure. It allows utilities and industrial customers to easily expand from a single computer to a full system, without re-engineering.</p><p>　　the directional protection basis</p>

29、<p>　　Early attempts to improve power-service reliability to loads remote from generation led to the dual-line concept. Of course, it is possible to build two lines to a load, and switch the load to whichever line

30、remains energized after a disturbance. But better service continuity will be available if both lines normally feed the load and only the faulted line is tripped when disturbances occur. Fig.14-1 shows a single-generator,

31、 two-line, single-load system with breakers properly arranged to supply </p><p>　　The magnitude of the fault current through breakers B and D is the same, regardless of the location of the fault on the line

32、terminal of breaker B or D. Therefore relay coordination must be based on characteristics other than a time delay that starts from the time of the fault. Observe that the direction of current flowing through either break

33、er B or D is a function of which line the fault is on. Thus for a fault on the line between A and B, the current flows out of the load bus through breaker </p><p>　　Relay coordination for the system shown in

34、 Fig.14-1 can now be achieved by their - salvations of directional over current time delay relays on breakers B and D. Breakers A and C can have no directional over current time delay relays. They may also now have insta

35、ntaneous relays applied. The relays would be set as follows: The directional relays could be set with no intentional time delay. They will have inherent time delay. The time delay over current relays on breakers A and C

36、would have current</p><p>　　Direction of current flow on an a. c. system is determined by comparing the current vector with some other reference vector, such as a voltage vector. In the system of Fig. 14-1 t

37、he reference voltage vector would be derived from the voltages on the load bus. Direction of current or power flow cannot be determined instantaneously on a. c. systems whose lines and equipment contain reactance. This i

38、s apparent from the fact that when voltage exists, the lagging current can be plus or minus or zero, </p><p>　　differential protection</p><p>　　Much of the apparatus used on a power system has s

39、mall physical dimensions when compared to the length of general transmission-line circuits. Therefore, the communications between the apparatus terminals may be made very economically and very reliably by the use of dire

40、ct wire circuit connections. This permits the application of a simple and usually very effective type of differential protection. In concept, the current entering the apparatus is simply compared against the current leav

41、ing the ap</p><p>　　The simplest application of differential relaying is shown in Fig. 14-4. Here one simple power conductor is protected by a differential relay. The relay itself usually consists of three c

42、oils, one of which is the coil that detects the difference current and initiates circuit tripping. It is called the operating coil and is designated by an O in the figure. The other two coils are restraint coils and are

43、designated by R in the figure. The restraint coils serve a practical purpose. They prevent op</p><p>　　本文譯自《電力英語閱讀》</p><p>　　A1.2 變電站與電力系統(tǒng)繼電保護</p><p>　　隨著電力電網(wǎng)事業(yè)的發(fā)展，全國聯(lián)網(wǎng)的格局已基本形成?？萍妓?/p>

44、得到提高，電力環(huán)境保護得以加強，使中國電力工業(yè)的科技水平與世界先進水平日漸接近。電力管理水平和服務(wù)水平不斷得到提高，電力發(fā)展的戰(zhàn)略規(guī)劃管理、生產(chǎn)運行管理、電力市場營銷管理以及電力企業(yè)信息管理水平、優(yōu)質(zhì)服務(wù)水平等普遍得到提高。</p><p>　　變電站的目的是改變電能特性以滿足使用要求。例如，從交流轉(zhuǎn)換為直流為城市鐵路供電，或者從一個電壓等級轉(zhuǎn)換為另一十電S等級，或者從一個頻率轉(zhuǎn)換為另一個頻率。變電站的功能包括：

45、</p><p>　　分支——為了經(jīng)濟性，大容量電力的遠距離傳輸必須在110kV以上的電壓下進行。從運行的角度來看，從這樣的高壓線直接引出向小容量負荷供電的變電站是不能令人滿意的，也是不經(jīng)濟的。因此，一個常規(guī)辦法是：沿著高壓線路在適合的地點設(shè)置一些變電站，將高傳輸電壓降到一個較低的二級傳輸電壓，從這個電壓向小容量負荷供電。</p><p>　　配電——任何用于將電能變換為可以直接配電和利用

46、的較低壓等級的電能的變電站都是配電變電站。這樣的變電站一般將從A條電壓相對高的線路接受電能，并向大量較低電壓線路配送電能。</p><p>　　工業(yè)——當(dāng)工廠需要大量電能時，設(shè)置一個自己的單獨的變電站是有必要的也是明智的，這個變電站直接從主高壓線路或較低電壓的二級輸電線路取得電能。其最簡單的形式?jīng)]有電壓的轉(zhuǎn)換，只由開關(guān)設(shè)備組成。但是，在大多數(shù)情況下需要一個電壓轉(zhuǎn)換，因此工業(yè)變電站應(yīng)該包括變壓器設(shè)備。</p&

47、gt;<p>　　分段——在很多高壓大容量的長線路中，尤其是幾條線路并聯(lián)運行時，經(jīng)常需要將線路分段，目的是為了使線路獲得適當(dāng)?shù)谋Ｗo和維護。這樣的變電站有助于隔寓線路中的故障段，保證連續(xù)供電。這種變電站通常只由開關(guān)設(shè)備組成。在長線路中，還可以提供功率因數(shù)調(diào)整設(shè)備。</p><p>　　輸電線路的電源——在發(fā)電廠的戶外設(shè)置高壓設(shè)備已經(jīng)變得越來越昔遍，安裝的裝置只不過是一個升壓電站，它以發(fā)電機電壓接受電能

48、，然后將電壓升高，并最終通過高壓輸電線路將電能送出。這種變電站只不過是將戶外配電變電站反過來，電壓是被升高而不是降低。</p><p>　　功率因數(shù)調(diào)整——隨著供電負荷的減小，長線路末端的電壓趨向于升高，而隨著供電負荷的增大，線路末端的電壓趨向于降低。由于電感和電容的影響，這個電壓的變化將伴隨著線路功率因數(shù)而變化，因此有必要在線路末端設(shè)置同步調(diào)相機。為了向同步調(diào)相機供電，就必須將高壓輸電線路的電壓降低，因此，一個

49、功率因數(shù)調(diào)整變電站將包括開關(guān)設(shè)備、變壓器和所有運行同步調(diào)相機所需要的設(shè)備。</p><p>　　鐵路——一般地，向鐵路供電的變電站分為兩類，即交流類和直流類。如果是交流變電站，其問題一般是一個電壓轉(zhuǎn)換和向鐵路機車負荷單相供電的問題。然而，也有可能在機車內(nèi)通過相位變換錨由單相電源向三相負荷供電。如果是直流鐵路，這種變電站一般由三相電源供電，并通過旋轉(zhuǎn)變流器、電動機——發(fā)電機組或者整流器等將交流變換為直流。</

50、p><p>　　照明和動力用直流——現(xiàn)在，仍然有一些在大城市以外的地區(qū)采用直流三線系統(tǒng)供電，這種電源總是從同步換流器獲得。另外，工廠中還有某些類型的電動機負荷要求采用直流電源，這些一般都是由旋轉(zhuǎn)換流器供電。對于電解工業(yè)，低壓直流電源絕對是必須的，因此也需要使用電動機——發(fā)電機組或旋轉(zhuǎn)變記器。</p><p>　　由于城市不斷發(fā)展，許多城市變電站已經(jīng)達到其負荷極限，所以市區(qū)配電系統(tǒng)經(jīng)常是超負荷

51、運行，許多配電站急需升級、檢修或擴建，問題是空間不足。市中心的業(yè)主不希望外觀“丑陋”的新變電站影響當(dāng)?shù)氐木坝^，商家和居民也不想將來被星羅棋布的電網(wǎng)所干擾。</p><p>　　變電站自動化的新趨勢是狀態(tài)維修。ABB公司與聯(lián)邦愛迪生公司合作開發(fā)了一套貫穿整個系統(tǒng)的規(guī)劃，一旦聯(lián)邦愛迪生公司的配電系統(tǒng)發(fā)生故障，可使電能流向發(fā)生改變。聯(lián)邦愛迪生公司的項目總裁邁克·羅維說：“對這幾個變電站的發(fā)行包括肥現(xiàn)有的輻射狀

52、的饋電系統(tǒng)改成環(huán)形母線系統(tǒng)，以增加系統(tǒng)的穩(wěn)定性?！?lt;/p><p>　　GE哈里其變電站綜合控制系統(tǒng)（ISCS）就是一個將設(shè)備監(jiān)測與變電站自動化相結(jié)合的系統(tǒng)。該項系統(tǒng)能夠?qū)碜宰冸娬鞠到y(tǒng)和設(shè)備在線監(jiān)控裝置的數(shù)據(jù)進行綜合，并輸入數(shù)據(jù)庫，然后由一個專家系統(tǒng)利用自我診斷程序進行分析，得出有關(guān)被監(jiān)測設(shè)備的運行善的信息。該信息被發(fā)送到電腦維修管理系統(tǒng)，自動發(fā)出并傳送維修工作指令。由于維修指令的發(fā)送得到了改善，極大地提高了基

53、于狀態(tài)進行維修程序的效率。ABB電力公司及其企業(yè)合作伙伴聯(lián)合開發(fā)了ABB電力系統(tǒng)軟件。該系統(tǒng)包括一套診斷維修系統(tǒng)，能夠在出現(xiàn)故障前提交必要的維修報告。有了這一套系統(tǒng)，電力公司和用電單位不須經(jīng)過重新改造，只需一臺電腦，就能輕而易舉地擁有一套完整的系統(tǒng)。</p><p><b>　　方向保護基礎(chǔ)</b></p><p>　　早期，對于遠離發(fā)電站的用戶，為改善其供電的可靠性

54、提出了雙回線供電的設(shè)想。當(dāng)然。也可以架設(shè)不同的兩回線給用戶供電。在系統(tǒng)發(fā)生故障后，把用戶切換至任一條正常的線路。但更好的連續(xù)供電方式是正常以兩回線同時供電。當(dāng)發(fā)生故障時，只斷開故障線。（圖14-1） 所示為一個單電源、單負載、雙回輸電線系統(tǒng)。對該系統(tǒng)配置合適的斷路器后，當(dāng)一回線發(fā)生故障時，仍可對負載供電。為使這種供電方式更為有效，還需配置合適的繼電保護系統(tǒng)，否則，昂貴的電力設(shè)備不能發(fā)揮其預(yù)期的作用?？梢钥紤]在四個斷路器上裝設(shè)瞬時和延時起

55、動繼電器。顯然，這種類型的繼電器無法對所有線路故障進行協(xié)調(diào)配合。例如，故障點在靠近斷路器D的線路端，D跳閘應(yīng)比B快，反之，B應(yīng)比D快。顯然，如果要想使繼電器配合協(xié)調(diào)，繼電保護工程師必須尋求除了延時以外的其他途徑。</p><p>　　無論故障點靠近斷路器B或D的哪一端，流過斷路器B和D的故障電流大小是相同的。因此繼電保護的配合必須以此為基礎(chǔ)，而不是放在從故障開始啟動的延時上。我們觀察通過斷路器B或D的電流方向是隨

56、故障點發(fā)生在哪一條線路上變化的。對于A和B之間的線路上的故障，通過斷路器B的電流方向為從負荷母線向故障點。對于斷路器D，電流通過斷路器流向負載母線。在這種情況下，斷路器B應(yīng)跳閘，D不應(yīng)該跳閘。要達到這個目的，我們可以在斷路器B和D上裝設(shè)方向繼電器，該方向繼電器的聯(lián)接應(yīng)該保證只有當(dāng)通過它們的電流方向為離開負載母線時才起動。</p><p>　　對于圖14-1所示的系統(tǒng)，在斷路器B和D裝設(shè)了方向過流延時繼電器后，繼電

57、器的配合才能實現(xiàn)。斷路器A和C裝設(shè)無方向的過流延時繼電器及瞬時動作的電流繼電器。各個繼電器整定配合如下：方向繼電器不能設(shè)置延時，他們只有本身固有的動作時間。A和C的延時過流繼電器通過電流的整定使它們在負載母線故障時不動作。于是快速保護可以保護發(fā)電機和負載之間線路長度的大部分。從圖中我們還可以看到，在斷路器A或C的線路側(cè)發(fā)生的故障使發(fā)電機電壓崩潰，在斷路器A和C上的瞬時繼電器不能真正瞬時切除故障，因為電力設(shè)備動作需要時間，在這個期間內(nèi)，流

58、過斷路器B和D的電流很小甚至為0，因此在這種故障狀態(tài)下，只有等到發(fā)電廠有關(guān)的斷路器動作后，斷路器B和D才動作。這就是我們所說的順序跳閘，通常在上述情況下這樣做是允許的。</p><p>　　在一個交流電路中，通過電流矢量與其他參考矢量（例如電壓矢量）的比較，可以確定電流的方向。圖14-1所示系統(tǒng)的參考矢量可以負載母線電壓矢量推導(dǎo)出。由于在該交流系統(tǒng)中，線路和設(shè)備含有電抗，電流和功率的瞬時方向不能確定，這是顯而易見

59、的，因為當(dāng)有電壓時，相位落后的電流取樣的瞬時值取決于它在電壓周期中的瞬間，可能為正，也可能為負或為零。因此，電壓、電流、電流矢量必須在一個時間間隔內(nèi)采樣。為了較為準確的采樣，時間間隔可從一個半周期到一個周期。目前正在進行更短時間的采樣的研究工作。這個研究工作是給繼電器加上一個預(yù)測電路，試圖以此確定未來時間內(nèi)矢量的情況。由于要在電力系統(tǒng)電磁暫態(tài)過程中預(yù)測，這項工作比較復(fù)雜。通常用于判斷方向的時間越短，所做判斷的可靠性越差。</p&g

60、t;<p><b>　　差動保護</b></p><p>　　用于電力系統(tǒng)的大多數(shù)電氣設(shè)備與一般輸電線路的長度相比，實際尺寸都比較小，因此用導(dǎo)線直接連接就可以使設(shè)備兩端之間的聯(lián)絡(luò)變得非常經(jīng)濟和可靠，保護配置就可以采用簡單而又非常有效的差動保護。從概念上講，流入設(shè)備的電流可以很簡單地與流出的電流進行比較。如果在流入、流出電流之間有差異，設(shè)備就被斷開，如無差異，設(shè)備正常運行，這種保

61、護原理可以設(shè)計為對于設(shè)備內(nèi)部故障相當(dāng)靈敏，對于外部故障則非常不敏感。因此采用差動原理的保護本身具有繼電保護的選擇性。</p><p>　　差動保護最簡單的應(yīng)用見圖14-4，圖中一段簡單的電力線路就是采用差動繼電器保護的。該繼電器通常由三個線圈組成，其一檢測差動電流并起動跳閘回路，我們稱之為工作線圈，在圖中用符號O表示。另外兩個線圈是制動線圈，在圖中用符號R表示。在實際中，由于制造和其他一些原因，兩側(cè)電流互感器的特

62、性不可能完全一致，存在一些差異，制動線圈能防止由此產(chǎn)生的誤動，而在理論上，制動線圈是不起作用的。圖14-4給出了在外部故障時，繼電器不動作跳閘情況下的電流流向。電流I1 進入電力回路后，在離開回路時并未改變，為了簡單起見，設(shè)電流互感器的變比為1：1，兩側(cè)電流互感器的二次繞組連接后，使I1僅通過差動繼電器的制動線圈循環(huán)流動。如果在兩個電流互感器之間，電流同時離開或者進入電力回（內(nèi)部故障），兩個電流互感器中的電流將不同，差電流將通過繼電器的