1、精選優質文檔-傾情為你奉上外文文獻一General Requirements to Construction of SubstationSubstations are a vital element in a power supply system of industrial enterprisesThey serve to receive ，convert and distribute electric energy .Depending on power and purpose ,the substations are divided into central distribution s

2、ubstations for a voltage of 110-500kV;main step-down substations for110-220/6-10-35kV;deep entrance substations for 110-330/6-10Kv;distribution substations for 6-10Kv;shop transformer substations for 6-10/0.38-0.66kV.At the main step-down substations, the energy received from the power source is tra

3、nsformed from 110-220kV usually to 6-10kV(sometimes 35kV) which is distributed among substations of the enterprise and is fed to high-voltage services.Central distribution substations receive energy from power systems and distribute it (without or with partial transformation) via aerial and cable li

4、nes of deep entrances at a voltage of 110-220kV over the enterprise territory .Central distribution substation differs from the main distribution substation in a higher power and in that bulk of its power is at a voltage of 110-220kV;it features simplified switching circuits at primary voltage; it i

5、s fed from the power to an individual object or region .Low-and medium-power shop substations transform energy from 6-10kV to a secondary voltage of 380/220 or 660/380.Step-up transformer substations are used at power plants for transformation of energy produced by the generators to a higher voltage

6、 which decreases losses at a long-distance transmission .Converter substations are intended to convert AC to DC (sometimes vice versa) and to convert energy of one frequency to another .Converter substations with semiconductor rectifiers are convert energy of one frequency to another .Converter subs

7、tations with semiconductor rectifiers are most economic. Distribution substations for 6-10kV are fed primarily from main distribution substations (sometimes from central distribution substations).With a system of dividing substations for 110-220kV, the functions of a switch-gear are accomplished by

8、switch-gears for 6-10kV at deep entrance substations.Depending on location of substations their switch-gear may be outdoor or indoor. The feed and output lines at 6-10kV substations are mainly of the cable type .at 35-220kV substations of the aerial type .When erecting and wiring the substations ,ma

9、jor attention is given to reliable and economic power supply of a given production.Substations are erected by industrial methods with the use of large blocks and assemblies prepared at the site shops of electric engineering organizations and factories of electrical engineering industry .Substations

10、are usually designed for operation without continuous attendance of the duty personnel but with the use of elementary automatic and signaling devices.When constructing the structural part of a substation .it is advisable to use light-weight industrial structures and elements (panels ,floors ,etc.) m

11、ade of bent sections .These elements are pre-made outside the erection zone and are only assembled at site .This considerably cuts the terms and cost of construction.Basic circuitry concepts of substations are chosen when designing a powersupply system of the enterprise .Substations feature primary

12、voltage entrances .transformers and output cable lines or current conductors of secondary voltage .Substations are mounted from equipment and elements described below .The number of possible combinations of equipment and elements is very great .Whenelaborating a substation circuitry ,it is necessary

13、 to strive for maximum simplification and minimizing the number of switching devices .Such substations are more reliable and economic .Circuitry is simplified by using automatic reclosure or automatic change over to reserve facility which allows rapid and faultless redundancy of individual elements

14、and using equipment.When designing transformer substations of industrial enterprises for all voltages , the following basic considerations are taken into account:1. Preferable employment of a single-bus system with using two-bus systems only to ensure a reliable and economic power supply;2. Wide use

15、 of unitized constructions and busless substations;3.Substantiated employment of automatics and telemetry ;if the substation design does not envisage the use of automatics or telemetry ,the circuitry is so arranged as to allow for adding such equipment in future without excessive investments and re-

16、work.4.Use of simple and cheap devices-isolating switches ,short-circuiting switches ,load-breaking isolators ,fuses ,with due regard for their switching capacity may drastically cut the need for expensive and critical oil ,vacuum ,solenoid and air switches .Substation and switch-gear circuitries ar

17、e so made that using the equipment of each production line is fed from individual transformers ,assemblies ,the lines to allow their disconnection simultaneously with mechanisms without disrupting operation of adjacent production flows.When elaborating circuitry of a substation, the most vital task

18、is to properly choose and arrange switching devices(switches ,isolators ,current limiters ,arresters ,high-voltage fuses).The decision depends on the purpose ,power and significance of the substation.Many years ago, scientists had very vague ideas about electricity. Many of them thought of it as a s

19、ort of fluid that flowed through wires as water flows through pipes, but they could not understand what made it flow. Many of them felt that electricity was made up of tiny particles of some kind ,but trying to separate electricity into individual particles baffled them.Then, the great American scie

20、ntist Millikan, in 1909,astounded the scientific world by actually weighing a single particle of electricity and calculating its electric charge. This was probably one of the most delicate weighing jobs ever done by man,for a single electric particle weighs only about half of a millionth of a pound.

21、 To make up a pound it would take more of those particles than there are drops of water in the Atlantic Ocean.They are no strangers to us, these electric particles, for we know them as electrons. When large numbers of electrons break away from their atoms and move through a wire,we describe this act

22、ion by saying that electricity is flowing through the wire.Yes,the electrical fluid that early scientists talked about is nothing more than electrical flowing along a wire.But how can individual electrons be made to break away from atoms? And how can these free electrons be made to along a wire? The

23、 answer to the first question lies in the structure of the atoms themselves. Some atoms are so constructed that they lose electrons easily. An atom of copper, for example ,is continually losing an electron, regaining it(or another electron),and losing it again. A copper atom normally has 29 electron

24、s, arranged in four different orbits about its nucleus. The inside orbit has 2 electrons. The next larger orbit has 8.The third orbit is packed with 18 electrons . And the outside orbit has only one electron.It is this outside electron that the copper atom is continually losing, for it is not very c

25、losely tied to the atom. It wanders off, is replaced by another free-roving electron, and then this second electron also wanders away. Consequently,in a copper wire free electrons are floating around in all directions among the copper atoms.Thus, even through the copper wire looks quite motionless t

26、o your ordinary eye, there is a great deal of activity going on inside it. If the wire were carrying electricity to an electric light or to some other electrical device, the electrons would not be moving around at random. Instead, many of them would be rushing in the same direction-from one end of t

27、he wire to the other.This brings us to the second question .How can free electrons be made to move along a wire? Well ,men have found several ways to do that .One way is chemical. Volta,s voltaic pile,or battery, is a chemical device that makes electricity(or electrons)flow in wires. Another way is

28、magnetic. Faraday and Henry discovered how magnets could be used to make electricity flow in a wire.Magnets Almost everyone has seen horseshoe magnets-so called because they are shaped like horseshoes. Probably you have experimented with a magnet, and noticed how it will pick up tacks and nails, or

29、other small iron objects. Men have known about magnets for thousands of years. Several thousand years ago, according to legend, a shepherd named Magnes lived on the island of Crete, in the Mediterranean Sea .He had a shepherds crook tipped with iron. One day he found an oddly shaped black stone that

30、 stuck to this iron tip.Later, when many other such stones were found, they were called magnets(after Magnets).These were natural magnets. In recent times men have learned how to make magnets out of iron. More important still, they have discovered how to use magnets to push electrons through wires-t

31、hat is, how to make electricity flow. Before we discuss this, there arecertain characteristics of magnets that we should know about.If a piece of glass is laid on top of a horse- shoes magnet, and if iron filings are then sprink ledon the glass, the filings will arrange themselves into lines. If thi

32、s same thing is trid with a bar magnet(a horseshoe magnet straightened out),the lines can be seen more easily. These experiments demonstrate what scientists call magnetic lines of force. Magnets, they explain, work through lines of force that ext- end between the two ends of the magnet. But electron

33、s seem to have magnetic lines of force around them, too.This can be proved by sticking a wire through a piece ofcard board, sprinkling iron filings on the cardboard, and connecting a battery to the wire. The filings will tend to form rings around the wire,as a result of the magnetism of the moving e

34、lectrons(or electricity).So we can see that there is arelationship between moving electrons and magnetism, Magnetism results from the movement of electrons. Of course, electrons are not really flowing in the bar magnet, but they are in motion, circling the nuclei of the iron atoms. However, in the m

35、agnet, circling thelined up in such a way that their electrons are circling in the same direction. Perhaps a good comparison might be a great number of boys whirling balls onstrings in a clockwise direction around their heads.翻譯：變電站建設的一般要求變電站(所)在電源系統的工業企業是一個至關重要的因素。他們接收,轉換和發送電能。根據能源和需求,變電站分為中央配電變電站電

36、壓為110-500kV；主要降壓變電所電壓為110-220/6-10-35kV； 深入口變電站為110-330/6-10kV；二次變電站的電壓為6-10Kv；車間變電所電壓為6-10/0.38-0.66kV。在主要的降壓變電所,電源能量轉化電壓為110-220kV，通常使用6-10Kv(有時為35kV變電所)的電壓分配給企業和被用來滿足高壓服務。中央配電變電站從電力系統接收能量并分發它(不包括或者包括部分變換) 給企業不同區域，通過空中電纜和地下電纜線路電壓為110-220kV。 中央分配變電站站不同于主配電變電它是一個更強大的電力設施,它的電壓大部分在110-220kV的電壓。它可以簡化初級

37、電壓、中級電壓或地區的開關電路。中低級別變電站改造能量來自6-10kv的電壓,它的二次側電壓為380/220或660/380。升壓變壓器變電站用于將電廠產生的能量轉化使發電機產生的電壓升高,從而有效地減少在遠距離輸電能量的損失轉換器變電站的目的是為了將直流轉換成交流(有時相反)和轉換成能量時改變頻率。轉換器變電站的能量轉換是用半導體整流器來變頻的。帶半導體整流器的轉化器變電站是最經濟的。6-10kV的配電變電站主要依據主配電變電站(有時依據中央配電變電站)。110-220kV變電站系統區域的劃分時，根據變電站設備功能劃分時是有學問的，6-10kV的變電站設備劃分在變電站的入口。根據變電站變的位

38、置，電站設備在可以露天或室內。6-10kV變電站的在電纜的類型主要是供給輸出線。在35-220kV變電站空中線路樣式,在變電站架線和接線,主要注重供電生產的可靠和經濟。用工業的方式建設變電站，是使用大量的數塊和在電氣工程組織和工廠電氣工程等行業的車間的位置進行組裝。變電站通常是專為不連續操作的責任人員所設計,但用的是基本的自動設備和信號裝置。當建立變電站結構的一部分,應當采用薄型建造結構以及由彎段組成的組件(板材、地板等)。這些元件是預先安裝區外面建造區域并且只是在這個位置組裝。這樣可以有效的削減變電所建造成本。變電站基本電路概念設計的選擇,是根據企業的供電系統特點得到的。變電站電壓特性主要入

39、口，變壓器和輸出電纜線路導線或當前導體的二次電壓.變電站安裝的設備和元件，設備和元件的若干種可能的組合是非常好的。當闡述了變電站的電路時爭取切換裝置最大的簡化和數目的最小化。這樣的變電站更可靠、經濟。電路簡化是采用自動接入或自動轉入儲備的方法,允許快速和無錯誤的自動接入每一個元件和使用設備。當設計工業企業全電壓變電站時,下面的基本因素都要考慮在內。1.優先使用采用兩編組的單總線系統可以確保可靠的和經濟的供應電力。2.配套建設和變電站廣泛使用。3.變電站使用自動化并且支持遙測技術;如果變電站的設計并不支持使用自動化或遙測、線路安而且不允許添加設備，確保以后沒有過度投資和返工。4.使用簡單、便宜的

40、裝置，有絕緣裝置的斷路器、短路開關、過載保護隔離器、保險絲,預期到他們的交換容量可考慮大幅度削減昂貴的器件需要和臨界油、真空、螺線管和空氣開關電路使用。變電站和開關電路,采用這樣的設備的每個生產線服從個體變壓器、裝配、允許他們同時的斷開而不破壞斷開連接的生產流程的機制的線條。變電站的線路的意義,最重要的一點是要妥善安排與選擇轉換器件(開關、隔離者、電流限制器等、避雷器、高低壓熔斷器),這決定了變電站的目的、功能和意義。很多年以前，科學家們對電仍只有很模糊的概念。他們之中不少人認為電是一種“流體”，這種流體就像水流經管道一樣流過導線。但他們并不了解是什么東西使電流動。他們之中的許多人覺得電是有某

41、種極小的微粒構成的，但試圖把電分離成單個的小顆粒他們卻束手無策。此后，以為偉大的美國科學家密利坎于1909年，真正地稱出了單個的電粒子的重量并算出它的電荷而使科學界震驚不已。這可能是人類做過的最細致的計量工作之一，因為一個單個的電粒子的重量僅為一磅的百萬分之一，百萬分之一的一半左右的重量。要合成一磅重需要的電粒子數將要比大西洋的全部水的水滴數還要多。這些電粒子，他們對我們并不陌生，因為我們知道他們就是電子。當大量電子擺脫原子跑出來并通過導線運動時，我們把這種現象說成是電通過導線“流動”。是的，早先的科學家所說的電的“流體”只不過是沿著導線流動的電子。那么，如何能使一些單個的電子擺脫原子的束縛而

42、跑出來呢？而且，又怎樣能使這些自由電子沿導線運動呢？第一個問題的答案就在于原子本身的結構上。某些原子的結構使他們很容易失去電子。例如，一個銅原子在正常情況下有29個電子，它們排列在核子周圍的4個不同的軌道上。最里層的軌道上有2個電子。第二層較大的軌道上有8個電子。第三層軌道上擠滿18個電子。而外層軌道上只有一個電子。正是這個外層電子，銅原子不斷丟掉它，因為這個電子受原子的約束不那么緊。它忽而游離而去，并被另一游離的電子所替代，然后，這后一個電子也游離而去。結果，在銅導線中自由電子在銅原子之間向四面八方漂浮。所以，盡管對你們的普通的肉眼來說，銅導線看來是完全不動的，但在它內部卻不斷地進行著大量的

43、活動。如果導線把電輸送到一盞電燈或者另外某個電氣設備那里，這些電子就不會雜亂無章地到處跑來跑去，而是它們中的許多電子將會向一個方向奔去-從導線的一端奔向另一端。這就把我們引向第二個問題，如何才能使自由電子沿導線運動呢？好啦，人們已經找到幾種方法來做到這一點。一種就是化學方法。伏特電堆，或者叫電池，就是能使電流在導線中流動的一種化學裝置。另一種方法就是電磁法。法拉第和亨利發現了怎樣能把磁鐵用來使電在導線中流動的辦法。磁鐵幾乎每個人都見過馬蹄形磁鐵-之所以這樣叫他是因為他們的形狀做成馬蹄形的。可能你們都用磁鐵做過試驗，并且看到它是怎樣吸起按釘，小釘子或者其他一些小鐵件的。人們了解磁鐵已經幾千年了。

44、據傳說，幾千年前有個名叫麥格尼斯的牧羊人住在地中海的克里特島上。他有一根牧羊人用的帶鐵頭的棍杖。一天，他發現一塊奇形怪狀的黑石頭黏在鐵頭上。后來，當又發現許多這種石頭時，人們就叫它們為磁鐵。這些就是天然磁鐵。近年來，人們已經掌握怎樣使用鐵來制成磁鐵。尤其重要的是，人們發現了如何使用磁鐵推動電子通過導線-也就是怎樣使電流動。在我們討論這點之前，磁鐵有某些特性我們應當了解。如果把一塊玻璃放在馬蹄形磁鐵的端部，然后把一些鐵粉末撒在玻璃上，那么鐵粉自己就會排成許多線。如果用一根棒做的話，就更容易看出這些鐵粉排成的線條了。這些實驗演示了科學家們所謂的磁力線。他們解釋說。磁鐵通過磁鐵兩端之間延伸出來的磁力

45、線起作用。但是，在電子周圍似乎也有磁力線。把一根導線穿過一塊硬紙板，在紙板上撒上鐵粉，并把電池與導線連通在一起，這點就可以得到證明。由于運動的電子的磁性的結果，鐵粉就會繞導線周圍形成一些圓環。因此，我們可以看到，在運動者的電子和磁性之間有一種關系。磁性就是由電子的運動引起的。當然，電子并不是在磁棒里真的“流動”，但它們卻是在運動，在繞鐵原子核做旋轉運動。然而，在磁鐵中，原子都排列的使它們的電子都向同一方向旋轉。也許可打一個恰當的比喻，就像許多小孩在他們頭頂上以順時針方向甩動系在線上的小球一樣。外文文獻二With the development of science and technology

46、, people in their daily lives is becoming more and more demand on the electrical and lighting, etc. In addition to the general demand for electricity with the addition there are many closely related, so we have the stable operation of power systems have become increasingly demanding, variable by ele

47、ctric power system and as an important component of stability as it plays an equally important role. The vast majority of electricity consumers by power companies to supply the electric power system, a complete power system from the distribution around the different types of power plants, boost and

48、step-down substations, transmission lines and users. As everyone knows, the power of modern industrial production is the major source of energy and power. Power not only easy from other forms of energy conversion from, but also easy to convert to other forms of energy used to supply; electricity tra

49、nsmission and distribution is simple and economic, and easy to control, regulation and measurement, and conducive to the realization of the production process automation.The protection of the main current of the protection of the grid, the grid distance protection, differential protection of power networks, power grids of high-frequency protection, automatic reclosing, power transformer relay protection, power capacitor protection. With the devel