電力專業(yè)英語(yǔ)第十一講

1、山東交通學(xué)院電氣系張建軍 詞匯New Words and Expressions layout leatn. 布局設(shè)計(jì); 布置圖，規(guī)劃圖;transmission trnsmn n. 輸電傳送; 播送; distribution dstrbju:nn. 配電分配，分布; 法 財(cái)產(chǎn)分配; 無(wú)線 頻率分布;generate v. 發(fā)電形成，造成; 產(chǎn)生物理反應(yīng); 產(chǎn)生（后代）; 引起;Hz 赫茲step-up substation 升壓變電站transformer trnsf:m(r) n. 變壓器改革者order n. 數(shù)量級(jí)秩序; 命令; 次序; 規(guī)則，制度step-down transfor

2、mer降壓變壓器recurring rk:ra. 重復(fù)的再發(fā)生，復(fù)發(fā)( recur的現(xiàn)在分詞 ); 再現(xiàn)centre of gravity n. 重點(diǎn)重心; terminate v. 端接結(jié)束; 使終結(jié); 解雇; 到達(dá)終點(diǎn)站outskirtsatsk:ts n. 外圍郊外; 邊緣; 市郊，郊區(qū); premise premsz n. 房屋（pl.）in terms of 按照 課文內(nèi)容Unit 8 輸配電系統(tǒng) Transmission and Distribution SystemsPart ALayout of Transmission and Distribution SystemsAs s

3、tated in the previous section power generation often takes place far away from the places of consumption of power. Figure 8.1 shows a diagram of how power is generated, transmitted over large distances and then sent to the consumer.Layout of Transmission and Distribution Systems輸配電系統(tǒng) 的布局the places o

4、f consumption of power消耗電能的地方It is clear from Fig. 8.1 that bulk amount of power is generated at the power house. Power is commonly generated at 11 kV, three phase Standard frequency used in our country is 50 Hz .From here, power goes to a nearby place called step-up substation where, by means of a

5、transformer, the voltage is increased from 11 kV to 132 or 220 kV. the power house發(fā)電廠step-up substation 升壓變電站by means of a transformer借助于變壓器The power is then carried at such high voltage over a long distance with the help of wires called transmission lines. The transmission lines are long because th

6、e place of generation is often far away from that of consumption.The power is then carried at such high voltage over a long distance電能于是在這樣高的電壓下進(jìn)行遠(yuǎn)距離輸送the place of generation is often far away from that of consumption.發(fā)電的地方經(jīng)常遠(yuǎn)離電能消耗的地方Power is transmitted at extra-high voltage (EHV) of 132 or 220 kV

7、because it results in minimum power loss in the line. The cost of extra-high voltage transmission lines is very high. extra-high voltage (EHV)超高壓高壓電的概念是隨著時(shí)代的變遷而逐步發(fā)展變化的：最初是說(shuō)500V以下為低壓，以上為高壓；后來(lái)隨工業(yè)發(fā)展變?yōu)?000V為高低壓界限（現(xiàn)在的普遍概念）；我國(guó)目前絕大多數(shù)電網(wǎng)來(lái)說(shuō)，高壓電網(wǎng)指的是110kV和220kV電網(wǎng)；超高壓電網(wǎng)指的是330kV，500kV和750kV電網(wǎng)。特高壓輸電指的是正在開(kāi)發(fā)的1000 kV

8、交流電壓和800kV直流電壓輸電工程和技術(shù)。because it results in minimum power loss in the line因?yàn)樗沟镁€路中的功耗最小The cost of extra-high voltage transmission lines is very high超高壓輸電線路的成本非常高It is economical to transmit power at extra-high voltage as long as bulk power (i.e large amount of power of the order of 100 MW and above

9、) over a long distance (i.e 100km and over) is to be transmitted. as long as bulk power (i.e large amount of power of the order of 100 MW and above) over a long distance is to be transmitted只要是遠(yuǎn)距離輸送大功率的電能 When the transmission line has covered a major distance, it is connected to step-down transform

10、ers at the “Primary substation”(see Fig. 8.1) where the voltage is stepped down to 66 or 33 kV. From this primary substation power at 66 or 33 kV is carried through subtransmission lines to different load centers.When the transmission line has covered a major distance當(dāng)輸電線路覆蓋了主要的距離Primary substation一

11、級(jí)變電站；主變電所subtransmission lines 次級(jí)輸電線From this primary substation power at 66 or 33 kV is carried through subtransmission lines to different load centers電能從一級(jí)變電站經(jīng)過(guò)66 或 33 kV 的次級(jí)輸電線送到負(fù)荷中心Figure 8.1 shows one such subtransmission line. The length of a subtransmission line is about 50 km and they carry

12、about 50 MW of power . For the power that they carry (about 50 MW ) and their length (about 50 km) it has been found that sending power through subtransmission lines at 33 or 66 kV is economical in terms of recurring losses(i.e. I2R)and the capital cost (i.e. cost of conductor, insulators and suppor

13、ts).they carry about 50 MW of power 它們輸送50 MW 的功率it has been found that sending power through subtransmission lines at 33 or 66 kV is economical 我們發(fā)現(xiàn)次級(jí)輸電線路以33 或 66 kV 輸送電能是經(jīng)濟(jì)的recurring losses經(jīng)常性損失capital cost 投資費(fèi)用The question now arises as to how the location of the primary substation is selected. T

14、he primary substations are located at places which are more or less the centers of gravity of the load to be supplied by the substations .The question now arises as to how the location of the primary substation is selected主變電所如何選址這一問(wèn)題現(xiàn)在被提出來(lái)。which are more or less the centers of gravity of the load t

15、o be supplied by the substations它們（主變電所）差不多是由其供電的負(fù)荷的中心The subtransmission lines terminate at another substation called the secondary substation which is situated in the outskirts of a city or town. The secondary substations step down the voltage by means of transformers from 66 or 33 kV to 11 kV. No

16、w, the power has to be supplied to the various consumers in the city. The subtransmission lines terminate at another substation called the secondary substation 這些次級(jí)輸電線路末端接于另一種叫做二級(jí)變電站的變電所outskirts of a city or town城市或城鎮(zhèn)的郊區(qū)This can not be done at 11 kV since the consumer voltage, both domestic and ind

17、ustrial, is at 240 and 415 v respectively. This necessitates the use of a step-down transformer. Therefore, the power from the secondary substation at 11 kV is supplied to 11 kV /415 kV transformers installed at Distribution Substations in the city. the consumer voltage用戶電壓Distribution Substations配電

18、變電所both domestic and industrial家庭用和工業(yè)用This necessitates這就需要The number of distribution substations inside a city depends upon its area and load. Each distribution substation is located near the centre of the load pockets in the city. depends upon its area and load取決于它的面積和負(fù)荷的大小the centre of the load p

19、ockets in the city城市中負(fù)荷的中心Most domestic, commercial and small-scale industrial consumers receive power at low voltage, is at 240 or 415 v respectively. However, large commercial organizations, industries and public buildings having load in excess of 100 kW, prefer to buy bulk power at 11 kV .Most do

20、mestic, commercial and small-scale industrial consumers receive power at low voltage大多數(shù)家庭、商業(yè)和小規(guī)模的工業(yè)用戶都是在低壓接受電能large commercial organizations大型商業(yè)機(jī)構(gòu)public buildings公共建筑prefer to更喜歡; 寧愿to buy bulk power at 11 kV 在11 kV 電壓下采購(gòu)大量的電能This is done by taking the 11 kV primary distribution line right up to the

21、 premises of such consumers and connecting it to a 11 kV/415 V transformer.the 11 kV primary distribution 11 kV 主配電線 premisespremsz n. 房屋（pl.）This is done by taking the 11 kV primary distribution line right up to the premises of such consumers and connecting it to a 11 kV/415 V transformer.實(shí)現(xiàn)這一點(diǎn)是通過(guò)把

22、11 kV 的主配電線連接到這些用戶的建筑物并和11 kV/415 V 變壓器連接起來(lái)。Part BElectric TransmissionPresent ChoicesGreat advances are anticipated in future electric transmission technology. Technologically speaking, transmission lines constitute in many ways the weakest links of the electric power systems. Electric Transmission

23、電力傳輸Great advances are anticipated in future electric transmission technology人們預(yù)期在電力傳輸技術(shù)上能有巨大的進(jìn)步。Technologically speaking, transmission lines constitute in many ways the weakest links of the electric power systems從技術(shù)上講，在許多方面輸電線路都是電力系統(tǒng)最薄弱的環(huán)節(jié)。Overhead lines are bulky, vulnerable in storms, and unsight

24、ly. They produce “noise pollution, and are the cause of many accidents! Neither is their energy-transmission capability very impressive in comparison with some other methods of transporting energy. Overhead lines are bulky架空線路非常笨重vulnerable in storms在風(fēng)暴中很脆弱impressive可觀的; 給人印象深刻的，感人的; 引人注目的; 顯赫;Consi

25、der, for example, a 400-kV overhead line carrying at best 2000 MW of power at a cost of about $1.00 per MWh per 100 miles. Compare this line with a typical 36-inch natural gas pipeline moving energy at the rate of about 1 billion Btu per hour (corresponding to 12,000 MW ) at a cost of about $0.1per

26、MWh per 100 miles. natural gas pipeline天然氣管道Btu是英熱單位（英制）,Btu/h就是“英熱單位每小時(shí)”,由于 1(英熱單位) = 1055.056(焦),而 1瓦特 = 1焦/秒.所以 1(英熱單位每秒) = 1055.056(瓦特),把秒換為小時(shí)就是:1英熱單位每小時(shí) = 1055.05585262(瓦特)*3600 = 0.293(瓦).Even an electric power engineer must agree that an underground gas pipeline is preferable to an overhead p

27、ower line defiling our great Western vistas if a choice would exist.defiling our great Western vistas玷污我們美好的西方前景if a choice would exist.如果這樣的選擇存在。Both existing and proposed overhead lines are being challenged with increasing opposition, particularly, in urban areas. As we move toward ultra-high volt

28、age (UHV) there are fears that the exposed electric field between the conductors and ground will negatively affect plants, small animals, and possibly humans.Both existing and proposed overhead lines 已有的和待建的架空線As we move toward ultra-high voltage (UHV) 當(dāng)我們把注意力轉(zhuǎn)向超高壓there are fears 有許多恐懼(擔(dān)憂）that the e

29、xposed electric field between the conductors and ground暴露在導(dǎo)體和大地之間的電磁場(chǎng) negatively affect 負(fù)面影響課堂練習(xí)：1.Realistically assessed, we will have to live with overhead power lines for many years yet. Presently the only alternative is the underground (UG) cable.2. Typically these cables are of high-pressure, oil-filled cellulose paper insulated design. Not only are UG cables vastly more expensive than overhead lines but they can be used (for ac transmission) over very short distances only at the most, a few kilometers.3.This la