电力专业英语第十一讲

1、山东交通学院电气系张建军 词汇New Words and Expressions layout leatn. 布局设计; 布置图，规划图;transmission trnsmn n. 输电传送; 播送; distribution dstrbju:nn. 配电分配，分布; 法 财产分配; 无线 频率分布;generate v. 发电形成，造成; 产生物理反应; 产生（后代）; 引起;Hz 赫兹step-up substation 升压变电站transformer trnsf:m(r) n. 变压器改革者order n. 数量级秩序; 命令; 次序; 规则，制度step-down transfor

2、mer降压变压器recurring rk:ra. 重复的再发生，复发( recur的现在分词 ); 再现centre of gravity n. 重点重心; terminate v. 端接结束; 使终结; 解雇; 到达终点站outskirtsatsk:ts n. 外围郊外; 边缘; 市郊，郊区; premise premsz n. 房屋（pl.）in terms of 按照 课文内容Unit 8 输配电系统 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输配电系统 的布局the places o

4、f consumption of power消耗电能的地方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发电厂step-up substation 升压变电站by means of a transformer借助于变压器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电能于是在这样高的电压下进行远距离输送the place of generation is often far away from that of consumption.发电的地方经常远离电能消耗的地方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)超高压高压电的概念是随着时代的变迁而逐步发展变化的：最初是说500V以下为低压，以上为高压；后来随工业发展变为1000V为高低压界限（现在的普遍概念）；我国目前绝大多数电网来说，高压电网指的是110kV和220kV电网；超高压电网指的是330kV，500kV和750kV电网。特高压输电指的是正在开发的1000 kV

8、交流电压和800kV直流电压输电工程和技术。because it results in minimum power loss in the line因为它使得线路中的功耗最小The cost of extra-high voltage transmission lines is very high超高压输电线路的成本非常高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只要是远距离输送大功率的电能 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当输电线路覆盖了主要的距离Primary substation一

11、级变电站；主变电所subtransmission lines 次级输电线From this primary substation power at 66 or 33 kV is carried through subtransmission lines to different load centers电能从一级变电站经过66 或 33 kV 的次级输电线送到负荷中心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 它们输送50 MW 的功率it has been found that sending power through subtransmission lines at 33 or 66 kV is economical 我们发现次级输电线路以33 或 66 kV 输送电能是经济的recurring losses经常性损失capital cost 投资费用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主变电所如何选址这一问题现在被提出来。which are more or less the centers of gravity of the load t

15、o be supplied by the substations它们（主变电所）差不多是由其供电的负荷的中心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 这些次级输电线路末端接于另一种叫做二级变电站的变电所outskirts of a city or town城市或城镇的郊区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用户电压Distribution Substations配电

18、变电所both domestic and industrial家庭用和工业用This necessitates这就需要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取决于它的面积和负荷的大小the centre of the load p

19、ockets in the city城市中负荷的中心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大多数家庭、商业和小规模的工业用户都是在低压接受电能large commercial organizations大型商业机构public buildings公共建筑prefer to更喜欢; 宁愿to buy bulk power at 11 kV 在11 kV 电压下采购大量的电能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 主配电线 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.实现这一点是通过把

22、11 kV 的主配电线连接到这些用户的建筑物并和11 kV/415 V 变压器连接起来。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、电力传输Great advances are anticipated in future electric transmission technology人们预期在电力传输技术上能有巨大的进步。Technologically speaking, transmission lines constitute in many ways the weakest links of the electric power systems从技术上讲，在许多方面输电线路都是电力系统最薄弱的环节。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架空线路非常笨重vulnerable in storms在风暴中很脆弱impressive可观的; 给人印象深刻的，感人的; 引人注目的; 显赫;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天然气管道Btu是英热单位（英制）,Btu/h就是“英热单位每小时”,由于 1(英热单位) = 1055.056(焦),而 1瓦特 = 1焦/秒.所以 1(英热单位每秒) = 1055.056(瓦特),把秒换为小时就是:1英热单位每小时 = 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玷污我们美好的西方前景if a choice would exist.如果这样的选择存在。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线As we move toward ultra-high voltage (UHV) 当我们把注意力转向超高压there are fears 有许多恐惧(担忧）that the e

29、xposed electric field between the conductors and ground暴露在导体和大地之间的电磁场 negatively affect 负面影响课堂练习：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