國網(wǎng)電力職稱英語補(bǔ)全短文(已排版)

1、Passage1 Functions of power transmissionThe function of （1）power transmission is to send power from power plants to load center or to exchange power between networks in order to attain the generation-consumption balance or the supply-demand balance between（2）power networks. Power transmission is com

2、pleted by step-up substations,（3）step-down substations and connected transmission equipment. The transmission line mainly consists of the transmission conductors (4)transmission at high voltage can reduce the line loss and the voltage drop, ensure the power quality, raise the economy of （5）power net

3、work operation. The increase of transmission line voltage can not only raise the amount of transmitted power, but also reduce the line loss and line voltage drop, and improve the voltage quality.Passage 2 Substation misoperation and its preventingThe misioeration that can lead to (1) accidents in th

4、e electrical operation of the substation mainly are: on-load switching of isolating switch; connecting (2) the grounding wire (closing the grounding switch) with power on; closing the circuit breaker (isolating switch)with ground lines (ground switch) earthed.The “five preventings” for (3) preventin

5、g the misoperation in substation includes: preventing the wrong opening or closing of circuit breaker; preventing the on load opening and closing of isolating switch; preventing (4)the closing of grounding switch with power on; preventing the closing of circuit breaker with grounding wire connected;

6、 preventing(5)the persons from illegal entering the lived bay.Passage 3 A brief introduction on the development of supercritical boilers and their main advantagesIn (1) some advanced countries great advantages on economy and environmental protection. As for its reliability, because the steam-water f

7、low passages in supercritical boiler is same as that in the (3) subcritical once-through boiler, there isnt anything special, But as far as hydraulic characteristic, a symbol of reliability, is concerned, in a supercritical boiler, under supercritical condition, medium is of single phase and water p

8、hase can be avoided. It is admitted that, if (5) whole process management is strengthened, both supercritical and subcritical units can get an excellent reliability index.Passage 4 Steam generation and use Steam is one of mans dependable servants. More and more in the background, steam is doing more

9、 and more work for man. In (1)an electrically heated home steam may be seen only at the teakettle, but the electricity used may be generated by burning coal or gas and producing steam to turn the generator rotors in the power plant. Even if (2) the fuel is uranium and the heat is supplied by nuclear

10、 fission, the generation of electricity is still accomplished by(3) first generating steam.In the the demand for electricity doubles every ten years. For the most part water resources suitable for power generation are already in service, except for emergency standby and peak-load units; approximatel

11、y 90% of (4) the new generating capacity being installed utilizes steam. The (5) use of steam for electric power generation is expanding in most countries of the world except for the countries where available water power resources are greater than power needs.Passage 5 Circuit breakerCircuit breaker

12、s are automatically operated high voltage (or high current) switches. Circuit breakers are required (1) to control electrical power networks by switching circuits on, by carrying load and by switching circuits off under manual or automatic supervision. Their duty is as follows: In closed position th

13、e circuit breaker must be a good conductor for the normal load current. In operating the circuit breaker must be able contacts shall have full insulation level. At operation the circuit breaker must close be able (2) to switch the current which can be from a few amperes to many thousands of amperes,

14、 and independently of the characteristics from purely inductive to fully capacitive. At closing operation the circuit breaker must close fast and be safe also against full short circuit conditions. They must, therefore, be effective instantaneously when are called upon (3) to perform any switching o

15、peration after long periods without movement. As the circuit breaker is the last link in the chain of protective equipment, the circuit breaker reliability is (4) of the highest importance for high reliability of the total electric power system. So the importance (5) of the circuit breaker cannot be

16、 over emphasized.Passage 6 The ration of distance to height of pumped-storage power plant For pumped-storage power plant, generally the ratio of distance to height (1) is used to evaluate topographic condition of power plant. Distance-height ratio (2)is the ration of horizontal distance between uppe

17、r and low reservoir to the drop between upper and low reservoir that is L/H. The head of simple pumped-storage power plant consists of two parts, they are natural topographic elevation difference and elevation difference formed by dam. Of course, the head derived from topographic elevation differenc

18、e(3)is most economic, so in selecting plant site, the condition that not only a height difference is available but also no very high dam of upper reservoir is necessary should be considered. Smaller L/H value indicates a shorter water transportation line, then the engineering construction cost can b

19、e saved. But in many circumstances, topographic condition (4)is not desirable, so we cant say the smallest L/H value (5) is the best. In newly constructed three large capacity pumped-storage power plants in our country, the L/H value respectively are: 7.12 in Guangzhou, 4.12 in Shisanling, 2.40 in T

20、ian huangping.Passage 7 Fuel cellsFuel cells are devices that when a fuel such as hydrogen or hydrogen-rich compounds and oxygen are supplied to materials arranged like the anode and cathode of a conventional battery, combine to convert chemical energy directly into electrical energy. Unlike convent

21、ional batteries where the conversion of chemical to electrical energy requires only the closing of a circuit between the cathode and anode to produce and electrical current, (1) there is no storage capacity in a fuel cell. These cells require the fuel and oxygen that will produce the chemical reacti

22、ons that produce an electrical output. Fuel cells have been made that will supply power in the megawatt range, and (2) further development is under way. Such cells are not yet widely used on power systems, but (3) as they are being developed there have been some applications to supply fuel cell powe

23、r to isolated loads. As the voltage output of a cell is in the order of to 2.5V, (4) many cells are operated in series to obtain voltages and power out put in ranges that are normally required. Inverters are used to (5) supply alternating current from fuel cells when and AC output is desired.Passage

24、 8 Substations pace into the Digital Age Substations constitute the main part of power transmission and distribution in a power grid. The substations (1) composed of a large number of primary and secondary equipments, with the responsibility for the electric power transmission and distribution in th

25、e grid. Over more than a decade of development, (2) substation automation technology has reached a certain level. In the rebuilding and constructing of power grid in rural and urban areas, automation technology is not only used in low-voltage substations to realize unattended operation, but also in

26、the 220kV and above extra-voltage substations, thus greatly enhancing the level of modernization of power grid construction, strengthening the power transmission and distribution and the possibility of power grid dispatching and reducing the total cost of substation construction, (3)all of which has

27、 become an indisputable fact. However, the development of technology is never-ending, and the increasing maturation of technology like intelligent switches, photoelectric current and voltage transformers, online condition monitoring of primary equipments,(4)simulation training technology for substat

28、ion operation, as well as the development and application of high-speed network in real- time system, is bound to have a profound impact upon the existing substation automation technology, and (5)a full-digital automation system is about to emerge.Passage 9 Overcoming the Problem of WasteMany large

29、cities are anything but beautiful. Streets are littered with trash. In this trash, however, (1) there is still something that can be useful.If people want to solve the problem of waste, (2) there is no time to be lost. They must work out ways of making use of good things which are just thrown away a

30、s waste. When a car gets too old, it may not run any more. But if the metal that the car was made of is still good,(it can be put to use again) bottle glass can be ground into sand and used to pave streets. Besides, garbage from food can be changed into fertilizer. But first you have to pick out all

31、 the glass and metal.Furthermore, garbage can also be a good source for making building blocks, which are then covered with concrete. Now, (4)more and more machines are designed for this purpose. Some day, people will watch films in a great cinema which has been built out of garbage. Future building

32、s, roads, and cities may be made from garbage. But so far, (5)building beautiful cities out of garbage is only a dream.Passage 10 HibernationThe weather in winter can be very cold. Some animals sleep during the winter, for its difficult for them to find food then. (1)They can sleep for a long time.

33、For example, their sleep can last from autumn to spring. (2)We call this kind of sleep in wintertime “hibernation”.Animals need food in winter to keep them warm and alive. If they move about more, they need eat more. (3)Hibernating animals dont need to eat much because they dont move. Their heart be

34、ats slowly. And they breathe slowly. They find a safe place to sleep. (4)So they dont need to worry about bad weather and other dangerous animals.In warn winter some animals like bears may wake up. If they see thick nosnow on the ground, they will get back to their sleep. (5)As it gets warmer and wa

35、rmer in spring, the sleeping animals begin to wake up and look around for food.Passage 11 SatellitesThe body that is neatest to the Earth is the moon. (1)It circles the Earth and is therefore know as a satellite of the Earth. This satellite is called natural satellite. Man made spacecraft which circ

36、le the Earth are called artificial satellites. Natural as well as artificial satellites circle the planets in a definite path or orbit. (2)A satellite stays in orbit because the planet gravitational force keeps pulling it into a circle.All the bodies in space like the moon, the planets and the stars

37、 also exert an attractive force on objects.(3)The bigger and heavier a body is ,the greater is its force of gravity. The moons gravitational force is only one-sixth that of the Earths. The Earths gravitational force of pull keeps us and everything else on Earth from floating away to space.(4)To get

38、out into space we have to overcome the Earths gravitational pull. There are many artificial satellites orbiting around the Earth. Some artificial satellites have been sent up to orbit the moon and even the planet Mars.(5)Artificial satellite can be used for various purposes.Passage 12 Secondary equi

39、pment in power systemThe secondary equipments in power system are 1. the equipments that provide protecting, monitoring, measuring, regulating, controlling primary equipments, the equipments that supply information, working condition for the operator or maintenance persons, and 2. the equipments tha

40、t send the command signals. The electric circuit connected with the secondary winding of CT or PT is called secondary circuit. The secondary equipment and secondary circuit belong to secondary system.The voltage and 3.current values in secondary system are: 110V, 22V, DC operating voltages, 100Vrate

41、d voltage of the potential transformer secondary winding and 4.5Arated current of the current transformer secondary winding. The related parameter values of secondary system after weak electrification are: 24V, 48V, 60V DC operating voltages, 5.50V rated voltage of PT secondary side, 0.5A rated curr

42、ent of CT secondary side.Passage 13 Switching overvoltage A sudden change in the configuration of transmission network caused 1.by the operation of a circuit breaker or by the appearance of a fault can cause a rapid surge known as switching overvoltages, which propagates throughout the network. It i

43、s these switching overvoltages which in 2.general determine the insulation requirements of transmission lines. Limitating these overvoltages is of extremely importance, because they have an important effect on both 3.the cost of transmission and line failure rate.These switching overvoltages can occ

44、ur 4.at both opening and closing of circuit breakers. If non-restriking circuit breakers is not used, it is at the instant of closing, and above all, This switching overvoltages is usually limited 5.by means of circuit breaker closing resistor in 500kV system.Passage 14 Transmission line and distrib

45、ution lineThe high voltage power line through which power is (1) transmitted from power plants step-up substation to step-down substation is called power transmission line. The voltage classes of 35kV and above are generally used. High voltage distribution line is (2) the power line that transmits t

46、he power from step down substation to distribution transformers. Low voltage distribution line is the line that transmits power from distribution transformer to the users. The normal voltage of power distribution line is 380V.The special sections of (3)the overhead transmission line refer to the sec

47、tions with large spanning, serious pollution, (4)lightning frequency happening and heavy raining. The overhead line section whose span is 1000m and longer or the height of the pole or tower is 100m and higher is called (5) large spanning line section.Passage 15 Transformer insulationThe insulation o

48、f a transformer can be categorized into internal insulation and external insulation. (1)The internal insulation refers to the insulation of various parts inside the oil tank. The external insulation is the insulation between the upper part of bushings and the ground and the insulation among the bush

49、ings. The internal insulation of transformer can be further subdivided into main insulation and longitudinal insulation.(2)The main insulation refers to the insulation between windings and grounding parts and the insulation between windings. The longitudinal insulation refers the insulation between

50、different parts of the same winding, such as insulation between different sections, layers and turns of the same winding. (3)The main insulation materials inside transformer are transformer oil, insulating pressboard, cable paper, corrugated paper, etc. The oil in transformer has two functions, one

51、is insulation, and the other is cooling, (4) The degradation of insulating properties of insulation materials under long period of influence by the factors such as temperature is called insulation aging. (5)If the winding temperature is within the scope of 80-140, for every 6 temperature rise the in

52、sulation life time of the paper used in transformer will decrease by half.Passage 16 The electricity market The aim of introducing market mechanism is to bring various parties more economic benefit through equitable competition, thereby promote economic development. Like other markets, it needs (B.

53、a wholesale market) where the sellers and buyers (suppliers) can trade electricity, and needs (D. a retail market ) where the suppliers can sell electricity to final customers. As in other markets, the participants need (A. to agree on the price and quantity to be traded ). Competition is introduced

54、 into generation and retail supplied to customers. Customers are free (E. to choose electricity suppliers). .If a customer chooses to buy electricity in the retail market, he should be able to choose electricity supp y from one of several competing retailers. If a customer decides to purchase direct

55、ly from the wholesale market, he will need (C. to register as a market customer). Power generation is disaggregated into separate companies to ensure adequate competition.Passage 17 Electric power Electric power is a most convenient, clean, safe, and useful form of energy which supplies the major po

56、rtion of energy needs of a modem society. At the present time (C. the lack of electricity (a blackout) ) is newsworthy. Electric power is so vital to the lives of people that (B. its unavailability) causes inconvenience, loss of production, and danger to many individuals who are in operation (such a

57、s cardiac operation) in hospital. A prolonged blackout, which is inevitable when a growing load is combined with no generation additions, could lead to (D. social disorder, and even national tragedy). With the developing of industry and improving in living standard, the electric power demand is grow

58、ing continuously and (A. its growth rate) is much greater than that of all other forms of energy. Now (E. high electric power consumption per capita) has been one of the indications of modernization of a country.Passage 18 Copyright piracy There are numerous examples of what has become known as copy

59、right piracy. The American chemical giant Du Pont, for example, recently introduced into one Asian country its famous Londax herbicide, which kills weeds in rice fields. The company invested millions of dollars in (B. the research and development ) of this product and ploughed another US $25 million into opening a local production plant. Les8 than one year later, however, very cheap bottles of Londax were openly on sale. The only difference between (D. the fake and real