国家电网专业技术人员电力英语水平考试补全短文.docx

1、国家电网专业技术人员电力英语水平考试补全短文 补 全 短 文Passage 1 Functions of power transmission The function of (1) is to send power from power plants to load center or to exchange power between power networks in order to attain the generation-consumption balance or the supply-demand balance between (2)Power transmission i

2、s completed by step-up substations，(3)The transmission line mainly consists of the transmission conductors (cables)，poles or towers，insulators，overhead ground wires，and grounding devices. The (4) can reduce the line loss and the voltage drop，ensure the power quality, raise the economy of (5)The incr

3、ease 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 A. step-down substations and connected transmission equipment B. power network operation C. power transmission D. transmission at

4、high voltage E. power networksPassage 2 Substation misoperation and its preventing The misopemtion that can lead to (1) mainly are：on-load switching of isolating switch；connecting (2)；closing the circuit breaker (isolating switch) with ground lines (ground switch) earthed The“five preventings”for (3

5、) includes：preventing the wrong opening or closing of circuit breaker；preventing the on load opening and closing of isolating switch；preventing (4)；preventing the closing of circuit breaker with grounding wireconnected；preventing(5) A. preventing the misoperation in substation B. the closing of grou

6、nding switch with power on C. accidents in the electrical operation of the substation D. the persons from illegal entering the lived bay E. the grounding wire (closing the grounding switch) with power onPassage 3 A brief introduction on the development of supercritical boilers and their main advanta

7、ges In (1) such as U.S.A，Japan and European countries，the supercritical boiler has been developed since the 60s of last centuryIt has been proved by data and experience，the supercritical unit has (2)As for its reliability, because the steam-water flow passages in supercritical boiler is same as that

8、 in the (3)，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 which has a (4). So that the problem caused by uneven distribution of steam phase and water phase c

9、an be avoidedIt is admitted that, if (5)，both supercritical and subcritical units can get an excellent reliability index. A. good homogenization of distribution B. some advanced countries C. whole process management is strengthened D. great advantages oil economy and environmental protection E. subc

10、ritical once-through boilerPassage 4 Steam generation and use Steam is one of mans dependable servants More and more in the background，steam is doing more and more work for man. In (1) steam may be seen only at the teakettle, but the electricity used may be generated by burning coal or gas and produ

11、cing steam to turn the generator rotors in the power plant Even if (2) by nuclear fission，the generation of electricity is still accomplished by (3). In the U.S.A. the demand for electricity doubles every ten years. For the most part water resources suitable for power generation are already in servi

12、ce, except for emergency standby and peak-load units; approximately 90% of (4) utilizes steam. The (5) is expanding in most countries of the world except for the countries where available water power resources are greater than power needs. A. first generating steam B. an electrically heated home C.

13、use of steam for electric power generation D. the new generating capacity being installed E. the fuel is uranium and the heat is suppliedPassage 5 Circuit breaker Circuit breakers are automatically operated high voltage (or high current) switches. Circuit breakers are required (1) by switching circu

14、its on，by carrying load and by switching circuits off under manual or automatic supervision. Their duty is as follows：In closed position the circuit breaker must be a good conductor for the normal load current. In open position the gap across the contacts shall have foil insulation level. At opening

15、 operating the circuit breaker must be able (2) to many thousands of amperes，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 eff

16、ective instantaneously when are called upon (3) without movement. As the circuit breaker is the last link in the chain of protective equipment, the circuit breaker reliability is (4) of the total electric power system so the importance (5) cannot be over emphasized. A to perform any switching operat

17、ion after long periods B. to control electrical power networks C. of the circuit breaker D. to switch the current which can be from a few amperes E. of the highest importance for high reliability Passage 6 The ratio of distance to height of pumped-storage power plant For pumped-storage power plant,

18、generally the ratio of distance to height (l), Distance-height ratio (2) 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, t

19、he head derived from topographic elevation difference ( 3 )，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

20、 engineering construction cost can be saved. But in many circumstances, topographic condition ( 4 ),so we cant say the smallest L/H value ( 5 ). 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，

21、2.40 in Tian huangping A. is most economic B. is used to evaluate topographic condition of power plant C. is not desirable D. is the ratio of horizontal distance between upper and low reservoir E. is the best Passage 7 Fuel cells Fuel cells are devices that when a fuel such as hydrogen or hydrogen-r

22、ich 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 conventional batteries. where the conversion of chemical to electrical energy requires only the closing of a ci

23、rcuit between the cathode and anode to produce and electrical current，(1). These cells require the fuel and oxygen that will produce the chemical reactions that produce an electrical 0utoutFuel cells have been made that will supply power in the megawatt range，and (2)Such cells are not yet widely use

24、d on power systems，but(3)to supply fuel cell power to isolated loads As the voltage output of a cell is in the order of l to 2.5V, (4) and power output in ranges that are normally required. Inverters are used to (5) when and AC output is desired. A . further development is under way B. there is no s

25、torage capacity in a fuel cell C. many cells are operated in series to obtain voltages D. supply alternating current from fuel cells E. as they are being developed there have been some applicationsPassage 8 Substations pace into the Digital Age Substations constitute the main part of power transmiss

26、ion and distribution in a power grid. The substations (1), with the responsibility for the electric power transmission and distribution in the grid. Over more than a decade of development, (2). In the rebuilding and constructing of power grid in rural and urban areas，automation technology is not onl

27、y used in low-voltage substations to realize unattended operation，but also in 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 dispatchin

28、g and reducing the total cost of substation construction, (3). 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), as well a

29、s 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) is about to emerge. A. substation automation technology has reached a certain level B. simulation training technology for substat

30、ion operation C. composed of a large number of primary and secondary equipments D. a full-digital automation system E. all of which has become an indisputable factPassage 9 Overcoming the Problem of Waste Many large cities are anything but beautiful Streets are littered with trash. In this trash, ho

31、wever, (1) If people want to solve the problem of waste, (2)They must work out ways of making use of good things which are just thrown away as wasteWhen a car gets too old，it may not rimany more. But if the metal that the car was made of is still good，(3). When a bottle is empty, it goes out in the

32、trash. But 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 the glass and metal. Furthermore, garbage can also be a good source for making building blocks, which are then covered with concrete. Now, (4) . Some day, people will watch films in a great cinema which has been built out of garbage Future buildings，roads，and cities may be made from garbage. But so far, (5). A. there is no time to be lost B. building beautiful cities