华北电力大学研究生课程考试试题(AB卷)

华北电力大学2015年硕士研究生入学考试初试试题电力系统分析基础A一．判断题（每题2分，共16分，如有错误请将错误更正）1.我国电力工业正在逐步进入全网解列和微网运行的新阶段。

2.我国已先后颁布了6个有关电能质量的国家标准，即供电电压偏差，电力系统频率偏差，公共电网谐波，电压波动和闪变，暂时过电压和瞬态过电压，公用电压间谐波。

3.在电气接线图上，强调电厂与变电所之间的实际位置关系，各条输电线的路径长度都按一定比例反映出来。

4.线路的始端和末端均可接有用电设备，而用电设备的端电压一般允许在额定电压的±10%以内波动。

因而不论有没有调压设备，线路始末两端之间的电压损耗都应该允许有10%的波动。

5.采用分裂导线改变了导线周围的电场分布，等效地减少了导线的半径，从而减小了每相导线的电抗。

6.在各种调压措施中，应首先考虑改变变压器变比调压，因为这种措施不需附加投资，只是改变一下运行方式即能调压。

7.对称分量法是把三相不对称的相量分解成一组对称的相量。

8.因为输电线是静止元件，改变相序会改变相间的互感，因此输电线路的负序阻抗和正序阻抗数值上是有差别的。

二．不定项选择题（每题2分，共16分）9.下列说法正确的是：（）A.保证电力系统可靠，不间断供电是电力系统运行的首要任务B.所有负荷都绝对不能停电C.一级负荷和二级负荷在可能的情况下要保证不间断供电D.电系统中出现供电不足时，三级负荷可以短时断电10.一般规定，电压偏移范围为额定电压的（），频率偏移范围为（）Hz。

A.±5%B.±0.5C.±（2%~5%）D.±（0.2~0.5）11.无备用接线的特点是（）A.简单，经济，运行方便B.供电可靠，电能质量高C.运行操作和继电保护复杂D.包括放射式，干线式，链式12.线路（）主要是由沿绝缘子的泄漏电流和电晕现象决定的。

A.电阻B.电抗C.电导D.电纳13.下列说法正确的是（）A.一般电压在110kV及其以上的中性点不接地或经消弧线圈接地B.电压在35kV及其以下的中性点直接接地C.对于中性点不接地系统，单相接地时，通过接地点的电容电流为未接地时每一相对地电容电流的2.5倍D.对于中性点不接地系统，如果故障处短路电流很大，在接地点会产生电弧14.在发电机端发生短路时，流过发电机定子回路的短路电流最大瞬时值可达发电机额定电流的（）倍。

1.电力系统生产的特点是什么？2.对电力系统的基本要求是什么？3.电能质量的指标是（）（）（）4.考核电力系统运行的经济型的指标（）（）5.电力系统中性点运行方式有（）（）比较两种中性点运行方式优缺点。

6.7.电力系统常用的接线图（）（）8.为什么要规定电力系统的电压等级？9.我国目前运行的电力系统交流和直流的最高电压等级分别是（）（）10.电力变压器的参数是通过哪两个实验测得（）（）11.变压器的不变损耗是（）变压器的可变损耗是（）为什么?12.电力线路的4个参数中，产生有功损耗的有（）（）产生无功损耗的有（）（）13.电力线路具有对地导纳参数的原因（）14.L GJ-400分别代表的含义？15.电力线路按结构分可分为（）（）两大类16.架空线路由（）（）（）（）（）组成。

电缆线路由（）（）（）组成17.采用扩径导线或分裂导线的目的？18.架空输电线为什么要换位？何谓“完全换位”？画出一次完全换位图。

19.铝线和铜线的电阻率是多少？20.21.正常的架空输电线的电导一般为（）S/km左右22.架空线路和电缆线路在电气参数上主要有哪些差别？23.在等值电路中，线路的对地支路是容性的，变压器的对地支路是感性的，为什么？比较两种等值电路有何异同？24.日负荷曲线上如果有很大的“峰谷差”对系统有什么影响？有何办法减小它？25.什么是负荷曲线？什么是负荷特性？日负荷曲线和年负荷曲线各有什么用处？26.电力线路的阻抗是A、B、C三相并联后的等值阻抗？27.变压器的励磁支路是感性的？28.线路末端电压高于始端的现象在电缆中尤为突出，为什么？29.发电机运行受哪些条件的约束？30.电力电容器吸收感性无功？发出容性无功？31.升压三绕组变压器三个绕组由内到外的排列顺序是（）降压排列顺序（）为什么？32.计算变压器参数和电力线路参数的公式？33.环网中的有功分点和无功分点是重合的？34.电压损耗在数值上等于电压降落的模值？35.线路末端的电压永远不会高于始端？36.潮流计算的功率是单相线路的功率？电压是线电压？阻抗和导纳代表单相参数？37.网络有功损耗最小的功率分布取决于支路阻抗?38.当单位长度参数一样时，环路功率的分布取决于环网线路的长度？39.当两个节点间无支路直接相连时，互导纳为0？40.P-Q分解法比牛顿拉夫逊法计算速度快的原因是迭代次数少？41.P-Q分解法修正方程中的稀疏矩阵可直接由节点导纳矩阵虚部组成？42.电力系统潮流计算中PQ节点的特点（）PV节点的特点（）平衡节点的特点（）43.潮流计算中节点电压方程的基本形式是（）44.P-Q分解法潮流计算的原理和简化条件是什么？写出其修正方程式？45.什么是电压降落，电压损耗，电压偏移？46.一般而言，牛顿拉夫逊的迭代次数比PQ分解法（）；收敛速度比PQ（）47.什么叫线路的自然功率？48.线路电压损耗是指电路始末两端电压的（）差49.N-L法确定雅克比矩阵各元素H/N/J/L/R/S的简单形式。

注：所有答案必须写在装订线外1．（10分）已知某电路的网络函数11)()()(0+==s s U s U s H s ，求)()(t t u s ε=和)()(t t u s δ=时的)(0t u 。

2．（15分）电路如题2图所示，开关接通前电路已处于稳态。

已知11V U =，22V U =，12R =Ω，234R R ==Ω，5H 6L =，0.2F C =。

求开关接通后的电容电压()u t 。

U题2图3．（15分）已知题3图所示电路中二端口网络N 的Y 参数矩阵为s Y ⎥⎦⎤⎢⎣⎡=4321。

求负载获得的功率。

-2U题3图4．（10分）求题4图示二端口网络的T 参数。

Ω1I Ω1-U 2题4图5． (10分)在题5图所示电路中，非线性电阻的VAR 为2i u =)0(>i ，试求：（1）u ，i ；（2）电压U 。

V3题5图6．（20分）电路及有向图分别如题6图 (a)和(b)所示，写出（1）该电路的降阶关联矩阵A ；（2）支路导纳阵Y ；（3）支路电压源列向量S U和支路电流源列向量SI ；（4）以1，2为树枝，写出基本回路矩阵和基本割集矩阵。

I ①1C j ω(a) (b) 题6图7．（10分）特性阻抗为1C Z的无损耗均匀传输线，终端负载Ω=252Z 。

已知Ω=1001c Z ，若要使1C Z 上没有反射波，加入如题7图4λ 无损耗线，问2c Z 为何值？ 2Z 4λ题7图8．（10分）要用4λ<l 的终端短路的无损线实现一个H 10m 的电感，如题8图所示，无损线的特性阻抗Ω=400c Z ，电源频率为 Hz 100M f =，波长为3m ，求线长l 。

H10m题8图。

华北电力大学（保定）817/518专业课模拟题1.一．单选题：（在本题的每一小题的备选答案中，只有一个答案是正确的，请把你认为正确答案的题号，填入题干的括号内，多选不给分。

每小题1分，共15分）1、下面所列各组电力网接线方式中，完全属于有备用接线的一组是（）。

A、两端供电网、环网、双回线路辐射网B、双回线路辐射网、环网、单回路链式网C、单回路辐射网、两端供电网、单回路干线网2、关于中性点不接地三相对称系统的中性点对地电压，下述说法中正确的是( )。

A、正常运行时为零，单相接地时升高为线电压；B、正常运行时为零，单相接地时升高为相电压；C、正常运行时无法确定，单相接地时为相电压。

3、220kv电力系统中性点应采用的接线方式是（）。

A、不接地；B、直接接地；C、经消弧线圈接地。

4、架空输电线路采用分裂导线的目的是( )。

A、减小输电线路电阻；B、减小输电线路电抗；C、增大输电线路电容。

5、500kv超高压输电线路两端装设并联电抗器的目的是( )。

A、防止输电线路重载时末端电压降低；B、防止输电线路轻载时末端电压升高；C、防止输电线路轻载时末端电压降低。

6、关于单侧电源电力网，下述说法中正确的是（）。

A、电力网的功率分布由负荷分布确定，其潮流无法调控；B、电力网的功率分布与线路阻抗有关，其潮流无法调控；C、电力网功率自然分布就是功率的经济分布。

7、在一个具有n个独立节点的系统中，节点阻抗矩阵的阶数为( )。

A、n×n阶；B、（n－1）×（n－1）阶；C、（n＋1）×（n＋1）阶。

8、系统中有功功率不足，会造成( )。

A、电压水平上升；B、电压水平下降；C、频率下降。

A、1号机组；B、2号机组；C、同时减小。

10、电力系统无功电源最优分配的目的是（）。

A、使电力系统总的能源消耗最少；B、使电力网的有功损耗最小；C、使电力系统的电能质量最好。

11、变压器空载损耗主要是___D__。

华电电气考研试题及答案试题：一、单项选择题（每题2分，共20分）1. 在电力系统中，通常所说的“无功功率”是指：A. 有功功率的反义词B. 与电路中的电感或电容元件相关的能量交换功率C. 电路中的总功率减去有功功率D. 电路中的总功率2. 对于一个理想变压器，其原边电压与副边电压的关系是：A. 正比于匝数比B. 反比于匝数比C. 与匝数比无关D. 无法确定3. 在三相交流电路中，线电压与相电压的关系是：A. 相电压是线电压的√3倍B. 线电压是相电压的√3倍C. 相电压与线电压无关D. 线电压与相电压相等4. 电力系统中，提高功率因数的意义在于：A. 减少线路损耗B. 提高发电设备的容量C. 增加系统的无功功率D. 降低系统的有功功率5. 以下哪种设备可以用于补偿无功功率：A. 电容器B. 电阻器C. 电感器D. 二极管6. 在输电线路中，输电电压的提高可以：A. 减少输电线路的损耗B. 增加输电线路的损耗C. 对输电线路损耗无影响D. 无法确定7. 对于一个纯电感电路，当电流与电压相位关系是：A. 电流滞后电压90度B. 电流超前电压90度C. 电流与电压同相位D. 电流与电压相位关系不确定8. 在电力系统中，短路故障通常指的是：A. 电路中的两个导体意外接触B. 电路中的两个绝缘体意外接触C. 电路中的负载过重D. 电路中的电源故障9. 电力系统中的“一次设备”通常指的是：A. 发电机、变压器等B. 断路器、隔离开关等C. 继电保护装置D. 控制和通信设备10. 在电力系统中，同步发电机的同步转速与什么有关：A. 发电机的额定功率B. 发电机的额定电压C. 发电机的极对数D. 发电机的额定频率二、简答题（每题10分，共20分）1. 简述电力系统暂态稳定性的概念及其重要性。

2. 描述输电线路的电晕现象及其对电力系统的影响。

三、计算题（每题15分，共30分）1. 已知一个星形连接的三相负载，每相负载的阻抗模为30Ω，相角差120度。

姓名学号班级口语班华北电力大学研究生课程考试试题（2011-12-24 ）GENERAL ENGLISH QUALIFYING TESTFOR NON-ENGLISH MAJOR GRADUATE STUDENTS监考及考试注意事项：1）考试时间：8：30---10：402）请学生不要在课桌内及身上携带任何书、本、纸片、电子文具、字典、手机，一经发现，即视为作弊。

书包，大衣请放到教室统一位置。

3）听力考试播音时间：9：004）学生按英语口语班坐位，收卷按英语口语班收卷。

机读卡左上角请注明英语口语班级。

5）调频台频率为FM 86.56）收卷时分别按试卷，答题纸，机读卡，收齐后机读卡分别用纸包好写上英语口语班级和份数，送交主楼C 705。

请口语老师把自己班的试卷拿走，批改听力Section C部分。

7）考生在答题卡的学生代号栏中填上完整的学生证号，且左对齐，剩余空格不填。

试卷，答题纸，机读卡均需写明姓名、学号、口语班号。

8）祝大家圣诞节快乐！PAPER ONEPART I LISTENING COMPREHENSION (22.5 points)Section A ( 1 point each)Directions: In this section, you will hear nine short conversations between two speakers. At the end of each conversation a question will be asked about what was said. Theconversations and the questions will be read ONLY ONCE. Choose the best answerfrom the four choices given by marking the corresponding letter with a single bar acrossthe square brackets on your machine-scoring Answer Sheet.1. A. He'll get promoted. C. He'll be disappointed.B. He'll get another job. D. He'll give a talk.2. A.$3.78. C. $3.87.B. $4.25. D. $4.15.3. A. It was just so-so. C. It was quite good.B. It was really special. D. It was awful.4. A. The woman should divorce her husband.B. The woman is thinking negatively.C. The woman is ignoring her husband.D. The woman is not imaginative.5. A. It seems too hard to most students.B. It is the most boring class.C. What is taught comes directly from the book.D. It is quite popular among students.6. A. Jennifer was a real stand-out.B. Jennifer had an impractical wish.C. Jennifer used to like eating pies.D. Jennifer realized her dreams.7. A. It's hard to explain. C. He cherishes their friendship.B. It's an unforgettable history. D. He is pretty busy.8. A. He is a gardener. C. He is a plumber.B. He is an electrician. D. He is a cleaner.9. A. Visit his doctor. C. Leave for a trip.B. Get a massage. D. Cancel an appointment.Section B (1 point each)Directions: In this section you will hear two mini-talks. At the end of each talk, there will be some questions. Both the talks and the questions will be read to you only once. After eachquestion, there will be a pause. During the pause, you must choose the best answerfrom the four choices given by marking the corresponding letter with a single baracross the square brackets on your machine-scoring Answer Sheet.Mini-talk One10. A. Columbia University. C. The University of Pennsylvania.B. Princeton University. D. Cornell University.11. A. It is settled. B. It is not controversial.C. It is uncertain.D. It has never been studied.12. A. 2%. C. 12%.B. 7% D. 17%.Mini-talk Two13. A. John Fitzgerald Kennedy. C. Dwight Eisenhower.B. Jacqueline Kennedy. D. Edward Durrell Stone14. A. Opera House. C. Family Theater.B. The Concert Hall. D. States Gallery.15. A. The performing arts. C. Methods of competition.B. Creation of new works. D. The history of western music.Section C (7.5 points, 1.5 point each)Directions: In this section you will hear a conversation. Listen to it and complete the notes about the conversation. ( Y ou will hear the recording twice.) (16—20题写在卷子上)16. My mom is one of millions of ________ ___________ (2 words) -------women whose husbands watch the games from __________ (1 word) until New Y ear’s Day and pay no attention to their wives and children.17. They're expected to be _______ ___________ (2 words) 'cause kids look to them as ________. (1 word)18. They earn millions ______ ________ (2 words) and by endorsing ___________ (1 word)19. Communities take ________ ___________ (2 words) in their teams, and it’s fun go to the ____________ (1 word)20. Colleges also________ _________ __________ __________ (4 words)from TV companies that broadcast the games.PART II VOCABULARY ( 5 points, 0.5point each)Directions: There are ten questions in this section. Each question is a sentence with something missing. Below each sentence are four words or phrases marked A, B, C and D.Choose one word or phrase that best completes the sentence. Mark the correspondingletter with a single bar across the square brackets on your machine-scoring AnswerSheet.21. Dayton Robles was on Monday sensationally __________ his world 110m hurdles title forobstruction of Liu Xiang.A. warded offB. stripped offC. called offD. paid off22. Since childhood, Crews had been _________ by health problems - fatigue, fever and troublebreathing.A. facilitatedB. consoledC. plaguedD. infected23. Grace urged students to stand by their beliefs and principles, and __________ themselves.A. believe inB. persist inC. consist inD. specialize in24. The Mexican settlers built cities and mansions in what _________ become California.A. used toB. had toC. ought toD. was to25. The President cancelled a foreign trip __________ growing concerns of a domestic crisis.A. forB. viaC. versusD. amid26. Healthy communication is essential for _______ through difficulties for a married couple.A. invadingB. navigatingC. composingD. contradicting27. With better drugs and medical facilities, ________ rates in hospitals have declined sharply.A. mortalityB. moralityC. modestyD. mobility28. A world-renowned scientist is scheduled to give a _________ on the future of biology.A. projectionB. prevalenceC. proficiencyD. presentation29. During the Gold Rush, many were gripped by an _________ desire for wealth and migrated tothe West.A. allocatingB. evaporatingC. overwhelmingD. illuminating30. Russia is ________ the largest country in the world, covering more than a ninth of the Earth'sland area.A. far fromB. by farC. at firstD. other thanPART III READING COMPREHENSIONSection A(20 points, 1 point each)Directions: In this part of the test, there are four short passages. Read each passage carefully, and then do the questions that follow. Choose the best answer from the four choices given and mark the corresponding letter with a single bar across the square brackets on your machine-scoring Answer Sheet.Passage OneIt happens to every college student. Every professor on campus assigns a paper the same week. V olunteer work and social activities fill the calendar. Before long, an assignment is due in the morning, so what else is there to do? Brew a pot of coffee and begin another of that most storied of college traditions: the all-nighter.Many college students have found themselves in this position. Although studying late intothe early hours is a pretty well-accepted part of college life, the scientific consensus is clear—insufficient sleep is bad for a student's performance, happiness and health.Sleep is one of the body's most vital processes, affecting everything from muscle strength to memory span. Sleep increases blood flow to muscles and repairs damaged cells. A recent study indicates that college basketball players perform better on the court if they sleep at least ten hours the night before. Sleep consolidates memories and prepares the brain to perform--students who get more sleep can improve recall ability and actually do better on tests.How much sleep a person needs varies, but Dr. William DeMent from Stanford University says college students need over eight hours per night. With assignments piling up, many students end up constantly sleep deprived. Students accumulate a "sleep debt" that can get larger over time and can only be "paid off' by getting the amount of sleep the body needs. Naturally, a person's body would force them to get enough sleep by making them feel sleepy. But caffeine, stimulants, pressing deadlines encourage students to ignore the body's natural signals and go without sleep far longer than they should.It's easy to get caught up in the excitement and stress of college life and to get in the habit of getting to bed later and later. But pushing bodies and schedules to their limits does not come without cost. In the short-term, sleep deprivation affects mood, mental ability and physical performance. It decreases reaction time and makes a person more easily distracted. That's bad for test taking, and even worse for students who are driving. In the long-term, not getting enough sleep can sacrifice your health and shorten your life span by causing irritability, frustration and proneness to mistakes, associated with high blood pressure, obesity and heart failure. There are more than enough reasons to hit the sack early tonight!31. The expression "all-nighter" in the first paragraph refers to those students who -------A. sleep soundly the whole nightB. stay up all night studyingC. spend the night drinking coffeeD. don't come back for the night32. It can be concluded from this passage that -------A. sleep is of great importance to college studentsB. most college students refuse to go to bed earlyC. college students go to bed late only occasionallyD. most colleges force students to work at night33. The harm that insufficient sleep does to test-takers is that --------A. they feel sleepy during the testB. they forget what is learnedC. they become lazy thinkersD. they are left inattentive34. This passage implies that sleep deprivation is ---------- among college students.A. rareB. commonplaceC. negligibleD. justified35. The underlined words in the last paragraph probably meanA. get down to workB. see a doctorC. take some medicineD. go to bedPassage TwoAt the beginning of a country's rise out of backwardness and poverty, more wealth does make a difference. However, citing surveys from China and South Korea, the economist RichardEasterlin points out: "In these countries, per capita income has doubled in 20 years but overall happiness does not seem to have followed the same path." Economists are surprised, because GNP has long been thought the best indicator of human welfare. More GNP generally means more money for most people, and more money improves the quality of life, and that means happiness.But, perhaps, the survey suggests that more money can make you happy only if those around you do not share in your good fortune. General prosperity may fail to enhance individual contentment. Perhaps it is a matter of being aware of your advantage, not that you need to get the highest salaries or be the object of envy. Maybe, individual goals vary too much to be generalized. Maybe one has nothing at all to do with the other. Freud was well aware that economic success did not make people happy. Most psychoanalysts and therapists today would agree. He thought only the realization of a deep childhood desire could provide such satisfaction.Another problem is that people are poor reporters of their own states of mind. They will usually tell you what they themselves want to believe. To know if someone is really happy or not, you have to catch him or her in the act of happiness. Being happy or acting happy are more reliable indicators than thinking too much about it.Professional therapists also know that what makes people happy defies explanation, but what prevents them from being happy doesn't. Poor self-esteem undermines all feelings of success. Hunger and cold make it harder to relax and enjoy one's experience. Insecurity and failure to engage one's work leave one dissatisfied. Anxiety penetrates all our perceptions and feelings, and brings us down.Economists can probably hope to measure how well our basic needs for security and health are met in society, and if those are reasonably OK, people tend to find the happiness they seek. Most of us want to enjoy life, spend time with our children, play at sports, sing, dance and travel. If we can do those things without dread, the amount of money we have is irrelevant.36. It seems to Richard Easterlin that higher GNP-----A. will certainly make people happierB. depends on the overall level of happinessC. does not necessarily add to people's happinessD. is a good indicator of human happiness37. According to the second paragraph, individual happiness arises from ------A. setting a high goalB. the respect fi'om your neighborsC. common prosperityD. your superiority over others38. Freud's doctrine is mentioned to show that -------A. goals vary from person to personB. a happy childhood means life-long happinessC. psychoanalysts and therapists think alikeD. wealth does not always make one happy39. It can be inferred from the passage that ---------A. our feelings of happiness tend to be the sameB. there are few people who are really happyC. people sometimes don't know exactly how they feelD. thinking about happiness can make you feel happy40. Professional therapists believe that --------A. it is easy to explain what makes people happyB. it is easy to tell what leaves people unhappyC. it is difficult to tell who is happyD. it is hard to distinguish happiness from unhappinessPassage ThreeIt may sound like something out of a science fiction plot, but Oxford researchers say that modern conventional medicine is gradually developing ways to change the moral states of humans through pharmaceutical drugs, and thus control the way people think and act in various life situations. These new drugs will literally have the ability to disrupt an individual's personal morality, and instead reprogram that person to believe and do whatever the drug designer has created that drug to do."Science has ignored the question of moral improvement so far, but it is now becoming a big debate," said Dr. Guy Kahane fi'om the Oxford Centre for Neuroethics in the UK. "There is already a growing body of research you can describe in these terms. Studies show that certain drugs affect the ways people respond to moral dilemmas by increasing their ability to share in another's feelings, group affiliation and by reducing aggression."While this may sound good in theory, mind control is already a very dangerous side effect of existing drugs. Take the antidepressant drug Prozac, for instance, which has been known to cause those taking it to lash out in violent rages. One young boy murdered his father by beating him and stabbing him in the head, and hit his mother with a crowbar and stabbed her in the face, shortly after starting to take Prozac.But the kinds of drugs Kahane and his colleagues are referring to imply designer drugs specifically designed to not only alter one's mental state, but also to change the way that person thinks about situations from a moral perspective. The end result is literally a type of drug-induced mind control where human subjects will be controlled by someone else, and unable to make conscious decisions .for themselves.Research on the subject, of course, tries to paint the idea of mind-control drugs in a positive light, suggesting that they could be used to help make the world a better place. Just imagine less violence, more trust, and more love, they say. This way of using words persuasively, though, is really just a tactic to further numb the already mind-numbed masses into accepting the idea as a good thing.41. The underlined part of the first sentence of the passage implies that --------A. developing drugs to change human morality sounds unbelievableB. modern conventional medicine can bring miracles to healthC. it is impossible to control human behavior through drugsD. Oxford researchers are writing sci-fiction about new drugs42. Guy Kahane believes that certain drugs can ---------A. induce crime among drug-takersB. cause death if taken at a high doseC. bring about moral improvementD. make some patients feel lonely43. The drug Prozac is mentioned as evidence that --------A. it is an effective drug for depressionB. some drugs can cause violent behaviorC. most drugs can make depression worseD. antidepressant drugs produce the desired effect44. The biggest side effect of designer drugs is that the users --------A. can become increasingly immoralB. can feel too upset to live a normal lifeC. can no longer make any decisionsD. can no longer control their own minds45. The author's attitude towards development of such drugs is -------A. supportiveB. indifferentC. negativeD. uncertain（46题不涂）Passage FourAmerica has been a land of naming freedom and self-expression. While other governments impose restrictions------German parents have to choose a name that clearly indicates the gender of the child and is not a surname, and the French, among others, forbid names that might expose a child to mockery-----in the United States, anything goes.When Lum and Chin Nguyen had their first child, 26 years ago, they wanted to give him an American name. Newly settled in North Carolina, they chose Duke, in honor of nearby Duke University. Best of all, the name could work in both their old and new cultures by spinning its spelling to Due. or Duck, as the boy's teachers insisted on pronouncing it, to the great amusement of his classmates. With his pride injured, Duc Nguyen decided to reinvent himself and his name. His new choice was tried-and-true American and impossible to screw up: Wes."Y our name is a way of marketing yourself," says Wes Nguyen, who turned his personal adventures in naming into a career as a corporate product namer. "When we create a new name for clients, we create imagery behind it, and I did that when I chose my own new name. Wes reminds me of the West Coast, of someone young and sophisticated and innovative. I think of a surfer, of someone who has work-life balance."The search for a name that screams "I'm unique!" leads some parents to invent names or play with traditional spelling. However, a downside of a "creative" name is that it may come with baggage, not all of it positive. "I always felt I was prejudged by my name," says Gestin Skaggs, 43, whose parents named her for a word they heard in a German love song. "I've either had to overcome some stereotype of a short, fat German man or live up to an expectation that I'm a really wild and creative thinker. People ascribe all kinds of personality traits to me that I don't have."But that's a small price to pay, say the teens with offbeat names we spoke with. "I've met a lot of people because of my name. They hear it and think it's cool," says Calypso Gibaldi, 15, named by her ocean-loving father for Jacques Cousteau's boat. "If my name was Jane, I'd be average like everyone else." （请注意以下5题按题号涂在机读卡上）57. By "anything goes" (Para. 1), the author means that in the U.S.A. baby naming tends to go with the trendB. parents can name their babies whatever they likeC. naming a baby should follow certain rulesD. a baby's name carries a special meaning58. According to Paragraph 2, the name DucA. was a good name connecting the two culturesB. was just a common English nameC. caused misunderstanding among studentsD. brought hurt feelings and bad memories59. Wes Nguyen chose this nameA. because he lives in the West CoastB. as a way of remembering his pastC. to promote his company productD. for the image that it reflects60. It can be seen from Gestin Skaggs' experience thatA. people tend to associate names with personal charactersB. names should be meaningful and easy to rememberC. a creative name tends to give a baby a good startD. people in general like unique names61. What does Calypso Gibaldi think of her name?A. It plays a positive role in her life.B. It has caused unexpected problems.C. She’s not sure of the role her name plays.D. She’d rather have a more common name.Section B (5 points, 0.5 point each)Directions: In this section, there is a passage with ten blanks. Y ou are required to select one term for each blank from a list of choices given in a word bank following the passage. Read the passage through carefully before making your choices. Each choice in the bank is identified by a letter. Please mark the corresponding letter for each item on your machine-scoring Answer Sheet with a single line through the centre. Y ou may not use any of the terms in the bank more than once.Crude-oil prices have been careening like steel balls in a ----47-- this autumn in response to news and rumors from the Middle East．In the first few days of October, the threat of armed conflict between Iran and Iraq sent crude prices ---48--- from $ 20 a barrel to almost $ 23,before sinking back down again．Even as the world is reminded of the ---49--- of its oil supply，consumption is soaring．Americans have fallen in love with gas ---50----- such as the Ford Expedition．In newly prosperous developing countries, ordinary people can afford cars for the first time．A recent survey in the China Y outh Daily found that 75％of Beijing families planned to buy a car within the next five years．Y ikes．Are we –51---- another oil crisis? Y ou might think so．Fort Worth investor Richard E．Rainwater has 30％of his $ 1.5 billion net worth sunk in oil and gas investments because he expects prices to rise 50％to 75％in the next 5 to 10 years．With free markets ---52---economic growth，says Rainwater，―We should see a tremendous amount of pressure on prices．‖Perhaps．But there’s another，quite different----53----- —namely，that oil prices，adjusted forinflation，won’t rise at all over the long term．They may even fall．Why? First，because producers in the Mideast and elsewhere need the cash from oil too much to let their supply be interrupted for long，---54---- political and military skirmishing．Second，and more important，because demand growth can’t push prices upward as long as it is ----55--- by supply growth．And the supply curve for oil—the amount offered at any given price—is being pushed steadily outward，---56---- technology．PAPER TWO (请注意本试卷PAPER TWO 答案一律写在答题纸上)PART IV PARAPHRASEDirections:Rewrite the following sentences in your own words. （7.5 points, 1.5 each）62. I suppose that goes with the territory of enrolling in a university six hours from home．63. The implication that all money spent from then on would be my own was scary，yet funny as well．64. What’s mor e，many independent oil companies have moved to the cutting edge．65. While incorporating enhanced security requirements，the building remains open and accessible．66. The Freedom Tower will further its distinction as a world class model of energy efficienc y and environmental sustainability．PART V WRITINGSupply the missing paragraphs (10 points)Directions:The following passage is incomplete with a couple of body paragraphs missing. Study the passage carefully and write the missing paragraphs in about 150 words. Make sure that your essay should illustrate the main point of the passage, and your tone and diction are in unity with the passage provided.The Myth of the Paperless OfficeWe’ve all been hearing about the approach of the paperless office for decades now, but the paper in our lives has only kept increasing. Technologies have emerged one after another to help us do away with what Egyptians first made out of riverside reeds several millennia ago, including electronic datebooks, ever-shrinking laptops, and the never-quite-ready e-book. We all know that paper takes up precious space, can be in only one place at a time, is extremely hard to index or search through, and lacks all the interactivity and linking ability of hypertext; and because we know this, we feel guilty about our continued reliance on it. Why haven't we been able to kick the habit?___________________________________________________________________________________________________________________________________________________________________________________________________All technologies come down to our trying to get what we want, what we desire, whether it’s faster travel, better health, a stronger golf game, sturdier office buildings, new kinds of entertainment, or simply money made from inventing. And much of what we desire comes down totaking control of our lives, doing what we please without being overwhelmed by what we don't please. We get overwhelmed by paper — by bills, reports, newspapers, magazines, books we should read, and so much else. We can’t help dreaming of a world where we can attain all we want from paper without expending the time and space it consumes. We want the benefits of paper without the paper itself.Someday, somewhere down the road, that may happen. But for now, at least, it looks both unlikely and pointless. One might as well have dreamed a century ago of the typewriter’s making the pencil obsolete．。

华北电力大学2014年硕士研究生入学考试初试试题考试科目：811电力系统分析基础一、判断题（15分）1.电力系统是指所有电源、电网、负荷及储能设备的总和（）2.电力系统总装机容量是指该系统实际安装的发电机组额定有功功率总和（√ ）3.有备用接线系统的供电可靠性高于无备用接线系统（√ ）4.对于电压在110kV及以上的电网，由于电压较高，因此采用中性点不接地方式（）5.中性点不接地系统当发生单相接地后，线电压仍三相对称（√ ）6.超导输电引起损耗低，输送容量大，是未来电力输送的发展方向（）7.同杆架设的双回输电线路的互感可以忽略不计，不影响线路的正常参数（√ ）8.线路的电导主要是由绝缘子的泄漏电抗和导线换位决定的（）9.输电线路的末端电压有时会高于始端（√ ）10.电力系统的功率平衡主要是靠储能系统实现的（）11.电力系统的电压水平主要决定于系统的频率特性（）12.当系统无功功率不足时，应考虑改变变压器分接头调压（）13.电力系统短路故障发生几率最大的是相间短路（）14.电力系统发生短路相当于改变了电网的结构，必定会引起系统中功率分布的变化（√ ）15.无限大功率电源可以看做是由多个有限功率电压并联组成，因而其内阻抗为零，电源电压保持恒定（√ ）二、不定项选择题（20分）16.我国目前最高的交流系统电压等级为（C ）A.500kVB. 750kVC. 1000kVD. 1150kV17.对电力系统运行的基本要求包括（ABC ）A.保证可靠持续的供电B. 保证良好的电能质量C. 努力提高电力系统运行的经济性D. 提高系统电压等级18.与有备用接线比起来，无备用接线的特点是（ BC ）A.可靠性高B. 经济C. 简单D. 电能质量好19.在同一电压等级中，各种电器设备的额定电压（D ）A.相互独立B. 完全相同C. 完全不相同D. 不完全相同20.假定选取系统容量基准值为100MW，电压基准值为500kV，那么标幺值为1p.u的电阻（B）欧姆A.500B. 250C. 0.02D. 0.00221.在电力系统中最多的节点类型是（A ）A.PQ节点B. PV节点C. 平衡节点D. 参考节点22.一台额定功率为50MW的发电机带一个40MW负荷运转，发电机的调差系数为4%，负荷的单位调节功率为1.5MW/HZ，那么系统的单位调节功率为（C）MW/HZ。

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华北电力大学（北京）2021年硕士研究生入学考试试题一、选择题（每题1分，共10分）1 、110kV架空线输电线路的经济输送功率和输送距离是：（3） (1)2~10MW;20~50km(2)3.5~30MW;30~100km (3)10~50MW;50~150km (4)100~500MW;100~300km 2、220kV输电系统中性点的运行方式是：（1）（1）直接接地（2）不接地（3）经消弧线圈接地（4）经小电阻接地3 、一台发电厂升压站从10kV升压到220kV的变压器额定变比是（4） (1)10/220kV (2)10.5/220kV (3)10/242kV (4)10.5/242kV 4、电晕主要影响线路的哪个参数？（3）（1）线路的电阻（2）线路的电抗（3）线路的电导（4）线路的电纳 5 、220kV架空输电线路悬式绝缘子的片数最少为：（2）（1）10片（2）13片（3）19片（4）25片 6 、架空输电线路采用分裂导线的主要目的是：（4）（1）增大电阻（2）减小电阻（3）增大电抗（4）减小电抗 7、电力系统潮流计算中PQ节点的特点是：（1）（1）节点有功和无功注入功率已知、电压模和电压角未知（2）节点有功和无功注入功率未知、电压模和电压角已知（3）节点有功注入功率和电压模已知、无功注入功率和电压角未知中公考研，让考研变得简单！更多资料，请关注中公考研网点这里，看更多考研真题（4）节点有功注入功率和电压模未知、无功注入功率和电压角已知 8、一台额定容量200M,额定频率50Hz的发电机的调差系数为（2） (1)1.6MW/Hz (2)160MW/Hz (3)2.0MW/Hz (4)200MW/Hz9、一无限大电源发生三相短路后出现非周期分量电流的原因是（4）（1）电容中的电压可以突变（2）电容中的电压不能突变（3）电感中的电流可以突变（4）电感中的电流不能突变10、一架空线避雷线对零序阻抗的影响是（1）（1）减小线路的零序电抗（2）增大线路的零序电抗（3）减小线路的负序阻抗（4）增大线路的负序阻抗二、填空题（每空2分，共20分）11、火力发电厂的能量转换工程主要有（化石能→热能→机械能→电能） 12、电能质量的主要指标包括（电压质量，频率质量，波形质量） 13、衡量电力系统运行经济性的主要指标是（煤耗率，线损率） 14、架空输电线路采用完全换位的目的是（减小三相参数的不平衡）?n?Ii ?YijUj） 15、潮流计算中节点电压方程的基本形式是（16、有功负荷的最优分配的基本准则是（等耗量微增率准则）17、电力系统无功电源主要有（发电机电容器调相机静止电容器静止补偿器电抗器）18、电力系统电压调整的主要措施包括（改变发电机端电压调压，改变变压器变比调压，并联电容器、调相机、静止补偿器调压，串联电容器调压）19、短路故障的类型主要有（单相接地短路，两相接地短路，两线短路，三相短路）20、不对称故障中负序分量的特点是（对称、相序与正序相反）i?1?三、简答和简单计算题（共40分）中公考研，让考研变得简单！更多资料，请关注中公考研网点这里，看更多考研真题21、（10分）电力系统生产运行的特点是什么？新形势下对电力系统的基本要求是什么？答：电力系统运行特点：① 电能与国民经济各部门之间关系密切分割④ 电能生产、输送、消费工况的改变十分迅速⑤对电能质量的要求颇为严格对电力系统的基本要求：可靠，优质，经济，环保。

华北电力大学研究生课程考试试题（A卷）
2013～2014学年第2学期
课程编号：50220621/50220731 课程名称：热能动力工程前沿/专题课程（热能动力工程前沿）
年级：13硕士生开课单位：能源与动力工程学院命题教师：杜小泽
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