问题 单项选择题

某企业新建35kV/10kV变电所,短路电流计算系统如下图所示,其已知参数均列在图上,第一电源为无穷大容量,第二电源为汽轮发电机,容量30MW,功率因数0.8,超瞬态电抗值χ″d=13.65%,两路电源同时供电,两台降压变压器并列运行,10kV母线上其中一回馈线给一台1500kW的电动机供电。电动机效率0.95,起动电流倍数为6,电动机超瞬态电抗相对值0.156。35kV架空线路的电抗为0.37Ω/km(短路电流计算,不计算元件电阻)。回答下列问题。 k2点三相短路时(Os),第二电源提供的短路电流和短路容量为下列哪组数值?()

A.2.32kA,41.8MVA

B.3.03kA,55.11MVA

C.4.14kA,75.3MVA

D.6.16kA,112MVA

答案

参考答案:B

填空题
阅读理解

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有一项为多余选项。

       _____ 1. Smith is a professor who does research on ancient buildings. This month, his university gives

a reward to him for his great contributions. So now an idea of traveling to a new place to continue his study

has come into his mind.

       _____ 2. Though Lola is a woman reporter, she is brave enough to go deep into the places at war. Next

month, she will go to a place at war, she is confident to do her work well and give people the most brief and

real reports. 

       _____ 3. Alice and Simon are going to get married. They want to hold an underwater wedding in a

special place, which has beautiful scenery, silver sand and delicious seafood and luxurious hotels, where they

can enjoy themselves. 

       _____ 4. Jane is a modern girl, who is a crazy fan of rock music and films. She has a romantic dream,

that is, one day, she will go to a beautiful place to appreciate all the attractive music and films with a cup of

coffee in her hand.

        _____ 5. Tom is really depressed these days. Owing to his bad management, his company closed. He

wants to go to a place to try his fortune so that he can start his business again in the near future.

A. Mauritius, an island lying off the southeast Africa in the Indian Ocean, which is rich in history, natural

     beauty and culture. It is a wonderful place for swimming and diving. The large number of interesting fish 

     means it is also an exciting place for those who like to go fishing.

B. Las Vegas is really a fascinated city. The most attractive thing here is gambling (赌博). Maybe you will

    become a millionaire or lose all your money overnight. What's so clever about Las Vegas is that it makes

    absolutely certain that you have such a good time you don't mind losing a bit of money along the way;

    that's why they don't even call it "gambling" anymore, but "gaming".

C. Few cities leave the visitors with such vivid impressions, the whole city is something of a work of art, the

    quiet River Seine, the Eiffel Tower, Palais du Louvre and so on are really feast to your eyes. And annual

    film festival is held with a refreshing emphasis on art. Few cities can compete with the thousands. of cafés,

     bars and restaurants that line every Parisian street.

D. Kitzbuhel is a paradise for all the skiers. With fine weather and breath-taking scenery, it is a world-class

     ski resort. Every winter, thousands of people come from all parts of the world to challenge themselves.

     If you can't ski, don't worry. The town offers many shops, café and a variety of entertainment.

E. As the cultural centre and biggest centre and biggest city in the region, Jerusalem is regarded as a holy

     place by Jews, Muslims and Christians. However, since the war broke out, people there have suffered a

     lot, the situation has been tense, and peace is just a dream.

F. The old Nile brought about the civilization of Egypt; people there regard it as "the mother river" of them.

     On both sides of the Nile stand noble pyramids which were built as the tombs of the ancient pharaohs

     (法老). And the constructions are beyond people's imagination.