问题 问答题 简答题

试绘出单母线接线并分析其优缺点。

答案

参考答案:

单母线接线优点:(1)简单清晰

(2)设备少、投资小

(3)运行操作方便

(4)有利于扩建和采用成套配电装置等。

其主要缺点是:可靠性和灵活性较差,如当母线或母线隔离开关故障或检修时,必须断开它所接的电源,与之相接的所有电力装置,在整个检修期间均需停止工作。此外,在出线断路器检修期间,必须停止该回路的工作。

阅读理解

Frank Smithson woke up and got up to turn off the alarm clock(闹钟). “Oh no!” he thought to himself. “Another day at that office; a boss (老板) who shouts at me all the time.”

As Frank went downstairs, his eyes fell on a large brown envelope (信封) by the door. He was very happy when he opened it and read the letter inside. “Bigwoods Football Pools (足球赌博公司) would like to congratulate you. You have won half a million pounds(英镑).”

Frank suddenly came to life. The cigarette fell from his lips (唇) as he let out a shout that could be heard halfway down the street.

At 11:30 Frank arrived at work. “Please explain why you're so late,” his boss said. “Go and jump in the lake,” said Frank. “I've just come into a little money so this is good-bye. Find yourself someone else to shout at.”

That evening Frank was smoking a very expensive Havana cigar (雪茄) when a knock was heard on the door. He rushed to the door. Outside were two men, neatly dressed in grey suits. “Mr. Smithson,” one of them said, “we're from Bigwoods Pools. I'm afraid there's been a terrible mistake…”

小题1:What do we know about Frank from the passage?

A.He was a lazy man.  

B.He was a lucky person.

C.He had made a lot of money.

D.He got on well with his boss.小题2:When he heard the knock at the door, Frank probably thought _________.

A.someone had come to say sorry to him

B.someone had come to give him the money

C.his friends had come to ask about the football pools

D.his friends had come to congratulate him on his luck小题3:On hearing “…there's been a terrible mistake…”, Frank was most likely to be_____.

A.disappointed (失望的)

B.worried

C.grateful

D.curious

单项选择题