问题 单项选择题

某300MVA火力发电厂、厂用电引自发电机,厂用主变压器接线组别为DYNllynll,容量40/25-25MVA,厂用电压6.3kV,高压厂用变压器低压侧与6kV开关柜用电缆相连接,电缆放在架空桥架上,校正系数K1=0.8,环境温度40℃,6kV最大三相短路电流为38kA,电缆芯热稳定整定系数C=150,如图所示。请回答下列问题。

6kV断路器额定开断电流为40kA,短路电流为38kA,其中直流分量60%,求此断路器开断直流分量的能力。()

A.22.5kA

B.24kA

C.32kA

D.34kA

答案

参考答案:C

阅读理解

阅读理解

       Two very good fishermen went fishing.  After a short time.  both were catching a lot of fish and many people came to watch them.      

       One of the fishermen was outgoing and talked pleasantly with the people around him.  The other was

 silent.      

       The people asked the outgoing fisherman to teach them how to fish.  He agreed but asked these 

people to give him one fish for every ten they caught.  If they caught less than lo fish, they wouldn't have

 to give him any fish.      

       So the fisherman started to teach everyone how to fish.  He spent the whole day teaching  them and

 got back a full basket of fish.  He also made friends with the people he taught to fish.      

       The other fisherman was lonely.  Nobody was watching him.  At the end of the day,  his  fish were

 far fewer than his friend's.      

       If we help others succeed, we harvest both success and friends.

根据短文内容,回答下列问题。  

1. Why did many people come to watch the two fishermen?

                                                                                                          

2. Which fisherman agreed to teach these people how to fish? 

                                                                                                          

3. What would the people do if they caught ten fish?

                                                                                                           

4. Did the silent fisherman have fewer fish than his friend at the end of the day?

                                                                                                            

5. What do you learn from the story?

                                                                                                            

单项选择题