问题 单项选择题

某火电厂装设2台600MW机组,高压厂用电每台机组设2段6kV工作母线,并设2段6kV公用母线。

主厂房汽机380V/220V低压供电拟分成二段(A段及B段),计算负荷A段为893kVA,B段为1037kVA,重复负荷为601kVA,汽机低压工作变压器台数和容量为( )。

A.选择1台1600kVA变压器供2段母线;
B.选择3台1250kVA变压器供2段母线;
C.选择2台1600kVA变压器分别供2段母线,互为备用;
D.选择1台1250kVA及1台1600kVA变压器分别供电2段母线。

答案

参考答案:C

解析: 两段总负荷为893+1073-601=1329(kVA),根据《火力发电厂厂用电设计技术规定》(DL/T 5153-2002)第4.7.5条。

阅读理解

Have you ever thought, “I wish I could take a year off and just travel around the word?” Well, three lucky American teenagers were able to do just that. The teens — two males and one female — got an all-expenses paid, yearlong hike to five continents.

This trip didn’t include any five-star hotels or shopping funs. Eighteen-year-old Jamie Fiel from Keller, Texas, 17-year-old Arsen Ewing from Canyon, California, and 16-year-old Tyler Robinson from Lincoln, Massachusetts, didn’t expect fancy treatment. They signed up for the experience of a lifetime, which included hard work, often uncomfortable accommodations, and encounters with some of nature’s most dangerous animals and environments.

Jamie, Arsen, and Tyler were among hundreds of high school kids nominated by their science teachers to take this trip. Earthwatch Institute sponsored this adventure. Each year, Earthwatch employs thousands of volunteers worldwide to help with scientific research projects.

The group went all around the world to get a close look at the most pressing environmental issues of our time. Their assignments were as varied as their locations, and included measuring and attending pink flamingos in Kenya’s Great Rift Valley, and tracking giant sea turtles in Costa Rica.

As they worked with the Earthwatch scientists, Jamie, Arsen, and Tyler began to understand that we are at a critical moment in the life of our planet. Time for change is running out. As the teens went from country to country and witnessed different environmental dangers and challenges, they understood that solutions to important environmental issues start with the power of one person’s actions. They realized that each of them can make a difference.

小题1:These teenagers went on the journey around the world      .

A.to experience the most serous environmental problems on the earth

B.to bring the kindness of America to the other parts of the world

C.to go on sightseeing around the world

D.to call on more teenagers to join Earthwatch Institute小题2:What’s TRUE about their journey?

A. They had to pay for their journey on their own expense.

B, They often had to move from one hotel to another.

C. They had to take great pains to collect environmental information.

D. They received a warm welcome every time they arrived at a new place.

小题3:It can be inferred that Earthwatch Institute could be          .

A. an international university that takes in students from all over the world

B. a TV station that makes programmes on the beautiful scenery of the earth

C. a travel agency that organizes adventure trips specially for school children

多项选择题