问题 问答题 论述题

什么是负荷率?提高负荷率主要方法有哪些?什么是配电网的日负荷率,日负荷率与负荷性质的关系如何?

答案

参考答案:平均负荷与最高负荷的比率,称为负荷率。

提高负荷率主要方法有:

统一安排轮流周休日;统一安排上下班时间;实行避峰用电,用户内部调荷等方法。

配电网的日负荷率,即配电网日平均负荷(Pav)与日最高负荷(Pmax)的比值,一般用γ表示。它反映一日之内配电网负荷变动的情况,是配电网的运行特征之一。

日负荷率与负荷性质的关系:

配电网的日负荷率因负荷性质的不同而异。工业用电负荷与行业性质、生产方式、生产班制、工艺用电、动力用电所占比重有关。电冶、化学工业、石油工业的生产过程在一昼夜间是连续的,负荷很均匀,几乎不受任何外来因素的影响,其γ值一般在0.9以上。其他工业用户的负荷受企业的生产轮班制度影响较大,一班制工业用电负荷的日负荷率最小,两班、三班制的相对较大。建材、造纸、纺织等工业用电的γ值一般为0.8~0.9;机械制造、仪器等工业用电负荷的γ值一般为0.6~0.7;城市生活用电负荷的日负荷率与城市人民生活水平有关,商业、文化、福利事业发达,日负荷率就越高。中国城市生活用电负荷的γ值一般为0.3~0.4。交通运输业用电负荷的γ值一般为0.4左右,其中电气化铁路负荷较均匀,γ值一般为0.7左右。农村用电负荷γ值一般均很低。中国目前农村工业大多为一或两班制生产,γ制一般在0.6左右,而农业排灌随季节影响变化较大,冬季负荷的γ值一般为0.1~0.2,夏季却高达0.9以上。

阅读理解

根据短文内容选择正确的答案。

      One day, Allan and his friend Henry went swimming in river. It was very hot. How happy they were in the

river! After they got out of the water, they played games in the sun for a while.

      On their way back, Henry saw some flowers. He liked flowers very much and ran into the green field to

look at them. Now Allan was walking by himself.

      Then he heard Henry calling out: " A snake! Help! "

      " What's wrong with you? " asked Allan.

      " A snake bit (咬) me in the leg. Come here! " 

      Allan ran over and saw a small red wound (伤口) on Henry's leg.

      " The snake was in the grass. I didn't see it."

      " Sit down quickly." Allan told Henry. 

      Allan put his mouth at the little red wound and began to suck (吸) at it. In this way he saved (挽救) Henry's

life. " Oh, Allan, it's very kind of you to help me."

      " That's all right. We are friends and we must always help each other."

1. It was ____________ when Allan and Henry went out.[ ]

A. hot

B. cold

C. raining

D. wet

2. After swimming, they played in the sun ____________.[ ]

A. the whole morning

B. for 2 hours

C. long

D. for a while

3. On their way home, ___________ got something wrong with his ____________.[ ]

A. Allan; leg

B. Allan; head

C. Henry; leg

D. Henry; head

4. Henry and Allan are ____________.[ ]

A. workers

B. good friends

C. brothers

D. farmers

5. Which of the following (下面的) is true?[ ]

A. Henry went to look at the flowers' with Allan.

B. Allan saved Henry's life.

C. Allan saw the snake.

D. They ran to the hospital at once.

判断题