【单选题】【消耗次数:1】
电源中性点直接接地,负载设备外露不与带电体相联接的金属导电部分与电源中性点引出的中性线(N线)相联接,我们称这种供电系统为( )。
TN-C
TT
TN-S
IT
参考答案:
复制
纠错
相关题目
【判断题】 施工现场专用的电源中性点直接接地的低压配电系统应采用TN-C接地保护系统
①  正确
②  错误
【单选题】 TN-C方式供电系统是用工作零线兼作接零保护线,可以称作保护中性线。
①  正确
②  错误
【判断题】 建筑供电系统属于电源中性点不接地的电力系统
①  正确
②  错误
【单选题】 在 TN 系统中,系统的中性点不接地或经阻抗接地,不引出 N 线,属三相三线制小电流接地系统。
①  正确
②  错误
【判断题】 经过漏电保护装置的中性线不得作为保护线、不得重复接地或连接设备外露可导电部分。
①  正确
②  错误
【判断题】 电力系统中性点工作方式:中性点直接接地、中性点不接地和中性点经消弧线圈接地。
①  正确
②  错误
【判断题】 TN-S方式供电系统是把工作零线?N?和专用保护线?PE?严格分开的供电系统,称作?TN-S?供电系统。
①  正确
②  错误
【判断题】 接零保护指的是将用电设备的人体可触及的金属外壳通过接地线与用电设备电源的中性点(也称为供电系统的接零点)连接。
①  正确
②  错误
【单选题】 TN-S 系统 中中性线与保护线有一部分是共同的,有一部分是分开的。
①  正确
②  错误
【单选题】 中性点不接地系统发生单相金属性接地故障,中性点对地电位升高为()
①  相电压
②  线电压
③  倍的相电压
④  倍的线电压
随机题目
【单选题】 语句Dim t(6,-3 to 5)As Integer定义的数组元素有( )个。
①  45
②  54
③  40
④  63
【单选题】 语句Dim t(-2 to 6)As Integer定义的数组元素有( )个。
①  6
②  7
③  8
④  9
【单选题】 阅读理解:阅读下列短文,回答文后问题,选择最佳答案Robert had just moved into the street and he felt strange that he was not wanted. He knew that perhaps the other boys were trying to get an idea of what kind of a boy he was. This did not help him to make himself less lonely. He was new and he had to be tested. Still, proving himself would not be all that easy. He did not want to run with the boys or get into something against the law to prove that he was strong. No! He must show what he was made of in a more helpful way. That’s when he got the idea.The next day was Saturday. He knew that most of the boys would be down on the playground and choose up sides for the Saturday game. Robert knew he could play well and that just might be enough to prove he was strong, and to make friends with them. He arrived early and did his step exercises. He shot the ball several times and did some other exercises—the most difficult and most wonderful in basketball. Then the boys came. Robert went through what he had done before the game and showed what he could do. No one said a word. The boys just looked at each other and thought about it. In the end, when it was all over, the biggest of the group just smiled and shook his head. Robert knew he had made it.4. What did the biggest of the group mean by shaking his head?
①  He did not want to say anything about what Robert had done.B. He had not thought Robert could play so wonderfully.C. He did not want to make friends with Robert.D. He did not think Robert played basketball well.
②  He had not thought Robert could play so wonderfully.
③  He did not want to make friends with Robert..
④  He did not think Robert played basketball well.
【单选题】 阅读理解:阅读下列短文,回答文后问题,选择最佳答案Robert had just moved into the street and he felt strange that he was not wanted. He knew that perhaps the other boys were trying to get an idea of what kind of a boy he was. This did not help him to make himself less lonely. He was new and he had to be tested. Still, proving himself would not be all that easy. He did not want to run with the boys or get into something against the law to prove that he was strong. No! He must show what he was made of in a more helpful way. That’s when he got the idea.The next day was Saturday. He knew that most of the boys would be down on the playground and choose up sides for the Saturday game. Robert knew he could play well and that just might be enough to prove he was strong, and to make friends with them. He arrived early and did his step exercises. He shot the ball several times and did some other exercises—the most difficult and most wonderful in basketball. Then the boys came. Robert went through what he had done before the game and showed what he could do. No one said a word. The boys just looked at each other and thought about it. In the end, when it was all over, the biggest of the group just smiled and shook his head. Robert knew he had made it.2. Why would it not be easy for Robert to prove himself?
①  Because he was not sure if he was really strong.
②  Because he was new and was not wanted in the street.
③  Because the other boys had found out what kind of a boy he was.
④  Because he must choose the best way to prove himself.
【单选题】 阅读理解:阅读下列短文,回答文后问题,选择最佳答案Robert had just moved into the street and he felt strange that he was not wanted. He knew that perhaps the other boys were trying to get an idea of what kind of a boy he was. This did not help him to make himself less lonely. He was new and he had to be tested. Still, proving himself would not be all that easy. He did not want to run with the boys or get into something against the law to prove that he was strong. No! He must show what he was made of in a more helpful way. That’s when he got the idea.The next day was Saturday. He knew that most of the boys would be down on the playground and choose up sides for the Saturday game. Robert knew he could play well and that just might be enough to prove he was strong, and to make friends with them. He arrived early and did his step exercises. He shot the ball several times and did some other exercises—the most difficult and most wonderful in basketball. Then the boys came. Robert went through what he had done before the game and showed what he could do. No one said a word. The boys just looked at each other and thought about it. In the end, when it was all over, the biggest of the group just smiled and shook his head. Robert knew he had made it.1.What does “This did not help to make him less lonely” mean?
①  Robert felt more lonely because the other boys wanted to test him.
②  Robert did not want himself to be less lonely.
③  Robert felt as lonely as before when the other boys tried to find out what kind of a boy he was.
④  The other boys did not want to make Robert feel less lonely.
【单选题】 阅读理解:阅读下列短文,回答文后问题,选择最佳答案Robert had just moved into the street and he felt strange that he was not wanted. He knew that perhaps the other boys were trying to get an idea of what kind of a boy he was. This did not help him to make himself less lonely. He was new and he had to be tested. Still, proving himself would not be all that easy. He did not want to run with the boys or get into something against the law to prove that he was strong. No! He must show what he was made of in a more helpful way. That’s when he got the idea.The next day was Saturday. He knew that most of the boys would be down on the playground and choose up sides for the Saturday game. Robert knew he could play well and that just might be enough to prove he was strong, and to make friends with them. He arrived early and did his step exercises. He shot the ball several times and did some other exercises—the most difficult and most wonderful in basketball. Then the boys came. Robert went through what he had done before the game and showed what he could do. No one said a word. The boys just looked at each other and thought about it. In the end, when it was all over, the biggest of the group just smiled and shook his head. Robert knew he had made it.Which of the following is the best title for this passage?
①  Ways to Prove Oneself.
②  Robert Is Lonely.
③  Just One of the Boys. D.
④  A Saturday Basketball
【单选题】 阅读理解:阅读下列短文,回答文后问题,选择最佳答案Robert had just moved into the street and he felt strange that he was not wanted. He knew that perhaps the other boys were trying to get an idea of what kind of a boy he was. This did not help him to make himself less lonely. He was new and he had to be tested. Still, proving himself would not be all that easy. He did not want to run with the boys or get into something against the law to prove that he was strong. No! He must show what he was made of in a more helpful way. That’s when he got the idea.The next day was Saturday. He knew that most of the boys would be down on the playground and choose up sides for the Saturday game. Robert knew he could play well and that just might be enough to prove he was strong, and to make friends with them. He arrived early and did his step exercises. He shot the ball several times and did some other exercises—the most difficult and most wonderful in basketball. Then the boys came. Robert went through what he had done before the game and showed what he could do. No one said a word. The boys just looked at each other and thought about it. In the end, when it was all over, the biggest of the group just smiled and shook his head. Robert knew he had made it.3.When did Robert decide to prove himself by playing basketball?
①  After he had thought about the other two ways mentioned in paragraph one.
②  Long before he moved into the street.
③  When the other boys came down to the playground.
④  As soon as he showed what he was made of in front of the other boys.
【单选题】 Do you know the man _______?
①  whom I spoke
②  to who spoke
③  I spoke to
④  that I spoke
【单选题】 The place _______interested me most was the Childrens Palace.
①  which
②  where
③  what
④  in which
【单选题】 That is the day ______Ill never forget.
①  which
②  on which
③  in which
④  when