【判断题】
发电厂中的厂用电是重要负荷,必须按电力系统中第一类用户对待
A. 对
B. 错
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答案
A
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在正常运行方式下、所有的厂用电源均投入工作,把没有明显断开的备用电源称为暗备用
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保安段的工作电源和事故电源之间进行切换时,应先断开其工作电源开关,然后再合上其备用电源开关
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厂用电在正常情况下,工作变压器投入,备用电源断开,这种方式叫做明备用
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6kV厂用电系统装有厂用电快切装置,当工作电源掉闸后,备用电源应快速自动投入
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UPS电源系统为单相两线制系统
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接触器按其吸持线圈使用的电源种类可分为直流接触器和交流接触器
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厂用电系统中的第二类负荷由两个独立的电源供电,当一个电源失电时,另一个电源迅速手动进行切换,使其恢复供电
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【判断题】
厂用电系统中的第一类负荷为常用负荷,一般由单电源供电
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同一机炉或在生产流程上相互关联的电动机和其他厂用电设备,应在同一分段上
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大型机组设置保安电源的目的是为了机组在厂用电事故停电时,保证安全停机以及在厂用电恢复后快速启动并网
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真空断路器由于绝缘强度很高,电弧容易熄灭,所以不容易产生危险的过电压
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当 UPS 逆变器损坏时,自动切换到 220V 直流对UPS供电
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UPS在正常市电供应下,整流器将交流市电转换为直流电源后,供电给逆变器,整流器的输出电压调整的数值比220V蓄电池组电压高,蓄电池组不输出电流
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当UPS逆变器发生异常状况,像温度过高、短路现象、输出电压异常或负载超载等情形,超过逆变器可承受范围时,逆变器会自动切断以防止损坏。若此时市电正常时,静态开关会将电源供应转为由备用电源(旁路电源)输出给负载使用
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厂用电快切并联切换:采取先合上备用电源,两电源短时并联,再跳开工作电源。这种方式多用于正常切换,如起、停机
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【判断题】
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厂用电快切不正常情况切换只能是单向切换,即只能由工作电源切向备用电源切换
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