施工现场临时用电技术

（施工现场临时用电技术专辑）内部资料禁止外传1目录1概述·················································································41.1临时用电简介···································································41.2注意事项·········································································42临时用电技术及要求····························································52.1电源中性点工作制·····························································52.2三级配电系统···································································52.3TN-S接零保护系统···························································62.3.1专项供电接零保护系统····················································62.3.2局部接零保护系统··························································62.3.3保护零线选择及其它·······················································72.3.4电气设备的接地与接零····················································72.4二级漏电保护系统····························································142.4.1安全电流······································································142.4.2安全电压······································································162.4.3漏电保护器原理·····························································182.4.4漏电保护器的接线图·······················································192.5电气防雷········································································192.5.1防雷要求······································································202.5.2防雷措施······································································202.5.3滚球法确定接闪器的保护范围···········································223临时用电组织设计·······························································273.1临时用电组织设计有关要求················································273.2临时用电施工组织设计主要内容··········································273.3设计依据········································································2723.4工程概况········································································283.5负荷计算书·····································································283.5.1负荷计算表···································································283.5.2负荷计算方法································································283.6变压器容量选择·······························································313.7电线电缆及开关的选择······················································313.7.1分配电箱至设备的电线电缆和开关的选择····························313.8供配电系统图··································································353.9电气平面图·····································································353.10安全技术措施和电气防火措施············································354触电的形式与急救·······························································364.1触电的几种形式·······························································364.1.1单相触电······································································374.1.2两相触电······································································374.1.3跨步电压触电································································374.2触电的现场急救方法·························································384.2.1解脱电源······································································384.2.2迅速诊断······································································394.2.3人工呼吸法···································································394.2.3心脏按摩法···································································401施工现场临时用电技术1概述1.1临时用电简介工程临时施工用电往往利用就近电源搭火后，通过变压器直接变为设备所要求的电压等级，一般为10kv/400v，有些情况下，需先经35kv/10kv或110kv/10kv，然后再10kv/400v/230v，变为我们所需要的电压等级。不管是经过怎样的电压变换，由于当前电力部门控制着用电线路中变压器及变压器前的电力设施的采购、安装，我们只能通过谈判，确定变压器的数量、容量、安设地点、一次性投入费用、无功损耗计费方式等问题，签订合同即可。即高压部分的设计、安装、调试、管理等工作均由当地电力部门承担，低压部分由我项目部承担。1.2注意事项投标时应注意业主招标文件中施工用电方面的条款，条款内容不同决定用电成本不同。工程开工后，用电量倍增，电力部门原有供电能力往往不足，需要作增容扩容处理，施工单位作为整个工程建设链条中的弱势群体，往往承担着本不应该承担的费用。因此在投标时，若发现条款中含糊不清，应请求业主在补遗文件中澄清，不予澄清的，则需充分考虑风险，做好风险评价。电力部门对区域用电是有规划的，工程完工后，在运营过程中也需要用电。因此可联合业主对当地电力部门进行谈判，尽可能争取电力部门承担部分费用。对电力部门谈判完毕，还应向业主进行谈判，争取其承担部分费用，以尽可能减少我们的投入。2临时用电技术及要求2《施工现场临时用电安全技术规范》（JGJ46-2005）自2005年7月1日起执行，代替原规范（JGJ46-88）。以下是对规范中不容易理解部分条款进行阐述各说明。1.0.3建筑施工现场临时用电专用的电源中性点直接接地的220/380V三相四线制低压电力系统，必须符合下列规定：1采用三级配电系统；2采用TN-S接零保护系统；3采用二级漏电保护系统。2.1电源中性点工作制电源中性点直接接地是变压器中性点工作制的一种，除了中性点直接接地，还有中性点不接地，通过电阻接地，通过电抗接地，经消弧线圈接地几种工作制。工程施工中大都采用中性点直接接地的工作制，在电力运行出现故障时，切换装置能够迅速切断电源，保证电气设备不会带故障运行；当安全条件要求较高，要求误触电时也不会出现触电伤亡，设备运行可靠不能轻易断电时，采用中性点不接地的工作制。本规范只适应于中性点直接接地的电力系统设计、安装、使用、维修和拆除。2.2三级配电系统三级配电系统是指配电系统中应设置配电柜或总配电箱、分配电箱、开关箱。总配电箱设置在靠近电源的地方，分配电箱距开关箱不大于30m，开关箱距设备不大于3m。开关箱直接控制设备，要求1个开关箱（一箱）只能控制1台设备（1机），每个箱子中必须要有1个漏电保护器（一漏）和1个电源总开关（一闸），即“一机一箱一闸一漏”。3总配电箱：应具备电源隔离、正常接通与分断电路以及短路、过载、漏电保护功能。分配电箱：必须装设总隔离开关、分路隔离开关以及总断路器、分路断路器或总熔断器、分路熔断器。开关箱：必须装设隔离开关、断路器或熔断器以及漏电保护器。2.3TN-S接零保护系统TN-S接零保护系统是指工作零线和保护零线分开设置的接零保护系统，原规范（JGJ46-88）要求采用TN-C接零保护系统，即工作零线和保护零线合一设置的接零保护系统。区别在TN-S比TN-C多使用一根导线，TN-S比TN-C更安全。2.3.1专项供电接零保护系统临时施工用电若采用专用变压器供电，必须采取TN-S接零保护系统，如下图：PE--保护零线N--工作零线L3--相线L2--相线重复接地重复接地重复接地单相负载两相负载三相负载三相+单相负载变压器L1--相线工作接地隔离开关漏电保护器专用变压器供电时TN-S接零保护示意图2.3.2局部接零保护系统当施工现场与外电线路共用同一供电系统时，电气设备的接地、接零保4护应与原系统一致。当原系统采用TN系统做保护接零时，保护零线必须由电源进线重复接地处引出形成局部TN-S接零保护系统。TN系统是指电源中性点直接接地时电气设备外露可导部分通过零线接地的接零保护系统。在TN-S接