【正文】 擊接地電阻 =1Ω時(shí)，接地裝置上電位升高為 20KV，而一般室內(nèi)低壓裝置的耐沖擊電壓最高為 8KV。其結(jié)果就使低壓電氣裝置絕緣較弱處可能被擊穿而造成短路，發(fā)生火災(zāi)、損壞設(shè)備，這是非常危險(xiǎn)的。因此，在設(shè)計(jì)中給予足夠的重視，對(duì)防雷建筑物實(shí)現(xiàn)全方位、多層次的防雷網(wǎng)絡(luò)，使雷電對(duì)建筑物的影響減至最小。 建筑物為高壓進(jìn)線時(shí)，高、低壓側(cè)各相上均設(shè)避雷器，用以防護(hù)由高壓進(jìn)線的雷電和操作 (斷路器動(dòng)作，投切大電動(dòng)機(jī)和電容器組等 )過(guò)電壓。建筑物為低壓進(jìn)線時(shí)，在電源總進(jìn)線處裝設(shè)過(guò)電壓保護(hù)器。 防雷建筑物的防雷分類 第一類防雷建筑物的防雷措施 :應(yīng)裝設(shè)獨(dú)立避雷針或架空避雷線，使被保護(hù)的建筑物及風(fēng)帽、放散管等突出屋面的物體均處于接閃器的保護(hù)范圍內(nèi)。 第二類防雷建筑物的防雷措施 :宜采用裝設(shè)在建筑物上的避雷網(wǎng)（帶）或避雷針或由其混合組成的接閃器。 第三類防雷建筑物防雷的措施 :宜采用裝設(shè)在建筑物上的避雷網(wǎng)（帶）或避雷針或由這兩種混 合組成的接閃器 。 預(yù)防雷電的方法有“抗”和“泄”兩種，現(xiàn)階段主要采用的方法是“泄”。防雷系統(tǒng)就是由三部分組成的泄電回路，即由接閃器、引下線和接地裝置三部分組成。其作用是把雷電流泄人大地，避免直接雷擊造成機(jī)械破壞、電磁力破壞或熱效應(yīng)破壞。對(duì)于不同防雷等級(jí)的建筑物，在進(jìn)行防雷設(shè)計(jì)時(shí)，對(duì)防雷系統(tǒng)的三部分要求是不同的。 5 導(dǎo)線與電纜選擇 住宅內(nèi)的電氣線路不同于企事業(yè)單位，它沒(méi)有專業(yè)電工維護(hù)，而居民往往不懂電氣安全知識(shí)，很容易發(fā)生電氣事故。另外，由于經(jīng)濟(jì)發(fā)展水平等原因，以往住宅的電氣 線路設(shè)計(jì)過(guò)小，隨著居民生活水平的提高，愈來(lái)愈多的家用電器被廣泛使用，致使一些樓房的線路不堪重負(fù)，頻繁跳閘，給生活和工作帶來(lái)極大的不便。更嚴(yán)重的是電氣線路長(zhǎng)期過(guò)載，導(dǎo)致絕緣下降，電氣事故不斷發(fā)生。據(jù)統(tǒng)計(jì)我國(guó)電氣火災(zāi)已躍居火災(zāi)起因的第一位，為此不得不對(duì)現(xiàn)有住宅線路進(jìn)行改造。住宅暗埋電氣線路是難以更換或增加的，因此在進(jìn)行住宅電氣設(shè)計(jì)時(shí)，應(yīng)盡量加大進(jìn)線，盡可能地滿足遠(yuǎn)期負(fù)荷的需要。但遠(yuǎn)期負(fù)荷很難估算，只能借鑒國(guó)外經(jīng)驗(yàn)并結(jié)合國(guó)情來(lái)確定。 住宅電氣從電方面可分為：一級(jí)負(fù)荷供電、二級(jí)負(fù)荷供電和無(wú)特 殊要求的住宅。隨著家用電器的不斷出新和發(fā)展，家用電氣設(shè)備越來(lái)越多，考慮到未來(lái)住宅用電發(fā)展的用電余量。 6 結(jié)論 在本次設(shè)計(jì)當(dāng)中主要包括強(qiáng)電部分，其主要內(nèi)容有供配電系統(tǒng)設(shè)計(jì)、照明系統(tǒng)設(shè)計(jì)、防雷接地系統(tǒng)設(shè)計(jì)等。其中有照度計(jì)算、負(fù)荷計(jì)算、電纜選擇等重點(diǎn)內(nèi)容。 在照明設(shè)計(jì)中，通過(guò)單位容量法進(jìn)行了照明計(jì)算。在照度計(jì)算當(dāng)中，先計(jì)算出每個(gè)房間的面積，通過(guò)表格查出單位面積安裝功率，計(jì)算出所需燈具的功率和數(shù)量。本住宅屬于三級(jí)負(fù)荷，運(yùn)用需用系數(shù)法算出計(jì)算電流，按允許載流量選擇導(dǎo)線截面積。配電系統(tǒng)也更加體現(xiàn)了安全和經(jīng)濟(jì)可靠的原則。 附錄二 Residential building construction high voltage electrical design 1 the introduction building electrical overview Along with our country social economy system reform and the rapid development of technology and economy, the national economy has been rapid development, personal consumption level unceasing enhancement, stimulate the residential building and people39。s environment construction to a large span and more high level forward. Modern residential development, makes dwelling house building electrical design and residential building electrical design at the same time has entered a rapid development of the new high tide. Residential electrical design in residential design is an important part of his house for beautiful, realize the use function of residential buildings, safeguard the resident39。s life and property safety, to reduce the cost of the house, all have certain effect. At present, the residential electrical design theory system and practice experience although increasingly mature, but in residential electrical design practice, there are still some problems worthy of further discussion. 2 power supply system design load classification power supply system load classification Power load should not, and there is no need to continue to meet electricity load at the same time, we should, in accordance with the power supply design should accord with the importance and need degree and the possibility of power supply, according to different load levels by different power supply mode. In our country electric power load according to the power supply reliability and interrupt the power supply in the political and economic loss caused by or influence, divided into primary load, secondary load and level 3 load. Load classification and the power supply requirements: Power load should be based on the power supply reliability requirements and interrupt the power supply in the political, economic loss caused by the degree of influence or classification, and ply with the following provisions: 1, level 1 load Interrupt the power supply will cause personal injury。 Interrupt the power supply will be in the political and economic causes great loss。 Interrupt the power supply will influence has great political and economic significance of the normal work of the power unit. Such as: major equipment, major products, an important transport hub, important munication hub, important hotels, large sports venues, often used in international activities of a large number of personnel concentration of public power unit, such as the important power load. When the interrupt the power supply will be poisoning, explosion and fire the load, and particularly important places are not allowed to interrupt the power supply load, should be regarded as particularly important load. Level 1 load power supply requirements: load demand level two power supply, when a power does not work or failure is, to ensure that another standby power will not damage at the same time, continue to power supply, ensure the normal work. 2, the secondary load Interrupt the power supply will be in the political and economic causes big loss Interrupt the power supply will affect the normal work of the important power units such as: the damage of equipment, products in large scale and continuous production process is upset, key enterprise of production, transportation hub, munication pivot New power unit, such as the important power load is damaged, and interrupt the power supply will cause large opera house, large market, more people concentrated important public order. This load belongs to secondary load. Secondary load power supply requirements: secondary load demand two loop power supply, power supply transformer also have two, when power is at fault can quickly restore。 When the cable line is, should use two root cable power supply, each root can bear 100% of the secondary load [1]. 3, level 3 load: Do not belong to the first and second load should be level 3 load. Level 3 load to the power supply and no special requirements. load calculation Load level is different, the power supply requirements is different, the power supply transformer capacity requirements are different. In order to determine the capacity of the power transformer, must the putational load capacity. load calculation method The putational load method: (1) according to the demand factor method to determine the putational load。 (2) classification prehensive power index method。 (3) family estimation。 (4) civil building load calculation 。 (5) single phase load calculation . load calcula