有些客戶(hu)在設(she)(she)計選(xuan)用低中(zhong)壓電力電纜(lan)(lan)(lan)過程中(zhong)，對(dui)電力電纜(lan)(lan)(lan)實(shi)(shi)際(ji)載流量和理論載流量在認識方面存在誤區，往(wang)往(wang)認為電力電纜(lan)(lan)(lan)選(xuan)用只要滿足設(she)(she)備(bei)的實(shi)(shi)際(ji)運行容量就可以(yi)了，而往(wang)往(wang)忽略實(shi)(shi)際(ji)敷設(she)(she)條件下對(dui)電纜(lan)(lan)(lan)實(shi)(shi)際(ji)運行載流量的校正，為電纜(lan)(lan)(lan)事故的發(fa)生(sheng)埋下了隱患。
某新建硅業公司， 廠(chang)區內部輸(shu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)的(de)(de)(de)(de)(de)(de)(de)50多根(gen)10kV 電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)，全(quan)部單穿(chuan)入(ru)厚(hou)質(zhi)白色(se)PVC塑料管(guan)中(zhong)，彼此(ci)無間(jian)隙隨意碼放(fang)堆積(ji)5層，然后(hou)直(zhi)埋(mai)敷(fu)(fu)(fu)(fu)設(she)(she)(she)，土壤埋(mai)設(she)(she)(she)深度約(yue)1米，每層敷(fu)(fu)(fu)(fu)設(she)(she)(she)的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)數量(liang)(liang)為10根(gen)，整(zheng)個(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)排管(guan)在(zai)地下的(de)(de)(de)(de)(de)(de)(de)分(fen)(fen)布斷(duan)面基本呈現(xian)長(chang)(chang)方形方式排列，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)線路的(de)(de)(de)(de)(de)(de)(de)總長(chang)(chang)度約(yue)1公里(li)。在(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)中(zhong)間(jian)接頭位置砌有(you)(you)兩(liang)個(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)井，便于(yu)(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)線路的(de)(de)(de)(de)(de)(de)(de)維護。這些(xie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)在(zai)連續(xu)通電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)運(yun)(yun)行(xing)(xing)1天左(zuo)右，就從電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)井口(kou)處冒(mao)出(chu)令人難聞(wen)的(de)(de)(de)(de)(de)(de)(de)由(you)于(yu)(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)塑料發(fa)(fa)(fa)(fa)熱(re)(re)分(fen)(fen)解的(de)(de)(de)(de)(de)(de)(de)焦糊味，一周(zhou)不(bu)到就有(you)(you)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)陸續(xu)發(fa)(fa)(fa)(fa)生(sheng)(sheng)(sheng)了熱(re)(re)擊穿(chuan)。終導致整(zheng)個(ge)10kV電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)線路無法(fa)正常使(shi)(shi)用(yong)。上述問(wen)題的(de)(de)(de)(de)(de)(de)(de)發(fa)(fa)(fa)(fa)生(sheng)(sheng)(sheng)就是對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)實(shi)(shi)際(ji)(ji)運(yun)(yun)行(xing)(xing)使(shi)(shi)用(yong)載流(liu)量(liang)(liang)缺乏科學(xue)認識，導致電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)事(shi)故的(de)(de)(de)(de)(de)(de)(de)典(dian)型案例。各(ge)種型號規格的(de)(de)(de)(de)(de)(de)(de)低中(zhong)壓(ya)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)都(dou)有(you)(you)有(you)(you)一個(ge)理論計(ji)算載流(liu)量(liang)(liang)，但對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)的(de)(de)(de)(de)(de)(de)(de)實(shi)(shi)際(ji)(ji)敷(fu)(fu)(fu)(fu)設(she)(she)(she)使(shi)(shi)用(yong)環(huan)(huan)境，須要充分(fen)(fen)考(kao)慮實(shi)(shi)際(ji)(ji)使(shi)(shi)用(yong)敷(fu)(fu)(fu)(fu)設(she)(she)(she)環(huan)(huan)境的(de)(de)(de)(de)(de)(de)(de)熱(re)(re)阻校正系(xi)數，對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)實(shi)(shi)際(ji)(ji)載流(liu)量(liang)(liang)進(jin)行(xing)(xing)校正，這在(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)選用(yong)施工(gong)(gong)前的(de)(de)(de)(de)(de)(de)(de)設(she)(she)(she)計(ji)階段須得充分(fen)(fen)進(jin)行(xing)(xing)考(kao)慮，否則一旦電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)施工(gong)(gong)完成(cheng)，將無法(fa)進(jin)行(xing)(xing)補救，造成(cheng)的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)經(jing)濟損(sun)失巨大。多根(gen)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)穿(chuan)入(ru)PVC塑料管(guan)，無間(jian)隙隨意碼放(fang)直(zhi)埋(mai)敷(fu)(fu)(fu)(fu)設(she)(she)(she)，每根(gen)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)的(de)(de)(de)(de)(de)(de)(de)環(huan)(huan)境熱(re)(re)阻系(xi)數較電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)直(zhi)接埋(mai)地敷(fu)(fu)(fu)(fu)設(she)(she)(she)方式大大增加。在(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)的(de)(de)(de)(de)(de)(de)(de)實(shi)(shi)際(ji)(ji)通電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)運(yun)(yun)行(xing)(xing)過程中(zhong)，位于(yu)(yu)排管(guan)內部每根(gen)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)周(zhou)圍的(de)(de)(de)(de)(de)(de)(de)介質(zhi)主要為塑料管(guan)和相鄰電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)，而不(bu)是純粹的(de)(de)(de)(de)(de)(de)(de)土壤，其熱(re)(re)阻將遠(yuan)遠(yuan)大于(yu)(yu)土壤；同時電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)在(zai)運(yun)(yun)行(xing)(xing)中(zhong)產生(sheng)(sheng)(sheng)的(de)(de)(de)(de)(de)(de)(de)發(fa)(fa)(fa)(fa)熱(re)(re)量(liang)(liang)也在(zai)不(bu)斷(duan)對(dui)塑料管(guan)和周(zhou)圍電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)在(zai)加熱(re)(re)，此(ci)時電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)力(li)(li)(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)實(shi)(shi)際(ji)(ji)敷(fu)(fu)(fu)(fu)設(she)(she)(she)環(huan)(huan)境已不(bu)是純粹的(de)(de)(de)(de)(de)(de)(de)直(zhi)接埋(mai)地敷(fu)(fu)(fu)(fu)設(she)(she)(she)，其實(shi)(shi)際(ji)(ji)運(yun)(yun)行(xing)(xing)允(yun)許載流(liu)量(liang)(liang)將大大下降，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)熱(re)(re)擊穿(chuan)事(shi)故的(de)(de)(de)(de)(de)(de)(de)發(fa)(fa)(fa)(fa)生(sheng)(sheng)(sheng)勢在(zai)必然。因此(ci)對(dui)于(yu)(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)敷(fu)(fu)(fu)(fu)設(she)(she)(she)工(gong)(gong)程的(de)(de)(de)(de)(de)(de)(de)初期設(she)(she)(she)計(ji)須要將電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)敷(fu)(fu)(fu)(fu)設(she)(she)(she)后(hou)的(de)(de)(de)(de)(de)(de)(de)實(shi)(shi)際(ji)(ji)熱(re)(re)阻充分(fen)(fen)考(kao)慮在(zai)內，及時進(jin)行(xing)(xing)校正設(she)(she)(she)計(ji)，否則造成(cheng)的(de)(de)(de)(de)(de)(de)(de)經(jing)濟損(sun)失巨大。
當多根(gen)(gen)電(dian)(dian)(dian)力電(dian)(dian)(dian)纜(lan)并排無(wu)間隙隨意碼放堆(dui)積敷設直(zhi)埋后，當其中的(de)(de)(de)一根(gen)(gen)電(dian)(dian)(dian)力電(dian)(dian)(dian)纜(lan)發(fa)生(sheng)故(gu)(gu)障(zhang)(zhang)時可能會(hui)將相鄰(lin)(lin)的(de)(de)(de)一根(gen)(gen)或多根(gen)(gen)電(dian)(dian)(dian)纜(lan)連帶(dai)燒(shao)毀，造(zao)成事故(gu)(gu)的(de)(de)(de)蔓延(yan)和擴大。同(tong)時還(huan)會(hui)引發(fa)熱擊穿事故(gu)(gu)的(de)(de)(de)發(fa)生(sheng)。電(dian)(dian)(dian)力電(dian)(dian)(dian)纜(lan)直(zhi)埋根(gen)(gen)數太(tai)多對于電(dian)(dian)(dian)纜(lan)線路故(gu)(gu)障(zhang)(zhang)的(de)(de)(de)實際維(wei)修開(kai)挖不利(li)，因為電(dian)(dian)(dian)纜(lan)數量(liang)多，開(kai)挖過程造(zao)成電(dian)(dian)(dian)纜(lan)機械損傷的(de)(de)(de)機會(hui)也將大大增(zeng)加(jia)，同(tong)時在開(kai)挖故(gu)(gu)障(zhang)(zhang)電(dian)(dian)(dian)纜(lan)時，相鄰(lin)(lin)電(dian)(dian)(dian)力電(dian)(dian)(dian)纜(lan)可能都(dou)處(chu)于通電(dian)(dian)(dian)狀態(tai)，人員(yuan)觸電(dian)(dian)(dian)事故(gu)(gu)和二(er)次事故(gu)(gu)引發(fa)的(de)(de)(de)停電(dian)(dian)(dian)范(fan)圍(wei)很(hen)可能會(hui)擴大。
對于多根電(dian)力(li)電(dian)纜(lan)同時直埋，根數(shu)好能控制在(zai)6根以(yi)(yi)下，敷設過程中盡(jin)量拉開距離，給(gei)電(dian)力(li)電(dian)纜(lan)足夠的散熱空間，在(zai)電(dian)纜(lan)選擇時，要對其周圍土壤或沙土的散熱性能充分(fen)加以(yi)(yi)考慮，進行熱阻系(xi)數(shu)的校正，才能確保電(dian)力(li)電(dian)纜(lan)正常(chang)放(fang)心使(shi)用(yong)，使(shi)其使(shi)用(yong)壽命得以(yi)(yi)充分(fen)發揮。
