擴(kuo)徑導(dao)線(xian)一般大多用在特(te)高(gao)壓線(xian)路(lu)、高(gao)海(hai)拔地(di)區、人口密(mi)集(ji)的地(di)區。按用途分為(wei)線(xian)路(lu)用和變電站用兩大類(lei)；按結構特(te)點分為(wei)大內(nei)徑鋁管(guan)支撐(cheng)型(xing)擴(kuo)徑導(dao)線(xian)、小內(nei)徑鋁管(guan)填充型(xing)擴(kuo)徑導(dao)線(xian)、疏絞型(xing)擴(kuo)徑導(dao)線(xian)、高(gao)密(mi)度聚乙烯支撐(cheng)型(xing)擴(kuo)徑導(dao)線(xian)。

特(te)(te)(te)高(gao)(gao)(gao)壓(ya)(ya)(ya)線(xian)路：特(te)(te)(te)高(gao)(gao)(gao)壓(ya)(ya)(ya)輸(shu)電(dian)處于超大規模(mo)電(dian)力輸(shu)送系統工程(cheng)(cheng)中的高(gao)(gao)(gao)端，特(te)(te)(te)高(gao)(gao)(gao)壓(ya)(ya)(ya)工程(cheng)(cheng)以建設(she)(she)“環境友好(hao)型(xing)”工程(cheng)(cheng)為(wei)目(mu)標，力求全面優化工程(cheng)(cheng)的設(she)(she)計方案，嚴格保證電(dian)場(chang)、磁(ci)場(chang)、可聽噪聲與無線(xian)電(dian)干擾水平滿足標準要求。

節約線(xian)(xian)(xian)(xian)(xian)(xian)(xian)(xian)路(lu)走廓用(yong)地(di)的措施之一是(shi)輸(shu)電(dian)(dian)(dian)線(xian)(xian)(xian)(xian)(xian)(xian)(xian)(xian)路(lu)采用(yong)V型絕(jue)緣(yuan)子(zi)串(chuan)(chuan)，這(zhe)樣(yang)可以減少拆(chai)遷(qian)、降(jiang)低工(gong)程(cheng)造(zao)價，經濟利益顯著，但(dan)是(shi)V型絕(jue)緣(yuan)子(zi)串(chuan)(chuan)的采用(yong)將(jiang)使(shi)(shi)輸(shu)電(dian)(dian)(dian)線(xian)(xian)(xian)(xian)(xian)(xian)(xian)(xian)路(lu)的電(dian)(dian)(dian)磁環境變差。為此，若輸(shu)電(dian)(dian)(dian)線(xian)(xian)(xian)(xian)(xian)(xian)(xian)(xian)路(lu)采用(yong)普(pu)通導(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)(xian)(xian)，則需要加大導(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)(xian)(xian)截面和增加導(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)(xian)(xian)的分裂根數，這(zhe)樣(yang)將(jiang)增大導(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)(xian)(xian)的使(shi)(shi)用(yong)量(liang)、鐵塔的結構(gou)尺(chi)寸(cun)和重量(liang)等，從而加大工(gong)程(cheng)投資(zi)。如果在滿(man)足輸(shu)電(dian)(dian)(dian)容量(liang)和線(xian)(xian)(xian)(xian)(xian)(xian)(xian)(xian)路(lu)工(gong)程(cheng)要求的前提下，設(she)計一種保證輸(shu)電(dian)(dian)(dian)導(dao)(dao)體(ti)載流能(neng)力的新(xin)型結構(gou)導(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)(xian)(xian)，并(bing)將(jiang)直徑(jing)擴大且盡可能(neng)使(shi)(shi)其表面光(guang)潔(jie)圓滑(hua)，這(zhe)樣(yang)就(jiu)會大大節約導(dao)(dao)體(ti)材料，并(bing)且使(shi)(shi)導(dao)(dao)線(xian)(xian)(xian)(xian)(xian)(xian)(xian)(xian)的外徑(jing)與表面能(neng)滿(man)足線(xian)(xian)(xian)(xian)(xian)(xian)(xian)(xian)路(lu)的輸(shu)電(dian)(dian)(dian)和電(dian)(dian)(dian)暈要求，從而顯著降(jiang)低線(xian)(xian)(xian)(xian)(xian)(xian)(xian)(xian)路(lu)投資(zi)。

采用(yong)適當(dang)的(de)擴徑導線(xian)有(you)利于降(jiang)低特(te)(te)高壓(ya)工程(cheng)投(tou)資，而且(qie)可以減輕(qing)交流(liu)工程(cheng)所(suo)用(yong)導線(xian)的(de)集膚效應，因此擴徑特(te)(te)別適用(yong)于交流(liu)特(te)(te)高壓(ya)工程(cheng)。