擴(kuo)徑導(dao)線(xian)線(xian)膨脹(zhang)系(xi)數(shu)較(jiao)好，電暈損(sun)失(shi)小，有良好的(de)散熱性。適用(yong)于(yu)高(gao)低壓輸電線(xian)中(zhong)電廠(chang)及變電站配電線(xian)路、母(mu)線(xian)等。減少(shao)電暈損(sun)失(shi)，節約有色(se)金屬。

擴徑(jing)(jing)(jing)導(dao)線(xian)(xian)(xian)(xian)(xian)就(jiu)是把普通(tong)的(de)導(dao)線(xian)(xian)(xian)(xian)(xian)做成中空（里面用多股芯(xin)線(xian)(xian)(xian)(xian)(xian)和支撐層做成）或者減(jian)少其中部分層單線(xian)(xian)(xian)(xian)(xian)數(shu)量（使該層單線(xian)(xian)(xian)(xian)(xian)間存在一定數(shu)量空隙(xi)），最終達到增加導(dao)線(xian)(xian)(xian)(xian)(xian)的(de)等效半徑(jing)(jing)(jing)的(de)目的(de)。當線(xian)(xian)(xian)(xian)(xian)路(lu)的(de)電(dian)(dian)壓超過220kv時(shi)，為了(le)降低線(xian)(xian)(xian)(xian)(xian)路(lu)電(dian)(dian)抗和電(dian)(dian)暈損耗，通(tong)常采用擴徑(jing)(jing)(jing)導(dao)線(xian)(xian)(xian)(xian)(xian)。

擴徑(jing)導線(xian)(xian)是以滿足(zu)技術條件的常規導線(xian)(xian)規格(ge)為(wei)基準，采(cai)取擴大導線(xian)(xian)外徑(jing)技術，在(zai)保證電暈所要求的導線(xian)(xian)外徑(jing)前提下，減少導線(xian)(xian)的鋁截面，從(cong)而減少導線(xian)(xian)的總重(zhong)量，減少鐵塔荷載和結構重(zhong)量，極大地降低(di)線(xian)(xian)路造(zao)價。