擴徑(jing)(jing)導(dao)線(xian)(xian)(xian)(xian)也就(jiu)是擴大導(dao)線(xian)(xian)(xian)(xian)外徑(jing)(jing)技(ji)術，當線(xian)(xian)(xian)(xian)路的電(dian)(dian)壓超過220kv時，為了降低線(xian)(xian)(xian)(xian)路電(dian)(dian)抗和(he)電(dian)(dian)暈損(sun)耗(hao)，通(tong)(tong)常采用擴徑(jing)(jing)導(dao)線(xian)(xian)(xian)(xian)。擴徑(jing)(jing)導(dao)線(xian)(xian)(xian)(xian)就(jiu)是把普通(tong)(tong)的導(dao)線(xian)(xian)(xian)(xian)做成中(zhong)空(kong)（里面(mian)用多股芯線(xian)(xian)(xian)(xian)和(he)支撐層(ceng)做成）或(huo)者減少其中(zhong)部(bu)分(fen)層(ceng)單線(xian)(xian)(xian)(xian)數(shu)量(liang)（使該層(ceng)單線(xian)(xian)(xian)(xian)間存在一定(ding)數(shu)量(liang)空(kong)隙），最終(zhong)達到增加導(dao)線(xian)(xian)(xian)(xian)的等(deng)效半(ban)徑(jing)(jing)的目的。

交流輸電(dian)線(xian)路(lu)的(de)(de)(de)電(dian)暈損失主要與(yu)導線(xian)表面場(chang)強(qiang)(qiang)和天氣有(you)關(guan)(guan)，根據絕緣水平要求確定了(le)相間距離后(hou)，導線(xian)表面場(chang)強(qiang)(qiang)主要與(yu)導線(xian)分(fen)(fen)裂數(shu)、分(fen)(fen)裂間距和 子(zi)導線(xian)直(zhi)(zhi)徑(jing)(jing)有(you)關(guan)(guan)，分(fen)(fen)裂數(shu)越多，子(zi)導線(xian)直(zhi)(zhi)徑(jing)(jing)越大， 表面場(chang)強(qiang)(qiang)越小。擴徑(jing)(jing)導線(xian)通過支撐鋁線(xian)疏繞的(de)(de)(de)方式 擴大了(le)導線(xian)外徑(jing)(jing)，這樣(yang)可減(jian)小導線(xian)表面的(de)(de)(de)電(dian)場(chang)強(qiang)(qiang)度和電(dian)暈放電(dian)，降低噪(zao)聲(sheng)，減(jian)少對無(wu)線(xian)電(dian)的(de)(de)(de)干(gan)擾。相 對于(yu)常(chang)規導線(xian)，擴徑(jing)(jing)導線(xian)重量較輕，安裝敷設(she)后(hou)的(de)(de)(de) 塑蠕伸長減(jian)小，導線(xian)永久變形減(jian)少，在滿足輸送容 量要求和環境(jing)保護(hu)指標的(de)(de)(de)前提下，可大幅降低線(xian)路(lu) 整體造價。簡單(dan)說來，擴徑(jing)(jing)導線(xian)是(shi)從(cong)常(chang)規導線(xian)中抽取數(shu)股 鋁線(xian)后(hou)繞制(zhi)而成的(de)(de)(de)，是(shi)常(chang)規導線(xian)時升級進化品(pin)。