橋架(jia)的(de)設計原理是什(shen)么？

      線(xian)(xian)(xian)(xian)(xian)損計算是降損節能、加(jia)強線(xian)(xian)(xian)(xian)(xian)損管理的重要技術管理手段。眾所周知，輸電(dian)(dian)線(xian)(xian)(xian)(xian)(xian)路(lu)(lu)損耗是負(fu)載(zai)電(dian)(dian)流通(tong)過(guo)線(xian)(xian)(xian)(xian)(xian)路(lu)(lu)時(shi)，在(zai)線(xian)(xian)(xian)(xian)(xian)路(lu)(lu)電(dian)(dian)阻(zu)上產生的功率損耗。然而(er)，實際電(dian)(dian)力線(xian)(xian)(xian)(xian)(xian)周圍的環(huan)境(jing)溫度(du)(du)是變化的；而(er)且負(fu)載(zai)電(dian)(dian)流通(tong)過(guo)導(dao)線(xian)(xian)(xian)(xian)(xian)電(dian)(dian)阻(zu)時(shi)會產生熱量(liang)，導(dao)線(xian)(xian)(xian)(xian)(xian)溫度(du)(du)升高，所以(yi)導(dao)線(xian)(xian)(xian)(xian)(xian)的實際電(dian)(dian)阻(zu)值會隨著環(huan)境(jing)、溫度(du)(du)、負(fu)載(zai)電(dian)(dian)流的變化。為了(le)簡化計算，導(dao)線(xian)(xian)(xian)(xian)(xian)電(dian)(dian)阻(zu)通(tong)常分(fen)為三(san)個分(fen)量(liang)：

      (1)導體R20的電阻值；當基本(ben)電阻為20時；

      (2)溫度(du)附加電阻RT；

   ;   (3)負(fu)載(zai)電(dian)流的附加(jia)電(dian)阻Rl。實際線(xian)(xian)(xian)路電(dian)阻為：R=R20RtRl。根據線(xian)(xian)(xian)損計算公式的分(fen)析，降(jiang)低輸電(dian)線(xian)(xian)(xian)路工作時的溫升是降(jiang)低線(xian)(xian)(xian)損的有(you)效途徑(jing)。