阐述了秦山500 kV联合开关站3.52 km出线段增容技改的必要性，详细分析了用4×AF（SZ）S4A-400/45增容导线替换4×LGJ-400/35导线的可行性，充分论证了该增容导线与新建的秦由5415/秦拳5416线4×LGJ-630/45导线接轨的参数匹配性。该增容改造方案为经济发达但线路走廊资源紧张地区提升电力输送能力，提供了可借鉴的经验。

This paper discussed the necessity of technique reformation of capacity expansion for the 3.52 km transmission lines directly connected Qinshan 500 kV combined switch station, and analyzed the feasibility of the replacement of the 4×AF (SZ) S4A-400/45 augmented capacity conductor for the 4×LGJ-400/35 conductor. The parameter matching performance between the augmented capacity conductor and the 4×LGJ-630/45 conductor of Qinyou 5415/Qinquan 5416 newly built was also studied. The technique reformation scheme of capacity expansion can provide references for the power transmission capacity increase in the developed area where there is not enough transmission line corridors.