采用增容导线对输电线路进行增容改造，能缓解现有线路输电能力不足的问题。在增容效果显著的同时，导线最高运行温度超过80 ℃，根据现行规程规定的弧垂定位已不适用。分析了采用增容导线时定位弧垂的计算方法，并根据算例对所提方法进行了验证。

The upgrading improvement by using augmented capacity conductor could alleviate the insufficient capacity problem of transmission lines. In spite of the significant capacity increase, the maximum temperature of conductors will exceed 80℃, thus it is inappropriate to use the sag calculated in the condition of 40℃, 50℃ or icing without wind to locate towers. The calculation method of location sag when using augmented capacity conductor is analyzed, and the verification according to examples is carried out.