**作者：**Yaw-Juen Wang and Shi-Jie Liu**中文摘要：**This paper reviews the three most commonly used methods for calculation of frequency-dependent impedance of overhead transmission lines: Carson's method, the complex depth of earth return method and the finite element method. The historical path along which these methods were developed is also reviewed. This is followed by an illustrative example that compares the frequency-dependent impedances of a 500 kV transmission line calculated using the tree methods. It is concluded that the complex depth of earth return method can, in most cases, replace Carson's method without impairing the calculation accuracy, and that the finite element method, though more complicated and computationally more cumbersome, is capable of treating problems resulting from practical geometric allocation of transmission conductors and is a promising method for use in the near future.**英文摘要：**--**中文關鍵字：**Carson's method, complex depth of earth return, finite element method, frequency-dependent impedance**英文關鍵字：**--