Abstract: The network structure and fault characteristics of high voltage DC (HVDC) transmission systems put forward higher requirements for the accuracy of line fault location schemes. A fault location method based on Tellegen's quasi-power (TQP) Theorem for DC transmission lines is proposed. First, based on the analysis of Bergeron distribution parameter model, the scheme of applying TQP theorem to DC line fault analysis is proposed for the first time, and the quasi-power analytical expressions are given. Secondly, the quasi-power reference value is constructed by using the Bergeron model, and the fault location is realized according to the principle that the reference value at the fault point is equal to the calculated value. Finally, through numerous fault cases, the correctness of the theoretical derivation and the quasi-power which can effectively reflect the fault location are verified; moreover, the scheme is not affected by the transition resistance and fault type. The target of high precision fault location at low sampling frequency can be realized.