The current algorithms of unsynchronized two-terminal fault location may lead to failure to locate the fault because of the false root. To overcome the defect

a new two-terminal fault location algorithm is proposed. Based on a distributed parameter model for the power transmission line

this paper uses the ratio of positive to negative sequence component of voltage or the ratio of voltage positive and fault positive sequence component to eliminate the asynchronous angle and then proposes a new algorithm of two-terminal fault location with asynchronous data based on the monotonicity of the phase. The algorithm without the false roots and the bisection method or secant method can be used to find out the fault position quickly. The EMTP simulation results show that this method is hardly affected by transition resistance

fault type and the asynchronous angle. The computation amount is small and the ranging precision high. This work is supported by Fundamental Research Funds for the Central Universities (No. 2014xs74).