According to the attenuation effect of the traction network line boundary on high-frequency transient, a single-ended power direction protection method for the traction network of the through-type auto transformer (AT) in-phase traction power supply system based on fast ensemble empirical mode decomposition (FEEMD) and Teager energy operator (TEO) is proposed. Obtain the instantaneous power of the collected voltage and current signals when the fault occurs, and perform Teager transformation on the transient power to obtain the polarity of the TEO waveform mutation point as the direction criterion to determine whether it is a forward fault or a reverse fault. If it is a forward fault (inside or outside the opposite side), the fault transient current signal is decomposed by FEEMD, the intrinsic mode function 1 (IMF1) component of the fault signal is extracted, and then TEO is performed on the IMF1 component to obtain the instantaneous value of the TEO spectrum of the high-frequency transient current signal. The absolute pair value is obtained and summed, so as to judge whether the fault is inside or outside the opposite. Finally, the through-type AT in-phase traction power supply system model is built through PSCAD/EMTDC simulation software, and a large number of simulation data are extracted under different fault conditions. The simulation results show that this scheme can effectively partition internal and external faults and protect the full length of the traction network line.