Abstract: When the inverter station has only one outgoing line, if the fault of the AC line near the inverter station occurs, the complex characteristics of the inverter station make it difficult for the traditional directional element to identify the fault direction. In this paper, the fault characteristics of AC transmission lines near inverter stations are analyzed. Then, the similarity between AC line current and current variation of the AC boundary element in time domain is proposed. And an electromagnetic transient calculation method is also proposed to calculate current of AC boundary elements by measuring voltage and current. Finally, based on the difference of the waveform distance coefficients between AC line current and AC boundary element current in time domain under forward fault and reverse fault conditions, a new fault direction discrimination principle is proposed. And its performance is verified by extensive simulations. The simulation results show that the proposed directional element can accurately identify the fault direction and has high reliability and sensitivity.