A voltage based method for fault identification in a transmission line, wherein said method comprises: measuring the real-time values of the currents and the voltages of the other unbroken healthy phase conductors when a single-phase fault occurs; calculating the inductive voltage (U X) and the capacitive coupling voltage on the faulted phase conductor according to the measured currents and the voltages respectively; characterized in that said method comprises: comparing the capacitive coupling voltage (U M) with the inductive voltage (U X) multiplied by a factor (K 1), in which the multiplication result is used as a self-adjusted threshold based on the real time load condition of the transmission line; and identifying the fault type based on the maximum of the capacitive coupling voltage (U M) and the multiplication result, wherein, if the capacitive coupling voltage (U M) is larger than the multiplication result, said method further comprises the following steps: measuring the terminal voltage (U f) at the terminal of the opened phase conductor, selecting the maximum multiplication result between the inductive voltage (U X) multiplied by a second factor (K 2) and the capacitive coupling voltage (U M) multiplied by a third factor (K 3), comparing the terminal voltage (U f) with the maximum multiplication result; and identifying that the fault is a transient fault if the terminal voltage (U f) is larger than the maximum, otherwise the fault is a permanent fault, and wherein, if the capacitive coupling voltage (U M) is less than the multiplication result, said method further comprises the following steps: measuring the terminal voltage (U f) at the terminal of the opened phase conductor; selecting the maximum multiplication result between the inductive voltage (Ux) multiplied by a fourth factor (K 4) and the capacitive coupling voltage (U M) multiplied by a fifth factor (K 5); comparing the terminal voltage (U f) subtracted half of the inductive voltage (U X /2) with the maximum multiplication result as well as the terminal voltage (U f) added half of the inductive voltage (U X /2) with the maximum multiplication result; and identifying that the fault is a transient fault if the subtraction result and the addition result are larger than the maximum multiplication result; otherwise the fault is a permanent fault. measuring the real-time values of the currents and the voltages of the other unbroken healthy phase conductors when a single-phase fault occurs; calculating the inductive voltage (U X) and the capacitive coupling voltage on the faulted phase conductor according to the measured currents and the voltages respectively; characterized in that said method comprises: comparing the capacitive coupling voltage (U M) with the inductive voltage (U X) multiplied by a factor (K 1), in which the multiplication result is used as a self-adjusted threshold based on the real time load condition of the transmission line; and identifying the fault type based on the maximum of the capacitive coupling voltage (U M) and the multiplication result, comparing the capacitive coupling voltage (U M) with the inductive voltage (U X) multiplied by a factor (K 1), in which the multiplication result is used as a self-adjusted threshold based on the real time load condition of the transmission line; and identifying the fault type based on the maximum of the capacitive coupling voltage (U M) and the multiplication result, measuring the terminal voltage (U f) at the terminal of the opened phase conductor, selecting the maximum multiplication result between the inductive voltage (U X) multiplied by a second factor (K 2) and the capacitive coupling voltage (U M) multiplied by a third factor (K 3), comparing the terminal voltage (U f) with the maximum multiplication result; and identifying that the fault is a transient fault if the terminal voltage (U f) is larger than the maximum, otherwise the fault is a permanent fault, and measuring the terminal voltage (U f) at the terminal of the opened phase conductor; selecting the maximum multiplication result between the inductive voltage (Ux) multiplied by a fourth factor (K 4) and the capacitive coupling voltage (U M) multiplied by a fifth factor (K 5); comparing the terminal voltage (U f) subtracted half of the inductive voltage (U X /2) with the maximum multiplication result as well as the terminal voltage (U f) added half of the inductive voltage (U X /2) with the maximum multiplication result; and identifying that the fault is a transient fault if the subtraction result and the addition result are larger than the maximum multiplication result; otherwise the fault is a permanent fault.