The traditional method for fault location of T-type lines is not able to identify the fault section correctly when the fault occurs near the T-type node

thus failing to locate the fault. To solve this problem

a novel branch identification criterion algorithm is proposed based on the principle of equal positive sequence voltage detected at both ends. It is concluded that the fault location function is monotonical and at the head and end the two values differ by approximately 180° at the fault branch

but the fault location function is also monotonical and at the head and end the two values are approximately equal at the healthy branch. With the phase difference in magnitude between the fault location function at the head and that at the end as the criterion for fault branch

the fault distance is solved using the analytical expression for fault distance. This branch identification criterion algorithm has remedied the drawback of traditional fault location methods. Despite the dead zone of fault location

no type identification is required

while the fault distance is obtained simply by calculating a few points with the corresponding formula. With its simple procedure and fast implementation

the proposed algorithm accuracy is in theory independent of fault type

fault resistance at fault point and operation mode

etc. The EMTP simulation results verify the validity and high precision of the algorithm.