Research on Infeeder Line Protection Scheme for Traction Substation Under Bilateral Power Supply Mode

The infeeder line of the traction substation(TS) serves as a critical transmission link connecting the power system and the electrified railway, and an effective protection scheme is of immense importance for the stable operation of both systems. The fault mechanisms and characteristics of the infeeder line under the bilateral power supply mode(BPSM) differ significantly from those under the conventional unilateral power supply mode(UPSM). However, existing research lacks a thorough discussion of infeeder protection under BPSM. This article establishes protection criteria based on local voltage and current, and proposes an exhaustive scheme capable of comprehensively revealing the characteristics of all fault types across various operational scenarios. The proposed scheme is simple to implement, operates independently of synchronous communication and avoids issues such as insufficient sensitivity and relay settings coordination conflicts caused by weak short circuit current feed effects. Additionally, it exhibits strong robustness and can reliably distinguishes potential transformer(PT) failure, regenerative braking energy feedback, and the TS on the healthy side. Finally, simulation results based on actual parameters verify the effectiveness and feasibility of the proposed protection scheme.