Analysis of theoretical line loss in metro distribution network

Introduction Novel cable traction power supply can eliminate phase splits and improve regenerative energy utilization in metro systems. However, the cable-based traction network has a relatively complex structure, making internal energy consumption and train-network line loss evaluation insufficiently studied. Methods To quantify train-network line losses, an equivalent solid-circuit model of the traction power supply system is established using an external cascade strategy. Combined with actual train operation load modeling, the traction transformer output power and network losses are computed and compared under both traction and regenerative braking operating conditions. Results The proposed modeling-and-calculation framework enables accurate evaluation of power output and line losses across operating modes, and effectively captures the electrical characteristics of the cable traction energy supply system. Discussion The developed theoretical line-loss calculation approach provides a quantitative basis for energy-consumption assessment and operational analysis of cable traction networks, supporting performance evaluation and planning of metro traction power supply systems.