Pantograph-catenary arc is a common fault that can significantly disrupt the stable operation of traction drive system. In high-altitude environments with low air pressure

the electrical characteristics of pantograph-catenary arc differ from those in plains

potentially affecting the system in a different manner. This paper models the pantograph-catenary arc-traction drive system and examines the influence of arc on voltage and harmonic characteristics under different pressures. The results show that lower air pressure increases the impact; short offline periods lead to more severe voltage drops and waveform distortions

while longer offline periods result in larger overvoltages. DC-side voltage drops more slowly after arc quenching

with increased harmonic distortion as pressure decreases. This study provides a valuable reference for the design of electrified trains operating on high-altitude routes.