electrified railway systems; static synchronous compensator; static VAR compensator; power factor improvement; voltage regulation.

An electric arc furnace is a nonlinear, time varying load with stochastic behavior, which gives rise to harmonics, interharminics and voltage flicker. Since a power system has finite impedance, the current distortion caused by a DC electric arc furnace load creates a corresponding voltage distortion in the supply lines. The current and voltage harmonic distortion causes several problems in electrical power system, such as electrical, electronic, and computer equipment damage, control system errors due to electrical noise caused by harmonics, additional losses in transmission and distribution networks and etc. This paper makes an effort to display the differences between two types of DC electric arc furnace feeding system from the viewpoint of total harmonic distortion at AC side. These Types of feeding system include controlled rectifier power supply and uncontrolled rectifier chopper power supply. Simulation results show that the uncontrolled rectifier chopper power supply is more efficient than the other one.