The Fault Detection Method for a DC Traction Rectifier Substation in Mass Rapid Transit Railway Systems

Reliability and safety are the critical issues for electric railway systems. The regulated DC voltage of 750 V for the traction substation is generated by a three-phase PWM rectifier with the appropriate controller design. Under the occurrence of faults in the three-phase PWM rectifier the desired performance of the electric railway system cannot be maintained. Therefore, the three-phase PWM rectifier is required to operate properly under fault tolerant conditions. In this paper, the fault detection method for the open-circuited switch fault of the three-phase PWM rectifier is proposed to enhance the fault tolerance requirement. The behavior of the three-phase PWM rectifier in both normal and fault modes is investigated. The proposed fault detection method relies on the measured values used for the controller without additional sensors. The simulation results implemented by the MATLAB SIMULINK software package show the effectiveness of the proposed method to detect a fast and accurate fault occurred in the three-phase PWM rectifier.