Analysis of the sheath voltage in High-speed railway feeder cable grounding in single-ended mode

摘要

With the scale construction of passenger dedicated line, in order to improve the reliability of traction power supply, 27.5 kV single core line cable is widely used in the power contact line of outlet and catenary power supply line. The high reliability of traction power supply system directly affects the overall reliability. When AC current flows through the conductor in cable, the shielding layer will generate a corresponding induced electromotive force of which the magnitude is mainly proportional to length of the cable and value of the current in the conductor. When value of induced electromotive force on the sheath is too large, it may cause the grounding fault of the cable and endanger the safety of the people and the equipment. In this paper, the simulation software PSCAD/EMTDC is used to build the model of the High-speed Railway All-parallel AT Traction Power Supply System. The feeder cable sheath one end direct grounding, the other end through the Cable sheath protector grounding, which is called Cable sheath single-grounded way; The feeder cable sheath middle direct grounding-two ends protector grounding, which is called Cable sheath midpoint-grounded way. Using PSCAD/EMTDC simulation software to measure the voltage of cable sheath under different length of cable, graph of voltage in cable sheath is obtained. Analyzing the voltage of cable sheath and graphic, applicable distance of the cable sheath single-grounded way and Cable sheath midpoint-grounded way are obtained. The result provides reference for the engineering.