Protection method and device for direct-current suspension power supply system

Abstract

The invention provides a protection method and device for a direct-current suspension power supply system. The method comprises the steps that the difference values of positive electrode currents andnegative electrode currents of all feed line loops of four feed lines of a traction substation are compared; if the difference value of the positive electrode current and the negative electrode current of one feed line loop of the traction substation is larger than those of the positive electrode currents and the negative electrode currents of the other free feed loops, a tripping signal is sent to the feed line loop with the largest difference value of the positive electrode current and the negative electrode current in the traction substation. According to the protection method for the direct-current suspension power supply system, when the direct-current suspension power supply system has an earthing short circuit failure, the feed line loop, supplying power to a failure point, in the traction substation is accurately judged, the tripping signal is sent to the feed line loop, and the power supply reliability of the direct-current suspension power supply system under a power supply mode is improved.

Description

technical field [0001] The invention relates to the technical field of rail transit, and more specifically, to a protection method and a protection device for a DC suspension power supply system. Background technique [0002] Medium and low-speed magnetic levitation, straddle monorail, subway, light rail and other rail transit systems using the fourth rail return flow adopt a suspension power supply system with both positive and negative poles insulated. After the positive and negative poles are insulated and installed, the ground leakage resistance can reach More than 100 megohms / km. [0003] When the positive pole or the negative pole is short-circuited to the ground, the existing protection scheme is: a grounding resistor is connected in series between the negative busbar of the traction traction substation and the ground. Under normal operating conditions, the leakage current generated on the grounding resistor (R) The voltage drop is less than the setting value of the ...

AI Technical Summary

Problems solved by technology

The fault current and voltage of the traction substation near the fault point can be monitored, but it is impossible to distinguish which feeder line directly provides the fault current to the fault point among the 4 feeder lines of the same traction substation, let alone Selectively pre-alarm or trip the circuit

This will cause all four DC feeder switches in the traction substation adjacent to the fault section to trip, and even cause all DC feeder switches in multiple adjacent traction substations to trip, resulting in a large-scale power outage on the line and seriously affecting normal operation.

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