Flexible traction power supply system and fault direction judgment method thereof

Abstract

The invention discloses a flexible traction power supply system and a fault direction judgment method thereof. The system comprises a first flexible traction substation and a second flexible traction substation, the first flexible traction substation comprises a first existing system traction transformer, a first flexible traction transformer, a first bus, circuit breakers QF1-QF2, a circuit breaker QF5, a circuit breaker QF7 and a circuit breaker QF9; the second flexible traction substation comprises a second existing system traction transformer, a second flexible traction transformer, a second bus, circuit breakers QF3-QF4, a circuit breaker QF6, a circuit breaker QF8 and a circuit breaker QF10. According to the flexible traction power supply system and the fault direction judgment method thereof, the fault occurrence direction at the feeder line can be accurately judged, and no fault direction judgment dead zone exists, so that the protection reliability can be improved, the protection configuration is simplified, and the system can solve the electric energy quality problems of reactive power, negative sequence, harmonic waves and the like in the existing traction power supply system.

Description

technical field [0001] The invention belongs to the technical field of relay protection for traction power supply systems, and in particular relates to a flexible traction power supply system and a fault direction judgment method thereof. Background technique [0002] At present, the existing electrified railway traction power supply systems in many countries in the world basically adopt a three-phase-two-phase (out-of-phase) power supply mode. The substation takes power from the three-phase grid through the traction transformer and steps it down, and then outputs it in two power supply arms to supply power for the traction grid. Since the voltage phase, amplitude and frequency of the power supply arms are difficult to be completely consistent, electric phase separation needs to be set between the power supply arms, and the existing traction power supply system has problems of low power quality and poor power supply capacity. [0003] The flexible traction power supply syst...

AI Technical Summary

Problems solved by technology

However, the power directional element widely used at present is due to the measurement voltage U when the metal short circuit at the protective installation m Too small to form a comparative square wave, so that phase comparison with the current cannot be performed, there is a directional dead zone, and the 90° wiring method cannot be used in a single-phase traction network, and the fault component directional element detected based on the fault component is due to flexible traction power supply The system uses a power electronic converter, and the amplitude and phase change range of the system impedance is too large, which will lead to wrong judgment of the fault direction and reduce the reliability of protection

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