Research on High Harmonic Resonance and Suppression of All Parallel AT Power Supply System

When the frequency of harmonic current caused by the locomotive is equal or close to the resonance frequency of traction network, harmonic resonance will occur in the system and overvoltage and overcurrent will be produced in traction network. The NORTON equivalent model of locomotive was set up and the mechanism of parallel resonant and series resonance and its features were analyzed. Simulation results show that once the resonance occurs, the unit of the harmonic current injection produces a few kV harmonic voltage in traction substation, and the harmonic current amplification is nearly 10 times. The traction network voltage and feeder current rise are mainly related to parallel resonant points, and the rise of network voltage and feeder current have little to do with series resonant points. The effectiveness of harmonic suppression scheme based on second-order damping filter was verified. The installation position of the filter were discussed in this paper, which can provide guidance for the high harmonic resonance research and the engineering application of harmonic suppression scheme.