Power quality in high-speed railway systems

Abstract

The proliferation of the new high-speed train has resulted in significant distortions in network voltage and current in both traction power supply system (TPSS) and the connected power system. The nonlinear and dynamic natures of the modern trains make the calculation and evaluation of such power quality (PQ) problems quite a difficult work. The typical PQ problems in highspeed railway (HSR) are the unbalance, reactive power, harmonic and harmonic resonance, low-frequency voltage fluctuation, etc. This article presents an overview on these power quality issues based on reported documents and field experiments, and further describes the modelling of the TPSS in China HSR systems, which is used to study the PQ issues. In order to improve the PQ performance, a number of mitigation approaches have been investigated and utilized through railway electrification history. Moreover, with the development of new power-electronics technologies, some novel solutions have been developed and implemented to achieve better PQ performance. Additionally, the article compares and summarizes different PQ improvements with respect to various power quality indices.

Measurement-Based Compartmental Modeling of Harmonic Sources in Traction Power-Supply System

“…ARMONIC pollution remains a major power quality concern for TPSS both in theory and practice [1]. As a special distribution network, TPSS acts as a major and important harmonic source for power system.…”

Power quality phenomena in electrified railways: Conventional and new trends in power quality improvement toward public power systems

“…The typical PQ problems in high-speed electrified railways are the system currents imbalance, harmonic content, low power factor, low-frequency voltage fluctuations and the voltage arcing [1]. The next subsections present a described overview of the PQ problems in electrified railways.…”

“…The PPS is considered balanced when the three-phase voltages and currents are sinusoidal and have the same amplitude with a phase angle difference of 120˚. However, in AC railway electrification, the NSCs of voltages are normally negligible since the TPS is connected to an infinite bus-bar of the PPS through several power transformers [1]. It is expected that the infinite bus-bar has always constant RMS voltage values.…”

“…It is expected that the infinite bus-bar has always constant RMS voltage values. Therefore, system imbalance in AC railway electrification usually refers to the NSCs of currents injected in the PPS [1]. Considering the other possibility, which could happen when the TPS is not connected to an infinite bus-bar, then, voltage drops in the three-phase system will be noticeable.…”

“…Railway electrification has been set out in the early of 20 th century. It was undertaken in many countries because of its advantages such as the lower air pollution, the higher efficiency, and the reduced Carbon Dioxide emissions [1]. From the early use of railway electrification, the power quality (PQ) improvement was a significant concern for the railway operators and the scholars.…”