Electrified railways are powered by dedicated traction power substations (TPSSs) that represent nonlinear loads for the utility supply network. Power Quality (PQ) problems affect both the three-phase network that feeds the TPSS and the contact line, which completes the traction system. The goal of this study was to evaluate the harmonics generated by an 18 pulse AC/DC rectifier for railway traction, and to compare the Total Harmonic Distortion (THD) between 6-pulse, 12-pulse, and 18-pulse conversion stations. Moreover, a new configuration of the 18-pulse conversion system is proposed, and the effects of low-voltage (LV) active filtering are reported. Starting from a MATLAB-Simulink model of the TPSS of 6 and 12 pulses, a software simulation of the 18-pulse rectifier was performed. Then, by using the software tool FFT Analyzer, a charter was generated showing the values of the harmonics at specific frequencies and the evaluation of the THD. The current and voltage harmonics introduced by rectifiers in the threephase power line providing power supply to the TPSS were evaluated. The 18-pulse configuration improved the THD on the currents by approximately 20% with respect to the 12-pulse configuration. The last part of the paper focuses on the new architecture proposed in this paper by connecting active filters in parallel to each converter to further improve PQ by 40%, allowing the revamping of existing substations.
Power quality analysis of railway traction power substation using eighteen-pulse rectifier phase-shifting transformer system
Michele De Santis;Luigi Rubino;
2024
Abstract
Electrified railways are powered by dedicated traction power substations (TPSSs) that represent nonlinear loads for the utility supply network. Power Quality (PQ) problems affect both the three-phase network that feeds the TPSS and the contact line, which completes the traction system. The goal of this study was to evaluate the harmonics generated by an 18 pulse AC/DC rectifier for railway traction, and to compare the Total Harmonic Distortion (THD) between 6-pulse, 12-pulse, and 18-pulse conversion stations. Moreover, a new configuration of the 18-pulse conversion system is proposed, and the effects of low-voltage (LV) active filtering are reported. Starting from a MATLAB-Simulink model of the TPSS of 6 and 12 pulses, a software simulation of the 18-pulse rectifier was performed. Then, by using the software tool FFT Analyzer, a charter was generated showing the values of the harmonics at specific frequencies and the evaluation of the THD. The current and voltage harmonics introduced by rectifiers in the threephase power line providing power supply to the TPSS were evaluated. The 18-pulse configuration improved the THD on the currents by approximately 20% with respect to the 12-pulse configuration. The last part of the paper focuses on the new architecture proposed in this paper by connecting active filters in parallel to each converter to further improve PQ by 40%, allowing the revamping of existing substations.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
