This paper describes the design of a (4-kV, 4.16-MVA) three-level neutral-point-clamped-, three-level flying-capacitor-, four-level flying-capacitor-, and nine-level seriesconnected H-bridge voltage-source converter on the basis of state-of-the-art 6.5-, 4.5-, 3.3- and 1.7-kV insulated gate bipolar transistors. The semiconductor loss distribution and the design of semiconductors and passive components are compared for a medium switching frequency assuming a constant converter efficiency of about 99%. To evaluate the converter characteristics in high switching frequency applications, a second comparison is realized for the maximum switching frequencies assuming a constant expense of semiconductors in all converters.

This paper compares the expense of power semiconductors and passive components of a (2.3 kV, 2.4 MVA) two-level, three-level neutral-point-clamped, three-level flying-capacitor, four-level flying-capacitor, and five-level series-connected H-bridge voltage source converter on the basis of the state-of-the-art 6.5-, 3.3-, 2.5-, and 1.7-kV insulated gate bipolar transistors for industrial medium-voltage drives. The power semiconductor losses, the loss distribution, the installed switch power, the design of flying capacitors, and the components of an sine filter for retrofit applications are considered.

Electric railway power systems (ERPS) as one of the most critical and high-power end-user loads of utility grids are characterized by outlandish power quality (PQ) problems all over the world. The extension and evolution of different supply topologies for these systems has resulted in significant and various forms of distortions in network voltage and current in all ERPS, the connected power system, and adjacent consumers. During the last years, numerous studies have been offered to investigate various aspects of PQs in a specific supplying topology. Variation in the supply structure of the ERPS and different types of locomotives has propelled the observation of different PQ phenomena. This versatility and development have led to confront considerable types of two-way interactive interfaces as well as reliability and PQ problems in ERPS. In addition, the lack of standards explicitly dedicated to ERPS has added to the ambiguity and complexity of this issue. In this paper, an extensive review of PQ distortions and phenomena in different configurations of ERPS is proposed and a systematic classification is presented. More than 140 scientific papers and publications are studied and categorized which can provide a fast review and a perfect perspective on the status of PQ indexes for researchers and experts.

This study presents a forward/backward sweep (FBS) load flow method for AC autotransformer (AT)-fed electrical railway networks considering dynamic movement of trains. Field measurements of Tehran–Golshahr suburban railway are compared with simulation results. Moreover, effects of the time headway reduction on this suburban railway and its transmission power supply system are investigated. Then, to minimise power losses, two methods of the reactive power compensation are studied; the pulse-width-modulated (PWM) trains and a static var compensator (SVC). For the aforementioned cases, fluctuations of the displacement factors (DISF), defined in p–q–r theory are simulated at the point of common coupling (PCC). MATLAB software is used for programming and simulations.

AC traction networks have inherently adverse impacts on the power supply grids which mainly consist of large negative sequence current, undesirable harmonics and low power factor. To compensate all of these power quality problems, a power quality conditioner called railway power conditioner (RPC) is proposed and discussed. However, the RPC power rating is considerably dependent on the traction load conditions, and it has also some influential effects on the initial costs. In this study, the RPC power rating is thoroughly analysed, and a reducing method is proposed based on thyristor switched capacitor in order to keep the power rating under the optimal value in different traction load conditions. Finally, a precise simulation study is done using MATLAB/SIMULINK program to verify the effectiveness of the proposed strategy.

This paper presents a stochastic bi‐objective model to reduce the operation cost and the carbon emission of a smart railway station along with dependent commercial buildings, according to a multi‐energy hub system's structure. The proposed energy hub system (EHS) includes a power, heating, and cooling subenergy hub. The recovered energy obtained from the regenerative braking (RB) during train deceleration is utilized to supply the load of EHS. To calculate the recovered energy, the motion of trains is simulated in MATLAB software. Furthermore, a demand response program (DRP) is integrated into the model to improve the flexibility of the EHS. Also, the uncertainty related to the photovoltaic generation and the power obtained from RB is considered. GAMS software is used to solve the bi‐objective model with the ɛ‐constraint approach. Then, to select the best possible solution, a fuzzy technique is engaged. Seven case studies are considered investigating the effect of exerting the DRP, utilizing the recovered energy, and employing the energy storage on operation cost and carbon emission. The simulation results demonstrate a significant improvement in operating cost and the carbon emission for the proposed EHS.