Capacity optimization design of reactive compensation device in urban rail traction power supply system

IEEE Trans. Veh. Technol.

Tricoli

et al. 2019

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Section: Introductionmentioning

confidence: 99%

Inverter Operating Characteristics Optimization for DC Traction Power Supply Systems

IEEE Trans. Veh. Technol.

Tricoli

et al. 2019

“… low power factor problem at AC grid interface. Studies indicate that it is usually caused by the equivalent capacitance of large amount of grid cables [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…However, compared with inverters, storage devices require more installation space, higher cost, and more safety constraints [17]. To improve power factor under light load condition, the traditional schemes based on Static Var Compensator (SVC) and Static Var Generator (SVG) are usually adopted in the TPSS [1,2,[26][27][28]. The total capacity of SVGs in a typical line is normally several MVars.…”

Section: Introductionmentioning

confidence: 99%

A new hybrid simulation integrating transient-state and steady-state models for the analysis of reversible DC traction power systems

International Journal of Electrical Power & Energy Systems

Tricoli

et al. 2019

This paper presents a new hybrid simulation method for reversible traction power supply systems (RTPSSs) supplied by four-quadrant converters (4QC). RTPSSs overcome several drawbacks of conventional DC electrification systems, such as wasting of braking energy, output voltage fluctuation, and low power factor at light load conditions. The paper introduces the system topology of a RTPSS and illustrates its advantages over standard DC systems. A hybrid simulation method is proposed to study the performance of the RTPSS taking into account the dynamics of multiple trains. This hybrid simulation integrates train motion, steady-state and transient-state models, and is able to evaluate both the system-level steady-state performance (voltage, current, power and energy) and the equipment-level transient-state performance (harmonics, ripple, power factor and stability). Structure and signals flow of this hybrid simulation system have been introduced, and the methodology of modeling has been presented. The validity and applicability of the proposed hybrid simulation method have been proved by a case study of a 10 km railway line with 6 substations. To date, no other work has accomplished the steadystate and transient-state study using a single integrated simulation.

“…Some of the regenerative braking energy has to be dissipated in the on-board braking resistors, causing huge energy waste and noticeable tunnel temperature rise [2]. In addition, capacitance distributed in a large amount of medium voltage cables leads to very low power factor during light-load period, which has to be solved by special reactive power compensating equipment such as SVG [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

A Novel Hybrid DC Traction Power Supply System Integrating PV and Reversible Converters

et al. 2018

Energies

A novel hybrid traction power supply system (HTPSS) integrating PV and reversible converter (RC) is proposed. PV is introduced to reduce the energy cost and increase the reliability of power systems. A reversible converter can achieve multiple objectives including regenerative braking energy recovery, PV energy inverting, DC voltage regulation and power factor improvement. In this paper, the topology and operating modes of the HTPSS are first introduced. Three-level boost converter (TLBC) is employed in the PV system. A double closed-loop control scheme considering both maximum power point tracking (MPPT) and midpoint potential balancing (MPB) is recommended. The reversible converter adopts a multi-modular topology and the independent control for active power and reactive power has been achieved by a current decoupling control. According to the working characteristic of each device, a coordinated control strategy is designed, and four basic principles are given. A system simulation model containing a hybrid traction substation and a train was built, and comprehensive simulations under multi-scenario were carried out. The results show that the reversible converter can accomplish PV energy inversion, DC voltage regulation, regenerative braking energy recovery and power factor improvement, by which a high utilization rate and energy-saving effect can be obtained.Energies 2018, 11, 1661 2 of 24 train runs between two substations, the braking time is only 10-15 s under normal circumstances. The relatively low utilization rate, in addition to the single function (just inverting), result in a long investment payback period. It is becoming the main obstacle for the massive application of inverters.Urban rail transit is becoming a big energy consumer and has significant impacts on energy consumption at a regional scale [15]. It turns out to be more and more urgent to reduce system energy consumption through all possible means. As a clean energy, photovoltaic has had rapid development all over the world recently, and the installed capacity has been increasing year by year [16,17]. Large-scale PV plants are mainly located in the desert regions due to the high solar irradiance and vast area, but the output power is usually constrained by the transmission capacity of the grid [18]. Future development will focus on the distributed PV system, which is located as close to the user as possible [19]. Railway companies have much potential to introduce PV system around railway premises, such as the roof of platforms, substations, vehicle depots, sound walls and other buildings or openings along the line [20]. It is reported that the PV system installed on platform roof of Tokyo station generates 340 MWh electric energy annually [20]. The possibility of introducing PV technologies into traction power supply system is discussed in [21], but solar energy is just used for air conditioning and lighting. In [22], a grid-connected PV system is introduced in TPSS. However, it is not an optimal scheme for the transmission and distribution of...