An intelligent strategy for regenerative braking energy harvesting in AC electrical railway substation

et al. 2019

This paper presents a modified power supply system based on the current alternating current (AC)-fed railways with neutral zones that can further improve the eco-friendliness and smart level of railways. The modified system complements the existing infrastructure with additional energy-storage-based smart electrical infrastructure. This infrastructure comprises power electronic devices with energy storage system connected in parallel to both sides of each neutral zone in the traction substations, power electronic devices connected in parallel to both sides of each neutral zone in section posts, and an energy management system. The description and functions of such a modified system are outlined in this paper. The system allows for the centralized-and distributed-control of different functions via an energy management system. In addition, a control algorithm is proposed, based on the modified system for regenerative braking energy utilization. This would ensure that all the regenerative braking energy in the whole railway electrical system is used more efficiently. Finally, a modified power supply system with eight power supply sections is considered to be a case study; furthermore, the advantages of the proposed system and the effectiveness of the proposed control algorithm are verified.The installation of equipment that provide clean energy from renewable sources (e.g., solar panels and wind generators) to feed the traction loads in rail may have a significant impact in the energy costs and CO 2 emissions of a railway system, increasing the environment friendliness of the railway [4][5][6]. The introduction of renewable energy is to partially reduce the depletion of non-renewable energy resources and thus reduce CO 2 emissions. These outcomes have been favored by scholars and many countries, such as North American, European, China, and Japan [6,7]. But in practice, the traction energy consumption of railways has not been reduced.By contrast, the efficient driving and regenerative braking schemes differ the renewable energy scheme. They can essentially reduce the traction energy consumption of railways.Efficient driving is an effective way to reduce the traction energy consumption of rolling stock. Typically, the running state of vehicles comprises three phases: braking, speed-holding (cruising) and acceleration. At present, many literatures have studied the efficient driving and realize the traction energy savings through the optimum combination of these phases [8][9][10][11][12][13]. To implement such trajectories and maximize savings, some auxiliary systems, such as driver advisory systems (DAS) [10,11] and automatic train operation (ATO) [12,13], must be provided to drivers. The trials of such systems have shown savings of 5-18%. However, with efficient driving, the savings of energy consumption may sacrifice service quality, such as the train speed, stopping time, etc. [1].Regenerative braking energy (RBE) recovery is a simple and efficient way to reduce energy consumption, which cannot influence the operati...

Section: Figure 20mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Energy-Storage-Based Smart Electrical Infrastructure and Regenerative Braking Energy Management in AC-Fed Railways with Neutral Zones

et al. 2019

“…Currently, many proposals have been put forward via PTDs to utilize RBE. A PTD can be connected in parallel to both sides of each neutral zone (NZ) in traction substations (TS) (such as railway power quality compensator (RPQC) [29] or railway power conditioner (RPC) [30]), or connected in parallel to both sides of each NZ in section posts (SP) (such as energy optimisation controller (EOC) [31] or RPC [2,23]). In this manner, RBE can be delivered to the adjacent power supply sections, thus realizing the simultaneous utilization of RBE.…”

Section: Introductionmentioning

confidence: 99%

Centralized-Decentralized Control for Regenerative Braking Energy Utilization and Power Quality Improvement in Modified AC-Fed Railways

et al. 2020

This paper proposes a centralized-decentralized control strategy for regenerative braking energy utilization and power quality improvement in the modified AC-fed railway system with energy-storage-based smart electrical infrastructure. The proposal of a centralized-decentralized control strategy can enhance the ability to withstand and rapidly recover from disruptions, thus providing further guarantees for safe and reliable operation and energy conservation for railway systems. First of all, the description and control strategy of the modified railway system are outlined, and then the control principles and implementation process of the centralized control and decentralized control strategies are given. Moreover, a method of load power detection and regulated power reference calculation is proposed. Finally, the effectiveness of the proposed strategy is verified in a case of a modified railway system consisting of four traction substations and eight power supply sections. The results demonstrate that regenerative braking energy can be efficiently utilized in railways and that power quality can be improved using the proposed centralized-decentralized control strategy.

“…To date, several solutions have been proposed by many scholars to adequately utilize the RBE of traction power supply systems. These are mainly categorized into three groups: energy storage, optimizing the train schedule and adding the power regulation devices [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…Since RPC is connected with the power supply arm through a step-down transformer, it can transmit bidirectional power and eliminate negative sequence current, compensate reactive power and suppress harmonics [14]. What is more, this back-to-back connection mode can realize the transfer and utilization of the RBE between two power supply arms in the same TS, which creates an opportunity to improve the utilization rate of the RBE [9,15]. In 2014, the East Japan Railway Company installed an RPC at the Ushiku sectoring post (between two TSs), about 2500 MW•h power per year was saved by transferring the remaining RBE of one power supply arm to another [1].…”

Section: Introductionmentioning

confidence: 99%

An Optimized Regulation Scheme of Improving the Effective Utilization of the Regenerative Braking Energy of the Whole Railway Line

et al. 2019

With respect to the problems of great impact on the utility grid, the increasing catenary voltage, the limited utilization rate of the regenerative braking energy (RBE) and the irreducible cost of electricity for locomotives caused by the RBE generated by electric locomotives of the whole railway line cannot be fully utilized in traction power supply systems. An energy management system (EMS) integrating electrical energy and information is proposed in this paper. A corresponding optimization algorithm is also proposed to calculate the distribution of the regenerative braking power in the whole railway line. The structure and working principle of the EMS are introduced. The basic principle and detailed steps of the proposed algorithm are given. Finally, the optimization calculation and simulation are carried out, the effectiveness and feasibility of the proposed EMS and the optimization algorithm are verified.