The use an inverter is one of the representative ways to utilize regenerative braking energy in railway systems. Due to the nature of urban railways that generate a large amount of regenerative energy, the economic advantages are clear. However, in the case of the existing inverter operation method, a method of operating the inverter using the threshold voltage is used, which has a disadvantage in that power cannot be utilized between the no-load voltage and the threshold voltage. Therefore, in this paper, we propose an optimal location selection method and capacity calculation method for installing a regenerative inverter in an urban rail system, and a control method according to the train brake position to increase the regenerative energy utilization rate. First, the inverter capacity and location were selected by selecting the maximum regenerative energy generation for each substation section through the train performance simulation (TPS) based DC power simulation (DCPS). An inverter control method based on train brake position (BP method) is introduced. Finally, PSCAD/EMTDC, a power analysis program, was used to verify the proposed method. As a result, the use of regenerative energy by an inverter increased by about 62.6%, and more energy was saved at nearby substations through the BP method.

This paper presents a Fuzzy logic-based train control algorithm designed to enhance energy efficiency across a complete railway route. The proposed framework dynamically integrates practical information such as curvature data, gradient profiles, and station schedules to optimize acceleration, coasting, and braking phases. By using Fuzzy logic, the algorithm adaptively balances energy consumption, travel time, and stopping precision. Key features include predictive speed scanning and adaptive PI control, enabling comprehensive energy optimization. Simulation results confirm significant energy savings while maintaining operational reliability and precision. This study highlights the potential of Fuzzy-based control systems in advancing sustainable railway operations.

This paper proposes a design for a one-coil long-stroke permanent magnet actuator (PMA) applied to a load breaker switch with a novel mechanism applicable to railways. As a new load breaker switch applicable to railway overhead lines has a double-insulation structure of the vacuum interrupter (VI) and a disconnect switch (DS) for higher insulation, the actuator to control the switch requires a very long stroke. While the traditional mechanism of the PMA implements a stroke of 10 to 30 mm, the load breaker switch with a double-insulation structure requires a stroke of 120 mm. To do so, we used the finite element method (FEM) and designed a novel one-coil long-stroke PMA. Then, values from FEM analysis were compared with measured holding force data, and a simplified prototype test-jig was used to confirm the actuator’s operating characteristics. In addition, the electromagnetic force, plunger rotation, and part weight ratio, which affect operating performance, were adapted in its design. By doing so, we confirmed the operating performance required for the one-coil long-stroke PMA for a new load breaker switch with a double-insulation structure with a VI average opening speed of 1.4 m/s and an average closing speed of 0.9 m/s at 1/2 of full stroke.

In this paper, power changes caused by no-load voltage control at DC urban railway substations were simulated, and methods of improving energy efficiency were analyzed through field test verification.The existing DC electric railway power supply system has a disadvantage in that it is impossible to adjust the output voltage because it supplies power using a diode rectifier or a DC/DC converter. If the output voltage is adjusted with facilities such as On Load Tap Changer (OLTC), changes in the use of power consumption and regenerative energy can be promoted. Therefore, the power change using the change in catenary voltage was simulated using PSCAD/EMTDC, a power analysis program, and the results were proved using actual measurement data from the substation of Railroad operator A, a domestic urban railroad operator in Korea.

In this paper, we introduce the method of reducing only the morning peak of the ESS and the method of calculating the maximum ESS capacity according to the method of reducing the entire day by using the characteristic that the load of the urban railway substation shows a different load pattern depending on weekdays, weekends, and holidays. Furthermore, an operation method suitable for urban railroad is introduced using the operation algorithm for each of the five points of time of the ESS according to the load pattern. To verify the introduced maximum capacity calculation method and ESS operation algorithm, power analysis program, PSCAD/EMTDC was used.