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Joorak Kim
Korea Railroad Research Institute, Uiwang, Korea

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Journal article
Published: 21 June 2021 in Applied Sciences
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This paper presents a Scott transformer model to be applied in electromagnetic transients (EMT) programs, particularly in the absence of a detailed Scott transformer model for performing real-time simulations (RTS). Regarding a Scott transformer, a common topology for converting a three-phase network into two single-phase networks, the transformer model in EMT programs is essential to simulate large-scale electric railway systems. A code-based model has been developed to simulate the transformer in RTS directly and contain the transformer’s actual impedance characteristics. By establishing a mathematical foundation with the current injection method, we presented a matrix representation in conjunction with a network solution of EMT programs. The proposed model can handle more practical parameters of Scott transformers with a relatively low computational load. Thus, it supports the flexible computation of real-time simulators with a finite number of processor units. The accuracy of the model is verified by simulating it and comparing the simulation results with an industrial transformer’s certified performance. Furthermore, a case study involving a comparison of the results with the field measurement data of an actual Korean railway system demonstrated the efficacy of the model.

ACS Style

Choongman Lee; Gyu-Jung Cho; Joorak Kim. Development of Scott Transformer Model in Electromagnetic Transients Programs for Real-Time Simulations. Applied Sciences 2021, 11, 5752 .

AMA Style

Choongman Lee, Gyu-Jung Cho, Joorak Kim. Development of Scott Transformer Model in Electromagnetic Transients Programs for Real-Time Simulations. Applied Sciences. 2021; 11 (12):5752.

Chicago/Turabian Style

Choongman Lee; Gyu-Jung Cho; Joorak Kim. 2021. "Development of Scott Transformer Model in Electromagnetic Transients Programs for Real-Time Simulations." Applied Sciences 11, no. 12: 5752.

Correction
Published: 15 June 2021 in Journal of Electrical Engineering & Technology
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ACS Style

Kisuk Kim; Jaewon Kim; Changmu Lee; Joorak Kim; Hansang Lee. Correction to: PSO-Based Initial SOC and Capacity Optimization for Stationary Energy Storage Systems in DC Electric Railway System. Journal of Electrical Engineering & Technology 2021, 16, 2291 -2291.

AMA Style

Kisuk Kim, Jaewon Kim, Changmu Lee, Joorak Kim, Hansang Lee. Correction to: PSO-Based Initial SOC and Capacity Optimization for Stationary Energy Storage Systems in DC Electric Railway System. Journal of Electrical Engineering & Technology. 2021; 16 (4):2291-2291.

Chicago/Turabian Style

Kisuk Kim; Jaewon Kim; Changmu Lee; Joorak Kim; Hansang Lee. 2021. "Correction to: PSO-Based Initial SOC and Capacity Optimization for Stationary Energy Storage Systems in DC Electric Railway System." Journal of Electrical Engineering & Technology 16, no. 4: 2291-2291.

Original article
Published: 03 May 2021 in Journal of Electrical Engineering & Technology
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This paper presents an PSO-based optimization methodology for estimating the capacities and initial SOC of an energy storage systems (ESSs) in a DC electric railway system. The proposed method calculates the optimal solution using the missing capacity caused by the limited storage capacity. The missing capacity can be estimated through continuous-powerflow analysis. In many previous studies, capacities was calculated by assuming the each ESS as an independent device. However, since each storage device affects the charging and discharging operation of each other, this assumption might affect the convergence characteristics. In this paper, to solve this problem, the missing capacity of the ESS at both sides is reflected by using the relating coefficient derived based on the electrical distance between storage devices. The case studies show that the most efficient operation without missing capacity is possible under the derived capacities and initial SOC.

ACS Style

Kisuk Kim; Jaewon Kim; Changmu Lee; Joorak Kim; Hansang Lee. PSO-Based Initial SOC and Capacity Optimization for Stationary Energy Storage Systems in DC Electric Railway System. Journal of Electrical Engineering & Technology 2021, 16, 2281 -2289.

AMA Style

Kisuk Kim, Jaewon Kim, Changmu Lee, Joorak Kim, Hansang Lee. PSO-Based Initial SOC and Capacity Optimization for Stationary Energy Storage Systems in DC Electric Railway System. Journal of Electrical Engineering & Technology. 2021; 16 (4):2281-2289.

Chicago/Turabian Style

Kisuk Kim; Jaewon Kim; Changmu Lee; Joorak Kim; Hansang Lee. 2021. "PSO-Based Initial SOC and Capacity Optimization for Stationary Energy Storage Systems in DC Electric Railway System." Journal of Electrical Engineering & Technology 16, no. 4: 2281-2289.

Correction
Published: 24 March 2020 in Journal of Electrical Engineering & Technology
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ACS Style

Hansang Lee; Jaewon Kim; Changmu Lee; Joorak Kim. Correction to: Novel Cooperative Controller Design of Heterogeneous Energy Storages for Economic Applications in Electric Railway Systems. Journal of Electrical Engineering & Technology 2020, 15, 1481 -1481.

AMA Style

Hansang Lee, Jaewon Kim, Changmu Lee, Joorak Kim. Correction to: Novel Cooperative Controller Design of Heterogeneous Energy Storages for Economic Applications in Electric Railway Systems. Journal of Electrical Engineering & Technology. 2020; 15 (3):1481-1481.

Chicago/Turabian Style

Hansang Lee; Jaewon Kim; Changmu Lee; Joorak Kim. 2020. "Correction to: Novel Cooperative Controller Design of Heterogeneous Energy Storages for Economic Applications in Electric Railway Systems." Journal of Electrical Engineering & Technology 15, no. 3: 1481-1481.

Original article
Published: 13 January 2020 in Journal of Electrical Engineering & Technology
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Owing to the consistently increased request about efficiency improvement through utilization of regenerative energy from braking railway vehicle in the DC electric railway systems, there are a lot of researches about energy storage applications. However, the feasibility of ESS technology application is usually limited by economic factors rather than technical factors of it. Therefore, this paper proposes the application of heterogeneous energy storage system based on ramp-rate-considered cooperative controller in order to improve economics. The heterogeneous combination of energy storage devices with different technical advantages can gives a more economical solution to respond to individual specifications required by the system. A ramp-rate-considered cooperative controller for the heterogeneous ESS application is presented numerically, and effectiveness of the proposed method has been verified through electromagnetic transient simulation.

ACS Style

Hansang Lee; Jaewon Kim; Changmu Lee; Joorak Kim. Novel Cooperative Controller Design of Heterogeneous Energy Storages for Economic Applications in Electric Railway Systems. Journal of Electrical Engineering & Technology 2020, 15, 979 -987.

AMA Style

Hansang Lee, Jaewon Kim, Changmu Lee, Joorak Kim. Novel Cooperative Controller Design of Heterogeneous Energy Storages for Economic Applications in Electric Railway Systems. Journal of Electrical Engineering & Technology. 2020; 15 (2):979-987.

Chicago/Turabian Style

Hansang Lee; Jaewon Kim; Changmu Lee; Joorak Kim. 2020. "Novel Cooperative Controller Design of Heterogeneous Energy Storages for Economic Applications in Electric Railway Systems." Journal of Electrical Engineering & Technology 15, no. 2: 979-987.

Journal article
Published: 25 December 2019 in Applied Sciences
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Electric railways use a single-phase system, with the line comprising a trolley wire (TF) that supplies power to the load with a neutral wire and an autotransformer (AF) feeder to absorb the return current of the rail. Testing the performance of the protective relay that detects the fault of the traction power-supply system (TPSS) and operates the circuit breaker is very important. Until now, the performance test of protective relays for the TPSS has been conducted via a simple-steady test or using an expensive real-time simulator. However, under a fast-moving environment in which the load consumes a large amount of power, the protective relay must always detect faults and operate properly. This paper proposes a digital simulator that enables the dynamic testing of protective relays without using any steady test and expensive real-time simulators. This simulator includes both external waveform import and internal waveform generation functions. Users can test the operation of the protective relay by entering the waveform generated externally or internally into the protective relay. Additionally, it has the ability to monitor the operating protection elements and pickup time when the protective relay detects a fault and orders the circuit breaker trip.

ACS Style

Joorak Kim; Gyu-Jung Cho; Jaewon Kim; Kim. Development of Railway Protective Relay Simulator for Real-Time Applications. Applied Sciences 2019, 10, 191 .

AMA Style

Joorak Kim, Gyu-Jung Cho, Jaewon Kim, Kim. Development of Railway Protective Relay Simulator for Real-Time Applications. Applied Sciences. 2019; 10 (1):191.

Chicago/Turabian Style

Joorak Kim; Gyu-Jung Cho; Jaewon Kim; Kim. 2019. "Development of Railway Protective Relay Simulator for Real-Time Applications." Applied Sciences 10, no. 1: 191.

Journal article
Published: 19 April 2018 in Energies
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Although electric railway systems have gone through many technological innovations in their electrical, mechanical and structural engineering since the energy paradigm conversion to electrical energy, the conventional feeding system based on the catenary contact is still being applied. In order to solve the problems of the contact-based feeding system that arise and to build up the energy-sustainable electric railway system simultaneously, this paper considers the wireless railway train (WRT), which is fed by storages mounted on the board without catenary contact during driving and charged at a platform during a stop. In order to maximize the energy improvement of WRTs’ operation, the optimal power and storage capacity estimation method considering the increased weight of the additional storage devices is proposed. Through case studies of the electrical and topographical conditions of the actual operating railway route, compared with the electrical performance of the existing railway trains, it is verified that the application of WRTs leads to facility capacity margin enlargement through the peak power reduction, and cost-effectiveness improvement through the reduction of catenary loss and driving energy.

ACS Style

Jaewon Kim; Joorak Kim; Changmu Lee; Gildong Kim; Hansang Lee; Byongjun Lee. Optimal Capacity Estimation Method of the Energy Storage Mounted on a Wireless Railway Train for Energy-Sustainable Transportation. Energies 2018, 11, 986 .

AMA Style

Jaewon Kim, Joorak Kim, Changmu Lee, Gildong Kim, Hansang Lee, Byongjun Lee. Optimal Capacity Estimation Method of the Energy Storage Mounted on a Wireless Railway Train for Energy-Sustainable Transportation. Energies. 2018; 11 (4):986.

Chicago/Turabian Style

Jaewon Kim; Joorak Kim; Changmu Lee; Gildong Kim; Hansang Lee; Byongjun Lee. 2018. "Optimal Capacity Estimation Method of the Energy Storage Mounted on a Wireless Railway Train for Energy-Sustainable Transportation." Energies 11, no. 4: 986.

Journal article
Published: 19 March 2010 in Electrical Engineering
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This paper proposes a real-time control system for a single-phase unified power flow controller (UPFC) which is constructed as a pilot power-quality compensation equipment of an electrical railway, and shows simulation and experimental results. For simulation, the control system is modeled in the form of block diagrams by using the Simulink, where the main control effort is focused on the power flow control with the UPFC and the hysteresis current controller is adopted to control the single-phase inverters of the UPFC. And for a small-scale rapid prototyping of the UPFC-equipped control system, the simulation blocks are modified and a real-time control platform is developed by using the real-time workshop and multiple digital signal processors. Both simulation and experiment results have proved the effectiveness of the proposed control system.

ACS Style

Moonho Kang; Joorak Kim. A real-time control system for single-phase unified power flow controllers. Electrical Engineering 2010, 91, 439 -450.

AMA Style

Moonho Kang, Joorak Kim. A real-time control system for single-phase unified power flow controllers. Electrical Engineering. 2010; 91 (8):439-450.

Chicago/Turabian Style

Moonho Kang; Joorak Kim. 2010. "A real-time control system for single-phase unified power flow controllers." Electrical Engineering 91, no. 8: 439-450.