• Journal of Power Electronics
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• v.17 no.2
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• pp.561-569
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• 2017

Power converter design requires simulation accuracy. In addition to the requirement of accurate models of power semiconductor devices, this paper highlights the role of considering a very good description of the converter circuit layout for an accurate simulation of its electrical behavior. This paper considers a simple experimental circuit including one switching cell where a MOSFET transistor controls the diode under test. The turn-off transients of the diode are captured, over which the circuit wiring has a major influence. This paper investigates the necessity for accurate modeling of the experimental test circuit wiring and the MOSFET transistor. It shows that a simple wiring inductance as the circuit wiring representation is insufficient. An adequate model and identification of the model parameters are then discussed. Results are validated through experimental and simulation results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.1
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• pp.37-46
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• 2015

In order to charge EVs, they have to be connected to distribution system. Therefore, if unprecedented numbers of EVs are connected to power systems, it could result in deterioration of power quality, overload, and other system problems. In this paper, the effects of voltage sag on the distribution system due to the connection of EVs is evaluated by considering related field data of Republic of Korea such as the number of gasoline-fueled vehicles, seasonal load of power system and the monthly and daily real-time traffic volume. The distribution system and EVs are modeled using the Electro Magnetic Transients Program (EMTP).

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.1
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• pp.47-53
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• 2006

A Voltage Bus Conditioner (VBC) is used to mitigate the voltage transients on a common power distribution bus. The VBC described here utilises inductive storage and unlike its counter part with capacitive storage, it can employ the entire stored energy towards transients' mitigation. The performances of adaptive duty ratio control and sliding mode control have been compared. The simulation results (with the package SABER) indicate that the sliding mode control results in the shortest and the smallest bus voltage excursions.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.2
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• pp.116-121
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• 2009

Distributed power systems (DPSs) has been widely used various industrial/military applications due to their various advantages. Furthermore, the "All electric" concept, in conjunction with DC DPS, appears to be more advanced and mature in the AEV(All-Electric Vehicular) industry. Generally, AEV carry many loads with varied functions. However, there may be large pulsed loads with short duty ratios which can affect the normal operation of other loads. In this paper, a converter with spilt capacitors and a simple adaptive controller is proposed as a active damping device to mitigate the voltage transients on the bus. The proposed converter allows the smaller capacitive storage. In addition, the proposed control approach has the advantage of requiring only one sensor and performing both the functions of mitigating the voltage bus transients and maintaining the level of energy stored. The control algorithm has been implemented on a TMS320F2812 Digital Signal Processor (DSP). Simulation and experimental results are presented which verify the proposed control principle and demonstrate the practicality of the circuit topology.

• Journal of computational fluids engineering
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• v.6 no.1
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• pp.56-62
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• 2001

A high speed train passing through a station may have undesired effects to passengers on platform due to abrupt pressure transients. Therefore it is very important to reduce the possible degree of danger by installing partition walls in passing lanes in designing the stations having passing train. In the present study, a pressure load to a passenger on platform is studied for the cases of various heights of the partition wall to assess the effectiveness of the wall on the passenger safety. From the results, it is seen that the pressure load on a passenger may be largely reduced by the partition wall. The heights of the partition wall for various passing speed are also studied based on the safety regulation.

• Journal of computational fluids engineering
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• v.12 no.3
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• pp.1-7
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• 2007

In the present study, the wind pressure transients on platform screen door in island platform caused by a passing train are investigated numerically. The transient compressible 3-D full Navier-Stokes solution is obtained with actual operational condition of subway train and the moving mesh technique adopted for the train movement. To achieve more accurate results, detailed shape of train is included in a computational domain and the entrance and exit tunnel of platform are also modeled. Numerical analyses are conducted on three operational conditions of different velocity variation.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.221_222
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• 2009

최근 전력 컨버터 사용의 증가로 배전계통에서의 고조파 왜곡이 날로 심각해지고, 따라서 고조파에 민감한 전력계통 기기와 고객 부하를 보호하기 위한 고조파 저감대책이 필요하다. 본 논문에서는 능동 필터와 Low-Pass Filter(LPF)를 전력계통 과도해석 프로그램인 Electro-Magnetic Transients Program(EMTP) 내의 Transients Analysis of Control Systems(TACS) 소자를 사용하여 모델링하고 고조파 발생시 능동필터에 LPF의 설치 유/무에 따른 배전계통에서의 상전류와 중성선 전류의 변화를 분석하였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.225_226
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• 2009

최근 전력산업의 화두가 되고 있는 지능형 전력망과 그린 에너지 사용의 확대로 인하여 배전계통은 더욱 복잡한 망구조를 띄고 있으며, 이에 따라 계통에서 발생하는 고장전류 증가 및 과도현상들도 매우 다양하게 나타나고 있다. 이와 같은 과도현상으로부터 배전계통을 보호하기 위해 전력용 퓨즈, Recloser, 과전류 계전기, 과전압 계전기 등이 사용된다. 이러한 보호 기기들이 정상 동작하기 위해서는 사전 모의를 통해 상시 부하 전류와 고장 전류 및 계통 이상 상태를 파악하고, 다른 보호기기와의 보호 협조를 고려해야 한다. 이러한 보호 장비들을 구현하고, 동작을 검증함에 있어 기존에는 EMTP(ElectroMagnetic Transients Program)와 같은 과도현상 해석 프로그램이 사용되어 왔다. 최근 상용 버전으로 개발된 EMTP-RV(ElectroMagnetic Transients Program-Restructured Version)는 기존의 컨트롤 소자들로만 구현해야 했던 한계점을 극복하기 위해 사용자 정의가 가능한 DLL(Dynamic Link Library) 기능을 제공함으로써 사용자가 EMTP-RV 개발자와 동일한 환경 하에서 계통 소자를 구현할 수 있도록 하였다. 본 논문에서는 새로운 모델링 기법인 DLL 기능을 이용하여 과전압계전기를 구현하고 결과를 검증하여 모델링 방법의 적합함을 보였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1720-1725
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• 2008

Because of the continuous increasing of energy consumption, metallic pipelines are widely used to supply services to customers such as gas, oil, water, etc. Most common metallic pipelines are underground and are now frequently being installed in nearby electric power lines. In recent years, buried gas pipeline close to power lines can be subjected to hazardous induction effects, especially during single line to ground faults. because it can cause corrosion and it poses a threat to the safety of workers responsible for maintenance. Accordingly, it is necessary to take into consideration for analysis of induced voltage on gas pipelines in transmission lines. This paper analyzed the induced voltage on the gas pipelines due to the 154kV transmission lines in normal case and in different faulty case conditions using EMTP (Electro-Magnetic Transients Program).

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.404-409
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• 2009

A DC power system has many loads with various functions. In particular, these sizable loads take the form of power electronic converters. When they are tightly regulated, the loads appear as constant power loads and result in negative incremental input impedance. Under certain conditions the effect of such loads on the power system is causes instability. In this paper, converter with a large storage capacitor and a lag compensator is proposed as a DC bus conditioner to mitigate the voltage transients on the bus. In addition, the proposed control approach has the advantage of performing both the functions of mitigating the voltage bus transients and maintaining the level of energy stored. Simulation and experimental results showed that the proposed control method was operated well in a small-scale DC power system that contained subsystems with constant power characteristics, such as DC/DC converters and electrical drives.