• 한국안전학회지
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• 제36권3호
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• pp.74-80
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• 2021

Korea Atomic Energy Research Institute (KAERI) has been operating an integral effects test facility, the Advanced Thermal-Hydraulic Test Loop for Accident Simulation (ATLAS), according to APR1400 for transient experimental and design basis accident simulation. Moreover, based on the experimental data, the domestic standard problem (DSP) program has been conducted in Korea to validate system codes. Recently, through DSP-05, the performance of the passive auxiliary feedwater system (PAFS) in the event of multiple steam generator tube rupture (MSGTR) has been analyzed. However, some errors exist in the reference input model distributed for DSP-05. Furthermore, the calculation results of the heat loss correlation for the secondary system presented in the technical report of the reference indicate that a large difference is present in heat loss from the target value. Thus, in this study, the reference model is corrected using the geometric information from the design report and drawings of ATLAS. Additionally, a new heat loss correlation is suggested by fitting the results of the heat loss tests. Herein, MSGTR-PAFS accident analysis is performed using MARS-KS 1.5 with the improved model. The steady-state calculation results do not significantly differ from the experimental values, and the overall physical behavior of the transient state is properly predicted. Particularly, the predicted operating time of PAFS is similar to the experimental results obtained by the modified model. Furthermore, the operating time of PAFS varies according to the heat loss of the secondary system, and the sensitivity analysis results for the heat loss of the secondary system are presented.

• 한국초전도ㆍ저온공학회논문지
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• 제7권4호
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• pp.10-13
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• 2005

Transport current and magnetic field which is generated by transport current make AC current - AC mag-netic field condition(AC-AC condition) in AC power application system using HTS tape. Therefore, characteristics of AC loss under the AC-AC condition are necessary to estimate AC loss of power device with accuracy such as HTS transformer. In this paper, we researched transport current loss, magnetization loss by perpendicular magnetic field and total loss which is represented as summation of both losses under the AC-AC condition in single HTS tape. As a result, magnetization loss showed increasing behavior under 65mT and decreasing behavior upper 65mT by influence of transport current. Transport current loss was increased continuously through out whole measurement ranges in the AC-AC condition. Total loss in HTS tape was dominated entirely by magnetization loss.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1376-1382
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• 2010

The propulsion Motor system has changed from the DC motor system to the induction motor system. Although the induction motor system has almost reached the stage of maturity, this system also need changed to the IPMSM system for direct drive without reduction gear. Thus, the IPMSM(Interior buried Permanent magnet synchronous Motor) has been adopted to meet the driving specification. In this paper, loss characteristic analysis of IPMSM has been performed using adopted F.E.M.

• Journal of Power Electronics
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• 제13권2호
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• pp.250-255
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• 2013

This paper proposes an optimal current distribution method of dual-rotor brushless DC machines (DR-BLDCMs) which have inner and outer surface-mounted permanent-magnet rotors. The DR-BLDCM has high power density and high torque density compare to the conventional single rotor BLDCM. To drive the DR-BLDCM, dual 3-phase PWM inverters are required to excite the currents of a dual stator of the DR-BLDCM and an optimal current distribution algorithm is also needed to enhance the system efficiency. In this paper, the copper loss and the switching loss of a DR-BLDCM drive system are analyzed according to the motor parameters and the switching frequency. Moreover, the optimal current distribution method is proposed to minimize the total electrical loss. The validity of the proposed method was verified through several experiments.

• 전력전자학회논문지
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• 제23권4호
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• pp.294-297
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• 2018

This paper analyzes the losses of the switching device for a full bridge inverter connected to the grid. As the development of power conversion system, losses are dominant factors in judging the efficiency of a system. The losses of a switching device can be divided into switching loss and conduction loss, both of which can be estimated by analyzing periodic switching waveform. The switching loss is generated when the switch is turned on and off, while the conduction loss is generated when the switch is turned on. The estimated losses of the MOSFET switch are compared with the simulation results.

• 한국통신학회논문지
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• 제24권9A호
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• pp.1306-1313
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• 1999

본 논문은 CDMA PCS 이동통신 시스템의 망 설계를 위하여 거리에 따른 신호 감쇄 현상 분석 모델(변형된 Hata path loss model) 및 통계적 신호 강도 분포 모델(Log-Normal 분포)을 제시한다. 제시된 모델에 대구 산적동 및 수성동 지역의 측정 데이터를 적용하여 이들 지역에서 신호 강도의 세기가 임계치를 초과하는 지역의 백분율을 산출하여 망 설계의 기본 자료로 활용할 수 있도록 하였다.

• 대한전기학회논문지
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• 제39권4호
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• pp.333-340
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• 1990

분산 송전송실정보에 의한 전력시스템의 경제운용=The transmission loss information produced in a line may be shared by both end buses connected to the line. Then, the loss may be seen as if it is discretely produced at both buses. Likewise, all transmission losses can be considered as if they are discretely produced at every bus distributed. The bus transmission loss equation can be defined, in which the loss information about connected lines are contained. This formulation can greatly enhance the computational efficiency for the economic control of both real powers and voltages. It requires solutions of two linear matrix equations, one for the calculation of incremental transmission losses and the other for the determination of voltage levels to be controlled. The Proposed approach is demonstrated through three sample systems and it is found that the solutions can be obtained after three iterations regardless of system sizes. This implies that only one-step search would be required for the solution if real informations would be available. Results are compared with those of optimal power flows.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2568-2571
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• 1999

Recently, new trend in telecommunication device is to apply low voltage, about 3.3V-1.5V. However, it is undesirable in view of high efficiency and power desity which is the most important requirement in the distributed power system. Rectification loss in the output stage in on-board converter for distributed power system are constrained to obtain high efficience at low output voltage power suppies. This paper is investigated conduction power loss in synchronouss rectifier with a parallel -connected Schottky Barrier Diode(SBD). Conduction losses are calculated for both MOSFET and SBD respectively. The SBD conduction power loss dissipates more than the MOSFET rectifier conduction power loss.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.948-949
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• 2008

In this paper, an effect on power conversion unit in next generation high-speed train by loss of contact between a contact wire and pantograph supplied electrical power to high-speed train are investigated. One of the most important needs accompanied by increasing the speed of high-speed train is reduced that arc phenomenon by loss of contact brings out EMI. To analysis of conducted EMI source on powering mode of next generation high-speed train, it is necessary electrical modeling system between the contact wire and the pantograph according with loss of contact. Therefore analytical model of a contact wire and a pantograph is constructed to simulate the behaviour of loss of contact. The reliability of the modeling system is verified by simulation implementation on loss of contact.

• 조명전기설비학회논문지
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• 제19권1호
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• pp.59-63
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• 2005

전력계통을 효율적으로 운용하려면 관련량을 정확하고 신속히 계산하는 좋은 알고리즘이 필요하다. 최근 IEEE Transaction on Power System에 위상각 이동을 이용한 손실 최적화 알고리즘이 발표되었다. 동일한 손실최적화 문제를 본 논문에서는 Standard method of Lagrange Multiplier 기법을 적용하여 해석하였으며, 그 결과 저자들은 두 가지 방법이 수학적으로 동일함을 증명하였다.