• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.317-318
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• 2006

전력 계통이 거대화되고 그 복잡성이 증가함에 따라 계통의 안정적인 운용을 위하여, 다양한 안정도 해석에 대한 요구가 제기되고 있다. 이에 따라 실시간 시뮬레이터를 이용한 계통의 과도현상 해석에 대한 연구 역시 증가하고 있는데, 이는 대규모 비선형 계통을 대상으로 할 경우 H/W의 제약으로 인해 현실적으로 많은 제한을 받는다. 하지만 FACTS등 새롭게 계통에 연계되는 전력 설비의 성능 검증 및 사례 연구를 위해서는 이러한 실시간 시뮬레이터를 이용한 실제 계통에 대한 다양한 과도현상 모의 및 해석이 필요하다. 이에 본 연구에서는 UPFC, SVC등 FACTS 기기가 포함된 한전의 실제 전력 계통을 대상으로 등가화 및 계통 축약 기법을 이용하여 해당 계통의 동적/정적 특성을 반영할 수 있는 등가계통을 PSS/E상에서 개발하고, 등가 계통과 실 계통에 대한 다양한 모의를 통해 그 타당성을 검증하였다. 이렇게 개발된 등가 계통 모델은 각 FACTS 기기에 대해 독립된 모델 계통으로 실시간 시뮬레이터를 이용한 FACTS 기기의 성능 검증 및 평가에 활용될 수 있을 것이다.

• Journal of the Korean Geotechnical Society
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• v.38 no.11
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• pp.119-135
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• 2022

This paper used dynamic centrifuge tests to examine the seismic response for a deep temporary retaining wall with four input motions of 100, 1,000, and 2,400 years of return periods. The centrifuge model was designed based on an actual deep excavation design with a 50 m maximum excavation depth. The model backfill was prepared with dry silica sand at a relative density of 55%, and the retaining wall was modeled as a 24.8 m height diaphragm wall supported by struts. Acceleration response was amplified at the backfill surface, top of the wall, and near bedrock. However, in the middle of the model, input motion was de-amplified. The member forces of the wall and strut induced by the seismic load, which excited, were compared with the member force at rest condition. The wall's maximum negative and positive moments were increased to 36% and 10% compared to the maximum moment at rest. The maximum axial force increases to 70% of the at rest axial force on the bottom strut. The equivalent static analysis using Mononobe-Okabe (M-O) and Seed-Whitman (S-W) seismic earth pressures were compared to the centrifuge results. Considering the bending moment, the analysis results with the M-O theory underestimates but that with the S-W theory overestimates.

• Journal of Aerospace System Engineering
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• v.12 no.4
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• pp.98-105
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• 2018

The satellite is exposed to various launch environments such as random vibrations and shock. Accordingly, structural design of electronic equipment mounted on satellite must meet reliability requirements at the box level. In addition, it is essential to secure the reliability of the solder joint applied to electronic equipment. In this paper, we performed a modal and quasi-static analysis for the purpose of satisfaction of the design requirements of the CCB (Camera Controller Box) present on the 500 kg-class compact advanced satellite (CAS500). In addition, structural safety of electronic components was verified by the Steinberg's method and random equivalent static analysis.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.461-462
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• 2007

실시간 시뮬레이터(RTDS)를 이용한 비선형 전력 계통의 과도현상 해석은 H/W의 제약으로 인해 계통의 규모에 따라 그 적용범위가 제한되므로, 대규모 계통의 RTDS 모의를 위해서는 대상 계통의 축약된 등가 계통의 개발이 요구된다. 이에 본 연구에서는 한전 계통의 RTDS 적용 및 모의를 위해, 실 계통의 정적, 동적 특성을 반영할 수 있는 적정규모의 등가 계통 개발에 대한 연구를 진행하고, 등가화 및 계통 축약 기법을 이용해 240기 986모선 규모의 한전 계통에 대한 42기 143모선의 규모의 등가 모델 계통을 개발하였다. 등가 모델 계통은 경제성을 고려하여 실 계통의 동특성을 반영하는 최소 규모의 모델로 개발되었으며, PSS/E를 이용한 다양한 모의를 통해 실계통의 특성을 적절히 반영하는 것을 확인하고 타당성을 검증하였다. 또한 PSS/E로 구성된 모델 계통을 RSCAD를 이용해 변환하고, RTDS를 이용한 모의를 진행하는 것으로 그 특성을 확인하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.445-453
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• 2013

This paper was calculated the earthquake load using ELFP(Equivalent Lateral Force Procedure) and RSA(Response Spectrum Analysis) for PSC Box Girder representative bridges by the Phase of KTX designed by ELFP and verified the difference of these analyses. It have been modeled 3 dimensional FE model of 5 bridges using a commercial FEM program for the comparison of these analyses using a commercial FEM program and were compared the earthquake load. It has been to confirm the increase of the difference ELFP of RSA calculated to seismic ground acceleration according to the ground condition and natural period. It is mean that the necessity of seismic reinforcement due to the application of a larger of earthquake load than designed earthquake load form the seismic performance evaluation result according to the difference of calculated earthquake loads.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.315-319
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• 2003

This paper presents modeling and analysis of static and dynamic characteristics in PWM Boost AC-AC converter used for input voltage sag compensation of custom power. Especially, using circuit DQ transformation technique, an equivalent circuit in fundamental frequency domain is obtained which has all the system characteristics. Moreover, voltage gain and input power factor is analytically induced and linearized state equation at the specific operating point is given. Finally, simulation results show the validity of the proposed modelling and analyses.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1514-1519
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• 2003

This paper presents modeling and analysis of static and dynamic characteristics in three phase PWM Boost AC-AC converter used for input voltage sag compensation of custom power. Especially, using circuit DQ transformation technique, an equivalent circuit in fundamental frequency domain is obtained which has all the system characteristics. Moreover, voltage gain and input power factor is analytically induced and linearized state equation at the specific operating point is given. Finally, PSIM simulation results show the validity of the Nosed modelling and analyses.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.234-235
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• 2011

계통에 대규모의 풍력발전의 투입양이 증가함에 따라 실효치 기반의 해석이 필요하다. 계통 내에 무효전력 불균형에 의한 풍력 발전의 한계량을 결정하기 위하여 연속조류법을 이용한 한계량 선정 알고리즘을 수립하였다. 이를 위하여 풍력발전단지를 등가화하고, 타입에 따른 풍력발전기의 정적 모델을 수립하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.3
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• pp.311-318
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• 2015

A nonlinear dynamic response structural optimization process is proposed for the television (TV) packing system that protects the damage from a drop situation using the equivalent static loads (ESLs). Topology optimization using ESLs is carried out for conceptual design, and shape optimization using stress ESLs for a virtual model is performed for detailed design. Stress ESLs are static loads that generate the same displacement as well as the stress fields of linear static analysis as those of nonlinear dynamic analysis. Thus, the response of nonlinear dynamic analysis can be utilized as a constraint in the linear static structural optimization. An actual example is solved to validate the process. The drop test of a television packaging system is analyzed by LS-DYNA, and NASTRAN is used for optimization.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3A
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• pp.497-512
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• 2006

In this paper, a simple but effective analysis procedure to estimate seismic capacities of multi-span continuous bridge structures is proposed on the basis of modal pushover analysis considering all the dynamic modes of structure. Unlike previous studies, the proposed method eliminates the coupling effects induced from the direct application of modal decomposition by introducing an identical stiffness ratio and an approximate elastic deformed shape. Moreover, in addition to these two introductions, the use of an appropriate distributed load {P} makes it possible to predict the dynamic responses for all kinds of bridge structures through a simpler analysis procedure. Finally, in order to establish the validity and applicability of the proposed method, correlation studies between rigorous nonlinear time history analysis and the proposed method are conducted for multi-span continuous bridges.