• 한국정보전자통신기술학회논문지
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• 제13권6호
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• pp.590-596
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• 2020

상용전력망과 계통연계가 어려운 도서지역에서는 독립적인 마이크로그리드로 생산된 에너지를 효율적으로 관리할 수 있는 방법을 찾는 것은 매우 중요한 일이다. 본 논문에서는 태양광과 풍력의 하이브리드 모델을 적용한 소규모 마이크로그리드에서 생산된 전력을 전력계측기와 수집된 데이터의 응답속도 테스트를 거쳐 P2P전력거래를 위한 프로슈머관리시스템을 구현하였다. 마이크로그리드 프로슈머 관리시스템의 전력망은 Mesh구조로 이루어져 있으며 P2P전력거래는 3곳의 독립적으로 구축된 off-grid 사이트에서 전력계측기와 DC전력전송기를 이용하여 테스트하였고, 이때 전력계측기의 측정값은 전압(평균값) : 380V + 0.9V, 전류(평균값) : + 0.01A, 전력 : 1000W ( - 1W)로 오차 허용범위인 ±1%이내로 나타나 그 유의성을 확인하였다. 실시간으로 50개의 데이터를 동시 전송하여 메인화면 0.32초, 일 발전량 2.61초, 누적발전량 2.77초, 전력거래 0.11초 등의 응답속도가 나타나 서버의 안정화를 확인하였다. 따라서 본 시스템은 한국전력의 중계 없이 독립적인 망으로 활용될 수 있는 P2P 전력거래시스템으로서 그 타당성이 입증되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1308-1309
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• 2011

스마트그리드가 출현함에 따라 향후 배전계통에 태양광, 풍력, 연료전지, 전력저장장치, 전기자동차(V2G) 등의 분산전원의 연계는 급속도록 증가할 것이며 더불어 배전계통은 더욱 더 복잡하게 될 것이다. 이로 인해 발생하는 가장 큰 문제는 계통의 전압변동 문제이다. 복잡한 전압변동 문제를 해결하지 못하면 스마트그리드 계통의 전력품질과 안정도에 악영향을 끼칠 것이다. 스마트그리드 계통 하에서 분산전원의 위치는 변전소 근처 전원단부터 부하 말단까지 전원사업자의 필요에 따라 설치하게 될 것으로 지금까지의 전압변동, 조류계산 등의 모델링 방법으로는 해결하지 못하는 문제가 발생하게 될 것이다. 이 논문에서는 분산전원 배전계통 연계 용량 확대를 위해 실 선로의 실시간 전압 측정값을 이용한 분산전원 연계 스마트그리드 계통의 통합 전압관리안정화 방법에 대해 제안하고자 한다.

• 한국초전도ㆍ저온공학회논문지
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• 제13권1호
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• pp.46-50
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• 2011

The electrical insulation design of high voltage superconducting fault current limiters (SFCLs) should be confirmed to be applied for the stabilization of the power grid. This paper describes numerical analysis and AC dielectric experiments for developing high voltage SFCLs. The electric field distributions between applied high voltage part and ground were calculated by finite element method (FEM) simulation tool and AC criterion of liquid nitrogen at 200 kPa was calculated from correlation between the field utilization factor and FEM simulation results. This paper deals with ceonceptual insulation design of a 154 kV class single-phase no-inductively wound solenoid type SFCL which was focused on gap distance between the cryostat and superconducting coils. Furthermore, the shield ring effect was confirmed to reduce maximum electric field at applied high voltage part.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.201-206
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• 2005

In order to realistically represent the complex turbulence-chemistry interaction at the partially premixed turbulent lifted flames encountered in the gas turbine combustors, the combined conserved-scalar/level-set flamelet approach has been adopted. The parallel unstructured-grid finite-volume method has been developed to maintain the geometric flexibility and computational efficiency for the solution of the physically and geometrically complex flows. Special emphasis is given to the swirl effects on the combustion characteristics of the lean-premixed gas turbine combustor. Numerical results suggest that the present approach is capable of realistically simulating the combustion characteristics for the lean-premixed gas turbine engines and the lifted turbulent jet flame with a vitiated coflow.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.32-38
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• 2006

A premixed flame propagating in a tube suffers strong variation in its shape and structure depending on boundary conditions. The effects of thermal boundary conditions and flow fields on flame propagation are numerically investigated. Navier-Stokes equations and species equations are solved with a one-step irreversible global reaction model of methane-air mixture. Finite volume method using an adaptive grid method is applied to investigate the flame structure. In the case of an adiabatic wall, friction force on the wall significantly affected the flame structure while in the case of an isothermal wall, local quenching near the wall dominated flame shapes and propagation. In both cases, variations of flow fields occurred not only in the near field of the flame but also within the flame itself, which affected propagation velocities. This study provides an overview of the characteristics of flames in small tubes at a steady state.

• JSTS:Journal of Semiconductor Technology and Science
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• 제13권2호
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• pp.114-126
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• 2013

In this paper, we present a set of methodologies to model the electromagnetic susceptibility (EMS) testing of I/O buffers for mobile system memory based on the bulk current injection (BCI) method. An efficient equivalent circuit model is developed for the current injection probe, line impedance stabilization network (LISN), printed circuit board (PCB), and package. The simulation results show good correlation with the measurements and thus, the work presented here will enable electromagnetic susceptibility analysis at the integrated circuit (IC) design stage.

• Structural Engineering and Mechanics
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• 제5권6호
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• pp.785-801
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• 1997

Reinforced Concrete beams with tension and compression softening material constitutive laws are studied. Energy-based and non-local regularisation techniques are presented and applied to a R.C. element. The element characteristics (sectional tangent stiffness matrix, element tangent stiffness matrix restoring forces) are directly derived from their symbolic expressions through numerical integration. In this way the same spatial grid allows us to obtain a non-local strain estimate and also to sample the contributions to the element stiffness matrix. Three examples show the spurious behaviors due to the strain localization and the stabilization effects given by the regularisation techniques, both in the case of tension and compression softening. The possibility to overestimate the ultimate load level when the non-local strain measure is applied to a non softening material is shown.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.134-135
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• 2012

This paper analyzes the characteristics of the power system of Jeju island in 2014, which has wind farms with the support of BESSs (Battery Energy Storage Systems). In the simulation, the electrical loads are predicted based on Korea Power Exchange's data and the wind turbines are considered with new installed plans within 2014. The situation that some wind farms are forced to disconnect from the grid instantaneously is considered. The BESSs are controlled by using SOC (State of Charge) and power smoothing control algorithm. The simulation results show the effectiveness of the proposed method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.498-500
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• 2012

According to the climatic characteristics of the wind power output is difficult to predict and a severe strain due to a change in output has been very influential in the grid. Jeju Hangwon wind farm, many of the wind generator is installed in a wide area because it is not have this device that artificially Smoothing is needed. In addition, By the requirements of the power company active power supply / control and improve power system reliability and energy storage during the peak demand for electricity using the energy stored in the power supply is needed. In this paper, Unit 12 in Jeju Hangwon demonstrated 0.5MW PCS and energy storage system associated with the wind through the stabilization of output and the leveling of output and test results will be introduced.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.503-505
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• 2012

본 연구에서는 실증기능 구현을 위해 75KW로 설계된 리튬-폴리머배터리(Lithium Polymer Battery 이하 배터리)와 ESS(Energy Storage System) 내장형 Hybrid-PCS(이하 PCS)을 이용하여 불균일한 풍력 발전원에 대한 Smoothing 제어 및 정출력 제어 대한 연구를 진행 하였다. 잦은 전류 변동으로 인해 발생되는 출력 변동의 안정화를 위해 인버터 전류제어, 벅/부스트 전압제어 기법을 사용하였다. 최적의 Smoothing 제어를 위한 필터 계수 값을 찾기 위한 시험을 진행 하였으며 Energy shift을 위한 정출력 시험도 진행 하였다. 또한 각 제어 모드에서 ESS 중요 파라미터인 SOC(State Of Charge 이하 SOC)변화를 배터리 특성과 관련하여 분석해 보았다.