• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.871-874
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• 2010

Needs for Smart Grid development are increasing all over the world as a solution to its problem according to depletion of energy resources, climatic and environmental rapidly change and growing demand for electrical power. Especially decentralized power is attracting world's attention. In this mood a new era for a unit scale of decentralized power environment is on its way in building. However there is a problem to have to be solved in the uniformity of power quality because the amount of power generated from renewable energy resources such as wind power and solar light is very sensitive to climate fluctuation. And thus this paper tries to suggest an energy management method on basis of real time monitoring for meteorological data. In the current situation of lacking in USN-based killer application in Smart Grid field, this paper proposes the USN-based DER management system which collects the meteorological data and control power system througout utilizing wireless sensor network technique this business. This communication technique is regarded to be efficient in aspects of installation cost and tits maintenance cost. The proposed EMS model embodies the method for predicting the power generation by monitoring and analyzing the climatic data and controling the efficient power distribution between the renewable energy and the existing power. The ultimate goal of this paper is to provide the technological basis for achieving zero-energy house.

• Journal of Ocean Engineering and Technology
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• v.31 no.3
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• pp.196-201
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• 2017

A cylindrical structure has a very long period of heave and pitch motion response in ocean waves. To obtain the dynamic stability of a cylindrical structure, it is necessary to obtain the suitable metacentric height (GM). However, in a structure with sufficient metacentric height, Mathieu instability can occur if the natural frequency of the heave motion is double the natural frequency of the roll and pitch motion. This study carried out numerical calculations and experiments for vertical-axis wind turbines with cylindrical floaters, which had three different centers of gravity. In the regular wave experiment, the divergence of the structure motion without yaw was observed when the natural frequency of the heave motion was double the natural frequency of the roll and pitch motion. In the irregular wave experiment, the motion spectra of the structures with the different centers of gravity were compared, and one was very high when the natural frequency of the heave motion was double the natural frequency of the roll and pitch motion.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2202-2211
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• 2010

The wind power prediction system is composed of a meteorological forecasting module, calculation module of wind power output and HMI(Human Machine Interface) visualization system. The final information from this system is a short-term (6hr ahead) and mid-term (48hr ahead) wind power prediction value. The meteorological forecasting module for wind speed and direction forecasting is a combination of physical and statistical model. In this system, the WRF(Weather Research and Forecasting) model, which is a three-dimensional numerical weather model, is used as the physical model and the GFS(Global Forecasting System) models is used for initial condition forecasting. The 100m resolution terrain data is used to improve the accuracy of this system. In addition, optimization of the physical model carried out using historic weather data in Jeju. The mid-term prediction value from the physical model is used in the statistical method for a short-term prediction. The final power prediction is calculated using an optimal adjustment between the currently observed data and data predicted from the power curve model. The final wind power prediction value is provided to customs using a HMI visualization system. The aim of this study is to further improve the accuracy of this prediction system and develop a practical system for power system operation and the energy market in the Smart-Grid.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.89-91
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• 2007

In this paper, a remote monitoring system of wind-photovoltaic hybrid generation system using mobile phone and internet has been developed. Many kinds of data can be acquired, analyzed and saved automatically by this system. The hybrid system is composed of 1[kW] PV with DC/DC converter, battery banks and 5[kW] wind power system with power inductor and AC/DC converter. In addition, wind monitoring sensors, voltage and current meters, current transformers and potential transformers are used as accessory instruments. All of these signals are fed into DAQ (Data Acquisition) board after converting the data which have been processed by many types of converters, dividing circuits and signal conditioning circuits. These data can not only be displayed on a computer, transmitted using the server program to remote computer and saved on a computer as a file day by day but also be sent as a CDMA message. The monitored-data can be downloaded, analyzed and saved from server program in real-time via mobile phone or internet at a remote place. All of the programs were designed with LabVIEW software.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.109-112
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• 2004

Photovoltaic energy and wind energy are very in constant depending on the season, time and extremely intermittent energy sources. Because of these reasons, in view of the reliability the solar and the wind generation system have many problems(energy conversion, energy storage, load control etc.) comparing with a conventional power plant. So, in order to solve these existing problems, hybrid generation system of photovoltaic(500W) and wind power(400W), which combines wind power energy and solar energy to have effect of supporting each other, was suggested. But hybrid generation system cannot always generate stable output with weather condition, the auxiliary power compensation apparatus that uses elastic energy of spiral spring to hybrid generation system was also added for the present study. And it may confirm that power was continuously provided to load by storing energy obtained from generating rotary energy of spiral spring generates in small scale generator.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.6
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• pp.307-315
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• 2003

This paper proposes a novel simulation method of WPGS (Wind Power Generation System). The rotation speed control method of turbine under variable wind speed using the pitch control is proposed. Moreover, when wind speed exceeds the cut-out wind speed, the turbine will be stopped by controlling pitch angle to 90$^{\circ}$, otherwise it will be controlled to steady-state operation. For the purpose of effective simulation, the SWRW (Simulation method for WPGS using Real Weather condition) is used for the utility interactive WPGS simulation in this paper, in which those of three topics for the WPGS simulation: user-friendly method, applicability to grid-connection and the utilization of the real weather conditions, are satisfied. It is impossible to consider the real weather conditions in the WPGS simulation using the EMTP type of simulators and PSPICE, etc. External parameter of the real weather conditions is necessary to ensure the simulation accuracy. The simulation of the WPGS using the real weather conditions including components modeling of wind turbine system is achieved by introducing the interface method of a non-linear external parameter and FORTRAN using PSCAD/EMTDC in this paper. The simulation of long-term, short-term, over cut-out and under cut-out wind speeds will be peformed by the proposed simulation method effectively. The efficiency of wind power generator, power converter and flow of energy are analyzed by wind speed of the long-term simulation. The generator output and current supplied into utility can be obtained by the short-term simulation. Finally, transient-state of the WPGS can be analyzed by the simulation results of over cut-out and under cut-out wind speeds, respectively.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.5
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• pp.410-420
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• 2015

This paper provides a comparison of power converter loss and thermal description for voltage source and current source type 5 MW-class medium-voltage topologies of wind turbines. Neutral-point clamped three-level converter is adopted for a voltage source type topology, whereas a two-level converter is employed for current source type topology, considering the popularity in the industry. To match the required voltage level of 4160 V with the same switching device of IGCT as in the voltage source converter, two active switches are connected in series for the case of current source converter. Transient thermal modeling of a four-layer Foster network for heat transfer is done to better estimate the transient junction and case temperature of power semiconductors during various operating conditions in wind turbines. The loss analysis is confirmed through PLECS simulations. Comparison result shows that the VSC-based wind turbine system has higher efficiency than the CSC under the rated operating conditions.

• Korean Architects
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• s.475
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• pp.65-74
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• 2008

1970년 초에 배럴당 1불하던 원유가가 지금은 120불을 상회하고 있다. 더욱 놀라운 것은 3년 전만 하더라도 40불 이하 수준이던 것이 불과 몇 년 사이에 3배 이상 급등해 버린 것이다. 우리는 아직 유가 100불 이상의 고유가 시대에 대한 고통을 실감하지 못하고 있지만, 빠른 시일 안에 대항한 형태로 우리를 불편하게 하고, 더가서는 사회 경제 문화 등 모든 우리의 활동패턴에 근본적 변화를 일으킬 것이라는데는 어느 누구도 이의를 달지 못할 것이다. 한편 90년대만 하더라도 친환경 건축기술은 선택적 사양으로 인식되어 왔으며, 일부 고급건물 또는 데모성격의 건물에만 반영되던 미래의 기술 분야로 간주되어왔다. 하지만 10년 남짓 지난 지금 우리 주변에서 가장 흔하게 접할 수 있는 용어 중의 하나가 친환경, 지속가능, 그린, 에코 등 이며, 최근 많은 건설사가 고민하고 있는 가장 중요한 이슈가 친환경 건축 관련 기술이 되어버렸다. 최근 유가의 급등세 보다는 더디다 할 지라도 몇 년 사이에 벌어지고 있는 제도적, 사회 경제적 변화 동향을 돌이켜 볼 때 건축계 또한 매우 빠른 속도로 변해가고 있으며, 부지불시간에 유가등급과 같이 변화된 환경에 놀라는 시기가 곧 도래할 것이다. 오랜 기간 에너지 및 친환경 관련 요소기술의 개발, 정부의 지원제도 확대, 보급 강화 등 각종 노력을 통해 이제는 건축 설계분야에서도 친환경건축물에 대한 저변이 크게 확대되었다고 볼 수 있다. 하지만 실상 우리주변에서 제대로된 친환경 건축물을 실제로 보고자 한다면 두손으로 꼽기도 힘들 정도인 사실에 놀라게 될 것이다. 이러한 배경하에 이번 연재에서는 그동안 오랜기간 떠들고 노력했음에도 불구하고 실제 제대로된 친환경 건축물을 우리 주변에서 찾기 힘든 이유를 건축실무자 측면에서 재고해 보고, 이에 대한 새로운 해결방안을 모색해 보는 계기를 갖고자 한다. 특히 많은 친환경 건축기술 중 최근 선진국을 중심으로 가장 큰 이슈가 되어 있고, 또한 건축사 입장에서 쉽게 접근하기 어려운 기술분야인 신재생에너지 건축응용 측면에서 다양한 최신 기술 및 실질적 접근방법과 사례를 주제별로 제시하고자 한다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.3
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• pp.165-170
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• 2016

Due to environmental issues such as global warming, the reduction of greenhouse gas emissions has become an inevitable measure to be taken. Among others, the building sector accounts for 50% of total carbon dioxide emissions, which is significantly high. Therefore, in order to reduce carbon dioxide emissions of the buildings, improving the energy efficiency by utilizing wind power among renewable energy sources is recommended. In case of buildings in the planning stage, it is possible to take the load of wind power generation systems into consideration when determining installed capacity. Already completed buildings, however, should be connected to small wind electric systems according to the live loads of the buildings based on the architectural design criteria. In order to connect to a building that has already been completed, it is necessary to consider the load of the small wind electric system as well as the live load of building. In addition, we need to generate the maximum electricity possible by determining the maximum installed capacity in a small area. In this paper, we propose the method for determining maximum capacity for building integrated small wind electric systems, which takes into account the considerations associated with connecting small wind electric systems to completed buildings. This can be developed into a system linked to solar power, which makes it possible to improve the energy independence of the building. In addition, carbon dioxide reduction by improving energy efficiency is expected.

• The Journal of the Convergence on Culture Technology
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• v.10 no.1
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• pp.363-368
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• 2024

Steel structures used in marine environments, such as ships, offshore structures or sub-structures in wind power generation facilities are prone to corrosion. In this study, the corrosion fatigue crack propagation characteristics due to the environmental load are examined by experiment at -1050 mV vs. SCE, which is equivalent to the anti-corrosion potential of zinc anodes that are widely used as sacrificial anodes. In this study, for this purpose, an experimental study is conducted on the effect of cathodic protection on the propagation of fatigue cracks in the seawater environment under the condition of -1050 mV vs. SCE, considering the wave period in synthetic seawater. Cathodic protection prevents corrosion; however, excessive protection generates hydrogen through chemical reactions as well as calcareous deposits. The fatigue crack propagation rate appeared to be faster than the rate in a seawater corrosion environment at the early stages of the experiment. As the crack length and stress intensity factor K increased, the crack propagation rate became slower than the fatigue crack propagation rate in seawater. However, the crack growth rate was faster than that in the atmosphere.