• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.954-958
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• 2003

새로운 에너지원인 풍력 발전에 대한 연구가 세계적으로 활발히 진행되고 있는 가운데 본 논문에서는 풍력 발전의 핵심 부분인 풍력 터빈에 관한 모의실험을 다루고자 한다. 실제 기상조건과 유사한 바람데이터를 실시간으로 생성, 이를 이용하여 풍력터빈 시뮬레이터용 DC motor의 토크제어 시스뎀을 설계 구현하였다. 본 연구는 기존의 단순 토크제어 시스템과는 달리 실시간으로 생성되는 데이터를 이용하여 보다 실제 풍력발전에 가까운 모의실험을 가능하게 한다. M/G Set를 기반으로한 DC motor 토크 제어 시스템은 바람데이터의 변화에 따른 풍력터빈의 토크와 발전단의 부하의 상관관계를 명확히 하는데 크게 이바지 할 것이며 더 나아가 발전기로의 정확한 토크 전달로써 계통 연계 연구에 많은 기여를 하고자 한다.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.166.1-166.1
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• 2011

The rotor design is fundamental to the performance and dynamic response of the Counter-rotating marine tidal current turbine. The wind industry has seen significant advancement single rotor blade technology, offering considerable knowledge and making it easy to transfer to tidal stream energy converters. In this paper, 3D flow and performance an alysis on a 100 kW counter-rotating marine current turbine blade was carried out by using the 3-D Navier-Stokes commercial solver(ANSYS CFX-11.0) to provide more efficient design techniques to design engineers. The front and rear rotor diameter is 8m and the rotating speed is 24.72rpm. Hexahedral meshing was generated by ICEM-CFD to achieve better quality of results. The rated power and its approaching stream velocity for design are 100 kW and 2 m/s respectively. The pressure distribution on the blade's suction side tells us that the pressure becomes low at the leading edge of the airfoil as it moves from the hub to the tip.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.7
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• pp.1299-1304
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• 2011

A wind turbine (WT) should be shut down as fast as possible to minimize its own damage in a storm-driven situation. Shutdown of a large wind farm requires a power grid to have a ramp-up capability large enough to balance between generation and consumption of electrical energy. This paper proposes a supervised shutdown algorithm of a wind farm to meet a required ramp-down rate in a grid code in the case of a storm-driven situation. The information on the speed and the direction of wind is measured at a wind mast (WM) installed around a wind farm. If the wind speed exceeds a cut-out speed, the number of WTs to be shut down simultaneously is decided to meet a required ramp-down rate of a grid-code. Arrival times to each WT from the WM are calculated and sorted in the order of time. Then a sequence of groups is generated. The shutdown start/end times of each group are decided to avoid superposition between adjacent two groups. The performance of the proposed shutdown algorithm is verified under various storm scenarios. Results indicate that the proposed algorithm can not only protect the wind farm in the case of a storm-driven situation but also meet the required ramp-down rate. In addition, the algorithm can produce more energy than that of a conventional shutdown algorithm.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.1
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• pp.81-89
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• 2012

Commonly used horizontal-axis wind turbines (HAWT) have the following structure: two or three blades, a nacelle which contains power converting equipments, generators, and a tower which supports the nacelle. The generated power is transmitted from the nacelle to the ground. Due to this structure, the power transmission lines are twisted when the nacelle is yawing. Thus, slip ring or additional yaw control mechanism is required. We propose a new structure of HAWT which is free of this transmission line problem. Moreover, the size of inverter can be reduced since two generators are connected in parallel in our mechanism so that power is distributed. A controller for yawing is developed so that it works in harmony with the controller for power generation. A MPPT (Maximum Power Point tracking) algorithm is implemented for the proposed system and efficiency of the system is validated by simulation.

• Journal of the Korean Solar Energy Society
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• v.32 no.3
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• pp.1-10
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• 2012

The purpose of this study was to promote the utilization of wind velocity of kitchen and bathroom exhaust ducts for wind power generation in high-rise apartments. The research content can be summarized as follows: 1) Nine high-rise apartments were examined for the installation of kitchen and bathroom exhaust ducts located in the pipe shaft (PS) section. After selecting simulation candidates, a simulation was performed with the STAR-CCM+ Ver 5.06 program. 2) Of nine high-rise apartments, seven had kitchen and bathroom exhaust ducts, whose cross section was in the range of $0.16m^2{\sim}0.4m^2$. The area ratio between the exhaust ducts and PS section (cross section of exhaust duct/area of PS section ${\times}$ 100) was on average 3.2%. 3) The simulation results were analyzed. As a result, the smaller cross section kitchen and bathroom exhaust ducts had, the more advantages there were for increasing exhaust wind velocity. If an out air inlet duct is installed to the old kitchen and bathroom exhaust ducts, it will increase exhaust wind velocity by 3.01~3.98m/s and contribute to the proper wind velocity level (3.0m/s). 4) When the simultaneous usage rate between the kitchen and bathroom exhaust fan increased from 20% to 60%, exhaust wind velocity increased. The "entire house holds" condition for exhaust fan operation provided more even exhaust wind velocity than the "some house holds" condition. 5) Exhaust wind velocity increased in the order of amplified (T-3), induced (T-2) and vertical (T-1) top of kitchen and bathroom exhaust ducts. Of them, the amplified type (T-3) was under the least influence of external wind velocity and thus the most proper for kitchen and bathroom exhaust duct tops.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.29-32
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• 2015

Since the characteristics of Renewable Energy Sources like wind turbine generators are very different from those of existing thermal power generators and their response to the sudden change of the frequency are not as good as that from thermal power generators. Especially when the penetration level of the wind power generation is substantially high, the output from the WTG would be possibly limited to keep the stability of power systems. For this, this paper implements the process for calculating the dynamic penetration limit of WTG and analyze the potential application of BESS for increasing the dynamic penetration limit of WTG.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2196-2202
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• 2018

The conventional power system allowed only downstream power flow. Therefore, even if a fault occurs, only the forward current flow is considered. However, with the interest in distributed generation (DG), DGs such as Photovoltaic (PV), Wind Turbine (WT) are being connected to a power system. DGs have many advantages, but they also have disadvantage such as generation of reverse flow. Reverse flow can severely disrupt existing protection systems that only consider downstream power flow. The major problems that may arise from reverse power flow are blinding protection and sympathetic tripping. In order to solve such problems, the methods of installing a directional relay or a fault current limiter is proposed. However, this method is inconceivable because of the economics shortage. Therefore, in this paper, a distance relay installed in existing power system is used to solve the protection problem. Modeling of distance relay has been carried out using ElectroMagnetic Transients Program (EMTP), and it has been verified through simulations that the above problems can be solved by a distance relay.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.1
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• pp.8-15
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• 2018

New methodology for probabilistic reliability based grid expansion planning of HVDC in power system including Wind Turbine Generators(WTG) is developed in this paper. This problem is focused on scenario based optimal selection technique to decide best connection bus of new transmission lines of HVDC in view point of adequacy reliability in power system including WTG. This requires two kinds of modeling and simulation for reliability evaluation. One is how is reliability evaluation model and simulation of WTG. Another is to develop a failure model of HVDC. First, reliability evaluation of power system including WTG needs multi-state simulation methodology because of intermittent characteristics of wind speed and nonlinear generation curve of WTG. Reliability methodology of power system including WTG has already been developed with considering multi-state simulation over the years in the world. The multi-state model already developed by authors is used for WTG reliability simulation in this study. Second, the power system including HVDC includes AC/DC converter and DC/AC inverter substation. The substation is composed of a lot of thyristor devices, in which devices have possibility of failure occurrence in potential. Failure model of AC/DC converter and DC/AC inverter substation in order to simulate HVDC reliability is newly proposed in this paper. Furthermore, this problem should be formulated in hierarchical level II(HLII) reliability evaluation because of best bus choice problem for connecting new HVDC and transmission lines consideration. HLII reliability simulation technique is not simple but difficult and complex. CmRel program, which is adequacy reliability evaluation program developed by authors, is extended and developed for this study. Using proposed method, new HVDC connected bus point is able to be decided at best reliability level successfully. Methodology proposed in this paper is applied to small sized model power system.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.4
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• pp.661-668
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• 2024

Based on the topology of the direct-drive permanent magnet synchronous wind power grid-connected system based on the power electronics full-power converter, the wind turbine model and the grid-side inverter model were studied, and the machine-side rectifier control based on current and speed double closed loops was designed. strategy, as well as a grid-side inverter control strategy based on current and voltage double closed loops, implementing a two-level back-to-back double closed-loop full control strategy. A system simulation model was built using Matlab/Simulink, and the operation of the unit was simulated when the wind speed changed step by step. The grid-connected current with the same phase and good sinusoidal nature of the grid voltage was output. The grid-connected system ran stably and efficiently. The simulation results The validity and rationality of the model, as well as the correctness and feasibility of the control strategy were verified.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.65-76
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• 2024

With the recent activation of the offshore wind power industry, there has been a development of power plants with a scale exceeding 400MW, comparable to traditional thermal power plants. Renewable energy, characterized by intermittency depending on the energy source, is a prominent feature of modern renewable power generation facilities, which are structured based on controllable inverter technology. As the integration of renewable energy sources into the grid expands, the grid codes for power system connection are progressively becoming more defined, leading to active discussions and evaluations in this area. In this paper, we propose a method for selecting optimal reactive power compensation capacity when multiple offshore wind farms are integrated and connected through a shared interconnection facility to comply with grid codes. Based on the requirements of the grid code, we analyze the reactive power compensation and excessive stability of the 400MW wind power generation site under development in the southwest sea of Jeonbuk. This analysis involves constructing a generation site database using PSS/E (Power System Simulation for Engineering), incorporating turbine layouts and cable data. The study calculates reactive power due to charging current in internal and external network cables and determines the reactive power compensation capacity at the interconnection point. Additionally, static and dynamic stability assessments are conducted by integrating with the power system database.