• Journal of Power Electronics
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• v.15 no.4
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• pp.1047-1053
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• 2015

A time-domain simulation tool to predict the dynamic power output of wind turbines in an offshore wind farm was developed in this study. A wind turbine model consisting of first or second order transfer functions of various wind turbine elements was combined with the Ainslie's eddy viscosity wake model to construct the simulation tool. The wind turbine model also includes an aerodynamic model that is a look up table of power and thrust coefficients with respect to the tip speed ratio and pitch angle of the wind turbine obtained by a commercial multi-body dynamics simulation tool. The wake model includes algorithms of superposition of multiple wakes and propagation based on Taylor's frozen turbulence assumption. Torque and pitch control algorithms were implemented in the simulation tool to perform max-Cp and power regulation control of the wind turbines. The simulation tool calculates wind speeds in the two-dimensional domain of the wind farm at the hub height of the wind turbines and yields power outputs from individual wind turbines. The NREL 5MW reference wind turbine was targeted as a wind turbine to obtain parameters for the simulation. To validate the simulation tool, a Danish offshore wind farm with 80 wind turbines was modelled and used to predict the power from the wind farm. A comparison of the prediction with the measured values available in literature showed that the results from the simulation program were fairly close to the measured results in literature except when the wind turbines are congruent with the wind direction.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1149-1157
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• 2015

As a key part in the wind turbine system, the power electronic converter is proven to have high failure rates. At the same time, the failure of the wind power converter is becoming more unacceptable because of the quick growth in capacity, remote locations to reach, and strong impact to the power grid. As a result, the correct assessment of reliable performance for power electronics is a crucial and emerging need; the assessment is essential for design improvement, as well as for the extension of converter lifetime and reduction of energy cost. Unfortunately, there still exists a lack of suitable physic-of-failure based evaluation tools for a reliability assessment in power electronics. In this paper, an advanced tool structure which can acquire various reliability metrics of wind power converter is proposed. The tool is based on failure mechanisms in critical components of the system and mission profiles in wind turbines. Potential methodologies, challenges, and technology trends involved in this tool structure are also discussed. Finally, a simplified version of the tool is demonstrated on a wind power converter based on Double Fed Induction Generator system. With the proposed tool structure, more detailed information of reliability performances in a wind power converter can be obtained before the converter can actually fail in the field and many potential research topics can also be initiated.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1596-1604
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• 2013

Coordinating operation between large-scale wind power and thermal units in multiple time scale is an important problem to keep power balance, especially for the power grids mainly made up of large coal-fired units. The paper proposes a novel operation mode of multi-scale unit commitment (abbr. UC) that includes mid-term UC and day-ahead UC, which can take full advantage of insufficient flexibility and improve wind power accommodation. First, we introduce the concepts of multi-scale UC and then illustrate the benefits of introducing mid-term UC to the wind-coal intensive grid. The paper then formulates the mid-term UC model, proposes operation performance indices and validates the optimal operation mode by simulation cases. Compared with day-ahead UC only, the multi-scale UC mode could reduce the total generation cost and improve the wind power net benefit by decreasing the coal-fired units' on/off operation. The simulation results also show that the maximum total generation benefit should be pursued rather than the wind power utilization rate in wind-coal intensive system.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.461-462
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• 2015

The government on Jeju Special Self-governing Province has a policy named 'Carbon Free Island Jeju by 2030'. The main purpose in this policy is to install wind power system with the total capacity of 1.35 GW by 2020. When the demand load on Jeju Island power system is lower than entire output power, a lot of dump power will be produced from the large-scale wind farms. It will be able to cause the wind power limit on Jeju Island. Consequently, the additional power facility must be installed to ensure stable power system operation in Jeju Island and increase wind power limit. From this point, this paper proposes the installation of MMC-HVDC, which can supply power in real time in the desired direction. The effectiveness of MMC-HVDC based on measured data of Jeju Island power system will be verified by using PSCAD/EMTDC simulation program.

• Journal of the Korean Solar Energy Society
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• v.29 no.4
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• pp.41-47
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• 2009

Wind/diesel hybrid operation can be one of the most effective option for electrical power production at a remote area such as Antarctica. The king Sejong station at Antarctica relies its power production on diesel engines and diesel oil is supplied every other year by ships. However, the oil transportation processes are liable to potential oil spillage caused by the floating ice around the King George island. The long-term storage of the oil at the station can also contaminate the surrounding soils. A l0kW wind turbine has been installed to save oil consumption and operated in connection with the diesel generators since 2006. The diesel engine that operated poorly during the first year of installation was replaced in 2008 to enhance power production an recent measurements indicate that both diesel power quality and the wind turbine availability have been dramatically improved by the replacement. This report discusses electrical power qualities of wind/diesel hybrid system operating at an isolated micro gird located in the king Sejong station. Our experience reveals that the similar technologies can be applied to domestic islands, for example, in the south sea.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.300-302
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• 2008

This paper will discuss the steps in building a wind farm and the modelling of AC power system for wind power generation. And take the JeJu island for an example, with its good wind power energy resource, the most important factor for a wind farm is a good power system interconnection to decrease the power loss including the transmission loss as less as possible. So in this paper, after the JEJU wind energy analysis, we will mainly discuss the development of the modelling on JEJU AC power system by using PSCAD. And also for using the real data of the wind power in the simulation, the modelling of the JeJu power system in 2011 will also be presented in this paper.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.197-198
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• 2015

As the global to increase the wind power penetration in the power system, grid-integration standards have been proposed for the stable integration of the large-scale wind farm. Particularly, the low voltage ride through function has been emphasized, as it relates to the voltage and reactive power control of the wind turbine and the rest generators. This paper proposes the non-wind power generator control method in order to improve the wind power penetration. To prove the effectiveness of the proposed strategy, the simulation study is implemented in the Jeju power system. It can improve the wind power penetration by the effective control of the control generators.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.339-344
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• 2014

An offshore wind power plant (WPP) is very expensive and different from an onshore wind power system in many ways. There has been a continuous increase in the capacity of the offshore WPPs. Therefore it is essential to analyze the feasibility and reliability of the offshore wind power to optimize their redundancy. Besides, it is very important to study a planning for grid interconnection of adjacent offshore WPPs. This paper proposes a economic evaluation method to interconnect with adjacent offshore substations in offshore wind power grid. Also, we suggest the probabilistic reliability method to calculate a probabilistic power output of the wind turbine and a cost of the expected energy not supplied that is used as the reliability index of the power system.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.127-129
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• 2005

Construction of wind power plant is increasing rapidly because Jeju island is known as the most suitable place for wind power plant. Rut wind power plant is difficult electric power control and it has a rapid electric power fluctuation. Such a problem has a bad influence on electric power network in small electric network like Jeju. Therefore, we forecast the amount of wind power plant construction by weather information and the rate of utilization for existing facility. We investigate the contribution degree for electric Power demand, economic effect, the case of power network influence. So we forecast influence of wind power plant for Jeju power network's operation in the near future.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.891-896
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• 2001

The recent technology of Wind Power Generation in the world is rapidly developed better than the past time. The extra-large wind power generation system of the MW-class and the large wind power generation system of the hundreds kW-class were developed and became for common use. So, this paper is basic experiment for wind power generation at low wind, and aimed for small wind power generation system.