• KEPCO Journal on Electric Power and Energy
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• v.2 no.4
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• pp.631-638
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• 2016

Offshore wind power can be an alternative for onshore wind power which suffers from not only civil complaints regarding to landscape damage and noise but also wind power siting due to lack of onshore site candidates. Compared to onshore wind power, offshore wind power is free from these problems considering that generally the sites are far enough from the coast. And more electricity is generated in offshore wind turbines due to abundant offshore wind resources. However high installation costs of offshore turbines could deteriorate the economical efficiency. The main cause of the high installation costs comes from a long-term lease of the heavy marine equipment and the consequential high rental cost. In this paper, the conceptual design of the support structure for offshore wind turbines will be suggested for the installation of them with less heavy marine equipment.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.254-259
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• 2014

In this paper, we describe construction of a wind stabilization demo-site and effects of output power control of wind turbines for suppression of ramp rate using ESS (Energy Storage System). It is difficult to control the output power of distributed generator such as wind turbine which of variation is very large. If the large capacity wind farm be interconnected into power system may cause blackout due to Power Quality. For these reasons, the international standards such as Grid-Code is limited to less than 10 [%/min] of renewable energy ramp rate. The case of Korea, government actively conducts propagating large-scale renewable energy for green growth policy, to interconnecting more renewable energy into power system is necessary for stabilization technology. For these reasons, the POSCO consortium has constructed a wind stabilization demo-site that is configured as 500 [kWh] battery energy storage systems can output up to 3 [C-Rate] and two wind turbines rated 750 [kW]. In POSCO consortium, which implements various methods stabilizing output power of wind turbine such as smoothing, section firming and ramp control, we derive the results of long-term demonstration that can be controlled to satisfy to the international standard about ramp rate [%/kW] of wind turbine output power.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2966-2970
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• 2013

In this paper, a simulation study on dynamic characteristics of wind turbine generators is performed. The generation of electricity using wind turbines is being recently spotlighted as a renewable way. The wind is an infinite primary energy source. Further, other environmental impacts of wind power are limited as well. Therefore, the wind turbine generation itself has many advantages. However, when generators using wind turbines are connected to the conventional power system, the impact of the power system is different from that of the power system that consists of only synchronous generators, especially in dynamic characteristics. Therefore, it is essential to examine the characteristics of wind turbines in order to ensure reliable wind turbine generation in the power system containing wind turbine generators. In this paper, the dynamic characteristics of GE1.5MW wind turbine are simulated by using PSS/E. In the simulation of GE1.5MW wind turbine, wind speed variation, load change and voltage deviation of infinite bus are considered.

• Journal of the Korean Solar Energy Society
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• v.23 no.2
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• pp.21-34
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• 2003

This study aims to present the applicability of wind turbine generator system to urban buildings for the utilization of clean renewable energy. The results are as follows; According to the wind resource analysis, it has been found that small sized wind power system can be viable for buildings application due to the amplification of wind velocity around buildings or building clusters, in spite of low mean velocity of 2-3m/s in Seoul and Kyunggi urban areas. But planners must perform micrositing analysis around building so that wind turbine can be located at high velocity zones. The system must be designed to avoid obstacles preventing prevailing wind in buildings. It should be recognized that wind speeds are changing depending on the height and length from buildings. The wind power system can be used as a symbol of landmark which shows a sustainable architecture from the scenary Itself A case study for apartment building in urban showed that wind power systems can be applicable in two kinds of place, rooftops and ground levels. Especially, the wind power systems must be carefully positioned so that wind resources do not decrease when it is installed at ground levels. and according to life cycle cost analysis, adaption of new small win4 power systems to buildings were proved to produce a profit if it is considered the expense of environment improvement and the wind speed increasing according to rise of building height. This research will ultimately achieve green architecture that preserves nature and at the same time provides pleasant environment to humans, and will play a great role in establishing the environment-preserving sustainable architecture of the 21th century.

• Wind and Structures
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• v.35 no.4
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• pp.229-242
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• 2022

Wind tunnel test is often adopted to assess the site-specific wind characteristics for the design of bridges as suggested by current design standards. To investigate the wind characteristics of flat and mountainous terrain, two topographic models are tested in a boundary layer wind tunnel. The wind characteristics, including the vertical and horizontal mean wind speed distributions, the turbulence intensity, and the wind power spectra, are presented. They are investigated intensively in present study with the discussions on the effect of wind direction and the effect of topography. It is indicated that for flat terrain, the wind direction has negligible effect on the wind characteristics, however, the assumption of a homogenous wind field for the mountainous terrain is not applicable. Further, the non-homogeneous wind field can be defined based on a proposed approach if the wind tunnel test or on-site measurement is performed. The calculated turbulence intensities and wind power spectra by using the measured wind speeds are also given. It is shown that for the mountainous terrain, engineers should take into account the variability of the wind characteristics for design considerations.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.6
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• pp.1138-1145
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• 2009

This paper presents an active and reactive power compensator for the wind power system with squirrel-cage induction generator. The output power of a wind power system changes irregularly according to the variation of wind speed. The developed system is able to continuously compensate the active and reactive power. The 3-phase inverter operates for the compensation of reactive power, while the DC/DC converter with super-capacitors operates for the compensation of active power. The operational feasibility of the proposed model was verified by simulations with PSCAD/EMTDC and the feasibility of hardware implementation was confirmed by experimental works with a scaled hardware model. The proposed compensator can be expected that developed system may be used to compensated the abrupt power variation due to sudden change of wind speed or sudden power-drop by tower effect. It can be also applied for the distributed generation and the Micro-Grid.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.951-958
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• 2008

This paper describes development of hardware simulator for the PMSG wind power system, which was designed considering wind characteristic, blade characteristic and blade inertia compensation. The simulator consists of three major parts, such as wind turbine model using induction motor, PMSG generator, converter-inverter set. and control system. The turbine simulator generates torque and speed signals for a specific wind turbine with respect to given wind speed. This torque and speed signals are scaled down to fit the input of 2kW PMSG. The PMSG-side converter operates to track the maximum power point, and the grid-side inverter controls the active and reactive power supplied to the grid. The operational feasibility was verified by computer simulations with PSCAD/EMTDC, and the implementation feasibility was confirmed through experimental works with a hardware set-up.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.50-62
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• 2011

In this paper, analytical techniques for performance characteristics analysis of wind power generator with outer permanent magnet rotor are proposed. Furthermore, the proposed analytical techniques are validated by performance experiments of the manufactured generator. In this part, characteristic equations of losses such as copper loss, core loss are derived. Using the derived loss characteristic equations, electrical parameters obtained in [15] and d-q axes method, constant load and constant speed characteristics of wind power generator are analyzed. And then, to analyze performance of wind power system according to wind speed, d-q analysis model considering wind turbine characteristics is proposed. Finally, the obtained performance characteristics results are validated in comparison with those by experiments.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.334-336
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• 2003

This paper describes the influences of the large scaled wind farm interconnected with 154 kV power networks on the operational characteristics of distance relay applied in the transmission line. The wind farm composed of wind turbine generators are one of the great energy sources: they can supply the power into an interconnected network not only the normal conditions, but also the fault conditions of power network. Therefore, the distance relay applied in the transmission tine may mal-operate due to the contribution of wind farm. This paper presents the operational characteristics of distance relay for the fault occurred in the transmission line interconnected with wind farm. Simulation results show that it is difficult to recognize the fault location due to the power output of wind farm.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.399-405
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• 2014

For stable integration of large-scale wind farms, integration standards (Grid codes) have been proposed by the system operator. In particular, voltage control of large-scale wind farms is gradually becoming important because of the increasing size of individual wind farms. Among the various voltage control methods, Secondary Voltage Control (SVC) is a method that can control the reactive power reserve of a control area uniformly. This paper proposes hybrid SVC when a large-scale wind farm is integrated into the power grid. Using SVC, the burden of a wind turbine converter for generating reactive power can be reduced. To prove the effectiveness of the proposed strategy, a simulation study is carried out for the Jeju system. The proposed strategy can improve the voltage conditions and reactive power reserve with this hybrid SVC.