• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.3
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• pp.79-85
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• 2016

This paper analyzed the influence of wind power fluctuations in grid frequency of a stand-alone microgrid that is hybrid generation system with diesel generator, wind turbine, and Battery Energy Storage System (BESS). The existing island area power system consists of only diesel generators. So the grid frequency can be controllable from load change. But hybrid generation system with Renewable Energy Sources (RES) such as wind energy that has the intermittent output can bring power quality problems. BESS is one of the ways to improve the intermittent output of the RES. In this paper, we analyzed the role of BESS in a stand-alone microgrid. We designed a modelling of wind power system with squirrel-cage induction generator, diesel power system with synchronous generator, and BESS using transient analysis program PSCAD/EMTDC. And we analyzed the variation of the grid frequency according to the output of BESS.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.1072-1079
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• 2014

This paper introduces a coordinated droop control for the stand-alone DC micro-grid, which is composed of photo-voltaic generator, wind power generator, engine generator, and battery storage with SOC (state of charge) management system. The operation of stand-alone DC micro-grid with the coordinated droop control was analyzed with computer simulation. Based on simulation results, a hardware simulator was built and tested to analyze the performance of proposed system. The developed simulation model and hardware simulator can be utilized to design the actual stand-alone DC micro-grid and to analyze its performance. The coordinated droop control can improve the reliability and efficiency of the stand-alone DC micro-grid.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.64-67
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• 2005

A vibration monitoring system for a small size wind turbine (WIT) is established and operated. The monitoring system consists of monolithic integrated chip accelerometer for vibration monitoring, anemometers for wind data acquisition and auxiliary sensors for atmospheric data. Using the monitoring system, vibration response of a 6kW stand alone WIT generator is investigated. Acceleration data of the WIT tower under various operation condition is acquired in real time using LabVIEW and the data are remotely transferred from the test site to the laboratory in school by internet. Vibration response characteristics of the tower structure are diagnosed in the aspect of stability of W/T. Wind data and electrical power performance are also investigated with the stability problem.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.2 s.119
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• pp.114-120
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• 2007

Vibration performance of a 6 kW stand-alone wind turbine(W/T) generator is investigated under the wind environment of Daegwanryung mountain area. In the W/T, wind condition, power performance and structural stability are correlated each other An integrated monitoring system which consists of accelerometers, anemometers, power meters and auxiliary sensors for atmospheric data are constructed to measure the required data simultaneously. Based upon the data acquired over a long period of time, vibration performance of the W/T structure is estimated with annual wind data and generating power performance. Within the operating speed range, possibility of severe nitration is diagnosed. Vibration sources are identified and countermeasures are proposed. The goal of the study is to offer the basic information on W/T vibration performance at the design stage of a small stand alone W/T structure.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.65-68
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• 2002

Most of the present demand in the world is met by fossil and nuclear power plants. A small part is met by renewable energy technologies. Among the renewable power sources, wind and solar energy have experienced a remarkably rapid growth in the past 10 years. Recently the utilization of wind power has been receiving close attention in this country, especially for the electrification of off-shore islands. The objective of this study is to demonstrate a small wind energy system as a stand-alone power source.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.4
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• pp.48-56
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• 2012

The object of this paper is the controller for supplying stably power in a separate house in which a hybrid electrical storage system with a stand-alone photovoltaic/wind power generation system and a small generator is applied. In the photovoltaic/wind hybrid power system used in the separate house, when only the battery is used in sunless days, the capacity of the battery is become larger. In particular, as in recent days, if cloudy days are frequent due to anomaly climate, it is difficult to estimate the number of sunless days. Accordingly, it is preferable to build the electrical storage system that numbers of sunshineless days are to be controlled and a shortage amount of the power generation capacity is to be handled by a small generator system. In order to supply stably power of new renewable energy such as solar to any separate houses, it is preferable to reduce the capacity of battery by decreasing the number of sunless days when estimating the capacity of battery and to drive the small generator for compensation of the power shortage. Such system needs components including inverters for photovoltaic and wind power generation system, batteries and controllers for automatically driving the small generator, based upon the nature of the stand-alone house, and it is preferable to use the controller having a simpler and higher stability by adopting the all-in-one scheme to facilitate its maintenance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.9
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• pp.26-32
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• 2011

The object of this paper is to optimize the battery system for supplying stably power in separate house in which a PV-wind hybrid power generation system is applied. In a power system to be used in a stand alone, it is very important to build optimize the electrical storage system and to utilize it for supplying stably output voltage when there is a shortage of the power generation capacity or there is no sunshine, or when power is to be supplied with a load. This paper provides an optimized method to evaluate capacity of battery by analyzing advantages and disadvantages of the existing battery evaluating method being used in each company for supplying stably power in separate house utilizing the new renewable energy such as a light of the sun.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1393-1401
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• 2014

In this paper the operational characteristics of stand-alone microgrid was analyzed using RTDS simulation models. The accuracy of developed simulation models were verified by comparing with the analysis results using the PSCAD/EMTDC simulation models. The proper scenarios and operation algorithms were developed and analyzed in accordance with various situations that can occur in the actual system, so as to establish operation scheme for the stand-alone microgrid system. The developed simulation models can be effectively utilized to design a newly installed stand-alone microgrid and to develop various operation scenarios for stand-alone microgrid. And these models can be applied for analyzing the transient phenomena due to system fault so that system protection can be properly designed.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.183.1-183.1
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• 2010

Recently, the increased interest in environmental issues has led to extensive research for development of green energy generation systems. However, only one type of generation system may not be sufficient for stand-alone mode because it cannot cope with the irregularity of weather condition. A hybrid generation system is able to make up for the weakness of each system. In this paper, a stand-alone hybrid wind/PV system is developed that can guarantee the stable energy supply. The system is suitable for power supply under 50W, and a vertical savonius type of blade was designed and applied for the wind generation system.

• Journal of Electrical Engineering and Technology
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• v.5 no.3
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• pp.443-450
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• 2010

An enhanced control strategy for variable-speed unbalanced stand-alone doubly-fed induction generator-based wind energy conversion systems is proposed in this paper. The control scheme is applied to the rotor-side converter to eliminate stator voltage imbalance. The proposed current controller is developed based on the proportional-resonant regulator, which is implemented in the stator stationary reference frame. The resonant controller is tuned at the stator synchronous frequency to achieve zero steady-state errors in rotor currents without decomposing the positive and negative sequence components. The computational complexity of the proposed control algorithm is greatly simplified, and control performance is significantly improved. Finally, simulations and experimental results are presented to verify the feasibility and the robustness of the proposed control scheme.