• 조명전기설비학회논문지
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• 제23권12호
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• pp.210-216
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• 2009

마이크로그리드는 전력시스템의 계획 및 실시간 운영에 있어서 매우 큰 영향을 미치며 중요한 역할을 할 것으로 판단된다. 따라서 본 연구에서는 빌딩의 마이크로그이드의 중요한 마이크로소오스인 마이크로터빈 발전시스템의 Matlab/Simulink 모델과 전압-주파수제어기를 개발하였다. 또한 부하에 독립적으로 전원을 공급하기 위한 전력시스템을 구성, 모의를 통하여 MTG시스템의 특성을 분석하였다.

• 전력전자학회논문지
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• 제18권1호
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• pp.63-71
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• 2013

This paper describes the coordinated droop control method for stand-alone type DC micro-grid to improve reliability and utilization of distributed generations and energy storage. The stand-alone type DC micro-grid consists of several distributed generations such as a wind power generation, solar power and micro-turbine, and energy storage. The proposed method which is based on autonomous control method shows high reliability and stability through coordinated droop control of distributed generations and energy storage and also capability of battery management. The operation of stand-alone type DC micro-grid was analyzed using detail simulation model with PSCAD/EMTDC software. Based on simulation results, a hardware simulator was built and tested with commercially available components and performance of system was verified.

• 한국멀티미디어학회논문지
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• 제18권10호
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• pp.1231-1240
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• 2015

Nowadays, in islands where electricity should be provided autonomously, stand-alone microgrid technologies using renewable energy such as sunlight generation and wind power generation come into wide use. The microgrid electricity generation using renewable energy is greatly affected by the natural environment of a site. In order to maintain stable electricity supply for fluctuating electricity generation due to natural environment, the energy management via EMS is positively necessary. In existing stand-alone microgrid EMS, system operation logic is not changeable flexibly because compiled or builded codes are released into the EMS of a site, respectively. In this paper, we designed a flexible operating script-based microgrid EMS Framework for various sites and applied it to some island sites. We could confirm its usability.

• 전기학회논문지
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• 제63권10호
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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.

• 조명전기설비학회논문지
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• 제25권9호
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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.

• 조명전기설비학회논문지
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• 제30권3호
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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.

• 조명전기설비학회논문지
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• 제26권4호
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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 Electrical Engineering and Technology
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• 제10권4호
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• pp.1432-1440
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• 2015

A dynamic economic dispatch and control method is proposed to minimize the overall generating cost for a stand-alone microgrid in DongAo Island, which is integrated with wind turbine generator, solar PV, diesel generator, battery storage, the seawater desalination system and the conventional loads. A new dispatching strategy is presented based on the ranking of component generation costs and two different control modes, in which diesel generator and battery storage alternate to act as the master power source to follow system power fluctuation. The optimal models and GA-based optimization process are given to minimize the overall system generating cost subject to the corresponding constraints and the proposed dispatch strategy. The effectiveness of the proposed method is verified in the stand-alone microgrid in DongAo Island, and the results provide a feasible theoretical and technical basis for optimal energy management and operation control of stand-alone microgrid.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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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 Power Electronics
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• 제16권5호
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• pp.1813-1820
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• 2016

Dual-mode photovoltaic power system should be capable of operating in grid-connected (GC) and stand-alone (SA) modes for distributed generation. Under different working modes, the optimal parameters of inverter output filters vary. Inverters commonly operate in GC mode, and thus, a small capacitance is beneficial to the GC topology for achieving a reasonable compromise. A predictive current control scheme is proposed to control the grid current in GC mode and thereby obtain high-performance power. As filter are not optimal under SA mode, a compound control strategy consisting of predictive current control, instantaneous voltage control, and repetitive control is proposed to achieve low total harmonic distortion and improve the output voltage spectrum. The seamless transfer between GC mode and SA mode is illustrated in detail. Finally, the simulation and experimental results of a 4 kVA prototype demonstrate the effectiveness of the proposed control strategy.