• 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.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.599-607
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• 2018

Distributed generation (DG) is being highlighted as an alternative for future power supplies, and the number of DG systems connected to conventional power systems is steadily increasing. DG generators are designed using power electronics and can give rise to various power quality problems, such as overvoltage or overcurrent. Particularly, unintentional islanding operation can occur in a conventional power system when the power grid is separated from the DG systems. Overvoltage may occur in this situation, depending on the power generation and power consumption. However, overvoltage phenomena might not happen even when islanding occurs. Therefore, it is necessary to analyze the fault characteristics during islanding. In this study, a fault analysis of islanding operation was carried out using PSCAD/EMTDC, and a countermeasure for the overvoltage problem is proposed.

• 대한전기학회논문지:전력기술부문A
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• 제52권2호
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• pp.69-78
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• 2003

This paper presents a voltage analysis method of distribution systems interconnected with DG(Distributed Generation). Nowadays, small scale DG becomes to be introduced into power distribution systems. But in that case, it is difficult to properly maintain the terminal voltage of low voltage customers by using only ULTC(Under Load Tap Changer). This paper presents a voltage analysis method of distribution systems with DC for proper voltage regulation of power distribution systems with ULTC. In order to develop the voltage analysis method, distribution system modeling method and advanced loadflow method are proposed. Proposed method has been applied to a 22.9 kV practical power distribution systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.206-208
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• 2002

Distributed generation (DG) is predicted to play an increasing role in the electric power system of the near future. Distributed generation is by definition that is of limited size (roughly 10MW or less) and interconnected at the substation, distribution feeder or customer load levels. The effects of generation sources within a distribution network on the system losses are investigated in this paper. WLAV state estimation is performed with the composite distribution system containing DG. Simulations with test cases are performed and the results are presented, using IEEE34 bus radial distribution system.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1240-1247
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• 2014

The applications of Distributed Generation (DG) in a smart distribution grid environment are widely employed especially for power balancing and supporting demand responses. Using these applications can have both positive and negative impacts on the distribution system. The sizing and location of their installations are the issues that should be taken into consideration to gain the maximum benefit from them when considering the economic aspects. This paper presents an application of the Bat Algorithm (BA) for the optimal sizing and siting of DG in a smart distribution power system in order to maximize the Benefit to Cost Ratio (BCR), subjected to system constraints including real and reactive power generation, line and transformer loading, voltage profile, energy losses, fault level as well as DG operating limits. To demonstrate the effectiveness of the proposed methodology and the impact of considering economic issues on DG placement, a simplify 9-bus radial distribution system of the Provincial Electricity Authority of Thailand (PEA) is selected for the computer simulation to explore the benefit of the optimal DG placement and the performance of the proposed approach.

• 전기학회논문지
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• 제58권8호
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• pp.1504-1511
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• 2009

By development of renewable energies and high-efficient facilities and deregulated electricity market, the operation cost of distributed generation(DG) becomes more competitive. The amount of distributed resource is considerably increasing in the distribution network consequently. Also, international environmental regulations of the leaking carbon become effective to keep pace with the global efforts for low-carbon paradigm. It contributes to spread out the business of DG. Therefore, the operator of DG is able to supply electric power to customers who are connected directly to DG as well as loads that are connected to entire network. In this situation, community energy system(CES) having DGs is recently a new participant in the energy market. DG's purchase price from the market is different from the DG's sales price to the market due to the transmission service charges and etc. Therefore, CES who owns DGs has to control the produced electric power per hourly period in order to maximize the profit. If there is no regulation for carbon emission(CE), the generators which get higher production than generation cost will hold a prominent position in a competitive price. However, considering the international environment regulation, CE newly will be an important element to decide the marginal cost of generators as well as the classified fuel unit cost and unit's efficiency. This paper will introduce the optimal operation of CES's DG connected to the distribution network considering CE. The purpose of optimization is to maximize the profit of CES and Particle Swarm Optimization (PSO) will be used to solve this problem. The optimal operation of DG represented in this paper is to be resource to CES and system operator for determining the decision making criteria.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
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• pp.105-110
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• 2009

Distributed Generation (DG) is predicted to play a important role in electric power system in the near future. insertion of DG system into existing distribution network has great impact on real-time system operation and planning. It is widely accepted that micro turbine generation (MTG) systems are currently attracting lot of attention to meet customers need in the distributed power generation market In order to investigate the performance of MT generation systems, their efficient modeling is required. This paper presents the modeling and simulation of a MT generation system suitable for grid-connected operation. The system comprises of a permanent magnet synchronous generator driven by a MT. A brief description of the overall system is given, and mathematical models for the MT and permanent magnet synchronous generator are presented. Also, the use of Power electronics in conditioning the power output of the generating system is demonstrated. Simulation studies with MATLAB/Simulink have been carried out in grid-connected operation mode of a DG system. The control strategies for grid connected operation mode of DG system is also presented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.120-121
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• 2017

This paper proposes an enhanced distributed generation (DG) unit with an adaptive virtual impedance control approach in order to address the inaccurate reactive power sharing problem. The proposed method can adaptively regulate the DG virtual impedance, and the effect of the mismatch in feeder impedances is compensated to share the reactive power accurately. The proposed control strategy is fully distributed and the need for the microgrid central controller is eliminated. Furthermore, the proposed method can be directly implemented without requirement of pre-knowledge of the feeder impedances. Simulations are performed to validate the effectiveness of the proposed control approach.

• 한국산학기술학회논문지
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• 제19권10호
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• pp.655-660
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• 2018

지리적 특성상, 도서지역에 전력을 공급하기 위해서 ICG(Internal combustion generation)가 사용되고 있으며, 이로 인하여 상당한 운영비, 염해문제 및 환경오염이 발생하고 있다. 이러한 도서지역에 대해서, KEPCO는 매년 상당한 운영결손액을 감당하고 있는데, 특히 연료비 및 지급수수료가 운영결손액의 상당 부분을 차지하고 있다. 특히, 지급수수료를 줄이기 위하여 근거리 도서 사이의 해저케이블을 통한 ICG 통합운영(integrated ICG, IICG)이 고려되고 있다. 한편, 저탄소 사회에 대한 수요 때문에 도서지역에 분산형전원(Distributed Generation, DG)이 도입되고 있다. 이러한 상황에서, 환경적 특성으로 인해 DG 출력이 불충분한 경우 보조 동력원으로 IICG가 사용되는, 즉, IICG에 DG를 도입한 하이브리드 내연발전(hybrid internal combustion generation, HICG)이 도입되고 있다. 따라서, 본 논문에서는 HICG에서 한전 운영결손액에 상응하게 도입될 수 있는 최적 DG 용량을 산정하는 알고리즘을 제안하였다. 시뮬레이션 결과, 연료비와 최대부하 크기는 최적 DG 용량에 큰 영향을 미치며, 최대부하가 서로 다른 여러 도서에 제안된 알고리즘을 적용하여 그 유효성을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제8권2호
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• pp.223-229
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• 2013

Restructuring and recent developments in the power system and problems arising from construction and maintenance of large power plants, increasing amount of interest in distributed generation (DG) source. Distributed generation units due to specifications, technology and location network connectivity can improve system and load point reliability indices. In this paper, the allocation and sizing of DG in distribution networks are determined using optimization. The objective function of the proposed method is to improve customer-based reliability indices at lowest cost. The placement and size of DGs are optimized using a Genetic Algorithm (GA). To evaluate the proposed algorithm, 34-bus IEEE test system, is used. The results illustrate efficiency of the proposed method.