• 전기학회논문지
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• 제56권3호
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• pp.491-497
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• 2007

As dispersed generators was driven in condition interconnecting with utility, it could cause a variety of new effects to the original distribution system that was running as considered only the one-way power flow. Therefore, the protection devices that is builted in distribution system should be designed to be able to operate with disposing of not only a fault of the generator, but also utility condition. Especially, the fault of the feeder interconnected with Dispersed Generator can cause the islanding phenomenon of open DG(Dispersed Generators). This phenomenon has many problems such as a machinery damage, electricity qualify degradation and a difficulty of the system recovery. In the fault therefore, we must separate Dispersed Generator from the system quickly. In this paper, for the fault classification of the interconnected DG and the outside feeder we judge the fault of the interconnected DG and the outside feeder in HMI through data provided by IED(Intelligent Electronic Device) on the network and decide whether it operates or not by sending the result to each relay.

• 조명전기설비학회논문지
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• 제20권10호
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• pp.172-177
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• 2006

본 연구에서는 배전계통의 부하지점의 부하형태에 따른 정전비용의 영향을 고려하여 분산전원을 설치함으로써 운영비용 및 정전비용을 최소화하는 방안을 제안하였다. 가정용, 산업용, 상업용, 사무용 및 농업용 등 부하형태를 실제 계통과 유사하게 고려함으로써 정확한 신뢰도 지수와 운영비용을 구할 수 있고, 이를 통해 총 운영비용 최소화에 더욱 접근할 수 있다. 특히 정전시 각 부하지점에 설치된 분산전원에 의해 전력이 공급되어 전력구입 비용과 정전비용의 경우 효과적으로 감소됨을 알 수 있었으며, 정전빈도와 정전시간이 감소되어 전력 공급률이 향상되어 신뢰도 지수가 좋아졌음을 알 수 있었다.

• 전기학회논문지
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• 제62권11호
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• pp.1511-1519
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• 2013

This paper proposes the allocation method for capacitor-reactor banks in a distribution system with dispersed generators to reduce the installation costs, the maintenance costs and minimize the loss of electrical energy. The expected lifetime and maintenance period of devices with moving parts depends on the total number of operations, which affects the replacement and maintenance period for aging equipment under a limited budget. In this paper, the expected device lifetimes and the maintenance period are included in the formulation, and the optimal operation status of the devices is determined using a genetic algorithm. The optimal numbers and locations for capacitor-reactor banks are determined based on the optimal operation status. Simulation results in a 69-bus distribution system with the dispersed generator show that the proposed technique performs better than conventional methods.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.800-804
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• 2005

Load flow and short circuit fault transients of a power distribution system with wind turbines as dispersed generation units is presented. Usage of renewable energies such as wind is already a small part of total installed power system in medium and low voltage networks. In this paper, a radial power distribution system with wind turbines is simulated using DIgSILENT PowerFactory software for their influence on load flow and short circuit fault transients. Short fault occurring in dispersed generation systems causes some problems for the system and costumers such as fault level increase or the problems of sudden fluctuations in the current, voltage, power and torque of the double fed induction machine utilized in the wind turbines which have been studied and investigated.

• 조명전기설비학회논문지
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• 제18권1호
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• pp.146-153
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• 2004

본 연구에서는 Fuzzy Goal Programming을 이용하여 배전계통에서 분산형 전원의 설치 및 운영에 대한 새로운 방안을 제시하였다. 분산형전원의 설치 및 운영을 위하여 최적화 알고리즘의 탐색공간의 크기를 줄이면서 계통상황 변동에 적합하게 정식화하였다. 특히, 목적함수인 계통 유효전력손실과 제약조건인 분산형전원의 수 또는 총용량 및 모선전압에 대하여 각각의 부정확한 성질을 평가하기 위하여 퍼지 Goal Programing으로 모델링 하였으며, 유전알고리즘을 사용하여 최적해를 탐색하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.127-129
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• 2002

This paper presents a fuzzy-GA method to resolve dispersed generator placement for distribution systems. The problem formulation considers an objective to reduce power loss costs of distribution systems and the constraints with the number or size of dispersed generators and the deviation of the bus voltage. The main idea of solving fuzzy nonlinear goal programming is to transform the original objective function and constraints into the equivalent multi-objectives functions with fuzzy sets to evaluate their imprecise nature and solve the problem using the proposed genetic algorithm, without any transformation for this nonlinear problem to a linear model or other methods. The method proposed is applied to the sample systems to demonstrate its effectiveness.

• 대한전기학회논문지:전력기술부문A
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• 제52권10호
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• pp.584-592
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• 2003

This paper presents a fuzzy-GA method for the allocation and operation of dispersed generator systems(DGs) based on load model in composite distribution systems. Groups of each individual load model consist of residential, industrial, commercial, official and agricultural load. The problem formulation considers an objective to reduce power loss of distribution systems and the constraints such as the number or total capacity of DGs and the deviation of the bus voltage. The main idea of solving fuzzy goal programming is to transform the original objective function and constraints into the equivalent multi-objectives functions with fuzzy sets to evaluate their imprecise nature for the criterion of power loss minimization, the number or total capacity of DGs and the bus voltage deviation, and then solve the problem using genetic algorithm. The method proposed is applied to IEEE 12 bus and 33 bus test systems to demonstrate its effectiveness. .

• 한국전기전자재료학회논문지
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• 제26권8호
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• pp.620-623
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• 2013

The carbon nanotube / poly-vinylidene fluoride (CNT/PVDF) composite films for the nano-generator devices were fabricated by spray coating method using the CNT/PVDF solution, which was prepared by adding PVDF pellets into the CNT dispersed N-Methyl-2-pyrroli-done (NMP) solution. The flexible CNT/PVDF composite films were investigated by the scanning electron microscopy, which revealed that the CNTs were uniformly dispersed in the PVDF matrix and thickness of the films was approximately $20{\mu}m$. Fourier transform infra-red spectra were used to investigate crystal structure of the as-spray-coated CNT/PVDF films, and we found that they revealed extremely large portion of the ${\beta}$ phase PVDF. The capacitance of the CNT/PVDF films increased by adding CNTs into the PVDF matrix, and finally saturated. However, the resistance didn't show any saturation effect in the CNT concentration range of 0~4 wt%. Finally, the resulting nano-generator devices revealed reasonable current output after given mechanical stress.

• 조명전기설비학회논문지
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• 제17권5호
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• pp.118-125
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• 2003

본 연구에서는 배전계통에서 부하불평형을 고려한 분산형 전원의 운영에 대한 계획을 제안하였다. 또한, 배전계통의 실제 부하구성 분포를 고려하기 위하여 부하모형은 가정용, 산업용, 상업용, 사무용 및 농업용 부하 등의 집단 부하로 모형화 하였다. 또한, 목적함수로는 계통 유효전력손실을 사용하였고 분산형전원의 수 또는 총용량 및 모선 전압을 제약조건으로 정식화하였으며, 이 목적함수와 제약조건에 대한 부정확한 성질을 평가하기 위하여 퍼지 Goal Programing으로 모델링 하였으며, GA를 사용하여 최적해를 탐색하였다.

• 대한전기학회논문지:전력기술부문A
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• 제53권5호
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• pp.266-274
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• 2004

This paper presents a scheme for the interconnection of dispersed generator systems(DGs) based on load .unbalance and load model in composite distribution systems. Groups of each individual load model consist of residential, industrial, commercial, official and agricultural load. The unbalance is involved with many single-phase line segment. . Voltage profile improvement and system loss minimization by installation of DGs depend greatly on how they are placed and operated in the distribution systems. So, DGs can reduce distribution real power losses and replace large-scale generators if they are placed appropriately in the distribution systems. The main idea of solving fuzzy goal programming is to transform the original objective function and constraints into the equivalent multi-objectives functions with fuzzy sets to evaluate their imprecise nature for the criterion of power loss minimization, the number or total capacity of DGs and the bus voltage deviation, and then solve the problem using genetic algorithm. The method proposed is applied to IEEE 13 bus and 34 bus test systems to demonstrate its effectiveness.