• Journal of Power Electronics
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• 제16권2호
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• pp.631-642
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• 2016

Usually, the output characteristics of a photovoltaic (PV) array are significantly affected by non-uniform irradiance which is caused by ambient obstacles, clouds, orientations, tilts, etc. Some local maximum power points (LMPP) in the current-voltage (I-V) curves of a PV array can result in power losses of the array. However, the output power at the global maximum power point (GMPP) is different in different interconnection schemes in a PV array. Therefore, based on the theoretical analysis and mathematical derivation of different topological structures of a PV array, this paper investigated the output characteristics of dual series PV arrays with different interconnections. The proposed mathematical models were also validated by experimental results. Finally, this paper also concluded that in terms of performance, the total cross tied (TCT) interconnection was not always the optimal structure, especially in a dual series PV array. When one of the PV modules was severely mismatched, the TCT worked worse than the series parallel (SP) structure. This research can provide guidance for switching the interconnection to gain the greatest energy yield in a changeable- structure PV system.

• Journal of Electrical Engineering and Technology
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• 제2권1호
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• pp.1-9
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• 2007

This paper presents the effects of an increase or a decrease of a power reserve by load flow calculations under the seasonal load patterns of each country for the future power shortages faced by the metropolitan areas or by the southeastern area of South Korea in North-East Asia. In this paper, the various cases of the power system interconnections in Far-East Asia are presented, and the resulting interconnected power systems are simulated by means of a power flow analysis performed with the PSS/E 28 version tool. Data for simulation were obtained from the 2-th long term plan of electricity supply and demand in KEPCO. The power flow map is drawn from simulated data and the comparative study is done. In the future, a power flow analysis will be considered to reflect the effects of seasonal power exchanges. And the plan of assumed scenarios will be considered with maximum or minimum power exchanges during summer or winter in North-East Asian countries.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.47-50
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• 2003

For large-scale systems which are composed of interconnections of many lower-dimensional subsystems, decentralized control is preferable since it can alleviate the computational burden, avoid communication between different subsystems, and make the control more feasible and simpler. A power system is such a large-scale system where generators are interconnected through transmission lines. Decentralized control is therefore considered for power systems. In this paper, a robust decentralized excitation control scheme for interactions is proposed to enhance the transient stability of multimachine power systems. First we employ a DFL(Direct Feedback Linearization) compensator to rancel most of the nonlinearities; however, the resulting model still contains nonlinear interconnections. Therefore, we design a robust controller in order to deal with Interconnection terms. In this procedure, an upper bound of interconnection terms is estimated by an estimator. The resulting adaptive scheme guarantees the uniform ultimate boundedness of the closed-loop dynamic systems in the presence of the uncertainties.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1192-1194
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• 1999

Recently, there has been growing interest in utilizing cogeneration(COGN) system which has high energy efficiency due to the lacking of energy resource, but insertion of cogeneration system into existing power distribution system can cause several problems such as voltage variations, reenergizing of feeder isolated by fault, increasing fault current because of reverse power of COGN. Also these problems increase the complexity of control, protection, and maintenance of power distribution systems. Hence, some problems according to COGN interconnection operation to power distribution system must be taken into account so that operation and security of power distribution system is not disturbed. This paper deals with momentary voltage variations and fault analysis caused by interconnection operation of COGN.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.313-316
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• 2006

As Decentralized Generation(DG) becomes more reliable and economically feasible, it is expected that a higher application of DG units would be interconnected to the existing grids. This new market penetration of DG technologies is linked to a large number of factors like technologies costs and performances, interconnection issues, safety, market regulations, environmental issues or grid connection constrains. Korea Electric Power Corporation (KEPCO) has researched performance characteristics of the 60k W class 1) basic start-up & shutdown operation analysis 2) interconnection test 3) MGT -absorption chiller-heater system in the local condition. Variations of heat recovery from exhaust gas has measured according to micro gas turbine output of 15, 30, 45, 60kW. From those results, the performance of the MGT-absorption chiller/heater system has been evaluated. The suggested strategy and experience for the evaluation of the distributed generation will be used for the introduction of other distributed generation technologies into the grid in the future.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.280-282
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• 2002

As EG(Embedded Generation : photo-voltaic, wind, combined heat and power, fuel cell, small hydro etc.) grows fast in adopting to peak load reducing at the middle or the end of distribution system, there much has been interested in interconnection of EG. This paper discusses the various issue of a embedded generator to power system and shows the simulation of its various situation that could happen (focusing on load-flow by EG) by using a commercial software CYME(PSAF) for load-flow. With a result of above simulation, this paper shows a way of possible solution briefly.

• 에너지공학
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• 제11권3호
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• pp.216-223
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• 2002

전력계통의 전원설비 방식은 대규모 집중전원방식과 소규모 분산전원방식으로 크게 분류할 수 있으나 지금까지의 우리나라의 전원방식은 대규모집중방식 위주로 전원계획을 수립하여 왔다. 그러나 최근에 신에너지 전원설비인 태양광, 연료전지 및 풍력발전 등의 환경 친화적인 전원방식이 급증하고 있는 추세이고 국가적으로도 이러한 전원설비를 장려하고 있다. 그러나 이러한 신에너지 전원방식은 독자적으로 모든 부하를 충당할 수 없으며 고장시 전원공급에 차질이 발생할 우려가 있어 전력계통과의 연계가 필수적이다. 따라서 본 논문에서는 이러한 여러 형태의 신에너지 전원설비 중 풍력발전시스템을 저압 및 특별고압계통에 연계하는 경우에 발생하는 보호문제에 대해서 시뮬레이션과 분석을 통해 각종 사고에 대한 보호방식과 협조방안에 대한 방안을 제시하였다.

• Journal of Information Processing Systems
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• 제13권1호
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• pp.95-103
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• 2017

The PCI Express is a widely used system bus technology that connects the processor and the peripheral I/O devices. The PCI Express is nowadays regarded as a de facto standard in system area interconnection network. It has good characteristics in terms of high-speed, low power. In addition, PCI Express is becoming popular interconnection network technology as like Gigabit Ethernet, InfiniBand, and Myrinet which are extensively used in high-performance computing. In this paper, we designed and implemented a evaluation platform for interconnect network using PCI Express between two computing nodes. We make use of the non-transparent bridge (NTB) technology of PCI Express in order to isolate between the two subsystems. We constructed a testbed system and evaluated the performance on the testbed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.448-453
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• 2004

In this paper, an adaptive robust decentralized excitation control scheme is proposed to enhance the transient stability of a multi-machine power system. We employ a state model where the terminal voltage of each generator is regarded as part of the state. Using this state model, the proposed controller is obtained in two steps: firstly, a robust controller is designed for the nominal system with no interconnection terms; then an adaptive compensator is proposed to deal with those interconnection terms, whose upper bounds are estimated. The resulting adaptive scheme guarantees the practical stability of the closed-loop, and also the uniform ultimate boundedness in the presence of disturbances.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 B
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• pp.345-347
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• 2000

This paper proses a soft-switching current-source inverter with a switched-capacitor module. The system operation was analyzed by a theoretical approach with equivalent circuits and verified by a computer simulation and experiment. The proposed system could be effectively applied for the power converter of photovoltaic power generation interconnected with the power system.