• Journal of Electrical Engineering and Technology
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• v.10 no.2
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• pp.487-495
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• 2015

This paper proposes a new robust decentralized power oscillation dampers (POD) design of doubly-fed induction generator (DFIG) wind turbine for damping of low frequency electromechanical oscillations in an interconnected power system. The POD structure is based on the practical $2^{nd}$-order lead/lag compensator with single input. Without exact mathematical model, the inverse output multiplicative perturbation is applied to represent system uncertainties such as system parameters variation, various loading conditions etc. The parameters optimization of decentralized PODs is carried out so that the stabilizing performance and robust stability margin against system uncertainties are guaranteed. The improved firefly algorithm is applied to tune the optimal POD parameters automatically. Simulation study in two-area four-machine interconnected system shows that the proposed robust POD is much superior to the conventional POD in terms of stabilizing effect and robustness.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.541-542
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• 2006

The dispersed generation is recently increased introduction for the energy supply rationalization and effective management of power system. But the dispersed generation causes to the various trouble that isn't occurred in the past, for example, the two way systems have an effect on the mistake action of protection equipment and the power quality. In this paper, we research the influence on the harmonic when the dispersed generation is interconnected with distribution system. To achievement, we construct the interconnecting dispersed generation and distribution system which is applied to the permission of harmonic emission. After that, we simulate about the harmonic of distribution system interconnection dispersed generation by the PSCAD/EMTDC analyzing transient state of the power system.

• Journal of Electrical Engineering and Technology
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• v.5 no.2
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• pp.246-254
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• 2010

This paper presents a multiagent system for microgrid operation in the grid-interconnected mode. An energy market environment with generation competition is adopted for microgrid operation in order to guarantee autonomous participation and meet the requirements of participants in the microgrid. The modified Contract Net Protocol (CNP) is used as a protocol for interactions among agents. The multiagent system for microgrid operation based on the modified CNP and the energy market environment is designed and implemented. To verify the feasibility of the suggested multiagent system, experiments on three operation conditions are carried out.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.478-480
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• 2002

Wind energy can be conversed into electrical power using wind generator. Wind farm is made up of many wind generators, and it is often interconnected into distribution system to supply power for utilities. There are many protection problems on distribution system connected with Wind farm. It can effect on power quality severely when faults are occurred on distribution line or Wind farms. Therefore the correct protective scheme must be set for distribution system which has a Wind farm. In this paper, A wind farm connected into distribution line is simulated with several fault types which can be occurred on distribution line and Wind farm using PSCAD/EMTDC. And this paper proposes necessary relays to protect both sides of distribution system and wind farm.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.177-178
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• 2008

Recently, the concern of PV(Photovoltaic) systems has increased because of an environmental problem and limitation of fossil fuel. In this paper, distribution system of existing one-way power flow and distribution system generating bidirectional power flow analyze voltage variation at distribution system interconnected multiple PV systems. Also, we analyze a supply voltage range of distribution system using LDC and ULTC voltage regulation method by case study.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.1
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• pp.1-11
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• 2007

To check feasibility of SMART(Steam Methane Advanced Reforming Technology) system, conceptual design and sensitivity analysis of operating variables have been performed based on the design program of two-interconnected fluidized beds. Among three configurations of two-interconnected fluidized beds systems, the bubbling-bubbling system was selected as the best configuration. Process design results indicate that the SMART system is compact and feasible. Based on the selected operating conditions, the effects of variables such as process capacity, pressure, and weight percent of $CO_2$ absorbable component have been investigated as well.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.61-63
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• 2005

Utility interactive photovoltaic systems is one of the most premising applications of photovoltaic systems. These systems are employed in applications where utility service is already available. In this case, there is no need for battery storage because utility power may be used to supplement photovoltaic systems when the load exceeds available PV generation. The load receives electricity from both the photovoltaic array and the utility inter-tied. In this paper, Principle and operating characteristic of Utility Interconnected Photovoltaic System is presented. For the purpose of optimal utility Inter-tied photovoltaic system design and installation. It is that demonstrate throughout the installed 3 PV system respectively, 3kW utility interconnected residential system.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.503-507
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• 1989

A new decentralized adaptive controller design is proposed. In large scale interconnected system with unknown parameters, nonlinearities and bounded disturbances, even though the interconnection is weak, the controller parameter drifts due to the interconnection, so the decentralized adaptive controller comes to be unstable. The proposed new decentralized adaptive controller guarantees exponential convergence of tracking and parameter errors to residual sets which depend on the bound for the local disturbances and interconnections as well as on some arbitrary design parameters.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.10
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• pp.53-58
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• 1992

This paper presents a decentralized model reference adaptive control scheme for an interconnected linear system composed of a number of single-input single-output subsystems in which outgoing interactions pass through the measurement channel and are subjected to bounded external disturbances. The scheme can treat the unknown strength of interactions as well as uncertainties in subsystem dynamics, and allows for the case when the relative degree of each decoulped subsystem does not exceed two.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.2
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• pp.122-129
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• 1988

A design method of decentralized state observer for large scale interconnected systems is proposed by the use of interconnection rejection approach and interconnection modelling technique. The proposed design method is developed based on the interconnection partitioning. Therefore partitioning conditions are suggested. And the conditions for observer pole assignment and observer parameter determination procedures are described for possible interconnection patterns. The decentralized state observer gives good estimates without any information on the interconnection variables and estimations. In addition, a numerical example is given to explain the design procedures and to show the estimation performance of the decentralized observer.