• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.4
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• pp.169-174
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• 2001

A novel simulation scheme of transient phenomenon for the photovoltaic (PV) generation system under the real weather conditions has been proposed in this paper. A grid connected PV array is simulated using PSCAD/EMTDC. The transient changes of the output current of PV array under the real weather conditions is described and the output current of DC/AC converter flowing through the utility power network is also analyzed with the PWM switching width. Moreover, the MPPT control of PV generation system is combined to the system during the simulation for the comparison purposes of the control schemes. The outcome of the simulation demonstrates the effectiveness of the proposed simulation scheme. The result shows that the cost effective verifying for the efficiency or availability and stability of PV generation systems and the comparison research of various control schemes like MPPT under the same real whether conditions are eventually possible.

• Journal of the Korean Solar Energy Society
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• v.26 no.2
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• pp.61-67
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• 2006

The use of the wind energy resource is a rapidly growing area world-wide. The number of installed units is continuously increasing, and therefore, it is important to respect and to deal with the impact of wind power generation system. From the view of an electric grid utility, there is a major problem with the impact of the wind system on the voltage of the electric grid, to which a turbine is connected. In this paper, it is investigated the voltage impact and transient state analysis on distribution line, with which wind power generation system is connected. Connections of wind power system usually occur to voltage drop due to reactive power absorption and sometime result in higher than nominal voltage.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.7
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• pp.9-19
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• 2010

Fuel cell (FC) distributed generation (DG) is gradually becoming more attractive to mainstream electricity users as capacity improves and costs decrease. New technologies including inverters are becoming available to provide a uniform standard interconnection of DGs with an electric power system. Some of the operating conflicts and the effect of DG on power quality are addressed and investigated through simulations on a real distribution network with an FC power plant. The results of these simulations have proved load tracking capability following the real and reactive power change of the load and have shown the flow of overcurrent from an FC power plant during the ground fault of a distribution line.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.3
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• pp.120-125
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• 2011

When we design the grounding grid, dangerous voltage ANSI/IEEE Std. 80 method has been commonly used in the domestic area. However, the suitability of the ground rules for the design environment available. However, the suitability of the ground rules for the design environment available. In this paper, sticks according to the electrode conductor in combination with the mesh in order to design the ground by the IEEE Std.80 was designed. So in this paper, we examined of IEEE Std. 80 touch voltage method marginal utility and we induced for those problems by comparison between IEEE Std. 80 touch voltage value and simulation experimentation value. Furthermore, this paper presents a new design grounding system method that complements the IEEE Std. 80 method.

• Journal of radiological science and technology
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• v.10 no.1
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• pp.69-74
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• 1987

Authors attempted grid performance test by film methods than can be used easily on the hospital. And we investigated the utility of it comparing with the values measured by fluorescence meter recommended to be used ordinarily. The result was that, the characteristic values obtained by film methods was almost the same as those obtained by fluorescence meter methods. And besides plain film methods that can be applied simply showed small standard deviation. Therefore, we considered that it can be adopted easily on the labor that was not ready for special measuring apparatus like fluorescence meter.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.39-41
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• 2018

독립형 인버터의 경우 상용 AC 계통(Utility Grid)이 없는 지역에서, 출력으로 단상 AC 전압(220Vrms / 60Hz)을 발생하는 전력 시스템이며 휘발유 연소 에너지, 풍력 에너지, 태양광 에너지 등 다양한 형태의 에너지를 전기 에너지로 변환하여 시스템의 입력으로 사용한다. 계통 연계 형 인버터의 경우 상용 AC 계통에 직접 연결하여, 발전된 전력을 계통에 주입(Inject)하는 전력 시스템을 말하며 출력으로 계통 전압과 동기화(Synchronization)된 단상 AC 전류를 발생시킨다. 기존 독립형 인버터의 출력에 계통 전원을 연결하면 작동이 불가능하고, 반대로 기존 연계형 인버터의 출력을 계통 전원 없이 동작하려고 하는 경우 또한 작동이 불가능하다. 본 논문에서는 상기 기존 기술의 한계를 극복할 수 있는 독립형 / 계통연계 호환형 단상 인버터를 제안하고 실제 구현을 통해 작동을 검증하였다.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.591-594
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• 2005

Islanding of PV systems occurs when the uitilty grid is removed but local sources continue to operate and provide power to local loads. Islanding Is one of the serious problems in an electric power system connected with dispersed power sources. Also, this scan present safety hazards and the possibility of damage to other electric equipments. If the real and reactive power of RLC load and PV system are closely matched, islanding phenomena can't be detected by the passive methods. Several active methods were proposed to detect islanding phenomena. The most effective method is SFS method which was suggested by Sandia National Laboratory. In this paper, a new anti-islanding algorithm is proposed and its validity is verified through simulation and experimental results for utility interconnection of PV system.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.329-332
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• 2005

Distributed generation (DG) systems fall in islanding operation when they still in operation even when the main grid is out of electric power Islanding operation is further classified into intentional islanding and unintentional islanding operations. In intentional islanding operation, the DG backs up critical loads while it separates from the main grid on islanding detection. Intentional islanding operation increases utilization of the DG system during the islanding operation. This paper proposes reasonal inverter topology and its control algorithm for seamless transfer of DG systems in intentional islanding operation.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.8
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• pp.391-397
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• 2002

This paper presents a modeling and simulation of a PI controller for maximum power extraction of a grid-connected wind energy conversion system with a link of a rectifier and an inverter. It discusses the maximum power control algorithm fnr a wind turbine and proposes, in a graphical form, the relationships of wind turbine output, rotor speed, power coefficient, tip-speed ratio with wind speed when the wind turbine is operated under the maximum power control. The control objective is to always extract maximum power from wind and transfer the power to the utility by controlling both the Pitch angle of the wind turbine blades and the inverter firing angle. Pitch control method is mechanically complicated, but the control performance is better than that of the stall regulation method. The simulation results performed on MATLAB will show the variation of generator's rotor angle and rotor speed, pitch angle, and generator output.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.338-341
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• 2003

This paper proposes the adaptive relaying algorithm of protective devices applied in the neighboring distribution feeders for reliable and efficient operations of a wind farm interconnected with distribution networks by dedicated lines. Generally, it would be highly possible that the wind turbine generators are influenced by abnormal grid conditions such as disturbances occurring in the neighboring distribution feeders as well as the dedicated power line. The delayed operation time of protective devices for satisfying the coordination might overly expose the interconnected wind turbine generators to the fault and cause damage to them. In order to reduce the damages on the interconnected wind farm about the faults happening in distribution networks, this paper describes the proper delayed operation time of protective relay.