• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.3
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• pp.104-110
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• 2015

This paper describes a power quality disturbance generator for the test of a microgrid. The generator provides phase-angle jump as well as voltage sag with simple structure. The main components of the generator are SCR thyristors and transformers, therefore, high reliability and high efficiency can be obtained without switching losses. The operating principle of the proposed scheme is described and the voltage and current characteristics in case of voltage sag with phase-angle jump is analyzed. The usefulness of the proposed topology is verified through simulations and experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.8
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• pp.42-49
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• 2012

Grid-connected photovoltaic generator system requires high performance PCS(Power Conditioning System) according to the standard of 'Distributed Generation Grid-Connected Technology Standards'. This paper presents the MPPT control method which improves output efficiency through fast tracking to the maximum power point of PV and a reduced self-excited vibration. Secondly, in this paper DVR function was applied to PCS to compensate the voltage sag frequently happening for a power system. The proposed PCS control is analyzed and compared to conventional PCS operating characteristic, the various insolation and loads, and voltage sag condition through PSIM tool. It proves the utility.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.12
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• pp.561-565
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• 2001

Recent trend of increasing automated factories needs supply of high quality power from the utilities. Among the items of the power quality, voltage sag can be compensated by Dynamic Voltage Restorer(DVR). The key feature of the DVR is high response with less transient period to recover from the voltage sag due to the lightning or line-to-ground faults. In this paper we report that $H_{\infty}$ controller is very promising for the practical application to the controller of DVR. Experimental results shown in this paper was obtained by applying the control algorithm to 20 kVA DVR system. The experimental set consists of IGBT-based three phase inverter and the TMS320C32-60 DSP used for main processor of the control board. To simulate the 50% voltage sag, the SCR-based experimental set was constructed.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.525-527
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• 2000

This paper presents a reliability evaluation method for considering the voltage quality. The proposed evaluation methods are contained the sustained interruption, momentary interruption and voltage sag. For momentary interruption, evaluation indexes are divided the duration based index and the interruption cost index. For voltage sag, the final result of evaluation method represents the magnitude for customers' risk due to the voltage sag. The proposed method is tested using the RBTS model and a reliability data in KEPCO's system.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.64-65
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• 2006

This paper presents a user-friendly application for stochastic assessment of voltage sag and effective visualization for analysis data. This developed tool provides basic functions for voltage sag assessment such as load flow analysis, short circuit analysis and vulnerability analysis. Particularly it has the ability to edit one-line diagram of power system and to visualize analysis results effectively using computer graphic and animation. In order to give the real sense, analysis results are displayed with geographical information in an intuitive and rapid manner.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.321-322
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• 2006

Faults on power systems are inevitable phenomena. These faults can be classified by two categories, temporary and permanent faults. Without distinction of fault types, the faults would induce several changes on power system such as transmission line trip. Especially, the most common phenomena which loads experience by the power system fault is voltage sag. Voltage sags mean that the bus voltage maintains under 0.9 p.u. of rating for several cycles, and they give serious effects to operation of load devices. To ensure proper operation of the load, the flywheel systems, one of the energy storage system, are suggested in this paper. This paper demonstrates the efficiency of flywheel energy storage system against voltage sag by PSCAD/EMTDC simulation.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.356-358
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• 2001

Voltage sags are known as a serious problem causing mal-operation of equipment, process controllers and adjustable-speed drives. We understand problems of the voltage sag that have a bad effect to the load and then we design for a new model of the compensator. We accomplished system modeling for both sensorless part and sensing part, and compare the merits and demerits of both.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.273-274
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• 2001

This paper presents the effects on 154kV electrical power customers' productive activities by the instantaneous voltage sag or interruption in power system. According to the survey all respondents (8customers) experienced the breakdown of facilities when instantaneous voltage sag over about twenty percents of pre-fault occurred in power system.

• Proceedings of the KIEE Conference
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• 2004.07e
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• pp.10-13
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• 2004

The recent growth in the use of impactive and nonlinear loads, electronic devices sensitive to power quality has caused many power quality problems. Dynamic voltage restorers(DVR) are known as the best effective and economic means to compensate for power quality problems(especially, voltage sag and sewll). In this paper, we adresses the detecting algorithsms and implementation techniques of an voltage sag for operating DVR.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.203-204
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• 2015

본 논문은 실제 전력계통을 모의한 A계통에서 3상 지락 사고가 발생하였을 때, 순시 전압강하를 보상하기 위한 동적전압보상기(Dynamic Voltage Restorer)의 동작에 따른 해당 부하의 영향성을 연구하였다. 동적전압보상기의 동작을 위한 전압강하 검출은 RMS Detection 기법을 통해 구현하였으며, IEEE Standard 1159-1995의 기술된 Voltage Sag의 정의에 따라 동적전압보상기의 on/off 제어를 수행하였다. A계통 모델링을 포함한 모든 시뮬레이션은 PSCAD/EMTDC 상에서 구현하였으며, RMS 전압 측정 및 Voltage Sag 검출 신호, 그리고 동적전압보상기의 동작 전 후에 따른 순시 부하전압 파형을 결과로 다룰 것이다.