• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.1
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• pp.9-16
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• 2003

In this paper, we propose a reliability evaluation method considering the momentary interruptions of power distribution systems. The results of research are concentrated on two parts. One is the analytic and probabilistic reliability evaluation of power distribution system considering the momentary interruptions and the other is the reliability cost evaluation that unifies the cost of sustained and momentary interruptions. This proposed reliability cost evaluation methodology is also divided into the analytic and probabilistic approach and the time sequential Monte Carlo method is used for the probabilistic method. The proposed methods are tested using the modified RBTS (Roy Billinton Test System) form and historical reliability data of KEPCO (Korea Electric Power Corporation) system. Through the case studies, it is verified that the proposed reliability evaluation and its cost/worth assessment methodologies can be applied to the actual reliability studies.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.202-205
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• 2002

This paper presents the reliability evaluation methods considering the momentary voltage quality in power distribution systems. The voltage qualify phenomena deal with this paper are sustained and momentary interruptions and voltage sags. Conventional evaluation indices and methods are summarized for the sustained interruptions, and the assessment methodologies of momentary interruptions and voltage sags are proposed. The evaluation methods are divided into the analytical method and Time Sequential Monte Carlo simulation. The proposed methods are tested using the modified RBTS (Roy Billinton Test System) form and historical reliability data of KEPCO system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1270-1275
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• 2009

The structure of a power distribution system will change in a loop configuration such as in the case of a smart grid. If power distribution system changes radial to loop form, the structure may have to be changed significantly. Therefore, we analyzed the reliability indices and calculated a CIC(Customer Interruption Cost) for the loop power distribution system. The power distribution system reliability depends on the protection scheme. This study is applied to the current protection scheme method and is compared with each model. When the CIC was evaluated, most studies performed calculations only for sustained interruptions. However, in actuality, momentary interruption frequencies occurred more than sustain interruptions. Thus, it is occurred the CIC additively. Therefore, we evaluated a CIC including momentary interruption, for each model, and then compared with MAIFI(Momentary Average Interruption Frequency Index)

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.5
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• pp.13-20
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• 2008

Power quality problems such as momentary interruptions and voltage sags do not great influence on loads at past. However, the interests in power quality problems increase as the use of sensitive loads with microprocessor like computers increases recently. Accordingly, power system reliability research focusing to sustained interruption and momentary interruption partially needs more accurate evaluation methods including momentary and instantaneous problems. That is, many sensitive loads being tripped by voltage sags result in interruption costs. In this paper, new reliability worth evaluation method is presented considering voltage sags. We calculated the magnitude of voltage sags using fault studies and the duration of voltage sags using the trip time of protective relays for each fault. Moreover, we includes the customer interruption cost resulted from sensitive load trip by voltage sags. Through case studies, we evaluate the effects of voltage sags for permanent faults.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.12
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• pp.705-712
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• 2003

In this paper, we propose new unified methodologies of reliability and its cost evaluation in power distribution systems. The unified method means that the proposed reliability approaches consider both conventional evaluation factor, i.e. sustained interruptions and additional ones, i.e. momentary interruptions and voltage sags. Because the three voltage quality phenomena generally originate from the outages on distribution systems, the basic and additional reliability indices are summarized considering the fault clearing mechanism. The proposed unified method is divided into the reliability evaluation for calculating the reliability indices and reliability cost evaluation for assessing the damage of customer. The analytic and probabilistic methodologies are presented for each unified reliability and its cost evaluation. The time sequential Monte Carlo technique is used for the probabilistic method. The proposed DVL(Demand Varying Load) model is added to the reliability cost evaluation substituting the average load model. The proposed methods are tested using the modified RBTS(Roy Billinton Test System) form and historical reliability data of KEPCO(Korea Electric Power Corporation) system. The daily load profile of the each customer type in domestic are gathered for the DVL model. Through the case studies, it is verified that the proposed methods can be effectively applied to the distribution systems for more detail reliability assessment than conventional approaches.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.606-610
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• 2001

Voltage harmonics resulting from current harmonics produced by the nonlinear loads have become a serious problem in many systems. Moreover momentary interruptions and voltage sags are responsible for many of the power quality problems found in typical industrial plants. In this paper, proposed power system using series active power filter is not only harmonic compensation but also harmonic isolation between supply and load, and voltage regulation and unbalance compensation. The effectiveness of the proposed system is verified through computer simulations and experiments

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.739-743
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• 2000

With significant development of power electronics technology the proliferation of nonlinear loads such as such as static power converters has deteriorated power quality in power transmission distribution systems. Notably voltage harmonics resulting from current harmonies produced by the nonlinear loads have become a serious problem in many systems Moreover momentary interruptions and voltage sags are responsible for many of the power quality problems found in typical industrial plants. Int his paper proposed 3 phase hybrid series active power filter is not only for harmonic compensation but also for harmonic isolation between supply and load and for voltage regulation and imbalance compensation Through computer simulations we have verified the effectiveness of the proposed system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1570-1575
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• 2018

The increased penetration of PV is impacting on grid operation and in particular the voltage within the local grid can be significantly influenced by the various PV systems. The increased penetration of PV is impacting on grid operation and in particular the voltage within the local grid can be significantly influenced by the various PV systems. This paper describes domestic technical standard of Photovoltaic(PV) PCS(Power Conditioning Systems)- Characteristics of the utility interface. Especially protective function test items of 1) Output overvoltage protection test, 2) Output undervoltage protection test, 3) Frequency rise protection test, 4) Frequency fall protection test, 5) System voltage's momentary interruptions, 6) System voltage distortion capability test. Therefore in this paper protective function test item of facilities evaluation detailed standards for new renewable energy, small, medium and large photovoltaic inverter standard is studied and analyzed and finally full tested by PV inverter performance function.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.10
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• pp.102-110
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• 2012

This paper propose the advanced topology of UPQC, its DC link is connected with Lithium battery, to compensate the momentary interruptions. The proposed system can be operated as UPS mode using the parallel inverter, which control the charge or discharge of battery, in case of the interruption. We dvelop 100kVA UPQC using the proposed topology to rise the power quality and the reliability of Microgrid. We verify its usefulness through voltage compensation test, UPS operation test and etc. using Microgrid test facility.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.76-80
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• 2001

Voltage harmonics resulting from current harmonies produced by the nonlinear loads have become a serious problems in many systems. Moreover momentary interruptions and voltage sags are responsible for many of the power quality problems found in typical industrial plants. In this paper, proposed power quality compensate system using photovoltaic system is not only for harmonic compensation but also for harmonic isolation between supply and load, and for voltage regulation and unbalance compensation. Through computer simulations, we have verified the effectiveness of the proposed system.