• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2003년도 학술대회논문집
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• pp.111-116
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• 2003

Recently, power-electronics equipments or machine that microprocessor is included and computers have been installed continuously in industrial process or region of electronics customer. So concern for power quality, especially sags has been increased. Because those equipments are very sensitive to sags. The sag is phenomenon that magnitude of load voltage temporarily decreases because of power system fault. If a certain equipment in industrial process have any trouble result from sag, it can cause utility to be charged for enormous economics loss. Therefore it need to analyze the characteristic of sag and then mitigation method for sags in distribution system in oder to increase reliability. This paper gives an overview of sags characteristic due to short circuit fault in distribution system and after a general discussion of the various forms mitigation, gives a sags mitigation method with concentrating on mitigation-device interface method, especially FCL that is Fault Current Limiter.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2002년도 학술대회논문집
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• pp.139-145
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• 2002

Recently, power-electronics equipments or machine that microprocessor is included and computers have been installed continuously in industrial process or region of electronics customer. So concern for power quality, especially sags has been increased. Because those equipments are very sensitive to sags. The sag is phenomenon that magnitude of load voltage temporarily decreases because of power system fault. If a certain equipment in industrial process have any trouble result from sag, it can cause utility to be charged for enormous economics loss. Therefore it need to analyze the characteristic of sag and then mitigation method for sags in distribution system in odor to increase reliability. This paper gives an overview of sags characteristic due to short circuit fault in distribution system and after a general discussion of the various forms mitigation, gives a sags mitigation method with concentrating on changing the distribution system like spot network, on-site generation.

• 조명전기설비학회논문지
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• 제18권4호
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• pp.88-96
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• 2004

전압저하는 전력계통상의 사고에 의해 부하전압의 크기가 일시적으로 감소하는 현상으로서 주로 단락회로 사고에 의해 발생한다. 산업공정에서 하나의 장비가 전압저하에 의해서 문제를 일으킨다면 네트워크처럼 연결된 전체설비에 파급적인 영향을 미치기 때문에 그로 인한 경제적 손실은 상당히 크게 발생한다. 따라서 전압저하를 효과적으로 대처할 수 있는 방법이 전력품질 향상을 위해서 상당히 중요하게 대두되고 있다. 본 논문에서는 배전계통에서 단락사고로 발생한 전압저하 현상을 저감하고자 FCL(Fault Current Limiter)장치를 사용하여 전압저하 현상을 효과적으로 대처할 수 있는 방법을 제시하고, PSCAD/EMTDC 컴퓨터 시뮬레이션 프로그램을 이용하여 전압저하 저감효과를 분석하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
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• pp.352-354
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• 2002

The sag is phenomenon that magnitude of load voltage temporarily decreases because of power system fault. If a certain equipment in industrial process have any trouble result from sag. it can cause utility to be charged for enormous economics loss. Therefore it need to analyze the characteristic of sag and then mitigation method for sags in distribution system in odor to increase reliability. This paper gives an overview of sags characteristic due to short circuit fault in distribution system and after a general discussion of the various forms mitigation, gives a sags mitigation method with concentrating on changing the distribution system like spot network, on-site generation.

• 전기학회논문지
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• 제59권6호
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• pp.1034-1040
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• 2010

This paper presents a calculation method of the area of severity for the stochastic assessment of voltage sags. In general, the annual expected numbers of voltage sags at an individual load point can be estimated stochastically. However, in order to assess the system voltage sag performance considering many sensitive load points together, it is necessary to determine and analysis the area of severity for the load points. The area of severity to voltage sags is the network region where the fault occurrences will simultaneously lead to voltage sags at different load points. In this paper, the concept of the voltage sag assessment and the calculation method of the area of severity are addressed. The analysis of the area of severity is performed on the IEEE 30-bus test system by using the proposed method. The method is useful for the stochastic assesment of voltage sags and the establishment of systematic plans for voltage sag mitigation.

• 전기전자학회논문지
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• 제14권3호
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• pp.236-243
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• 2010

전력품질 문제는 다양한 산업분야에서 중요한 역할을 차지한다. 전력품질솔루션 선택의 폭은 점점 다양해지고 있으며, 특히 순간전압강하와 정전에 대한 보상장치를 선정하는 것은 전력회사나 수용가 모두에게 중요한 과제이다. 이것은 기술적인 관점에서 뿐만 아니라 경제적인 관점에서도 같이 고려되어야 하는데 불행히도 지금까지는 주로 경험에 의해 결정되어졌다. 본 논문에서는 순간전압강하 보상장치 선정을 위한 위험도 분석을 확정적 방법과 확률론적 방법으로 수명비용을 계산하여 두 가지 방법의 결과 해석에 대한 차이점을 모의사례를 통하여 비교하고자한다.

• 전기학회논문지
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• 제64권11호
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• pp.1611-1617
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• 2015

This paper presents an effective approach for establishing countermeasures against voltage sags based on the concept of area of severity. In order to apply preventive measures against faults such as lightning arrester, overhead earth wires and so on, it is important to find optimal points for installing the preventive measures. The optimal points can be determined by the calculation of the area of severity(AOS) to voltage sags and the expected sag frequency per unit length of line. In this paper, an effective method to find optimal points to apply countermeasures against voltage sags is addressed with case studies.

• 전기학회논문지
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• 제64권1호
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• pp.29-34
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• 2015

This paper presents a method to select optimal device for mitigating voltage sags. The method is based on economic evaluation and voltage sag assessment involving sag duration as well as magnitude. The economic evaluation is performed by using the operation cost and economic benefit of the mitigation devices. The optimal device can be determined from the values of NPV (net present value) which is widely accepted in cost-benefit analysis. The proposed method can help sensitive customers to select optimal mitigation device. In this paper, the case study considering two sensitive customers was performed by using the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1114-1116
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• 2003

Voltage sags are known as a serious problem causing mal-operation of equipment like computers, process controllers and adjustable-speed drives. In this paper, characterization of voltage sag and an overview of methods used in the mitigation of voltage sags are presented. Moreover a fast detection method for voltage disturbances is explored. The algorithm is based on the theory that allows a set of three-phase voltages be converted the d-q value. The utility input voltages are sensed and then converted to some quantities in the d-q transformation. And the difference between reference value and input value are showed that some disturbances happened in the system.