• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2000년도 학술대회논문집
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• pp.251-256
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• 2000

The assessment of the condition of a transformer winding which is suspected of having suffered short circuit damage can be difficult. Conventional test such as winding resistance, magnetisation current or insulation resistance will only detect damage if a permanent electrical fault exists. Visual inspection of windings necessitates the removal of oil and in many cases only a very small proportion of the winding can be seen. We describe the characteristics. As the front rise time of recurrent-surge generator pulse less than 1000ns and the peak value of pulse is about 500V, we have the good results of detecting winding deformation in the LVI test of transformers.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.1109-1111
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• 1997

The purpose of this paper is to analyze the effects of switching-over control for power system stabilization. Switching-over control is applied to western part of korea electric power system to improve transient stability and short-circuit capacity. It's effectiveness is demonstrated in terms of fault current level and critical clearing time which is quantitative evaluation means of transient stability. The effect of generator tripping for power system stabilization is also presented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.701-703
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• 2005

Recently, There has been growing interest in Distributed Generations with high-energy efficiency due to the Increasing energy consumption and environmental pollution problems. but an insertion of Distributed Generations to existing power distribution system can cause several problems such as voltage variations, harmonics, protective coordination, increasing fault current etc, because of reverse power. This paper was applied to Sukumar M[l] proposal schemes and identity the faulted section performing short-circuit analysis by MATLAB program to distribution systems interconnected a large number of distributed generations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.37-39
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• 1998

This paper presents the pressure-rise of the puffer cylinder in a model gas circuit breaker and the analyzed results of thermal interruption capability in SLF(short line fault) to the diameter of the puffer cylinder. This paper can be applied to the design of the EHV interrupter.

• 한국초전도ㆍ저온공학회논문지
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• 제21권4호
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• pp.44-47
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• 2019

This paper is a study of recovery under load process of superconducting fault current limiter (SFCL). SFCL consists of five parallel-connected high-temperature superconductor (HTS) tapes additionally stabilized by stainless tape. Previously, HTS was heated by current pulse to simulate a short circuit in a power grid. During the cooling period, the current amplitude decreased to 23% or less of HTS critical current value, which is the simulation of network re-switching. When HTS with a polymer coating is cooled, temperature gradient on thermal insulation layer occurs, that prevents a boiling crisis and improves the heat sink into liquid nitrogen. Two samples are coated with a 30 ㎛ and 50 ㎛ polylactide (PLA) layers, reference sample has no polymer coating on it. Samples with a polymer coating show 3-5 times faster cooling than the reference one.

• Advances in Energy Research
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• 제3권3호
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• pp.133-142
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• 2015

A large wind farm can be simplified by the aggregated wind farm models for load flow, steady and transient stability studies. When a fault (such as a short circuit) happens in a large wind farm, some of wind turbines trip while others do not. This paper is to design a controller to modify the aggregated wind farm model in the case of one or more unit removed or added from the complete model. This is without stopping the simulation process during performing the steady state and transient analysis of the whole system. This controller can modulate the status of the wind turbines in the aggregated model in a given farm according to any change in this farm. By this controller, we save effort and time to change the status of wind turbines in the aggregated model. The proposed wind farm is composed of some smaller farms of permanent magnet synchronous generators (PMSGs) and others of squirrel cage induction generators (SCIGs).

• 대한전기학회논문지:전력기술부문A
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• 제48권5호
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• pp.538-544
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• 1999

One of the most important requirements for the development of computerized relay setting system is its openness to abbommodate the various changes like new panel additions. This paper describes the relay settein-coordination system(PROSET2000), which has an open system architecture and adopts the dbject oriented programming paradigm. Its main features include the intelligent fault type identification, automatic running of the short circuit analysis, ren-time rulebase modification, automatic documentation, ect.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.229-231
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• 1998

One of the most important requirements for the development of computerized relay setting system is its openness to accommodate the various changes like new panel additions. This paper describes the relay setting system(PROSET2000), which has an open system architecture and adopts the object oriented programming paradigm. Its main features include the intelligent fault type identification, automatic running of the short circuit analysis, run-time rulebase modification, automatic documentation, etc.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 추계학술대회
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• pp.9-11
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• 2018

This paper studies on the development of an electric fire prevention system with the detection and alarm in case of parallel arc fault occurrence in low voltage distribution lines. The proposed detector has the characteristics of high speed operation responsibility and superior system reliability from composition using a large number of semiconductor devices. The line voltage is always feedback, and when an arc or a spark occurs, these are detected by the microcomputer. In addition, we design and develop algorithms using high speed and high precision microcomputer. A new conceptual control technique is adopted that RCD cuts-off by forming a forced short circuit between the phase voltage and ground in the event of an electrical accident. Some experimental tests of the proposed system also confirm practicality and the validity of the analytical results.

• 한국전자통신학회논문지
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• 제16권4호
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• pp.643-652
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• 2021

송·배전시스템에서 사고나 장애는 결코 완벽하게 피할 수 없으며, 단락 및 지락사고는 계통운영자의 노력에도 불구하고 발생한다. 최근 대용량 신재생 분산전원의 송·배전계통에 연계가 급증하여 계통 운영에 다양한 영향을 주고 있어, 이를 최소화하기 위해 FRT(Fault-Ride-Through)와 같은 연계기준을 마련하여 풍력터빈 또는 태양광 인버터가 계통의 중대 장애 시 연계유지 또는 신속한 계통분리 등을 원활히 수행하여 운영자가 안정적으로 계통을 운영할 수 있도록 지원을 하여야 한다. 본 논문에서는 대표적인 신재생 분산전원의 계통연계 기준인 FRT 조건의 충족여부를 적절하게 판단하기 위하여 동기페이저 측정을 하는 PMU(Phasor Measurement Unit)를 사용한 검출 시스템을 설계 및 구축하고 발전기 탈락으로 인한 계통사고 사례를 기반으로 제시한 시스템을 분석하고 평가한다.