• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1364-1366
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• 2004

When an underground pipeline runs parallel with DC-powered railways, it suffers from electrolytic corrosion caused by the stray current leaked from the railway negative returns. Perforation due to the electrolytic corrosion may bring about large-scale accidents even cathodically protected systems. Traditionally, bonding methods such as direct drainage, polarized drainage and forced drainage have been used in order to mitigate the damage on pipelines. In particular, the forced drainage method is widely adopted in Seoul. In this paper, we report the analysis of the stray current conditions in Seoul subway DC electrification system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.373-375
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• 2003

The subway, a typical electrified transit, is operated by the 1500 V DC-powered system with the overhead positive feeder and the rails negative return. This return path would bring about considerable stray current circuits, that is, from the bottom of rails to sell and then to the station ground, unless the rail-to-soil resistance is sufficiently high. The stray current can cause electrolytic corrosion of subway metallic structures and adjacent underground utilities. In this paper, we reports on-site investigation of the stray current condition, especially influenced by drainage method. The drainage method including both forced drainage and polarized drainage, extensively adopted as a countermeasure for electrolytic corrosion of underground pipelines, was found out to exert a harmful influence upon rail components as well as the pipelines.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.220-222
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• 2007

With the wide spread of direct current (DC) electric railroads in Korea, the stray currents or leakage currents from negative return rails become a pending problem to the safety of nearby underground infrastructures. The most widely used mitigation method for this interference is the stray current drainage method, which connects the underground metallic structures to the rails with diodes (polarized drainage) or thyristor (forced drainage). Although this method inherently possesses some drawbacks, its cost effectiveness and efficiency to protect the interfered structures has been the main reason for the wide adoption. In this paper, we show the field test results for the application of stray current drainage system to a city gas pipeline paralleling a depot area of a metropolitan rapid transit system. The process for optimal positioning is briefly illustrated. The effectiveness of constant voltage, constant current, and constant potential drainage schemes was also described.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.270-272
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• 2005

With the wide spread of direct current (DC) electric railroads in Korea, the stray currents from negative return rails become a pending problem to the safety of nearby underground infrastructures, such as gas pipelines, water distribution lines, heat pipelines, POF cables, etc. The mitigation of such interference, however, is mainly dependent on stray current drainage bond methods, which connect the underground metallic structures to the negative feeder cables attached to the rails with diodes (polarized drainage) or thyristors (forced drainage). Despite some merits of these methods, they increase the total amount of stray currents from rails and cause other interference problems. In this paper, we summarize the domestic conditions of stray current interference and describe a conceptual design of other mitigation methods for such interference.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1367-1369
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• 2004

When an underground pipeline runs parallel with subway DC electrification system, it suffers from stray current corrosion caused by the stray current from the rails negative returns. Perforation due to the stray current corrosion may bring about disastrous accidents such even in cathodically protected systems. Traditionally, bonding methods such as direct drainage, polarized drainage and forced drainage have been used in order to mitigate the damage on pipelines. In particular, the forced drainage method is widely adopted in Busan. In this paper, we report the real-time measurement data of the pipe-to-soil potential variation in the presence and absence of the IR compensation. The drainage current variation was also measured using the Stray Current Logger developed. By analyzing them, the problems of current countermeasures for stray current corrosion are discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.273-275
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• 2005

The national need to establish a new stray current mitigation method to protect the underground metallic infrastructures in congested downtown area forced us to design and develop the distributed impressed current cathodic protection (DICCP) system. The main purpose of this system is to replace the stray current drainage bond methods, which is widely adopted by pipeline owners in Korea. Currently, forced drainage makes up about 85% of total drainage facilities installed in Korea because polarized drainage can neither drain perfectly the stray currents during normal operation of electric vehicle nor drain the reverse current during regenerative braking at all. The forced drainage, however, has been abused as an alternative cathodic protection system, which impresses currents from rails to the pipelines and accordingly uses the rails as anodes. As a result, it is necessary to consider a new method to both cathodically protect the pipelines and effectively drain the stray currents. In this paper, we describe the design parameters and installation schemes of DICCP system that can meet these demands.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.217-219
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• 2007

With the wide spread of direct current(DC) electric railroads in Korea, the stray current or leakage currents from negative return rails become a pending problem to the safety of nearby underground Infrastructures. The most widely used mitigation method for this interference is the stray current drainage method, which connects the underground metallic structures to the rails with diodes (polarized drainage) or thyristor (forced drainage). This method, however, inherently possesses some drawbacks such as an increase of total leakage torrents from rails, expansion of interference zone, etc. In order to resolve these drawbacks, we developed a rapid potential-controled rectifier and applied to a depot area where stray current inference is very severe. The effect of this method was analyzed from the field tell data and we suggest this method can be an excellent alternative to the drainage-bond-based mitigation methods.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 전기설비
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• pp.115-117
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• 2005

The electrolytic protection is classified according to the current supplied. And there are the Sacrificial Anode System, the Impressed Current System, the Polarized Drainage System, the Forced Drainage System. This study is intended to design and analyze the electrolytic protection at water transmission pipes which is occurred the corrosion, and to show the methods protecting corrosions at water transmission pipes.

• 한국가스학회지
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• 제10권3호
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• pp.41-47
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• 2006

가스배관, 상수관, 송유관 등의 지중 매설배관이 직류 전기철도와 인접해 있는 경우, 전기철도 시스템의 귀선 회로로 사용되는 레일에서 누설되는 표유전류에 의해 이들 금속배관에는 전기적 부식, 즉 전식이 발생할 수 있다. 전식에 의한 집중 부식은 전기방식으로 보호되는 배관에 있어서도 지속적인 재료의 열화와 이에 따른 파손을 일으킬 수 있어 대형사고로 발전할 소지를 가지고 있다. 국내에서는 이러한 표유전류에 대한 대책으로 배관과 레일을 전기적으로 접속하는 배류법이 적용되고 있는데 특히 가스배관을 중심으로 한 강제배류법의 급속한 증가에 의해 간섭문제가 매우 복잡해지고 있다. 본 논문에서는 직류전기철도시스템과 매설배관 사이의 전기적 간섭 문제를 서울과 부산 지역에서 수행한 현장 실태조사의 결과를 통해 살펴본다.