전차선로 순환전류 발생원인과 대책에 관한 연구

한학수(Han Hag-Su),민경윤(Min Kyung-Yun) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

Electric car tract plays the role of supply high electric power to the electric car from the substation by using Pantograph of the electric car. It is always exposed to the external atmosphere, which results in quite substantial fluctuations in current and voltage during operation of electric car. This generates possibility of occurrence of accident at all times. Since range of wiring metallic globe installed on the catenary cannot achieve complete electrical contact, accidents are occurring due to circulating current caused by arc caused by incomplete contact due to occurrence of hairline fracture of Pantograph due to pressure or vibration of wiring. Furthermore, rapid increase in the operational current due to increase in the operational frequency of the electric car is causing erosion and short circuit of the metallic globe at the contact points. This study on arc is generated as current transmitted out of the substation courses through power line or wiring metallic globe other than the main circuit as the current is being collected at the electric car through feeder and feeder divergence device. Accordingly, since heat generated by the arc becomes the cause for generation of circulating current due to melting of metal or softening of metal due to increase in temperature accompanying increase in contact resistance, this research shall describe causes and measures against occurrence of circulation current.

전력케이블 절연보강 공법 적용사례 연구

한학수(Han Hag-Su),최병운(Choi Byung-Un),배상만(Bae Sang-Man),박은구(Park Eun-Gu),김영은(Kim Young-Eun) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.11월

In comparison with Over-head electric power line, Underground electric power line system has benefits such as power supply and city environment beautification, so 22.9㎸ distribution electric power cable of KEPCO is installed around the metropolis highways. Also, the electric power cable that Urban railroad is using is stretched in a narrow underground space by using pipelines or troughs. The electric power blackout paralyzes the function of subway in operational state as well as brings about social confusion. Furthermore, the weakness of XLPE cable, as a result of water tree thermal phenomenon, real life span compared with life expectancy is by far a long way and water tree thermal preventive measure has been constantly increasing up to now. Therefore, the necessity of the failure prevention of underground electric power cable is urgently needed and the reliability improvement of power supply is on gradual increase. A study shows that more than 50% of underground cable failure are caused by water tree defect, in order to avoid the damage of electric power cable that take places under operation by adding high voltage to the electric power cable, the insulation efficiency is measured by using the method of IRC analysis that can be measured in operational state, and we try to find the instance study on Silicone Fluid/XL construction method reinforced insulation efficiency by preventing water penetration within cable and get rid of penetrated water to control the water tree thermal of electric power cable.

전력케이블 열화 감시방안에 관한 연구

한학수(Han Hag-Su),민경윤(Min Kyung-Yun),유기선(Ryu Ki-Son) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

Electric Power cable is the apparatus that receives electric power from the Korea Electric Power Corporation and supplies electric power to electric train and annex facilities of each railway station. With substantial ripple effect during power blackout accidents, such power blackout accidents must be coped with by discriminating the status of insulation deterioration of electric power cable in advance. Discrimination of insulation deterioration of the electric power cable is normally executed while the power is disconnected and it is very difficult to discover, at early stage, the insulation deterioration of the power cable in operational state since the duration of inspection is limited. This research aims to consider method of diagnosing the insulation deterioration of electric power cable in On-Line state rather than diagnosis in Off-Line state in order to secure reliability of power supply by reducing duration of power blackout (accidental blackout and blackout during works) and by seeking reduction in equipment and manpower used in diagnosis of deterioration through prevention of the accident itself prior to occurrence through early restoration of accident due to insulation deterioration of the electric power cable and assessment of performance of the cable under operation.

전철용 공랭식 정류기 성능 향상방안에 관한 연구

한학수(Han Hag-Su),최병운(Choi byoung-un),배상만(Bae sang-man),김찬식(Kim chan-sik),김영은(Kim Young-eun) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.5월

The rectifier for Electric railway is one of the most important facilities in DC urban railway which converts power from KEPCO(AC 22.9kV) to the electric rail car(DC 1.5kV), therefore it should be managed as the best condition for the drive. There are several things to cause performance degradation and deterioration of parts such as pollutants occurred by it established under the ground such as dust or foreign substances, rapid changes of driving current, and pyrogen which put the rectifier for Electric railway in malfunction. On the flow of time, the rectifier for Electric railway is causing a malfunction or failure which drive electric rail car in operations as well as loss of life. In this research we try to find the way of removing the various components of mal-functions in the performance of the rectifier for Electric railway by Over-Haul and reform itself, which gives us to get the chance investment of the reduction, the reliability of power supply to the electric rail car.

도시철도역사의 저압선로 및 기기에서의 지락사고 방지 방안에 관한 검토

민경윤(Min Kyung-Yun),김진호(Kin Jin-Ho),한학수(Han Hag-Su) 한국철도학회 2005 한국철도학회 학술발표대회논문집 Vol.- No.-

In the station of the railway and the subway various illumination equipment and a general power equipment for a passenger convenience, the signal equipment and the communication equipment which is necessary to the train operation provided. At the all of like this equipment from the electric room which is established in each station by changing from high voltage to low voltage and it supplies from the illumination transformer, the power transformer and the signal transformer. If it supplies to theequipment from the high voltage to the low voltage, it must be established to contact protection device in between the high voltage coil and the low voltage coil. Also it must do the grounding faulting device at the low voltage lines, the earthing devices at apparatus for the protection of an electric shock and an electric fire by the electric relation law. Compared the related regulations between the facilities which require protective functions such as grounding fault or earthing in public utilities like subway stations, and the facilities which do not require line earthing or protective functions such as electricity supplied for signalling the train. Also, will describe a countermeasure for the accident from a grounding fault.

다공성 탄소나노재료를 사용하는 Capacitive Deionization 공정의 염수 제거효과

양천모 ( Yang Cheon Mo ),최운혁 ( Choe Un Hyeog ),조병원 ( Jo Byeong Won ),조원일 ( Jo Won Il ),윤경석 ( Yun Gyeong Seog ),한학수 ( Han Hag Su ) 한국공업화학회 2004 공업화학 Vol.15 No.3

다공성 탄소재료를 이용하여 만든 전극을 사용해서 전기화학적으로 이온을 흡착시켜 제거시키는 capacitive deionization (CDI) 특성을 다공성 탄소재료의 종류에 따라서 조사하였다. CDI에 의한 담수화는 충전 시, 두 개의 다공성 탄소전극에 적절한 전압을 인가하고 그 사이로 이온들이 함유된 물을 흘려주어 양이온은 음극에, 음이온은 양극에 흡착되어 이온들이 서로 분리되고, 양이온과 음이온으로 포화된 탄소전극은 반대 전압을 인가하거나 탄소전극을 서로 연결(Short circuit)해주면 흡착된 이온들이 탈리되는 원리이다. 다공성 탄소 전극 재료로는 탄소에어로젤 (specific surface area : 950 ㎡/g, pore volume : 3.71 ㏄/g, pore diameter : 15.19 ㎚)과 활성탄소(BP-25: specific surface area 2500 ㎡/g, Kansai Coke & Chemicals Co. Ltd), 탄소나노튜브(MWNT type, 10~20 ㎚ diameter, ILJIN Nanotach), 그리고 탄소나노섬유(straight type, 130~150 ㎚ diameter, Nanomirae Co. Ltd)를 전극 활물질로 사용하여 침지법으로 CDI용 탄소전극을 각각 제조하였으며, 0.9 V 충전과 -0.001 V 방전, 휴기(rest) 과정을 1회로 하여 CDI 특성을 탄소전극 활물질의 종류에 따라 10회 동안 조사하였다. 충전과 방전 시 평균 전하량은 활성탄소를 이용한 전극에서 각각 0.229〔Aㆍmin〕와 0.143〔Aㆍmin〕으로 가장 높았으며, 활물질의 양을 고려한 평균 방전 비전하량의 경우, 전극 활물질로서 탄소에어로젤이 0.593〔Aㆍmin〕으로 가장 높게 나타났다. 10회 충-방전 싸이클에 대한 전하량 효율은 탄소에어로젤이 63.98%로 가장 우수하였으며, 활성탄소(62.45%)와 탄소나노섬유(56.50%)도 비교적 안정하게 나타났다. Capacitive deionization (CDI) process is a removal process of ions via electrochemical adsorption using porous carbon materials. The ions are adsorbed onto the surface of porous carbon electrodes by applying electric field to brackish water. Adsorbed ions are desorbed from the surface of the porous carbon electrdes by eliminating the field or reversing electric field, resulting in the regeneration of electrodes. Recently, carbon aerogel electrodes, one of the porous carbon materials, are bring used for CDI process. In this study, the electrode using carbon aerogel (specific surface area: 960m^(2)/g, pore volume: 3.71 cc/g, and pore diameter: 15.19 nm), activated carbon(BP-25: specific surface 2500m^(2)g, frpm Kansai Cole & Chemicals Co. Ltd), carbon nanotube (MMMT type, 10-20 nm diameter, from ILJIN Nanotech) and carbon nanofiber (straight type, 130∼150 nm diameter, from Nanomirae Co. Ltd) were fabricated by dip coating method. Porous carbon electrodes were charged at 0.9 V, discharged at -0.001 V, cycled 10 times, and their CDI performances were compared with CDI characteristics. An activated carbon electrode showed higher average charge and discharge coulombs than others and its average charge and discharges were 0.229 [Aㆍmin] and 0.143 [Aㆍmin], respectively. At the average discharge specific-coulombs, a carbon aerogel electrode had highest average specific discharge coulomb of 0.593 [(Aㆍmin)/g]. The values of coulombic-efficiencies showed 63.98% for the carbon aerogel electrode, 62.45% for the activated carbon, and 56.50% for the carbon nanofiber.