• 한국ITS학회 논문지
• /
• 제12권1호
• /
• pp.121-135
• /
• 2013

전 세계적으로 지구온난화로 인한 환경문제가 심각한 위기로 인식되어지면서 세계 각국에서는 전 산업분야에 걸쳐 이산화탄소 배출을 줄이고자 노력하고 있다. 국내 에너지 부문 CO2 배출량의 약 20%를 차지하는 수송 분야의 이산화탄소 배출을 감소시키기 위해서는 전기자동차 보급 확산이 필수적이다. 최근 정부에서 전기자동차 보급 활성화를 위해 많은 노력을 기울이고 있으나 긴 충전시간과 배터리의 가격에 의한 비싼 차량가격, 짧고 불규칙한 운행거리와 부족한 충전 인프라 등으로 인하여 향후 전기자동차의 보급 확대는 매우 불투명한 상태이다. 이러한 단점을 해결하고 효과적으로 전기자동차를 보급할 수 있는 방법 중 하나가 바로 배터리 공용제 기반의 배터리 자동교환형 전기자동차 시스템이다. 이를 위해서는 배터리를 자동으로 교환해주는 시설인 배터리 교환소 (BSS: Battery Swapping Stations)가 필요하게 되는데, BSS는 배터리 교환을 통해 전기자동차가 긴 충전시간을 소모할 필요 없이 짧은 시간 내에 배터리를 충전하고 이동할 수 있도록 하는 시스템이다. 이러한 시스템을 대중교통, 특히 공공버스에 적용함으로써 보다 빠른 시간 안에 전기자동차를 보급, 확산시키는 것이 가능하다. 일반버스를 전기버스로 전환하여 버스 노선을 운영할 경우 전기버스가 중간에 멈추지 않도록 적절한 위치에 충전시설을 구축할 필요가 있다. 전기버스에 대한 충전시설은 버스 노선의 기 종점 및 기존 버스정류장에 추가로 설치하여 버스가 승객의 승 하차를 위해 정차할 때 신속하게 배터리를 교환할 수 있게 구축해야 한다. 본 연구에서는 전기버스를 위한 배터리 자동교환충전시설의 위치선정 문제를 Set Covering Problem에 적용하여 해결하였다. 배터리 충전 시 최대 주행거리를 영향권으로 설정하였으며 메타 휴리스틱 기법인 그리디 알고리즘을 활용하여 배터리 교환형 충전인프라 배치 최적화 모델을 개발하였고 현재 운영 중인 서울시의 버스노선을 대상으로 실제 충전시설의 위치를 선정하였다.

• 한국가스학회지
• /
• 제25권2호
• /
• pp.28-33
• /
• 2021

최근 친환경 자동차에 대한 관심이 높아짐에 따라 공해물질을 배출하지 않는 수소연료전지 차량에 대한 관심과 구매가 증가하고 있다. 최근 정부의 수소에너지 보급정책에 따라 수소충전소의 확충과 핵심부품의 국산화를 지원하고 있다. 본 연구에서는 그중에서도 수소 유량제어 밸브의 차압에 따른 유동특성을 연구하였다. 차압이 높아 짐에 따라 질량유량과 유량계수는 체적유량과 다른 경향을 보임을 확인하였다. 그리고 병목 구간에서의 노즐효과로 인해 수소온도에 영향을 주게되고, 밀도의 변화를 일으켜 질량유량에 영향을 주게 되는 것을 확인 하였다.

• 한국가스학회지
• /
• 제25권6호
• /
• pp.92-97
• /
• 2021

2021년 2월 '고압가스 안전관리법 시행규칙' 개정에 따라 2021년 8월27일부터 수소자동차 충전소에 설치한 가스누출검지경보장치, 긴급차단장치 및 화염검지기 등 안전장치 작동상태를 실시간으로 한국가스안전공사에서 관리하는 전산시스템으로 전송하여 운영하고 있다. 모니터링 시스템 구축결과와 함께 그동안 발생한 이상신호 통계분석 결과를 공유하여 수소충전소 안전관리에 활용토록 하고, 향후 안전관리 방향을 모색하고자 한다.

• 한국산업융합학회 논문집
• /
• 제24권6_2호
• /
• pp.773-779
• /
• 2021

CNG, which has recently been attracting attention as an alternative fuel in the transportation field to reduce emissions caused by global warming, is natural gas with abundant reserves and mainly composed of methane. Being in a gaseous state, natural gas requires the compression and liquefaction processes for transportation. Until now, general shut-off valves for liquid and gas piping have been developed in Korea, but there are few studies on shut-off valves for high pressures of about 200 bar. Currently, research on the flow analysis of valves is being actively conducted around the world. However, there are relatively many studies on large valves such as low-pressure valves or shipbuilding and marine, and the safety factor through structural analysis to check the structural integrity of the valve is checked at the design stage. Since it is necessary to have a fast response speed while minimizing pressure and speed loss due to flow change, basic research was conducted on the flow analysis of the valve to secure design data, and the numerical analysis was performed on high-pressure automatic shut-off valves applied to CNG refueling stations. After securing the basic valve shape through reverse engineering for advanced products, we compared the valve flow coefficient Cv coefficient with advanced products. As a result, it was found that the reverse engineering model was at the level of about 60%. However, we compared the Cv coefficient by modifying the reverse engineering model, and the result showed that it was improved to about 96%.

• 한국전기전자재료학회논문지
• /
• 제21권7호
• /
• pp.679-685
• /
• 2008

This paper describes the degraded properties of between the charge and discharge current for ${\gamma}$-ray irradiated in electric power cable rubbers using in nuclear power generating station. The charge and discharge current of degradation in EPR(Ethylene Propylene Rubber), which were irradiated with the radiant capacity of 0.033 Mrad/h, have been measured in order to investigate the influence of the atmosphere(in amount of reinforcing agent, moisture absorption and heat treatment) on electrical properties. When ${\gamma}$-ray were irradiated on the EPR with more reinforcing agent from 4 to 40 Phr, charge and discharge currents was increase due to the amount of reinforcing agent. It was verified that the discharging and charging currents irradiated by ${\gamma}$-ray were higher than those that was not irradiated. The amount of the degraded current was more after moisture absorption than before moisture absorption. The charge and discharge current after heat treatment was similar to that of before heat treatment and it was decreased with the time elapsed. As these properties related with ${\gamma}$-ray irradiation dose, it is suggested that these properties can be utilized as a index of irradiation degradation.

• 전기학회논문지
• /
• 제64권12호
• /
• pp.1776-1781
• /
• 2015

Electric power trains receive electric power from overhead cables via a pantograph system. Power collector system in trains increase the cross section of tunnel and require a massive coreless filter reactor in propulsion inverter because of the power disturbance by contact loss phenomenon of a train. In this paper we proposed a wireless train which can run to next station with charging energy of ultra-capacitor module block. We designed DC-DC converter to charge and discharge ultra-capacitor modules by using Next Train running test results and confirm the feasibility of the proposed system through simulation.

• 신재생에너지
• /
• 제18권2호
• /
• pp.50-59
• /
• 2022

The Korean government announced the "1st Basic Plan for the Transition to Hydrogen Economy" in 2021 and declared the establishment of a hydrogen industry ecosystem by 2040. To build a low-carbon power system, resources that can efficiently accommodate renewable energy are required, and green hydrogen is considered a potential solution. This study analyzed the economic feasibility of green hydrogen-based sector coupling to reduce curtailment of renewable generation in the Jeju power system by 2025 under the scenario of with or without HVDC#3. The result showed that HVDC#3 significantly reduced the frequency of curtailment from 16.1% to 3.0%. In addition, green hydrogen-based sector coupling was an economically feasible option as result showed an IRR of 4.86% when HVDC#3 was connected and 11.45% when it was not under the condition of achieving 50% curtailment reduction. This study shows that the higher the level of renewable energy deployment, the more delayed the HVDC connection between Jeju and the main land, and the lower the SMP, the more economically feasible the green hydrogen-based sector coupling is. Furthermore, this study suggests that the policy goal of completely reducing curtailment is not economically efficient.

• 한국유체기계학회 논문집
• /
• 제17권6호
• /
• pp.104-108
• /
• 2014

The recent Fukushima nuclear power plant accidents shows that the core make up at high RCS pressure condition is very important to prevent core melting. The core make up flow at high pressure condition should be driven by gravity force or passive forces because the AC-powered safety features are not available during a Station Black Out (SBO) accident. The reactor Coolant System (RCS) mass inventory is continuously decreased by releasing steam through the pressurizer safety valves after reactor trip during a SBO accident. The core will be melted down within 2~3 hours without core make up action by active or passive mode. In the new design concept of a Hybrid Safety Injection Tank (Hybrid SIT) both for low and high RCS pressure conditions, the low pressure nitrogen gas serves as a charging pressure for a LBLOCA injection mode, while the PZR high pressure steam provides an equalizing pressure for a high pressure injection mode such as a SBO accident. After the pressure equalizing process by battery driven initiation valve at a high pressure SBO condition, the Hybrid SIT injection water will be passively injected into the reactor downcomer by gravity head. The SBO simulation by MARS code show that the core makeup injection flow through the Hybrid SIT continued up to the SIT empty condition, and the core heatup is delayed as much.

• 한국인터넷방송통신학회논문지
• /
• 제21권1호
• /
• pp.189-194
• /
• 2021

최근 1인 가구의 비율이 높아짐에 따라 2016년을 시작으로 전동킥보드, 전동 휠 등 국내 공유형 퍼스널 모빌리티(Personnel Mobility) 시장이 급성장하였다. 전동킥보드와 같은 개인 형 이동수단은 전기를 사용한 동력장치로 친환경이고, 가벼우며 별도의 주차공간을 차지하지 않는다. 무엇보다 중단 거리를 이동하기에 편리하다는 장점이 있어 합리적인 소비를 추구하는 젊은 층 사용자들의 많은 수요를 얻을 수 있었고, 이에 따라 관련 시장이 빠르게 성장하였다. 하지만, 전동킥보드의 충전스테이션 부재로 사용이 완료된 전동킥보드들이 도로 곳곳에 방치되며 미관상뿐만 아니라 안전상의 위협요인으로 대두 되고 있다. 이에 본 논문은 공유 형 전동킥보드의 효율적 회수를 위한 새로운 IoT 관리 시스템을 연구하고, 제안하고자 한다. 이러한 시스템을 통해 전동킥보드의 높은 회수율을 유지하고, 결론적으로 사용자와 주변 환경의 안전성 향상을 도모할 수 있을 것으로 기대된다.

• 한국해양공학회지
• /
• 제35권1호
• /
• pp.1-12
• /
• 2021

As increasing the international community's awareness of greenhouse gas reduction, the demand for eco-friendly ship fuel has accelerated recently. The fundamental aim of this study is to develop a new type of fully electrified ferry for passengers and cars considering Korean domestic coastal environmental conditions. Several technical difficulties are encountered in applying a fully electric propulsion system based on removable battery systems into a ship due to limitations imposed by the batteries' size and capacity. This paper reviews and analyzes marine environment regulations strengthened recently, technology trends related to fully electric propulsion vessels in each country, and Korean domestic coastal environments. We propose a new fully electrified car ferry design with a displacement of 400 t applied in Korea. It is powered by removable battery systems pre-charged in a safe inland charging station. The mobile battery system is developed to enable roll-on and roll-off using wheels. The characteristics of the ship motion are analyzed based on the weight and location of the battery systems. We expect our battery systems to be applicable to larger ships in the future.