• 한국군사과학기술학회지
• /
• 제20권5호
• /
• pp.717-725
• /
• 2017

Traditionally, a design has been applied on a various defense area for the improvement of the mobility, reducing the radar detection area and other reasons. In case of Korean Wheeled Armored Vehicle(WAV), a design has been also applied for retaining the agility and threatening feature in the battlefield. However some figures has been changed because of constraints such as assembling and manufacturing in the development stage. Today, the government has planned to develop the Wheeled Armored Command Post Vehicle(CPV), a variant of WAV, and it is necessary to apply the latest design trend, which is suitable for the concept of the CPV, on it.

• KEPCO Journal on Electric Power and Energy
• /
• 제2권3호
• /
• pp.425-431
• /
• 2016

Supply Capability of the generator, if the maximum demand occurs, refers to the maximum power that can be stably supplied and it is possible to maintain stable power supply to be greater than actual load. However, unexpected power demand and reduction in supply Capability due to stop of unexpected generator in operation can temporarily make a big chaos in power system. In fact, due to a lack of power supply Capability in the country, enforced emergency load adjustment to the September 15, 2011, the circulation power outage has occurred in several cities. As the result, interrupted operation of the elevator and stopped hospital medical equipment led to a great deal of trouble to people's lives, causing a social problem. At that time, it was found that a failed frequency control because of smaller actual supply Capability than that of predicted. The difference was about 1,170 MW with Gas turbine power plant. By accurately calculating the generator supply capability, we can not only grasp the power reserve rate, but also correspond to the time of power supply instability.

• 한국산학기술학회논문지
• /
• 제12권5호
• /
• pp.2279-2284
• /
• 2011

기존의 수지상 배전계통은 사고 등에 대한 설비보호 및 전력공급 신뢰도 향상을 위하여 과전류보호협조방식을 채택하고 있다. 국내 배전계통의 경우, 그 보호방식 협조체계는 배전용변전소 동일 변압기 동일 모선에서 다수의 배전선이 각각 CB(변전소 차단기)를 통하여 인출되어 각 배전선로 이하에서 사고발생시 고장전류를 검출하여 해당 CB를 차단하도록 되어있다. 그러나, 이와 같은 보호방식을 채용하고 있는 배전계통에 분산전원이 도입될 경우 변전소 인출차단기의 차단용량은 영향을 받게 되므로 충분한 검토가 필요하다. 본 논문에서는 분산전원 도입시, 국내 배전용 변전소의 인출차단기에 대한 차단용량을 초과하지 않는 보호협조방법을 제시하고, 이를 PSCAD-EMTDC 계통해석 S/W Tool에 의하여 모의하여 검증하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2011년도 제42회 하계학술대회
• /
• pp.1406-1407
• /
• 2011

태양광발전은 태양의 복사에너지를 직접 전기에너지로 변환하는 시스템으로 가동부분이나 열기관이 없어 수명이 길고 운전과 유지보수가 용이하며 모듈로 구성되기 때문에 수요나 지형에 맞게 설계할 수 있다. 이러한 특성으로 인해 태양광 발전은 차세대 성장 에너지원으로 각광 받고 있으며, 최근 문제되고 있는 지구환경문제 해결에도 부합할 수 있는 잠재력을 갖고 있다. 또한 계통 연계형 태양광 발전시스템의 확대 보급시 태양광 발전시스템의 출력특성에 의한 기존 전력계통의 피크전력을 감소시키는 효과도 기대할 수 있다. 국내 태양광발전은 정부 지원정책에 힘입어 지속적으로 보급이 확대되고 있으며, 2009년도 기준으로 약 400 MWp 이상의 설비가 전력시장에 진입하여 상업 운전중에 있다. 태양광발전시스템은 육상에 설치하는 것이 주류를 이루고 있었으나 태양광 입지조건에 적합한 부지를 확보하는 것이 쉽지않기 때문에 최근에는 건물옥상이나 벽에 설치하는 사례가 증가되고 있다. 본 논문에서는 한전전력연구원(대전시 유성구 문지동)의 건물옥상에 설치되어 운전하고 있는 9.52kW급 BIPV 형식의 태양광발전시스템을 대상으로 2010년도 1년간의 운전특성에 대하여 분석 평가하고 이를 통해 BIPV시스템의 운전에 대한 기초자료를 제시하고자 한다.

• 한국산학기술학회논문지
• /
• 제11권10호
• /
• pp.3898-3904
• /
• 2010

본 논문에서는 저압배전계통에 연계되어 있는 분산전원의 과도특성을 해석하기 위하여, 실 계통을 모의하여 구축한 분산전원 실증시험센터의 설비를 이용하여, 순간전압강하, 순간전압상승, 고조파, 순간정전 등 배전계통에서 일어날 수 있는 비정상 상태 요소를 발생시켜, 분산전원의 과도특성을 해석하였다. 본 연구에서 제시한 과도특성에 대한 시험결과에 의하여, 분산전원 계통연계기술기준(가이드라인)에서 정해진 각종 규정에 대하여 저압선로에 연계되어 운용되고 있는 분산전원의 적합여부를 파악할 수 있었어, 본 연구의 유효성을 확인할 수 있었다.

• KEPCO Journal on Electric Power and Energy
• /
• 제3권1호
• /
• pp.9-16
• /
• 2017

The performance test is conducted for the purpose of determining the accurate thermal performance of the power generation facility or deriving the factors of thermal efficiency degradation. Compared to the acquisition method of power plant thermal performance test data by compensating cable or transmission cable, performance test using wireless instrument can acquire digital data in order to shorten the period due to installation and demolition of instrument and enhance safety of workers and relatively accurate data can be acquired thereby improving work efficiency. Wireless instruments have already been introduced to the market a long time ago, and some of them are used in industry such as petrochemical industry. However, there is no example which has been conducted for performance test of power generation facilities. In order to apply power generation facilities, a reliable system capable of acquiring performance data smoothly without affecting the control system is required. The wireless measurement system can eliminate the measurement defects and errors such as the damage due to the movement of the connecting cable, the extension due to the extension of the shield wire, the contact failure at the contact point between the measuring sensor and the connecting wire, This method has the advantage of collecting relatively accurate performance test data.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
• /
• pp.110.1-110.1
• /
• 2011

This study analyzed the performance of long term operation photovoltaic system The 50 kWp grid connected photovoltaic system which was installed at KEPRI site in 1999 has been operated more than 12 years. In order to acquire long term operation characteristics of medium size photovoltaic system, the operation test data related on power generation electricity and capacity factor of 50 kWp system, which have been collected since 1999, were analysed. From the analysing results, 57.7 MWh in annual power generation electricity of 50 kWp photovoltaic system in 1999 has been decreased 49.1 MWh in 2005 and reached 38.0 MWh in 2010. In addition to, the capacity factor of 50 kWp photovoltaic system also showed 13.2 % in 1999, 11.2% in 2005 and finally reached 8.8% in 2011. The operation test data showed a trend of decreasing of generation electricity and capacity factor during the 12 years operation time and we guessed that was caused by solar cell performance degradation and decreasing of PCS system efficiency.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
• /
• pp.109.2-109.2
• /
• 2011

A photovoltaic system is getting the spotlight for a environment-friendly energy source. But its location is limited because a lot of land is necessary for photovoltaic arrays. Nevertheless, its dissemination is rapidly increasing more than 40 % every year and exceeded about 400 MW in 2009. The radical growth of a photovoltaic system aggravated a lack of sites, so that forests and farmland were destroyed. It is demanded to make use of a vacant lot or little piece of land for the way to solve the lack of sites and improve the location requirements for a photovoltaic system. General photovoltaic arrays are consist of a single layer structure and needs enough separation distances to maximize the amount of solar radiation and to eliminate influences by the shadow of other arrays. So that a large amount of land is required for the site. The solar cell arrays with long separation distances can not be placed in a small vacant lot and its site application efficiency is low. This study optimized photovoltaic arrays as multilayered structure with movable sleeves for the efficient photovoltaic in a small site. The existing photovoltaic arrays with a single layer structure were fixed or tracking systems. In this experimental equipment, photovoltaic arrays attached to the multilayers have rectilinear movement and rotary motion using sleeves. Therefore, shadow influences were removed and the generation capacity was improved. On the simulation result, generation increased by about 30% in the same site considering shadow influences and so on.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
• /
• pp.109.1-109.1
• /
• 2011

KEPCO was operating power plants with diesel generators in 49 islands including Baekryeong-Do, and the generation capacity was about 66 MW in 2008. The cost of fuel is increasing by the international oil price inflation and continuous rise of oil price is predicted. For the stabilizing of electric power supply to the separate islands, renewable energy and fuel cell systems were considered. Hydrogen is made using renewable energy such as wind power and solar energy, and then a fuel cell system generates electricity with the stored hydrogen. Though the system efficiency is low, it is treated as the only way to secure the stable electric supply using renewable energy at this present. The analytic hierarchy process was used to select suitable candidate island for the system installation and 5 islands including Ulleung-Do were selected. Economic evaluation for the system composed of a kerosene generator, a wind power, an electrolysis, and a fuel cell system was conducted with levelized generation cost based on present value methode. As the result, the necessity of renewable energy combined generation system and micro grid composition in the candidated islands was confirmed. Henceforth, the development of an integration technology which connects micro grid to the total power grid will be needed.

• 신재생에너지
• /
• 제7권2호
• /
• pp.28-35
• /
• 2011

Recently, photovoltaic systems have been devolved into much larger systems up to MW-scale. Photovoltaic industry participants give their focus on power generation capability of photovoltaic modules because their benefits can be decided from the amount of generation. The information on long-term performance change of photovoltaic modules helps to estimate the amount of power generation and evaluate the economic cost-benefits. Long-term performance of a PV system has been analyzed with operation data for 12 years from 1999 to 2010. In the first year, the amount of yearly power generation was 57.7 MWh with 13.2% capacity factor. In 2007, the amount of yearly generation was 44.3 MWh with 10.14% capacity factor, and in 2010, the amount was decreased down to 38.1 MWh with 8.7% capacity factor. The result means that long-term capacity factor has been 4.5% decreased for 12 years and that the amount of generation has been decreased 34.0% for 12 years which is 2.8 % per year. The latter capacity factor has been decreased faster than 0.20%, the average rate for 10 years. The performance decrease of the PV system is meant to be accelerated. The decrease of performance and utilization is due to aged deterioration of photovoltaic modules and lowering conversion efficiency of PCS.