• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.11
• /
• pp.746-752
• /
• 2020

As environmental issues have been taken seriously, the number of solar power generation facilities has rapidly increased in Korea. The voltage at the output stage of an inverter increases in a system that connects a small-capacity photovoltaic power generation to low-voltage power distribution. This degrades the quality of the low-voltage distribution system and adversely affects the load facility. In this study, a solution was obtained to increase the voltage at the output stage of the solar inverter according to the connection of the low-voltage distribution system. The voltage can be controlled by using reactive power factor control inverters. If the secondary tap is adjusted, the voltage can be adjusted to about 15 V, but there is a problem in that the tap is not adjusted unless the KEPCO distribution regulation voltage is out of the range of 220±13V. If the number of inverters is limited, the inverter can be started within the inverter overvoltage range. If it is connected to three phases, the voltage is distributed. The results indicated that power factor control and active voltage control inverters were easy to apply in the field.

• Journal of the Korean Solar Energy Society
• /
• v.34 no.6
• /
• pp.19-25
• /
• 2014

Alternative sources of energy take a higher interest in order to reduce the greenhouse gas under the Climate Change Convention, fossil fuel consumption, and lower social anxiety about nuclear power such as crisis involving the Fukushima plant, problem of obsolete equipment. The energy consumption of agriculture, forestry and fisheries in South Korea is 3,082,000toe by 2011, reliance on electrical energy(35%) and oil(57.2%) is very high with 92.2%. In this study, we examined reserves and available capacity of temperature difference energy for thermal discharge from plant, treated sewage, river water, dam, and agricultural reservoir in rural community. Reserves of unutilized energy are 455,735Tcal/yr in rural community, these accounts for 78% of total reserves 582,385Tcal/y. Thermal discharge from plant has the most reserves of unutilized energy in rural community, it is estimated that it has the reserves of 277,410Tcal/y. Available capacity of unutilized energy in rural community is total 134,147Tcal/y, thermal discharge from plant available for heating is the most 128,035Tcal/y, and it shows in the order of treated sewage 4,318Tcal/y, river water 1,653Tcal/y, and reservoir 141Tcal/y. Elevating temperature area of green house by 2012 is 21,208ha. The amount of energy required for heating the greenhouse a year is dbout 11,365Tcal/y with 8.5% of the total available capacity of unutilized energy.

• Journal of Korea Multimedia Society
• /
• v.23 no.9
• /
• pp.1171-1180
• /
• 2020

The number of the PV systems installed in south korea has been gradually increasing. Interest of operation & management of PV System is rising up as PV System installation trends to increase. The vital function of operation & management is the monitoring system. Most monitoring systems are only available for equipment of suppliers and manufacturers. In this study, a monitoring system was implemented to support multi-domain equipment (inverter, junction box, water distribution board, environmental sensors) that are not limited to specific manufacturers. Monitoring system includes a visualization function, which makes it easy for users to check the power generation and the operation status of the equipment of PV System. In the future, this monitoring system will be utilized as an operation & maintenance foundation element in the PV system industry.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2011.05a
• /
• pp.216-219
• /
• 2011

신.재생에너지는 머지않아 고갈될 것이라 예측하고 있는 화석에너지의 대체에너지로서 대형 홍수와 국지적 집중호우, 가뭄과 전염병, 기근 등 우리인류의 생존을 위협하는 재앙을 어느 정도 줄일 수 있고, 온실효과 가스를 저감하고자 하는 하나의 방법으로서 가스배출량이 적은 수력, 풍력, 태양광 등의 재생에너지를 이용한 방법이다. 이 중 물은 무한적인 자원이 아니기 때문에 소중히 여기고 순환과정을 통하여 재활용 될 수 있고, 친환경적이고 장기적인 수명과 다른 자원을 사용하는 발전소들보다 더 효율적이며 복원 가능성이 크고 다른 오염유발 에너지 자원을 대신한다. 본 연구에서는 경상북도 북부지역 5개 지점의 소수력발전 후보지점에 대한 평 갈수기 및 홍수기의 유량측정에서 수위-유량관계곡선식의 유도등의 목적을 달성하기 위하여 2009년 3월부터 2010년 9월까지 5개 지점을 대상으로 현지조사 및 자료수집, 측량작업, 유량측정 등을 실시하였다. 본 유량측정을 통하여 경상북도 북부지역의 최적 소수력 발전지점 선정을 위한 기초자료를 제공할 수 있을 것으로 판단된다.

• Journal of Environmental Impact Assessment
• /
• v.19 no.6
• /
• pp.625-631
• /
• 2010

The objective of this work was to investigate how carbon sink and sequestration of vegetation and soil in the development project area can impact the land use plan, in addition to carbon emission capacity of the development project when we conduct environmental impact assessment. Especially, we did this work for a development project of solar power plant which would be constructed in forest area. Through this work, we found that 1) the amount of carbon sink and sequestration largely decreased due to reduction of the green area, 2) in terms of carbon sink and sequestration, conservation of natural green area is better than construction of newly vegetated area, 3) biochar application into soil can become an alternative for increase of carbon sink, and 4) even though a solar power production does hugely reduce carbon emissions and offset the carbon sink and sequestration capacity from the forest, it is necessary to consider the public value of the forest(reduction of heat island, habitat etc.) in siting for development area.

• Journal of IKEEE
• /
• v.23 no.1
• /
• pp.151-158
• /
• 2019

In this paper, we construct a Virtual D-STATCOM using a number of grid-connected inverters installed in solar and wind power plants and compensate the reactive power of the cable depending on the reactive power of the load of the power distribution system and the distance to the power distribution line We propose a method to compensate the reactive power of the PCC stage near the substation without installing the existing single large capacity D-STATCOM. The proposed method is verified by Matlab Simulink simulation and its operation principle and reactive power compensation.

• Journal of Energy Engineering
• /
• v.25 no.2
• /
• pp.94-100
• /
• 2016

ESS(Energy Storage System) is an important source that keeps power supply stable and utilizes electricity efficiently. For example, ESS contributes to resolve power supply imbalance, stabilize new renewable energy output and regulate frequency. ESS is predicted to be expanded to 55.9GWh of installed capacity by 2023, which is 30 times more than that of 2014. To raise competitiveness of domestic ESS industry in this increasing world market, we have disseminated load-shift ESS for continuous power supply imbalance with FR ESS, and also necessity to secure domestic track record is required. However in case of FR ESS, utility of installing thermal power plant is generally generated within 5% range of rated capacity, so that scalability of domestic market is low without dramatic increase of thermal power plant. Necessity of load-shift ESS dissemination is also decreasing effected by surplus backup power securement policy, raising demand for new dissemination model. New dissemination model is promising for $CO_2$ reduction effect in spite of intermittent output. By stabilizing new renewable energy output in connection with new renewable energy, and regulating system input timing of new renewable energy generation rate, it is prospected model for 'post-2020' regime and energy industry. This research presents a policy alternatives of REC multiplier calculation method to induce investment after outlining PV-connected ESS charge/discharge mode to reduce GHG emission, This alternative is projected to utilize GHG emission reduction methodology for 'Post-2020' regime, big issue of new energy policy.

• Journal of Energy Engineering
• /
• v.26 no.2
• /
• pp.99-120
• /
• 2017

In SS branch of Korea District Heating Corporation, Combined Heat & Power power plant with 99MW capacity and 98Gcal / h capacity is operated as a district electricity business. In this region, it is difficult to operate the generator due to the problem of surplus heat treatment between June and September due to the economic recession and the decrease in demand, so it is urgent to develop an economical energy new business model. In this study, we will develop an optimized operation model by introducing a renewable energy hybrid system based on actual operation data of this site. In particular, among renewable energy sources, fuel cell (Fuel Cell) power generation which can generate heat and electricity at the same time with limited location constraints, photovoltaic power generation which is representative renewable energy, ESS (Energy Storage System). HOMER (Hybrid Optimization of Multiple Energy Resources) program was used to select the optimal model. As a result of the economic analysis, 99MW CHP combined cycle power generation is the most economical in terms of net present cost (NPC), but 99MW CHP in terms of carbon emission trading and renewable energy certificate And 5MW fuel cells, and 521kW of solar power to supply electricity and heat than the supply of electricity and heat by 99MW CHP cogeneration power, it was shown that it is economically up to 247.5 billion won. we confirmed the results of the improvement of the zone electricity business condition by introducing the fuel cell and the renewable energy hybrid system as the optimization process model.

• Journal of Energy Engineering
• /
• v.15 no.1 s.45
• /
• pp.74-81
• /
• 2006

In this study, on the basis of an analytic hierarchy process (AHP) method and through a questionnaire on subjective preference and importance, various power supply systems were comprehensively compared with multiple decision criteria such as environmental, social, healthy, and economic viewpoints and then overall priority was assessed. When a decision-making problem is modelled by a hierarchy structure, the AHP method is regarded as a useful tool for extracting subjective opinions via the aforementioned questionnaire. Here, the overall preferences were obtained by linearly aggregating weighting vector and preference matrix. The energy systems such as nuclear, coal, and LNG power plants were selected because they took share over 90% of domestic electricity supply in Korea. Furthermore, wind power and photovoltaic solar systems were included as representative renewable energy systems in Korea. According to the results of this demonstration study, the following comprehensive comparison indicators were yielded: 1) weighting factors for 4 types of main criteria as well as for 11 types of sub-criteria; 2) preference valuation for 7 types of energy systems under consideration; 3) overall score for each energy systems.

• Journal of the korean veterinary medical association
• /
• v.46 no.4
• /
• pp.342-362
• /
• 2010

최근 국내의 각종 공사장부근에서 일어나는 가축에 대한 환경분쟁(소음, 진동, 먼지 등)피해를 호소하는 농가가 지속적으로 늘고 있으나, 피해 농가의 피해를 입증할 수 있는 객관적인 자료가 부족한데 따라 보고서를 작성하는 데 여간 어려웠던 적이 한, 두번이 아님에 많은 아쉬움을 가졌다. 각종 공사로 인해 가축 사육 장소인 목장(농장)내 도로개설 및 관통으로 인한 목장의 지속여부, 겨울철 수렵시기에 총성으로 인한 한우 성장지연, 육질 저하 등에 미치는 영향, 태양광 발전소가 축사 인근에 있어 사육 한우가 성장지연 등의 피해를 호소하는 농가가 있으나, 이에 대한 관련 연구자들의 많은 연구가 이뤄졌으면 한다. 그런 가운데서 우리 임상수의사들의 관련 자료나 정보를 입수하여 보다 적극적으로 대처하여 피해 축산농가들에 대한 보상에 도움을 줘야 하나, 피해 목장내 사육가축의 진단서나 소견서등 발부요청에 미온적이거나 회피하는 경우들을 적잖게 목도를 하고 실망감을 감출 수가 없었다. 진단서 등의 각 항목의 기재 내용의 누락, 여러 마리를 한 장(1두 1매 원칙)에 작성한다거나 유 사 조산시 정확한 월(일)령의 비기재, 환경분쟁과 관련된 피해사실의 누락이나 전혀 무관한 병명으로 발급하는 경우 및 수의사법 등에서 승인된 양식을 이탈하여 임의로 작성하는 등의 예를 간혹 보아왔는 터라 개선이 시급하다 하겠다. 임상 수의사들이 발급하는 진단서나 소견서 등은 어디까지 관련 전문가나 법원 등의 감정시 어디까지나 참고용으로 활용되고, 발급에 따른 제 비용은 인정될 경우에는 피해농가들에게 되돌려주며, 절대적으로 피해를 주는 일이 없다는 것을 강조해두고 싶다. 따라서 필자는 환경분쟁사건을 현지조사내지는 보고서를 작성하면서 아직도 우리 임상 수의사들은 새로운 분야에 대한 능동적인 대처가 더더욱 요구되는 시기에 수동적이거나 미온적으로 대하는 사례에 안타까움을 호소하며, 환경분쟁시 가축에 미치는 영향과 최근 새로이 제시된 배상액의 산정기준을 소개하여 도움을 주고 싶다.