• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1996.04a
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• pp.107-110
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• 1996

연료전지 발전방식중 용융탄산염형 연료전지 발전방식은 동작온도가 $650^{\circ}C$의 고온에서 동작되기 때문에 발전효율이 높고 석탄가스를 연료로 사용할 수 있으며 또한 배기가스를 이용하여 복합발전시스템으로 구성할 수 있는 등 전력사업에 적용가능성이 가장 큰 새로운 발전방식이다. 이와 같은 이유로 전력연구원에서 개발하고 있는 2kW급 용융탄산염형 스택은 전극유효면적이 1,000$ extrm{cm}^2$인 단위전지를 20단 적층한 Co Flow형 MCFC스택으로, 연료로, 연료극에 H2, CO2, H2O 혼합가스를 그리고 산소극에는 공기, CO2 혼합가스를 이용하여 150A 정부하 상태에서 초기성능이 전압 14.28V, 출력 2.142W의 발전 운전시험에 성공하였고 이때 스택의 단위전지 평균전압은 0.714V를 나타내었다.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.350-351
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• 2018

본 논문은 가변속 양수발전 시스템의 모델링 및 양수발전용 전력변환장치 제어 구조를 분석하고 모델링하였다. 기존 양수발전 시스템은 동기 발전기를 사용하였지만 신재생 에너지원의 출력 변동 및 부하 변동에 따른 주파수의 변화에 빠른 대응을 위한 가변속 양수발전 시스템을 채용하여 계통 전력과 전압, 주파수 등을 보상한다. 양수 발전소의 터빈, 게이트, 조속기 등을 분석하여 모델링하였으며, Doubly fed induction generator를 위한 back-to-back 전력 변환 장치를 발전 및 양수 모드에 사용하기 위해 벡터제어, 속도제어, 유효-무효 전력 제어기 등을 모델링 하였다.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.1
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• pp.45-50
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• 2021

우리나라 서해안 및 동해안지역에는 대규모 발전단지가 집중되어 운영 중이며 이 발전단지들의 발전력을 송전하고 있는 765kV 송전선로 2 회선 고장이 발생하는 경우 송전선로의 용량부족으로 인해서 수 GW 규모의 발전력을 불시에 탈락시키도록 보호체계(SPS, Special Protection System)가 운영 중이다. 이 SPS 가 동작하여 대규모 공급능력이 불시에 상실되면 급격한 주파수 하락이 발생하게 되어 저주파수계전기(Under Frequency Relay, UFR)가 동작할 수 있기 때문에 SPS 탈락 발전기의 출력을 상시에 감소시키는 제약비발전(Constraint off)을 시행하고 있다. 이 제약비발전으로 인해 매년 수천억원의 제약비용이 발생하고 있기 때문에 제약을 완화시키기 위한 방안으로 배터리 에너지저장장치(BESS)를 적용하는 사업이 추진되고 있다. 이는 "발전제약완화 에너지저장장치(이하 발전제약완화용 ESS) 사업"으로 불리며 전국 19 개 변전소에 총 1.4GW(2C-Rate)의 에너지저장장치가 설치되는 국내 최대규모의 BESS 사업이다. 향후 송전망 확충에 의해서 발전제약이 해소되는 경우 주파수 조정용, 재생에너지 변동성 완화용 등의 다목적 ESS 로 활용될 계획이다. 본 보고서에서는 발전제약완화 ESS 사업의 기술적 효과를 실효치 기반의 시뮬레이션(PSS/E v33.3)을 통해서 검토하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.1
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• pp.45-52
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• 2023

The power generation method using expensive diesel has operation problems such as high cost diesel generator and a lack of reserved power due to increase of power demand in some islands, requiring expansion of power generation facilities. To solve this problems, it is necessary to improve the efficiency of power generation facilities through an ORC(Organic Rankin Cycle) system application that uses waste heat as a heat source. Therefore, localized application technology of price competitive and highly reliable ORC power generation system is needed, and optimization technology of generators is having great effect, so this study performed two generator designs to get a high-efficiency generator with an optimized 30kW output. The comparison of simulation data for two designed models showed that a generator with SPM factor of 46.2% had an efficiency of 92.1% and a power ouput of about 23.2kW based on 12,000rpm, a generator with SPM factor of 44.46%, had a power output of 27.9kW and efficiency of 93.6% based on above rpm. For the verification of improved design model with SPM factor of 44.46%, the prototype test system with 110kW motor dynamometer was installed and got to the efficiency of 92.08% with conditions of the rated capacity 25kW at 12,000rpm, the test results of prototype generator showed the validity of generator design.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.513-518
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• 2015

Salinity gradient power (SGP) has attracted significant attention because of its high potential. In this study, we evaluate reverse electrodialysis (RED) with various compositions of available resources. The polarization curve (I-V characteristics) shows linear behavior, and therefore the power density curve has a parabolic shape. We measure the power density with varying compartment thicknesses and inlet flow rates. The gross power density increases with decreasing compartment thickness and increasing flow rate. The net power density, which is the gross power density minus the pumping power, has a maximum value at a compartment thickness of 0.2 mm and an inlet flow rate of 22.5 mL/min. The power density in RED is also evaluated with compositions of desalination brines, seawater, river water, wastewater, and brackish water. A maximum power density of $1.75W/m^2$ is obtained when brine discharged from forward osmosis (FO) and river water are used as the concentrated and the diluted solutions, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.8
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• pp.661-668
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• 2015

We present a design methodology for horizontal-axis tidal turbine blades based on blade element momentum theory, which has been used for aerodynamic design and power-performance analysis in the wind-energy industry. We design a 2-blade-type 1 MW HATT blade, which consists of a single airfoil (S814), and we present the detailed design parameters in this paper. Tidal turbine blades can experience cavitation problems at the blade-tip region, and this should be seriously considered during the early design stage. We perform computational fluid dynamics (CFD) simulations considering the cavitation model to predict the power performance and to investigate the flow characteristics of the blade. The maximum power coefficient is shown to be about 47 under the condition where TSR = 7, and we observed cavitation on the suction and pressure sides of the blade.

• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.420-428
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• 2018

In this paper, represented uninterruptible power supply (UPS) equipment maintaining constant output voltage, the proposes a photovoltaic system constructed with a step up boosting chopper and single phase pulse width modulation (PWM) voltage source inverter. as power source disconnection, voltage variation and output current variation with load variation. This system is driven by being synchronized voltage fed inverter and AC source, and in the steady state of power source charge battery connected to DC side with solar cell using a Photovoltaic that it was so called constant voltage charge. It can be results of saving electric power, and through a normal operation of energy storage system (ESS), the system operated the LED a calling on signal changes at the airport in an efficient manner. In addition, better output waveform was generated because of PWM method, and it was proved to test by experiment maintained constant output voltage regardless of AC source disconnection, load variation, and voltage variation of AC power source.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.2
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• pp.54-63
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• 2007

Recently, a fuel cell with low voltage and high current output characteristics is remarkable for new generation system. It needs both a DC-DC step-up converter and DC-AC inverter to be used in fuel cell generation system. Therefor, this paper, consists of an isolated DC-DC converter to boost the fuel cell voltage $380[V_{DC}]$ and a PWM inverter with LC filter to convent the DC voltage to single-phase $220[V_{AC}]$. Expressly, a tapped inductor filter with freewheeling diode is newly implemented in the output filter of the proposed high frequency isolated ZVZCS PWM DC-DC converter to suppress circulating current under the wide output voltage regulation range, thus to eliminate the switching and transformer turn-on/off over-short voltage or transient phenomena. Besides the efficiency of 93-97[%]is obtained over the wide output voltage regulation ranges and load variations.

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.654-664
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• 2018

In this paper, this system is operated by PCS that is driven by being synchronized voltage fed inverter and AC source, and in the steady state of power source charge battery connected to DC side with solar cell using a photovoltaic (PV) that it was so called constant voltage charge. it can cause the effect of energy saving of electric power, from 10 to 20%. and through a normal operation of electric energy storage system (EESS). In addition, better output waveform was generated because of pulse width modulation (PWM) method, and it was Proved to test by experiment maintained constant output voltage regardless of AC source disconnection, load variation, and voltage variation of AC power source.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.6
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• pp.610-616
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• 2012

All the countries in the world is currently facing the full scale of energy-climate era currently, and making strong energy policy that will lead to green growth of the future energy resources by utilizing renewable energy as the basis of entering the advanced country becomes the goal of development that satisfies the demand for energy in 21st century. Recently, ocean energy attracted the attention along with the necessity of developing renewable energy. Ocean energy is the one of most prominent recyclable and clean resources that has not been developed yet. So, it is highly required to develop good tidal current energy conversion system in coastal area. The inflow angle that acts against tidal current turbine, seabed effect and the change of efficiency along the occurrence of cavitation were investigated through the wake flow characteristics in this study. Power coefficient degradation by seabed effect did not appear in the condition of this calculation. Efficiency degradation appeared from above $10^{\circ}$ regarding inflow angle and power coefficient was calculated as lower by 7 % at $45^{\circ}$. Torque and power coefficient increased as inflow velocity rose, but power coefficient degradation appeared from above 3m/s when the cavitation happened. So, it was recognized that the larger inflow angle and occurrence of cavitation become the reason for power degradation through the flow characteristics.