• 설비공학논문집
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• 제24권7호
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• pp.591-597
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• 2012

For the past few years, the concern for clean energy has been greatly increased. Ocean thermal Energy Conversion(OTEC) power plants are studied as a viable option for the supply of clean energy. In this study, we examined the thermodynamic performance of the OTEC power system for the production of electric power. Computer simulation programs were developed under the same condition and various working fluids for closed Rankine cycle, regenerative cycle, Kalina cycle, open cycle, and hybrid cycle. The results show that the regenerative cycle showed the best system efficiency. And then we examined the thermodynamic performance of regenerative cycle OTEC power system using the condenser effluent from Uljin nuclear power plant instead of the surface water. The highest system efficiency of the condition was 4.55% and the highest net power was 181 MW.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.719-728
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• 2015

This paper presents the results of field tests on Voltage Management System (VMS) using hybrid voltage control, which utilizes coordinated controls of various reactive power resources such as generators, FACTS and switched shunt devices to regulate the pilot bus voltage in a voltage control area. It also includes the results of performance test on RTDS-based test bed in order to validate the VMS before installing it in Jeju power system. The main purpose of the system is adequately to regulate the reactive power reserve of key generators in a normal condition with coordination of discrete shunt devices such as condensers and reactors so that the reserves can avoid voltage collapse in emergency state in Jeju system. Field tests in the automatic mode of VMS operation are included in steady-states and transient states. Finally, by the successful operation of VMS in Jeju power system, the VMS is proved to effectively control system voltage profiles in steady-state condition, increase system MVAR reserves and improve system reliability for pre- and post-contingency.

• 조명전기설비학회논문지
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• 제22권1호
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• pp.132-140
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• 2008

제주의 전력계통은 HVDC로 육지계통과 연계되어 있으며, 2곳의 풍력발전단지가 연계되어 있다. 향후 대용량의 풍력발전이 연계된 상황에서 HVDC Overhaul을 시행하거나 어떤 사고로 HVDC가 끊어진다면 제주계통을 정상적으로 유지하는 것이 어려울 수도 있다. 이에 본 논문은 Overhaul 및 풍력발전이 제주계통에 어떤 영향을 미치는지를 분석하기 위하여 지난 5월에 이루어진 Overhaul 기간에 변전소 2곳 및 풍력발전단지 2곳을 선정하여 전력품질을 측정하고 분석하였다. 또한 풍력발전량에 따른 인근 D/L의 전력품질을 측정함으로써 풍력발전이 전력계통에 미치는 영향을 분석하였고 그 영향정도가 명확하지 않은 부분에 대해서는 통계 데이터를 이용하여 분석하였다. Overhaul 기간에는 주파수가 매우 불안정하였으며, 전압왜형률이 규정치를 초과하기도 하였다. 풍력발전량에 비례한 고조파 전류가 계통으로 유입되었으며, 발전량이 3,000[kW] 이상일 때 인근 D/L의 전압파형이 발전량에 비례하여 왜곡되는 것을 확인할 수 있었다.

• 한국태양에너지학회 논문집
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• 제38권1호
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• pp.13-24
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• 2018

As part of the "Carbon free Island 2030" policy, the local government of Jeju Island is currently working to reduce carbon through renewable energy supply. However, renewable energy is difficult to predict due to intermittent characteristics. If the share of renewable energy increase, it is difficult to plan of supply of electricity to grid due to that characteristic of renewable. In this paper analyze the fluctuation rate and the capacity credit of wind power and PV to find out how much wind power and PV contribute to supply of electricity of power system in Jeju. As a result mean value of variation rate of wind power and PV is about 3%, 5% and capacity credit is about 10% and 2% respectively.

• 한국태양에너지학회 논문집
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• 제39권1호
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• pp.51-58
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• 2019

This paper deals with the operation of a hybrid power generation system made with photovoltaic cells and piezoelectric materials. The system can produce power from the wind as well as from the sun subject to their availability. Irrespective of the largeness of their power production, the power developed by both generators (i.e., phtovoltaic cells and piezoelectric cells) were combined and stored before it was applied to a load. Especially, the AC power (current) developed from each piezoelectric generator was converted by a full wave bridge rectifier and then combined prior to its storage in a capacitor. It was observed that the system can produce a maximum output power of 6.49 mW at loading resistance of $100{\Omega}$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.22-24
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• 2008

Construction of wind power plant is rapidly increasing since Jeju is known as the most suitable regarding wind power plants in Korea. But implementing wind power generation inevitably introduces new challenges due to its intermittent nature. In the paper, it is introduced the influence analysis and Han-Kyung wind power plants contribution on Jeju power system.

• 전기학회논문지
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• 제64권1호
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• pp.23-28
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• 2015

Two old synchronous condensers in Jeju are being replaced by new machines to operate Jeju AC network with Haenam-Jeju HVDC system stably. Before new synchronous condensers operate on site, voltage stability analysis is conducted to verify stable operation of jeju AC network. Through impedance analysis of the synchronous machine, transformer and ac network, the equivalent circuit is constructed and the voltage drop during start-up is calculated. Then, PSS/E fault analysis is performed to acquire short-circuit capacity according to the generator operation scenarios. Voltage variation when starting synchronous condenser is simulated in PSCAD/EMTDC and satisfies the operating condition of jeju AC network and HVDC #1 system.

• 전기학회논문지
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• 제58권9호
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• pp.1695-1699
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• 2009

This paper analyzed the characteristics of the demand of electric power in Jeju by year, day. For this analysis, this research used the correlation between the changes in the temperature and the demand of electric power in summer, and cleaned the data of the characteristics of the temperatures, using the coefficient of correlation as the standard. And it proposed the algorithm of forecasting the short-term electric power demand in Jeju, Therefore, in the case of summer, the data by each cleaned temperature section were used. Based on the data, this paper forecasted the short-term electric power demand in the exponential smoothing method. Through the forecast of the electric power demand, this paper verified the excellence of the proposed technique by comparing with the monthly report of Jeju power system operation result made by Korea Power Exchange-Jeju.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.388-389
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• 2013

This paper presents the method for the fluctuation smoothing control by using relaxation time variable control of battery. When the output power of wind farm is changed suddenly, it is necessary to control the output power of wind farm. The smoothing relaxation time is changed within limits of battery output power. Using the hybrid energy storage system (HESS) combined with battery energy storage system and electric double layer capacitor, it is possible to control the output power of wind farm. The capacity of battery is determined by considering the case of the disconnecting wind farm from the grid. To verify the proposed method, simulations are carried out by using PSCAD/EMTDC with actual data of wind farm in the Jeju Island.

• 한국태양에너지학회 논문집
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• 제35권3호
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• pp.57-63
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• 2015

This paper presents a solution by introducing energy storage system(ESS) to solve an annual blackout due to a typhoon or electrical failure in Udo Island. This island is now receiving electrical power through undersea cables from the Jeju Island. During blackout period, ESS will supply the electricity. And it is necessary to estimate the ESS capacity and control the transient state for the operation of stable power system. For the verification of proposed method, ESS capacities have been estimated according to base load and the minimum capacity of only home appliance in Udo Island. Also, in case of restoring from the fault, the algorithm for synchronization is proposed. Finally, the simulation results by using the PSCAD/EMTDC program will show the feasibility.