• 전기학회논문지
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• 제65권4호
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• pp.539-546
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• 2016

With the growing interest of microgrid systems all over the world, many studies on microgrid operation are being carried out. The battery energy storage system(BESS) and the diesel generator are key equipments in the microgrid. In this paper, we analyze the characteristics of fuel consumption according to the power ratio of the diesel generator. Then, the formula to represent the unit cost of generation according to the power ratio of the diesel generator is derived. A new modeling of battery operation is presented considering the lifetime reduction according to increasing the cycles of charge/discharge operation of the battery. The methodology of determining the optimal operation of the battery and the diesel generator is presented by the use of the formula of fuel consumption of the diesel generator and the new modeling of battery operation. It is shown that this optimization methodology can be applied effectively for economical operation of the BESS and the diesel generator of a microgrid by case studies.

• 한국도로학회논문집
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• 제16권6호
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• pp.51-57
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• 2014

PURPOSES : An conventional method for electric power generation is converting thermal energy into mechanical energy then to electrical energy. Due to environmental issues such as global warming related with $CO_2$ emission etc., were the limiting factor for the energy resources which resulting in extensive research and novel technologies are required to generate electric power. Thermal energy harvesting using thermoelectric generator is one of energy harvesting technologies due to diverse advantages for new green technology. This paper presents a possibility of application of the thermoelectric generator's application in the direct exchange of waste solar energy into electrical power in road space. METHODS : To measure generated electric power of the thermoelectric generator, data logger was adopted as function of experimental factors such as using cooling sink, connection methods etc. Also, the thermoelectric generator、s behavior at low ambient temperature was investigated as measurement of output voltage vs. elapsed times. RESULTS : A few temperature difference between top an bottom of the thermoelectric generator is generated electric voltage. Components of an electrical circuit can be connected in various ways. The two simplest of these are called series and parallel and occur so open. Series shows slightly better performance in this study. An installation of cooling sink in the thermoelectric generator system was enhanced the output of power voltage. CONCLUSIONS : In this paper, a basic concepts of thermoelectric power generation is presented and applications of the thermoelectric generator to waste solar energy in road is estimated for green energy harvesting technology. The possibility of usage of thermoelectric technology for road facilities was found under the ambient thermal gradient between two surfaces of the thermoelectric module. An experiment results provide a testimony of the feasibility of the proposed environmental energy harvesting technology on the road facilities.

• Journal of Power Electronics
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• 제8권1호
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• pp.10-22
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• 2008

The wind-driven doubly fed induction generator (DFIG) is currently under pressure to be more grid-compatible. The main concern is the fault ride-through (FRT) requirement to keep the generator connected to the grid during faults. In response to this, the paper introduces a novel model and new control scheme for the DFIG. The model provides a means of direct stator power control and considers the stator transients. On the basis of the derived model, a robust linear quadratic (LQ) controller is synthesized. The control law has proportional and integral actions and takes account of one sample delay in the input owing to the microprocessor's execution time. Further, the influence of the grid voltage imperfection is mitigated using frequency shaped cost functional method. Compensation of the rotor current pulsations is proposed to improve the FRT capability as well as the generator performance under grid voltage unbalance. As a consequence, the control system can achieve i) fast direct power control without instability risk, ii) alleviation of the problems associated with the DFIG operation under unbalanced grid voltage, and iii) high probability of successful grid FRT. The effectiveness of the proposed solution is confirmed through simulation studies on 2MW DFIG.

• Nuclear Engineering and Technology
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• 제38권4호
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• pp.391-398
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• 2006

It is recommended to clean steam generators of nuclear power plants during plant outages. Under normal operations, sludge is created and constantly accumulates in the steam generators. The constituents of this sludge are different depending on each power plant characteristics. The sludge of the Kori Unit 1 steam generator, far example, was found to be composed of 93% ferrous oxide, 3% carbon and 1% of silica oxide and nickel oxide each. The research to develop a lancing system that would remove sludge deposits from the tubesheet of a steam generator was started in 1998 by the Korea Electric Power Research Institute (KEPRI) of the Korea Electric Power Corporation (KEPCO). The first commercial domestic lancing system in Korea, the $KALANS^(R)-I$ Lancing System, was completed in 2000 for Kori Unit 1 for cleaning the tubesheet of its Westinghouse Delta-60 steam generator. Thereafter, the success of the development and site implementation of the $KALANS^(R)-I$ lancing system for YGN Units 1&2 and Ulchin Units 3&4 was also realized in 2004 for sludge removal at those sites. The upper bundle cleaning system for Westinghouse model F steam generators is now under development.

• KIEE International Transactions on Power Engineering
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• 제5A권1호
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• pp.31-39
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• 2005

This paper illustrates a tie line constrained equivalent assisting generator (TEAG) model considering forced outage rates of transmission systems for reliability evaluation of interconnected power systems. Interconnections between power systems can provide improved levels of reliability. It is expected that the TEAG model developed in this paper will prove useful in the solution to problems related to the effect of transmission system uncertainties in the reliability evaluation of interconnected power systems. It is important that interconnection between power systems can provide the improved levels of reliability. Therefore, It is expected that the TEAG model developed in this study will provide some solution among many problems for interconnected power systems as an optimal tie line capacity and a connected point between assisting systems and assisted system. The characteristics and validity of this developed TEAG considering transmission systems are introduced by case study of three IEEE MRTS interconnected.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 전력전자학술대회 논문집
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• pp.95-96
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• 2014

450mm 반도체 CVD 장비 개발 및 300mm F-CVD (Flowable CVD) 공정 개발에 있어서 공정 마진 확보 및 막질 품질 개선을 위해 주파수 가변형 RF Generator가 필수적으로 요구되고 있다. 20nm이하 STI (Shallow Trench Isolation), PMD (Pre-metal Dielectric) & IMD (Inter-Metal Dielectric) 미세공정 gap fill에 많은 문제점이 도출되고 있으며, 이유로는 Generator 고정 주파수에서 Matching Time delay 또는 Shooting에 의한 산포의 한계로 파악되었으며, 주파수 가변에 의한 고속 Tune 기능이 요구되어진다. 따라서 400kHz 주파수 가변형 RF-Generator 개발을 진행하였으며 본 논문을 통해 개발되어진 장비의 성능과 시험 평가한 결과를 소개하고자 한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.601-604
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• 1996

It is well known that steam generator water level control at low power operation has many difficulties in a PWR (pressurized water reactor) nuclear power plant. The reverse process responses known as shrink and swell effects make it difficult to control the steam generator water level at low power. A new automatic control logic to remove the reverse process responses is proposed in this paper. It is implemented in PLC (programmable logic controller) and evaluated by using test equipment in Korea Atomic Energy Research Institute. The simulation test shows that the performance requirements is met at low power (below 15%). The water level control by new control logic is stabilized within 1% fluctuation from setpoint, while the water level by YGN 3 and 4 control logic is unstable with the periodic fluctuation of 25% magnitude at 5% power.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.74.5-74
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• 2001

The wave power plant is a generating system to convert the wave energy resources to electric energy. ´CHUJEON A´, which is a prototype of wave power plant developed by KORDI(Korea Ocean Research and Development Institute), has been launched for its performance test. A wound rotor induction machine is adopted as a generator for the power plant to acquire constant frequency and voltage over wide range of rotor speed. Because the generator of ´CHUJEON A´ has no connection to the power grid line on land, all of the processes to generate and consume the electricity have to be conducted on the floating plant. This paper deals with the design and implementation of the unmanned control system for ´CHUJEON A´. The system includes generator control system, power conversion and charging system, data acquisition and wireless communication system ...

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1769-1773
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• 1996

The remaining life of generator stator winding has been the controversial issue amomg many experts in this area. The report from Japan claims that they can predict the remaining life of generator winding, while the North American has the negative opinion about it. This study aimed at verifying the validity of both Japanese criteria and North American argument on evaluation of generator winding insulation. Non destructive and destructive tests were performed on two hydro-generators. The test results showed that the trend analysis of stator winding insulation was the better option.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.398-403
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• 1998

This paper describes a controller design for the stator reactive power generator in the transmission system. The controller of static reactive power generator was designed using a mathematical model and non-linear state feedback. The performance of controller was verified using computer simulation with EMTP code and experimental work with scaled-model. The dynamic interaction with a simple power system was also analyzed using both the simulation model and hardware scaled-model. Both simulation and experimental results prove that the controller using PI block and non-linear state feedback offers better performance than the controller using PI block only.