• Journal of Power System Engineering
• /
• v.9 no.2
• /
• pp.93-98
• /
• 2005

The performance of cooling tower is dependent on the thermal performance of the packings. It's assessed by heat transfer rate and fan power. In this study, new packing was developed for application in compact type cross-flow cooling tower. The packing characteristic curve and the pressure drop curve were obtained by measuring packing characteristic values and pressure drops of small sized filler in comparison to existing mid-large sized filler. The heat transfer characteristics on small sized filler are about 66% higher than existing mid-large sized filler. The pressure drop characteristics on small sized filler are about two times of the pressure drop characteristics on existing mid-large sized filler.

• Proceedings of the KIEE Conference
• /
• 2003.10b
• /
• pp.278-282
• /
• 2003

This paper presents TPS(Train Performance Simulation) which identified the condition of train operationing in short time. Using the program, the location of train, maximum current, metering power and regenerating of train, could be identified. This is an important part for Power Simulation. It is supposed that the grade, the curve, the limit speed and the current speed be constant within the time step in the conventional papers. In addition, the errors of the grade and the curve in each station interval are neglected. This paper will introduce improvement method the problem of TPS.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.448-451
• /
• 2005

This paper presents the methodology to analyze flow duration characteristics and performance prediction for small hydro power(SHP) plants and its application. The flow duration curvecan be decided by using monthly rainfall data at the most of the SHP sites with no useful hydrological data. It was proved that the monthly rainfall data can be characterized by using the cumulative density function of Weibull distribution and Thiessen method were adopted to decide flow duration curve at SHP plants. And, the performance prediction has been studied and development. One SHP plant was selected and performance characteristics was analyzed by using the developed technique. Primary design specfications such as design flowrate, plant capacity, operational rate and annual electricity production for the SHP plant were estimated. It was found that the methodology developed in this study can be a useful tool to predict the performance of SHP plants and candidate sites in Korea.

• Proceedings of the KIEE Conference
• /
• 2005.07a
• /
• pp.736-738
• /
• 2005

For calculating optimal generation composition of The Basic Plan of Long Term Electricity Supply & Demand, the Screening Curve Method that using generation cost for planning is needed. This paper will induce optimal power system ratio included Combined Head and Power and suggest the method for optimal generation composition of The Basic Plan of Long Term Electricity Supply & Demand that considered policy side.

• Proceedings of the KIEE Conference
• /
• 1992.07a
• /
• pp.106-109
• /
• 1992

This paper Introduces the concept of the generation cost of generating utilities and its calculation methods. Also, the economic evaluation method using generation cost which is called as a screening curve method will be presented along with the benefits and disadvantages of this concept. Next, the least-cost electric utility planning techniques which is used very widely in many countries will be Introduced In comparison with screening curve method. In this aspects, the optimal dynamic mix can be determined as a result. By comparing these two concepts, we will get the concrete concept why the economic evaluation method using generation cost can not be used for the future generation expansion planning.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.8 no.5
• /
• pp.72-82
• /
• 1998

Power transformer protective relay should block the tripping during magnetizing imrush and rapidly operate the tripping during internal faults. But traditional approaches maloperate in the case of magnetizing inrush with low second harmonic component and internal faults with high second harmounic component. To enhance the fault detection sensitivities of conventional technuques, flux-differential current derivative curve by fuzzy theory approaches is used. This paper deals with fuzzy logic based protective relaying for power transformer. The proposed fuzzy based relaying algorithm consisits of flux-differential current derivative curve, harmonics restraint, and precentage differential characteristic curv. The proposed relaying was tested with relaying signals obtained from Salford EMTP simulation package and showed a fast and accurate trip operation.

• Journal of Magnetics
• /
• v.16 no.2
• /
• pp.129-133
• /
• 2011

This paper shows the entire future market volume of the HTS power industry, one of main smart grid equipment, in the case of the final market penetration ratio reaching 100% in the domestic market (South Korea). In this paper, the market penetration ratio is determined using the judgment method, with the market penetration S-curve induced using the Delphi method and the Product Life Cycle from 2011 (supposed launching year, not realistic physical year), to 2050 (expected final target year). This paper analyzes the HTS market penetration ratio of each stage, apparent innovation, early adapters, and the early/late majority and laggard stage, using the S-curve, thus calculating the total future market volume of HTS equipment in the positive sense. Finally, this paper estimates the quantitative analysis results for the HTS4-items (cable, FCL, transformer, rotation machine) of each year within the domestic market.

• Proceedings of the KIPE Conference
• /
• 2018.07a
• /
• pp.126-128
• /
• 2018

Solar array simulator (SAS) is a special DC power supply that regulates the output voltage or current to emulate characteristics of photovoltaic (PV) panels. Especially, the control of SAS is a challenging task due to the nonlinearity in the output curve, which is dependent on irradiance as well as temperature and is determined by panel materials. Conventionally, both current-mode control and voltage-mode control should be alternated by partitioning the operating curve into multiple sections, which is not only for the measurement noise problem with the feedback sensing but also for the control stability issue near the maximum power point. However, the occurrence of transition among different controllers may deteriorate the overall performance. To eliminate the mode transitions, a novel single controller scheme has been introduced in this paper, where the reference operating projection technique enables simple, smooth and numerically stable control. Theoretical consideration on the loop stability issue is discussed and the performance is verified experimentally for the emulation of a PV panel data in view of stability and response speed.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.51 no.10
• /
• pp.560-567
• /
• 2002

This paper presents the calculation of opening characteristics for puffer GCB with the equations of the flow field and the motion of the driving mechanism. To obtain the stroke curve, the motion equation is solved simultaneously with the Euler equations. For a given Piston location, the flow field is solved. The pressure inside the Puffer chamber is then used to calculate the moving velocity and the new position of the piston. The FVFLIC method is employed to solve the axisymmetric Euler equations and the motion equation is solved by the Runge-Kutta method. The method is applied to the puffer GCB model and the stroke curve and the pressure rise in puffer chamber under no load condition are compared with the measured ones.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.96-101
• /
• 2004

Cast austenitic stainless steel is used for several components, such as primary coolant piping, elbow, pump casing and valve bodies in light water reactors. These components are subject to thermal embrittlement at the reactor operating temperature. The objective of this study is to summarize the method of estimating ferrite content, Charpy impact energy and J-R curve and to evaluate the thermal embrittlement of the cast austenitic stainless steel piping used in the domestic nuclear power plants. The result of evaluation, two domestic nuclear power plants used CF-8M and CF-8A material has adequate fracture toughness after saturation.